ffmpeg_mux_init.c

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/*
 * Muxer/output file setup.
 *
 * This file is part of FFmpeg.
 *
 * FFmpeg is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * FFmpeg is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with FFmpeg; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */
 
#include <string.h>
 
#include "cmdutils.h"
#include "ffmpeg.h"
#include "ffmpeg_mux.h"
#include "ffmpeg_sched.h"
#include "fopen_utf8.h"
 
#include "libavformat/avformat.h"
#include "libavformat/avio.h"
 
#include "libavcodec/avcodec.h"
 
#include "libavfilter/avfilter.h"
 
#include "libavutil/avassert.h"
#include "libavutil/avstring.h"
#include "libavutil/avutil.h"
#include "libavutil/bprint.h"
#include "libavutil/dict.h"
#include "libavutil/display.h"
#include "libavutil/getenv_utf8.h"
#include "libavutil/iamf.h"
#include "libavutil/intreadwrite.h"
#include "libavutil/log.h"
#include "libavutil/mem.h"
#include "libavutil/opt.h"
#include "libavutil/parseutils.h"
#include "libavutil/pixdesc.h"
 
#define DEFAULT_PASS_LOGFILENAME_PREFIX "ffmpeg2pass"
 
static int check_opt_bitexact(void *ctx, const AVDictionary *opts,
                              const char *opt_name, int flag)
{
    const AVDictionaryEntry *e = av_dict_get(opts, opt_name, NULL, 0);
 
    if (e) {
        const AVOption *o = av_opt_find(ctx, opt_name, NULL, 0, 0);
        int val = 0;
        if (!o)
            return 0;
        av_opt_eval_flags(ctx, o, e->value, &val);
        return !!(val & flag);
    }
    return 0;
}
 
static int choose_encoder(const OptionsContext *o, AVFormatContext *s,
                          OutputStream *ost, const AVCodec **enc)
{
    enum AVMediaType type = ost->type;
    const char *codec_name = NULL;
 
    *enc = NULL;
 
    opt_match_per_stream_str(ost, &o->codec_names, s, ost->st, &codec_name);
 
    if (type != AVMEDIA_TYPE_VIDEO      &&
        type != AVMEDIA_TYPE_AUDIO      &&
        type != AVMEDIA_TYPE_SUBTITLE) {
        if (codec_name && strcmp(codec_name, "copy")) {
            const char *type_str = av_get_media_type_string(type);
            av_log(ost, AV_LOG_FATAL,
                   "Encoder '%s' specified, but only '-codec copy' supported "
                   "for %s streams\n", codec_name, type_str);
            return AVERROR(ENOSYS);
        }
        return 0;
    }
 
    if (!codec_name) {
        ost->par_in->codec_id = av_guess_codec(s->oformat, NULL, s->url, NULL, ost->type);
        *enc = avcodec_find_encoder(ost->par_in->codec_id);
        if (!*enc) {
            av_log(ost, AV_LOG_FATAL, "Automatic encoder selection failed "
                   "Default encoder for format %s (codec %s) is "
                   "probably disabled. Please choose an encoder manually.\n",
                    s->oformat->name, avcodec_get_name(ost->par_in->codec_id));
            return AVERROR_ENCODER_NOT_FOUND;
        }
    } else if (strcmp(codec_name, "copy")) {
        int ret = find_codec(ost, codec_name, ost->type, 1, enc);
        if (ret < 0)
            return ret;
        ost->par_in->codec_id = (*enc)->id;
    }
 
    return 0;
}
 
static char *get_line(AVIOContext *s, AVBPrint *bprint)
{
    char c;
 
    while ((c = avio_r8(s)) && c != '\n')
        av_bprint_chars(bprint, c, 1);
 
    if (!av_bprint_is_complete(bprint))
        return NULL;
 
    return bprint->str;
}
 
static int get_preset_file_2(const char *preset_name, const char *codec_name, AVIOContext **s)
{
    int i, ret = -1;
    char filename[1000];
    char *env_avconv_datadir = getenv_utf8("AVCONV_DATADIR");
    char *env_home = getenv_utf8("HOME");
    const char *base[3] = { env_avconv_datadir,
                            env_home,
                            AVCONV_DATADIR,
                            };
 
    for (i = 0; i < FF_ARRAY_ELEMS(base) && ret < 0; i++) {
        if (!base[i])
            continue;
        if (codec_name) {
            snprintf(filename, sizeof(filename), "%s%s/%s-%s.avpreset", base[i],
                     i != 1 ? "" : "/.avconv", codec_name, preset_name);
            ret = avio_open2(s, filename, AVIO_FLAG_READ, &int_cb, NULL);
        }
        if (ret < 0) {
            snprintf(filename, sizeof(filename), "%s%s/%s.avpreset", base[i],
                     i != 1 ? "" : "/.avconv", preset_name);
            ret = avio_open2(s, filename, AVIO_FLAG_READ, &int_cb, NULL);
        }
    }
    freeenv_utf8(env_home);
    freeenv_utf8(env_avconv_datadir);
    return ret;
}
 
typedef struct EncStatsFile {
    char        *path;
    AVIOContext *io;
} EncStatsFile;
 
static EncStatsFile   *enc_stats_files;
static          int nb_enc_stats_files;
 
static int enc_stats_get_file(AVIOContext **io, const char *path)
{
    EncStatsFile *esf;
    int ret;
 
    for (int i = 0; i < nb_enc_stats_files; i++)
        if (!strcmp(path, enc_stats_files[i].path)) {
            *io = enc_stats_files[i].io;
            return 0;
        }
 
    ret = GROW_ARRAY(enc_stats_files, nb_enc_stats_files);
    if (ret < 0)
        return ret;
 
    esf = &enc_stats_files[nb_enc_stats_files - 1];
 
    ret = avio_open2(&esf->io, path, AVIO_FLAG_WRITE, &int_cb, NULL);
    if (ret < 0) {
        av_log(NULL, AV_LOG_ERROR, "Error opening stats file '%s': %s\n",
               path, av_err2str(ret));
        return ret;
    }
 
    esf->path = av_strdup(path);
    if (!esf->path)
        return AVERROR(ENOMEM);
 
    *io = esf->io;
 
    return 0;
}
 
void of_enc_stats_close(void)
{
    for (int i = 0; i < nb_enc_stats_files; i++) {
        av_freep(&enc_stats_files[i].path);
        avio_closep(&enc_stats_files[i].io);
    }
    av_freep(&enc_stats_files);
    nb_enc_stats_files = 0;
}
 
static int unescape(char **pdst, size_t *dst_len,
                    const char **pstr, char delim)
{
    const char *str = *pstr;
    char *dst;
    size_t len, idx;
 
    *pdst = NULL;
 
    len = strlen(str);
    if (!len)
        return 0;
 
    dst = av_malloc(len + 1);
    if (!dst)
        return AVERROR(ENOMEM);
 
    for (idx = 0; *str; idx++, str++) {
        if (str[0] == '\\' && str[1])
            str++;
        else if (*str == delim)
            break;
 
        dst[idx] = *str;
    }
    if (!idx) {
        av_freep(&dst);
        return 0;
    }
 
    dst[idx] = 0;
 
    *pdst    = dst;
    *dst_len = idx;
    *pstr    = str;
 
    return 0;
}
 
static int enc_stats_init(OutputStream *ost, EncStats *es, int pre,
                          const char *path, const char *fmt_spec)
{
    static const struct {
        enum EncStatsType  type;
        const char        *str;
        unsigned           pre_only:1;
        unsigned           post_only:1;
        unsigned           need_input_data:1;
    } fmt_specs[] = {
        { ENC_STATS_FILE_IDX,       "fidx"                      },
        { ENC_STATS_STREAM_IDX,     "sidx"                      },
        { ENC_STATS_FRAME_NUM,      "n"                         },
        { ENC_STATS_FRAME_NUM_IN,   "ni",       0, 0, 1         },
        { ENC_STATS_TIMEBASE,       "tb"                        },
        { ENC_STATS_TIMEBASE_IN,    "tbi",      0, 0, 1         },
        { ENC_STATS_PTS,            "pts"                       },
        { ENC_STATS_PTS_TIME,       "t"                         },
        { ENC_STATS_PTS_IN,         "ptsi",     0, 0, 1         },
        { ENC_STATS_PTS_TIME_IN,    "ti",       0, 0, 1         },
        { ENC_STATS_DTS,            "dts",      0, 1            },
        { ENC_STATS_DTS_TIME,       "dt",       0, 1            },
        { ENC_STATS_SAMPLE_NUM,     "sn",       1               },
        { ENC_STATS_NB_SAMPLES,     "samp",     1               },
        { ENC_STATS_PKT_SIZE,       "size",     0, 1            },
        { ENC_STATS_BITRATE,        "br",       0, 1            },
        { ENC_STATS_AVG_BITRATE,    "abr",      0, 1            },
        { ENC_STATS_KEYFRAME,       "key",      0, 1            },
    };
    const char *next = fmt_spec;
 
    int ret;
 
    while (*next) {
        EncStatsComponent *c;
        char *val;
        size_t val_len;
 
        // get the sequence up until next opening brace
        ret = unescape(&val, &val_len, &next, '{');
        if (ret < 0)
            return ret;
 
        if (val) {
            ret = GROW_ARRAY(es->components, es->nb_components);
            if (ret < 0) {
                av_freep(&val);
                return ret;
            }
 
            c          = &es->components[es->nb_components - 1];
            c->type    = ENC_STATS_LITERAL;
            c->str     = val;
            c->str_len = val_len;
        }
 
        if (!*next)
            break;
        next++;
 
        // get the part inside braces
        ret = unescape(&val, &val_len, &next, '}');
        if (ret < 0)
            return ret;
 
        if (!val) {
            av_log(NULL, AV_LOG_ERROR,
                   "Empty formatting directive in: %s\n", fmt_spec);
            return AVERROR(EINVAL);
        }
 
        if (!*next) {
            av_log(NULL, AV_LOG_ERROR,
                   "Missing closing brace in: %s\n", fmt_spec);
            ret = AVERROR(EINVAL);
            goto fail;
        }
        next++;
 
        ret = GROW_ARRAY(es->components, es->nb_components);
        if (ret < 0)
            goto fail;
 
        c = &es->components[es->nb_components - 1];
 
        for (size_t i = 0; i < FF_ARRAY_ELEMS(fmt_specs); i++) {
            if (!strcmp(val, fmt_specs[i].str)) {
                if ((pre && fmt_specs[i].post_only) || (!pre && fmt_specs[i].pre_only)) {
                    av_log(NULL, AV_LOG_ERROR,
                           "Format directive '%s' may only be used %s-encoding\n",
                           val, pre ? "post" : "pre");
                    ret = AVERROR(EINVAL);
                    goto fail;
                }
 
                c->type = fmt_specs[i].type;
 
                if (fmt_specs[i].need_input_data && !ost->ist) {
                    av_log(ost, AV_LOG_WARNING,
                           "Format directive '%s' is unavailable, because "
                           "this output stream has no associated input stream\n",
                           val);
                }
 
                break;
            }
        }
 
        if (!c->type) {
            av_log(NULL, AV_LOG_ERROR, "Invalid format directive: %s\n", val);
            ret = AVERROR(EINVAL);
            goto fail;
        }
 
fail:
        av_freep(&val);
        if (ret < 0)
            return ret;
    }
 
    ret = pthread_mutex_init(&es->lock, NULL);
    if (ret)
        return AVERROR(ret);
    es->lock_initialized = 1;
 
    ret = enc_stats_get_file(&es->io, path);
    if (ret < 0)
        return ret;
 
    return 0;
}
 
static const char *output_stream_item_name(void *obj)
{
    const MuxStream *ms = obj;
 
    return ms->log_name;
}
 
static const AVClass output_stream_class = {
    .class_name = "OutputStream",
    .version    = LIBAVUTIL_VERSION_INT,
    .item_name  = output_stream_item_name,
    .category   = AV_CLASS_CATEGORY_MUXER,
};
 
static MuxStream *mux_stream_alloc(Muxer *mux, enum AVMediaType type)
{
    const char *type_str = av_get_media_type_string(type);
    MuxStream *ms;
 
    ms = allocate_array_elem(&mux->of.streams, sizeof(*ms), &mux->of.nb_streams);
    if (!ms)
        return NULL;
 
    ms->ost.file       = &mux->of;
    ms->ost.index      = mux->of.nb_streams - 1;
    ms->ost.type       = type;
 
    ms->ost.class = &output_stream_class;
 
    ms->sch_idx     = -1;
    ms->sch_idx_enc = -1;
 
    snprintf(ms->log_name, sizeof(ms->log_name), "%cost#%d:%d",
             type_str ? *type_str : '?', mux->of.index, ms->ost.index);
 
    return ms;
}
 
static int ost_get_filters(const OptionsContext *o, AVFormatContext *oc,
                           OutputStream *ost, char **dst)
{
    const char *filters = NULL;
#if FFMPEG_OPT_FILTER_SCRIPT
    const char *filters_script = NULL;
 
    opt_match_per_stream_str(ost, &o->filter_scripts, oc, ost->st, &filters_script);
#endif
    opt_match_per_stream_str(ost, &o->filters, oc, ost->st, &filters);
 
    if (!ost->enc) {
        if (
#if FFMPEG_OPT_FILTER_SCRIPT
            filters_script ||
#endif
            filters) {
            av_log(ost, AV_LOG_ERROR,
                   "%s '%s' was specified, but codec copy was selected. "
                   "Filtering and streamcopy cannot be used together.\n",
#if FFMPEG_OPT_FILTER_SCRIPT
                   filters ? "Filtergraph" : "Filtergraph script",
                   filters ? filters : filters_script
#else
                   "Filtergraph", filters
#endif
                   );
            return AVERROR(ENOSYS);
        }
        return 0;
    }
 
    if (!ost->ist) {
        if (
#if FFMPEG_OPT_FILTER_SCRIPT
            filters_script ||
#endif
            filters) {
            av_log(ost, AV_LOG_ERROR,
                   "%s '%s' was specified for a stream fed from a complex "
                   "filtergraph. Simple and complex filtering cannot be used "
                   "together for the same stream.\n",
#if FFMPEG_OPT_FILTER_SCRIPT
                   filters ? "Filtergraph" : "Filtergraph script",
                   filters ? filters : filters_script
#else
                   "Filtergraph", filters
#endif
                   );
            return AVERROR(EINVAL);
        }
        return 0;
    }
 
#if FFMPEG_OPT_FILTER_SCRIPT
    if (filters_script && filters) {
        av_log(ost, AV_LOG_ERROR, "Both -filter and -filter_script set\n");
        return AVERROR(EINVAL);
    }
 
    if (filters_script)
        *dst = file_read(filters_script);
    else
#endif
    if (filters)
        *dst = av_strdup(filters);
    else
        *dst = av_strdup(ost->type == AVMEDIA_TYPE_VIDEO ? "null" : "anull");
    return *dst ? 0 : AVERROR(ENOMEM);
}
 
static int parse_matrix_coeffs(void *logctx, uint16_t *dest, const char *str)
{
    const char *p = str;
    for (int i = 0;; i++) {
        dest[i] = atoi(p);
        if (i == 63)
            break;
        p = strchr(p, ',');
        if (!p) {
            av_log(logctx, AV_LOG_FATAL,
                   "Syntax error in matrix \"%s\" at coeff %d\n", str, i);
            return AVERROR(EINVAL);
        }
        p++;
    }
 
    return 0;
}
 
static int fmt_in_list(const int *formats, int format)
{
    for (; *formats != -1; formats++)
        if (*formats == format)
            return 1;
    return 0;
}
 
static enum AVPixelFormat
choose_pixel_fmt(const AVCodecContext *avctx, enum AVPixelFormat target)
{
    const enum AVPixelFormat *p;
    const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(target);
    //FIXME: This should check for AV_PIX_FMT_FLAG_ALPHA after PAL8 pixel format without alpha is implemented
    int has_alpha = desc ? desc->nb_components % 2 == 0 : 0;
    enum AVPixelFormat best= AV_PIX_FMT_NONE;
    int ret;
 
    ret = avcodec_get_supported_config(avctx, NULL, AV_CODEC_CONFIG_PIX_FORMAT,
                                       0, (const void **) &p, NULL);
    if (ret < 0)
        return AV_PIX_FMT_NONE;
 
    for (; *p != AV_PIX_FMT_NONE; p++) {
        best = av_find_best_pix_fmt_of_2(best, *p, target, has_alpha, NULL);
        if (*p == target)
            break;
    }
    if (*p == AV_PIX_FMT_NONE) {
        if (target != AV_PIX_FMT_NONE)
            av_log(NULL, AV_LOG_WARNING,
                   "Incompatible pixel format '%s' for codec '%s', auto-selecting format '%s'\n",
                   av_get_pix_fmt_name(target),
                   avctx->codec->name,
                   av_get_pix_fmt_name(best));
        return best;
    }
    return target;
}
 
static enum AVPixelFormat pix_fmt_parse(OutputStream *ost, const char *name)
{
    const enum AVPixelFormat *fmts;
    enum AVPixelFormat fmt;
    int ret;
 
    fmt = av_get_pix_fmt(name);
    if (fmt == AV_PIX_FMT_NONE) {
        av_log(ost, AV_LOG_FATAL, "Unknown pixel format requested: %s.\n", name);
        return AV_PIX_FMT_NONE;
    }
 
    ret = avcodec_get_supported_config(ost->enc_ctx, NULL, AV_CODEC_CONFIG_PIX_FORMAT,
                                       0, (const void **) &fmts, NULL);
    if (ret < 0)
        return AV_PIX_FMT_NONE;
 
    /* when the user specified-format is an alias for an endianness-specific
     * one (e.g. rgb48 -> rgb48be/le), it gets translated into the native
     * endianness by av_get_pix_fmt();
     * the following code handles the case when the native endianness is not
     * supported by the encoder, but the other one is */
    if (fmts && !fmt_in_list(fmts, fmt)) {
        const char *name_canonical = av_get_pix_fmt_name(fmt);
        int len = strlen(name_canonical);
 
        if (strcmp(name, name_canonical) &&
            (!strcmp(name_canonical + len - 2, "le") ||
             !strcmp(name_canonical + len - 2, "be"))) {
            char name_other[64];
            enum AVPixelFormat fmt_other;
 
            snprintf(name_other, sizeof(name_other), "%s%ce",
                     name, name_canonical[len - 2] == 'l' ? 'b' : 'l');
            fmt_other = av_get_pix_fmt(name_other);
            if (fmt_other != AV_PIX_FMT_NONE && fmt_in_list(fmts, fmt_other)) {
                av_log(ost, AV_LOG_VERBOSE, "Mapping pixel format %s->%s\n",
                       name, name_other);
                fmt = fmt_other;
            }
        }
    }
 
    if (fmts && !fmt_in_list(fmts, fmt))
        fmt = choose_pixel_fmt(ost->enc_ctx, fmt);
 
    return fmt;
}
 
static int new_stream_video(Muxer *mux, const OptionsContext *o,
                            OutputStream *ost, int *keep_pix_fmt,
                            enum VideoSyncMethod *vsync_method)
{
    MuxStream       *ms = ms_from_ost(ost);
    AVFormatContext *oc = mux->fc;
    AVStream *st;
    const char *frame_rate = NULL, *max_frame_rate = NULL, *frame_aspect_ratio = NULL;
    int ret = 0;
 
    st  = ost->st;
 
    opt_match_per_stream_str(ost, &o->frame_rates, oc, st, &frame_rate);
    if (frame_rate && av_parse_video_rate(&ost->frame_rate, frame_rate) < 0) {
        av_log(ost, AV_LOG_FATAL, "Invalid framerate value: %s\n", frame_rate);
        return AVERROR(EINVAL);
    }
 
    opt_match_per_stream_str(ost, &o->max_frame_rates, oc, st, &max_frame_rate);
    if (max_frame_rate && av_parse_video_rate(&ost->max_frame_rate, max_frame_rate) < 0) {
        av_log(ost, AV_LOG_FATAL, "Invalid maximum framerate value: %s\n", max_frame_rate);
        return AVERROR(EINVAL);
    }
 
    if (frame_rate && max_frame_rate) {
        av_log(ost, AV_LOG_ERROR, "Only one of -fpsmax and -r can be set for a stream.\n");
        return AVERROR(EINVAL);
    }
 
    opt_match_per_stream_str(ost, &o->frame_aspect_ratios, oc, st, &frame_aspect_ratio);
    if (frame_aspect_ratio) {
        AVRational q;
        if (av_parse_ratio(&q, frame_aspect_ratio, 255, 0, NULL) < 0 ||
            q.num <= 0 || q.den <= 0) {
            av_log(ost, AV_LOG_FATAL, "Invalid aspect ratio: %s\n", frame_aspect_ratio);
            return AVERROR(EINVAL);
        }
        ost->frame_aspect_ratio = q;
    }
 
    if (ost->enc_ctx) {
        AVCodecContext *video_enc = ost->enc_ctx;
        const char *p = NULL, *fps_mode = NULL;
        const char *frame_size = NULL;
        const char *frame_pix_fmt = NULL;
        const char *intra_matrix = NULL, *inter_matrix = NULL;
        const char *chroma_intra_matrix = NULL;
        int do_pass = 0;
        int i;
 
        opt_match_per_stream_str(ost, &o->frame_sizes, oc, st, &frame_size);
        if (frame_size) {
            ret = av_parse_video_size(&video_enc->width, &video_enc->height, frame_size);
            if (ret < 0) {
                av_log(ost, AV_LOG_FATAL, "Invalid frame size: %s.\n", frame_size);
                return AVERROR(EINVAL);
            }
        }
 
        opt_match_per_stream_str(ost, &o->frame_pix_fmts, oc, st, &frame_pix_fmt);
        if (frame_pix_fmt && *frame_pix_fmt == '+') {
            *keep_pix_fmt = 1;
            if (!*++frame_pix_fmt)
                frame_pix_fmt = NULL;
        }
        if (frame_pix_fmt) {
            video_enc->pix_fmt = pix_fmt_parse(ost, frame_pix_fmt);
            if (video_enc->pix_fmt == AV_PIX_FMT_NONE)
                return AVERROR(EINVAL);
        }
 
        opt_match_per_stream_str(ost, &o->intra_matrices, oc, st, &intra_matrix);
        if (intra_matrix) {
            if (!(video_enc->intra_matrix = av_mallocz(sizeof(*video_enc->intra_matrix) * 64)))
                return AVERROR(ENOMEM);
 
            ret = parse_matrix_coeffs(ost, video_enc->intra_matrix, intra_matrix);
            if (ret < 0)
                return ret;
        }
        opt_match_per_stream_str(ost, &o->chroma_intra_matrices, oc, st, &chroma_intra_matrix);
        if (chroma_intra_matrix) {
            if (!(video_enc->chroma_intra_matrix = av_mallocz(sizeof(*video_enc->chroma_intra_matrix) * 64)))
                return AVERROR(ENOMEM);
            ret = parse_matrix_coeffs(ost, video_enc->chroma_intra_matrix, chroma_intra_matrix);
            if (ret < 0)
                return ret;
        }
        opt_match_per_stream_str(ost, &o->inter_matrices, oc, st, &inter_matrix);
        if (inter_matrix) {
            if (!(video_enc->inter_matrix = av_mallocz(sizeof(*video_enc->inter_matrix) * 64)))
                return AVERROR(ENOMEM);
            ret = parse_matrix_coeffs(ost, video_enc->inter_matrix, inter_matrix);
            if (ret < 0)
                return ret;
        }
 
        opt_match_per_stream_str(ost, &o->rc_overrides, oc, st, &p);
        for (i = 0; p; i++) {
            int start, end, q;
            int e = sscanf(p, "%d,%d,%d", &start, &end, &q);
            if (e != 3) {
                av_log(ost, AV_LOG_FATAL, "error parsing rc_override\n");
                return AVERROR(EINVAL);
            }
            video_enc->rc_override =
                av_realloc_array(video_enc->rc_override,
                                 i + 1, sizeof(RcOverride));
            if (!video_enc->rc_override) {
                av_log(ost, AV_LOG_FATAL, "Could not (re)allocate memory for rc_override.\n");
                return AVERROR(ENOMEM);
            }
            video_enc->rc_override[i].start_frame = start;
            video_enc->rc_override[i].end_frame   = end;
            if (q > 0) {
                video_enc->rc_override[i].qscale         = q;
                video_enc->rc_override[i].quality_factor = 1.0;
            }
            else {
                video_enc->rc_override[i].qscale         = 0;
                video_enc->rc_override[i].quality_factor = -q/100.0;
            }
            p = strchr(p, '/');
            if (p) p++;
        }
        video_enc->rc_override_count = i;
 
        /* two pass mode */
        opt_match_per_stream_int(ost, &o->pass, oc, st, &do_pass);
        if (do_pass) {
            if (do_pass & 1)
                video_enc->flags |= AV_CODEC_FLAG_PASS1;
            if (do_pass & 2)
                video_enc->flags |= AV_CODEC_FLAG_PASS2;
        }
 
        opt_match_per_stream_str(ost, &o->passlogfiles, oc, st, &ost->logfile_prefix);
        if (ost->logfile_prefix &&
            !(ost->logfile_prefix = av_strdup(ost->logfile_prefix)))
            return AVERROR(ENOMEM);
 
        if (do_pass) {
            int ost_idx = -1;
            char logfilename[1024];
            FILE *f;
 
            /* compute this stream's global index */
            for (int idx = 0; idx <= ost->file->index; idx++)
                ost_idx += output_files[idx]->nb_streams;
 
            snprintf(logfilename, sizeof(logfilename), "%s-%d.log",
                     ost->logfile_prefix ? ost->logfile_prefix :
                                           DEFAULT_PASS_LOGFILENAME_PREFIX,
                     ost_idx);
            if (!strcmp(ost->enc_ctx->codec->name, "libx264") || !strcmp(ost->enc_ctx->codec->name, "libvvenc")) {
                if (av_opt_is_set_to_default_by_name(ost->enc_ctx, "stats",
                                                     AV_OPT_SEARCH_CHILDREN) > 0)
                    av_opt_set(ost->enc_ctx, "stats", logfilename,
                               AV_OPT_SEARCH_CHILDREN);
            } else {
                if (video_enc->flags & AV_CODEC_FLAG_PASS2) {
                    char  *logbuffer = file_read(logfilename);
 
                    if (!logbuffer) {
                        av_log(ost, AV_LOG_FATAL, "Error reading log file '%s' for pass-2 encoding\n",
                               logfilename);
                        return AVERROR(EIO);
                    }
                    video_enc->stats_in = logbuffer;
                }
                if (video_enc->flags & AV_CODEC_FLAG_PASS1) {
                    f = fopen_utf8(logfilename, "wb");
                    if (!f) {
                        av_log(ost, AV_LOG_FATAL,
                               "Cannot write log file '%s' for pass-1 encoding: %s\n",
                               logfilename, strerror(errno));
                        return AVERROR(errno);
                    }
                    ost->logfile = f;
                }
            }
        }
 
        opt_match_per_stream_int(ost, &o->force_fps, oc, st, &ost->force_fps);
 
#if FFMPEG_OPT_TOP
        ost->top_field_first = -1;
        opt_match_per_stream_int(ost, &o->top_field_first, oc, st, &ost->top_field_first);
        if (ost->top_field_first >= 0)
            av_log(ost, AV_LOG_WARNING, "-top is deprecated, use the setfield filter instead\n");
#endif
 
#if FFMPEG_OPT_VSYNC
        *vsync_method = video_sync_method;
#else
        *vsync_method = VSYNC_AUTO;
#endif
        opt_match_per_stream_str(ost, &o->fps_mode, oc, st, &fps_mode);
        if (fps_mode) {
            ret = parse_and_set_vsync(fps_mode, vsync_method, ost->file->index, ost->index, 0);
            if (ret < 0)
                return ret;
        }
 
        if ((ost->frame_rate.num || ost->max_frame_rate.num) &&
            !(*vsync_method == VSYNC_AUTO ||
              *vsync_method == VSYNC_CFR || *vsync_method == VSYNC_VSCFR)) {
            av_log(ost, AV_LOG_FATAL, "One of -r/-fpsmax was specified "
                   "together a non-CFR -vsync/-fps_mode. This is contradictory.\n");
            return AVERROR(EINVAL);
        }
 
        if (*vsync_method == VSYNC_AUTO) {
            if (ost->frame_rate.num || ost->max_frame_rate.num) {
                *vsync_method = VSYNC_CFR;
            } else if (!strcmp(oc->oformat->name, "avi")) {
                *vsync_method = VSYNC_VFR;
            } else {
                *vsync_method = (oc->oformat->flags & AVFMT_VARIABLE_FPS)  ?
                                ((oc->oformat->flags & AVFMT_NOTIMESTAMPS) ?
                                VSYNC_PASSTHROUGH : VSYNC_VFR) : VSYNC_CFR;
            }
 
            if (ost->ist && *vsync_method == VSYNC_CFR) {
                const InputFile *ifile = ost->ist->file;
 
                if (ifile->nb_streams == 1 && ifile->input_ts_offset == 0)
                    *vsync_method = VSYNC_VSCFR;
            }
 
            if (*vsync_method == VSYNC_CFR && copy_ts) {
                *vsync_method = VSYNC_VSCFR;
            }
        }
#if FFMPEG_OPT_VSYNC_DROP
        if (*vsync_method == VSYNC_DROP)
            ms->ts_drop = 1;
#endif
    }
 
    return 0;
}
 
static int new_stream_audio(Muxer *mux, const OptionsContext *o,
                            OutputStream *ost)
{
    MuxStream *ms = ms_from_ost(ost);
    AVFormatContext *oc = mux->fc;
    AVStream *st = ost->st;
 
    if (ost->enc_ctx) {
        AVCodecContext *audio_enc = ost->enc_ctx;
        int channels = 0;
        const char *layout = NULL;
        const char *sample_fmt = NULL;
 
        opt_match_per_stream_int(ost, &o->audio_channels, oc, st, &channels);
        if (channels) {
            audio_enc->ch_layout.order       = AV_CHANNEL_ORDER_UNSPEC;
            audio_enc->ch_layout.nb_channels = channels;
        }
 
        opt_match_per_stream_str(ost, &o->audio_ch_layouts, oc, st, &layout);
        if (layout && av_channel_layout_from_string(&audio_enc->ch_layout, layout) < 0) {
            av_log(ost, AV_LOG_FATAL, "Unknown channel layout: %s\n", layout);
            return AVERROR(EINVAL);
        }
 
        opt_match_per_stream_str(ost, &o->sample_fmts, oc, st, &sample_fmt);
        if (sample_fmt &&
            (audio_enc->sample_fmt = av_get_sample_fmt(sample_fmt)) == AV_SAMPLE_FMT_NONE) {
            av_log(ost, AV_LOG_FATAL, "Invalid sample format '%s'\n", sample_fmt);
            return AVERROR(EINVAL);
        }
 
        opt_match_per_stream_int(ost, &o->audio_sample_rate, oc, st, &audio_enc->sample_rate);
        opt_match_per_stream_str(ost, &o->apad, oc, st, &ms->apad);
    }
 
    return 0;
}
 
static int new_stream_subtitle(Muxer *mux, const OptionsContext *o,
                               OutputStream *ost)
{
    AVStream *st;
 
    st  = ost->st;
 
    if (ost->enc_ctx) {
        AVCodecContext *subtitle_enc = ost->enc_ctx;
 
        AVCodecDescriptor const *input_descriptor =
            avcodec_descriptor_get(ost->ist->par->codec_id);
        AVCodecDescriptor const *output_descriptor =
            avcodec_descriptor_get(subtitle_enc->codec_id);
        int input_props = 0, output_props = 0;
 
        const char *frame_size = NULL;
 
        opt_match_per_stream_str(ost, &o->frame_sizes, mux->fc, st, &frame_size);
        if (frame_size) {
            int ret = av_parse_video_size(&subtitle_enc->width, &subtitle_enc->height, frame_size);
            if (ret < 0) {
                av_log(ost, AV_LOG_FATAL, "Invalid frame size: %s.\n", frame_size);
                return ret;
            }
        }
        if (input_descriptor)
            input_props = input_descriptor->props & (AV_CODEC_PROP_TEXT_SUB | AV_CODEC_PROP_BITMAP_SUB);
        if (output_descriptor)
            output_props = output_descriptor->props & (AV_CODEC_PROP_TEXT_SUB | AV_CODEC_PROP_BITMAP_SUB);
        if (input_props && output_props && input_props != output_props) {
            av_log(ost, AV_LOG_ERROR,
                   "Subtitle encoding currently only possible from text to text "
                   "or bitmap to bitmap\n");
            return AVERROR(EINVAL);
        }
    }
 
    return 0;
}
 
static int
ost_bind_filter(const Muxer *mux, MuxStream *ms, OutputFilter *ofilter,
                const OptionsContext *o, char *filters,
                AVRational enc_tb, enum VideoSyncMethod vsync_method,
                int keep_pix_fmt, int autoscale, int threads_manual,
                const ViewSpecifier *vs)
{
    OutputStream       *ost = &ms->ost;
    AVCodecContext *enc_ctx = ost->enc_ctx;
    char name[16];
    int ret;
 
    OutputFilterOptions opts = {
        .enc              = enc_ctx->codec,
        .name             = name,
        .format           = (ost->type == AVMEDIA_TYPE_VIDEO) ?
                            enc_ctx->pix_fmt : enc_ctx->sample_fmt,
        .width            = enc_ctx->width,
        .height           = enc_ctx->height,
        .color_space      = enc_ctx->colorspace,
        .color_range      = enc_ctx->color_range,
        .vsync_method     = vsync_method,
        .sample_rate      = enc_ctx->sample_rate,
        .ch_layout        = enc_ctx->ch_layout,
        .sws_opts         = o->g->sws_dict,
        .swr_opts         = o->g->swr_opts,
        .output_tb        = enc_tb,
        .trim_start_us    = mux->of.start_time,
        .trim_duration_us = mux->of.recording_time,
        .ts_offset        = mux->of.start_time == AV_NOPTS_VALUE ?
                            0 : mux->of.start_time,
        .vs               = vs,
 
        .flags = OFILTER_FLAG_DISABLE_CONVERT * !!keep_pix_fmt |
                 OFILTER_FLAG_AUTOSCALE       * !!autoscale    |
                 OFILTER_FLAG_AUDIO_24BIT * !!(av_get_exact_bits_per_sample(enc_ctx->codec_id) == 24),
    };
 
    snprintf(name, sizeof(name), "#%d:%d", mux->of.index, ost->index);
 
    if (ost->type == AVMEDIA_TYPE_VIDEO) {
        if (!keep_pix_fmt) {
            ret = avcodec_get_supported_config(enc_ctx, NULL,
                                               AV_CODEC_CONFIG_PIX_FORMAT, 0,
                                               (const void **) &opts.formats, NULL);
            if (ret < 0)
                return ret;
        }
        if (!ost->force_fps) {
            ret = avcodec_get_supported_config(enc_ctx, NULL,
                                               AV_CODEC_CONFIG_FRAME_RATE, 0,
                                               (const void **) &opts.frame_rates, NULL);
            if (ret < 0)
                return ret;
        }
        ret = avcodec_get_supported_config(enc_ctx, NULL,
                                           AV_CODEC_CONFIG_COLOR_SPACE, 0,
                                           (const void **) &opts.color_spaces, NULL);
        if (ret < 0)
            return ret;
        ret = avcodec_get_supported_config(enc_ctx, NULL,
                                           AV_CODEC_CONFIG_COLOR_RANGE, 0,
                                           (const void **) &opts.color_ranges, NULL);
        if (ret < 0)
            return ret;
    } else {
        ret = avcodec_get_supported_config(enc_ctx, NULL,
                                           AV_CODEC_CONFIG_SAMPLE_FORMAT, 0,
                                           (const void **) &opts.formats, NULL);
        if (ret < 0)
            return ret;
        ret = avcodec_get_supported_config(enc_ctx, NULL,
                                           AV_CODEC_CONFIG_SAMPLE_RATE, 0,
                                           (const void **) &opts.sample_rates, NULL);
        if (ret < 0)
            return ret;
        ret = avcodec_get_supported_config(enc_ctx, NULL,
                                           AV_CODEC_CONFIG_CHANNEL_LAYOUT, 0,
                                           (const void **) &opts.ch_layouts, NULL);
        if (ret < 0)
            return ret;
    }
 
    if (threads_manual) {
        ret = av_opt_get(enc_ctx, "threads", 0, (uint8_t**)&opts.nb_threads);
        if (ret < 0)
            return ret;
    }
 
    if (ofilter) {
        ost->filter = ofilter;
        ret = ofilter_bind_ost(ofilter, ost, ms->sch_idx_enc, &opts);
    } else {
        ret = init_simple_filtergraph(ost->ist, ost, filters,
                                      mux->sch, ms->sch_idx_enc, &opts);
    }
    av_freep(&opts.nb_threads);
    if (ret < 0)
        return ret;
 
    ret = sch_connect(mux->sch, SCH_ENC(ms->sch_idx_enc),
                                SCH_MSTREAM(mux->sch_idx, ms->sch_idx));
    if (ret < 0)
        return ret;
 
    return ret;
}
 
static int streamcopy_init(const Muxer *mux, OutputStream *ost, AVDictionary **encoder_opts)
{
    MuxStream           *ms         = ms_from_ost(ost);
 
    const InputStream   *ist        = ost->ist;
    const InputFile     *ifile      = ist->file;
 
    AVCodecParameters   *par        = ost->par_in;
    uint32_t             codec_tag  = par->codec_tag;
 
    AVCodecContext      *codec_ctx  = NULL;
 
    AVRational           fr         = ost->frame_rate;
 
    int ret = 0;
 
    codec_ctx = avcodec_alloc_context3(NULL);
    if (!codec_ctx)
        return AVERROR(ENOMEM);
 
    ret = avcodec_parameters_to_context(codec_ctx, ist->par);
    if (ret >= 0)
        ret = av_opt_set_dict(codec_ctx, encoder_opts);
    if (ret < 0) {
        av_log(ost, AV_LOG_FATAL,
               "Error setting up codec context options.\n");
        goto fail;
    }
 
    ret = avcodec_parameters_from_context(par, codec_ctx);
    if (ret < 0) {
        av_log(ost, AV_LOG_FATAL,
               "Error getting reference codec parameters.\n");
        goto fail;
    }
 
    if (!codec_tag) {
        const struct AVCodecTag * const *ct = mux->fc->oformat->codec_tag;
        unsigned int codec_tag_tmp;
        if (!ct || av_codec_get_id (ct, par->codec_tag) == par->codec_id ||
            !av_codec_get_tag2(ct, par->codec_id, &codec_tag_tmp))
            codec_tag = par->codec_tag;
    }
 
    par->codec_tag = codec_tag;
 
    if (!fr.num)
        fr = ist->framerate;
 
    if (fr.num)
        ost->st->avg_frame_rate = fr;
    else
        ost->st->avg_frame_rate = ist->st->avg_frame_rate;
 
    // copy timebase while removing common factors
    if (ost->st->time_base.num <= 0 || ost->st->time_base.den <= 0) {
        if (fr.num)
            ost->st->time_base = av_inv_q(fr);
        else
            ost->st->time_base = av_add_q(ist->st->time_base, (AVRational){0, 1});
    }
 
    if (!ms->copy_prior_start) {
        ms->ts_copy_start = (mux->of.start_time == AV_NOPTS_VALUE) ?
                            0 : mux->of.start_time;
        if (copy_ts && ifile->start_time != AV_NOPTS_VALUE) {
            ms->ts_copy_start = FFMAX(ms->ts_copy_start,
                                      ifile->start_time + ifile->ts_offset);
        }
    }
 
    for (int i = 0; i < ist->st->codecpar->nb_coded_side_data; i++) {
        const AVPacketSideData *sd_src = &ist->st->codecpar->coded_side_data[i];
        AVPacketSideData *sd_dst;
 
        sd_dst = av_packet_side_data_new(&ost->st->codecpar->coded_side_data,
                                         &ost->st->codecpar->nb_coded_side_data,
                                         sd_src->type, sd_src->size, 0);
        if (!sd_dst) {
            ret = AVERROR(ENOMEM);
            goto fail;
        }
        memcpy(sd_dst->data, sd_src->data, sd_src->size);
    }
 
    switch (par->codec_type) {
    case AVMEDIA_TYPE_AUDIO:
        if ((par->block_align == 1 || par->block_align == 1152 || par->block_align == 576) &&
            par->codec_id == AV_CODEC_ID_MP3)
            par->block_align = 0;
        if (par->codec_id == AV_CODEC_ID_AC3)
            par->block_align = 0;
        break;
    case AVMEDIA_TYPE_VIDEO: {
        AVRational sar;
        if (ost->frame_aspect_ratio.num) { // overridden by the -aspect cli option
            sar =
                av_mul_q(ost->frame_aspect_ratio,
                         (AVRational){ par->height, par->width });
            av_log(ost, AV_LOG_WARNING, "Overriding aspect ratio "
                   "with stream copy may produce invalid files\n");
            }
        else if (ist->st->sample_aspect_ratio.num)
            sar = ist->st->sample_aspect_ratio;
        else
            sar = par->sample_aspect_ratio;
        ost->st->sample_aspect_ratio = par->sample_aspect_ratio = sar;
        ost->st->r_frame_rate = ist->st->r_frame_rate;
        break;
        }
    }
 
fail:
    avcodec_free_context(&codec_ctx);
    return ret;
}
 
static int ost_add(Muxer *mux, const OptionsContext *o, enum AVMediaType type,
                   InputStream *ist, OutputFilter *ofilter, const ViewSpecifier *vs,
                   OutputStream **post)
{
    AVFormatContext *oc = mux->fc;
    MuxStream     *ms;
    OutputStream *ost;
    const AVCodec *enc;
    AVStream *st;
    AVDictionary *encoder_opts = NULL;
    int ret = 0, keep_pix_fmt = 0, autoscale = 1;
    int threads_manual = 0;
    AVRational enc_tb = { 0, 0 };
    enum VideoSyncMethod vsync_method = VSYNC_AUTO;
    const char *bsfs = NULL, *time_base = NULL, *codec_tag = NULL;
    char *filters = NULL, *next;
    double qscale = -1;
 
    st = avformat_new_stream(oc, NULL);
    if (!st)
        return AVERROR(ENOMEM);
 
    ms  = mux_stream_alloc(mux, type);
    if (!ms)
        return AVERROR(ENOMEM);
 
    // only streams with sources (i.e. not attachments)
    // are handled by the scheduler
    if (ist || ofilter) {
        ret = GROW_ARRAY(mux->sch_stream_idx, mux->nb_sch_stream_idx);
        if (ret < 0)
            return ret;
 
        ret = sch_add_mux_stream(mux->sch, mux->sch_idx);
        if (ret < 0)
            return ret;
 
        av_assert0(ret == mux->nb_sch_stream_idx - 1);
        mux->sch_stream_idx[ret] = ms->ost.index;
        ms->sch_idx              = ret;
    }
 
    ost = &ms->ost;
 
    if (o->streamid) {
        AVDictionaryEntry *e;
        char idx[16], *p;
        snprintf(idx, sizeof(idx), "%d", ost->index);
 
        e = av_dict_get(o->streamid, idx, NULL, 0);
        if (e) {
            st->id = strtol(e->value, &p, 0);
            if (!e->value[0] || *p) {
                av_log(ost, AV_LOG_FATAL, "Invalid stream id: %s\n", e->value);
                return AVERROR(EINVAL);
            }
        }
    }
 
    ost->par_in = avcodec_parameters_alloc();
    if (!ost->par_in)
        return AVERROR(ENOMEM);
 
    ms->last_mux_dts = AV_NOPTS_VALUE;
 
    ost->st         = st;
    ost->ist        = ist;
    ost->kf.ref_pts = AV_NOPTS_VALUE;
    ost->par_in->codec_type  = type;
    st->codecpar->codec_type = type;
 
    ret = choose_encoder(o, oc, ost, &enc);
    if (ret < 0) {
        av_log(ost, AV_LOG_FATAL, "Error selecting an encoder\n");
        return ret;
    }
 
    if (enc) {
        ost->enc_ctx = avcodec_alloc_context3(enc);
        if (!ost->enc_ctx)
            return AVERROR(ENOMEM);
 
        ret = sch_add_enc(mux->sch, encoder_thread, ost,
                          ost->type == AVMEDIA_TYPE_SUBTITLE ? NULL : enc_open);
        if (ret < 0)
            return ret;
        ms->sch_idx_enc = ret;
 
        ret = enc_alloc(&ost->enc, enc, mux->sch, ms->sch_idx_enc);
        if (ret < 0)
            return ret;
 
        av_strlcat(ms->log_name, "/",       sizeof(ms->log_name));
        av_strlcat(ms->log_name, enc->name, sizeof(ms->log_name));
    } else {
        if (ofilter) {
            av_log(ost, AV_LOG_ERROR,
                   "Streamcopy requested for output stream fed "
                   "from a complex filtergraph. Filtering and streamcopy "
                   "cannot be used together.\n");
            return AVERROR(EINVAL);
        }
 
        av_strlcat(ms->log_name, "/copy", sizeof(ms->log_name));
    }
 
    av_log(ost, AV_LOG_VERBOSE, "Created %s stream from ",
           av_get_media_type_string(type));
    if (ist)
        av_log(ost, AV_LOG_VERBOSE, "input stream %d:%d",
               ist->file->index, ist->index);
    else if (ofilter)
        av_log(ost, AV_LOG_VERBOSE, "complex filtergraph %d:[%s]\n",
               ofilter->graph->index, ofilter->name);
    else if (type == AVMEDIA_TYPE_ATTACHMENT)
        av_log(ost, AV_LOG_VERBOSE, "attached file");
    else av_assert0(0);
    av_log(ost, AV_LOG_VERBOSE, "\n");
 
    ms->pkt = av_packet_alloc();
    if (!ms->pkt)
        return AVERROR(ENOMEM);
 
    if (ost->enc_ctx) {
        AVIOContext *s = NULL;
        char *buf = NULL, *arg = NULL;
        const char *enc_stats_pre = NULL, *enc_stats_post = NULL, *mux_stats = NULL;
        const char *enc_time_base = NULL, *preset = NULL;
 
        ret = filter_codec_opts(o->g->codec_opts, ost->enc_ctx->codec_id,
                                oc, st, ost->enc_ctx->codec, &encoder_opts,
                                &mux->enc_opts_used);
        if (ret < 0)
            goto fail;
 
        opt_match_per_stream_str(ost, &o->presets, oc, st, &preset);
        opt_match_per_stream_int(ost, &o->autoscale, oc, st, &autoscale);
        if (preset && (!(ret = get_preset_file_2(preset, ost->enc_ctx->codec->name, &s)))) {
            AVBPrint bprint;
            av_bprint_init(&bprint, 0, AV_BPRINT_SIZE_UNLIMITED);
            do  {
                av_bprint_clear(&bprint);
                buf = get_line(s, &bprint);
                if (!buf) {
                    ret = AVERROR(ENOMEM);
                    break;
                }
 
                if (!buf[0] || buf[0] == '#')
                    continue;
                if (!(arg = strchr(buf, '='))) {
                    av_log(ost, AV_LOG_FATAL, "Invalid line found in the preset file.\n");
                    ret = AVERROR(EINVAL);
                    break;
                }
                *arg++ = 0;
                av_dict_set(&encoder_opts, buf, arg, AV_DICT_DONT_OVERWRITE);
            } while (!s->eof_reached);
            av_bprint_finalize(&bprint, NULL);
            avio_closep(&s);
        }
        if (ret) {
            av_log(ost, AV_LOG_FATAL,
                   "Preset %s specified, but could not be opened.\n", preset);
            goto fail;
        }
 
        opt_match_per_stream_str(ost, &o->enc_stats_pre, oc, st, &enc_stats_pre);
        if (enc_stats_pre &&
            (type == AVMEDIA_TYPE_VIDEO || type == AVMEDIA_TYPE_AUDIO)) {
            const char *format = "{fidx} {sidx} {n} {t}";
 
            opt_match_per_stream_str(ost, &o->enc_stats_pre_fmt, oc, st, &format);
 
            ret = enc_stats_init(ost, &ost->enc_stats_pre, 1, enc_stats_pre, format);
            if (ret < 0)
                goto fail;
        }
 
        opt_match_per_stream_str(ost, &o->enc_stats_post, oc, st, &enc_stats_post);
        if (enc_stats_post &&
            (type == AVMEDIA_TYPE_VIDEO || type == AVMEDIA_TYPE_AUDIO)) {
            const char *format = "{fidx} {sidx} {n} {t}";
 
            opt_match_per_stream_str(ost, &o->enc_stats_post_fmt, oc, st, &format);
 
            ret = enc_stats_init(ost, &ost->enc_stats_post, 0, enc_stats_post, format);
            if (ret < 0)
                goto fail;
        }
 
        opt_match_per_stream_str(ost, &o->mux_stats, oc, st, &mux_stats);
        if (mux_stats &&
            (type == AVMEDIA_TYPE_VIDEO || type == AVMEDIA_TYPE_AUDIO)) {
            const char *format = "{fidx} {sidx} {n} {t}";
 
            opt_match_per_stream_str(ost, &o->mux_stats_fmt, oc, st, &format);
 
            ret = enc_stats_init(ost, &ms->stats, 0, mux_stats, format);
            if (ret < 0)
                goto fail;
        }
 
        opt_match_per_stream_str(ost, &o->enc_time_bases, oc, st, &enc_time_base);
        if (enc_time_base && type == AVMEDIA_TYPE_SUBTITLE)
            av_log(ost, AV_LOG_WARNING,
                   "-enc_time_base not supported for subtitles, ignoring\n");
        else if (enc_time_base) {
            AVRational q;
 
            if (!strcmp(enc_time_base, "demux")) {
                q = (AVRational){ ENC_TIME_BASE_DEMUX, 0 };
            } else if (!strcmp(enc_time_base, "filter")) {
                q = (AVRational){ ENC_TIME_BASE_FILTER, 0 };
            } else {
                ret = av_parse_ratio(&q, enc_time_base, INT_MAX, 0, NULL);
                if (ret < 0 || q.den <= 0
#if !FFMPEG_OPT_ENC_TIME_BASE_NUM
                    || q.num < 0
#endif
                    ) {
                    av_log(ost, AV_LOG_FATAL, "Invalid time base: %s\n", enc_time_base);
                    ret = ret < 0 ? ret : AVERROR(EINVAL);
                    goto fail;
                }
#if FFMPEG_OPT_ENC_TIME_BASE_NUM
                if (q.num < 0)
                    av_log(ost, AV_LOG_WARNING, "-enc_time_base -1 is deprecated,"
                           " use -enc_time_base demux\n");
#endif
            }
 
            enc_tb = q;
        }
 
        threads_manual = !!av_dict_get(encoder_opts, "threads", NULL, 0);
 
        ret = av_opt_set_dict2(ost->enc_ctx, &encoder_opts, AV_OPT_SEARCH_CHILDREN);
        if (ret < 0) {
            av_log(ost, AV_LOG_ERROR, "Error applying encoder options: %s\n",
                   av_err2str(ret));
            goto fail;
        }
 
        ret = check_avoptions(encoder_opts);
        if (ret < 0)
            goto fail;
 
        // default to automatic thread count
        if (!threads_manual)
            ost->enc_ctx->thread_count = 0;
    } else {
        ret = filter_codec_opts(o->g->codec_opts, AV_CODEC_ID_NONE, oc, st,
                                NULL, &encoder_opts,
                                &mux->enc_opts_used);
        if (ret < 0)
            goto fail;
    }
 
 
    if (o->bitexact) {
        ost->bitexact        = 1;
    } else if (ost->enc_ctx) {
        ost->bitexact        = !!(ost->enc_ctx->flags & AV_CODEC_FLAG_BITEXACT);
    }
 
    opt_match_per_stream_str(ost, &o->time_bases, oc, st, &time_base);
    if (time_base) {
        AVRational q;
        if (av_parse_ratio(&q, time_base, INT_MAX, 0, NULL) < 0 ||
            q.num <= 0 || q.den <= 0) {
            av_log(ost, AV_LOG_FATAL, "Invalid time base: %s\n", time_base);
            ret = AVERROR(EINVAL);
            goto fail;
        }
        st->time_base = q;
    }
 
    ms->max_frames = INT64_MAX;
    opt_match_per_stream_int64(ost, &o->max_frames, oc, st, &ms->max_frames);
    for (int i = 0; i < o->max_frames.nb_opt; i++) {
        char *p = o->max_frames.opt[i].specifier;
        if (!*p && type != AVMEDIA_TYPE_VIDEO) {
            av_log(ost, AV_LOG_WARNING, "Applying unspecific -frames to non video streams, maybe you meant -vframes ?\n");
            break;
        }
    }
 
    ms->copy_prior_start = -1;
    opt_match_per_stream_int(ost, &o->copy_prior_start, oc, st, &ms->copy_prior_start);
    opt_match_per_stream_str(ost, &o->bitstream_filters, oc, st, &bsfs);
    if (bsfs && *bsfs) {
        ret = av_bsf_list_parse_str(bsfs, &ms->bsf_ctx);
        if (ret < 0) {
            av_log(ost, AV_LOG_ERROR, "Error parsing bitstream filter sequence '%s': %s\n", bsfs, av_err2str(ret));
            goto fail;
        }
    }
 
    opt_match_per_stream_str(ost, &o->codec_tags, oc, st, &codec_tag);
    if (codec_tag) {
        uint32_t tag = strtol(codec_tag, &next, 0);
        if (*next) {
            uint8_t buf[4] = { 0 };
            memcpy(buf, codec_tag, FFMIN(sizeof(buf), strlen(codec_tag)));
            tag = AV_RL32(buf);
        }
        ost->st->codecpar->codec_tag = tag;
        ost->par_in->codec_tag = tag;
        if (ost->enc_ctx)
            ost->enc_ctx->codec_tag = tag;
    }
 
    opt_match_per_stream_dbl(ost, &o->qscale, oc, st, &qscale);
    if (ost->enc_ctx && qscale >= 0) {
        ost->enc_ctx->flags |= AV_CODEC_FLAG_QSCALE;
        ost->enc_ctx->global_quality = FF_QP2LAMBDA * qscale;
    }
 
    if (ms->sch_idx >= 0) {
        int max_muxing_queue_size       = 128;
        int muxing_queue_data_threshold = 50 * 1024 * 1024;
 
        opt_match_per_stream_int(ost, &o->max_muxing_queue_size, oc, st,
                                 &max_muxing_queue_size);
        opt_match_per_stream_int(ost, &o->muxing_queue_data_threshold,
                                 oc, st, &muxing_queue_data_threshold);
 
        sch_mux_stream_buffering(mux->sch, mux->sch_idx, ms->sch_idx,
                                 max_muxing_queue_size, muxing_queue_data_threshold);
    }
 
    opt_match_per_stream_int(ost, &o->bits_per_raw_sample, oc, st,
                                   &ost->bits_per_raw_sample);
 
    opt_match_per_stream_int(ost, &o->fix_sub_duration_heartbeat,
                             oc, st, &ost->fix_sub_duration_heartbeat);
 
    if (oc->oformat->flags & AVFMT_GLOBALHEADER && ost->enc_ctx)
        ost->enc_ctx->flags |= AV_CODEC_FLAG_GLOBAL_HEADER;
 
    opt_match_per_stream_int(ost, &o->copy_initial_nonkeyframes,
                             oc, st, &ms->copy_initial_nonkeyframes);
    switch (type) {
    case AVMEDIA_TYPE_VIDEO:      ret = new_stream_video     (mux, o, ost, &keep_pix_fmt, &vsync_method); break;
    case AVMEDIA_TYPE_AUDIO:      ret = new_stream_audio     (mux, o, ost); break;
    case AVMEDIA_TYPE_SUBTITLE:   ret = new_stream_subtitle  (mux, o, ost); break;
    }
    if (ret < 0)
        goto fail;
 
    if (type == AVMEDIA_TYPE_VIDEO || type == AVMEDIA_TYPE_AUDIO) {
        ret = ost_get_filters(o, oc, ost, &filters);
        if (ret < 0)
            goto fail;
    }
 
    if (ost->enc &&
        (type == AVMEDIA_TYPE_VIDEO || type == AVMEDIA_TYPE_AUDIO)) {
        ret = ost_bind_filter(mux, ms, ofilter, o, filters, enc_tb, vsync_method,
                              keep_pix_fmt, autoscale, threads_manual, vs);
        if (ret < 0)
            goto fail;
    } else if (ost->ist) {
        int sched_idx = ist_output_add(ost->ist, ost);
        if (sched_idx < 0) {
            av_log(ost, AV_LOG_ERROR,
                   "Error binding an input stream\n");
            ret = sched_idx;
            goto fail;
        }
        ms->sch_idx_src = sched_idx;
 
        if (ost->enc) {
            ret = sch_connect(mux->sch, SCH_DEC_OUT(sched_idx, 0),
                                        SCH_ENC(ms->sch_idx_enc));
            if (ret < 0)
                goto fail;
 
            ret = sch_connect(mux->sch, SCH_ENC(ms->sch_idx_enc),
                                        SCH_MSTREAM(mux->sch_idx, ms->sch_idx));
            if (ret < 0)
                goto fail;
        } else {
            ret = sch_connect(mux->sch, SCH_DSTREAM(ost->ist->file->index, sched_idx),
                                        SCH_MSTREAM(ost->file->index, ms->sch_idx));
            if (ret < 0)
                goto fail;
        }
    }
 
    if (ost->ist && !ost->enc) {
        ret = streamcopy_init(mux, ost, &encoder_opts);
        if (ret < 0)
            goto fail;
    }
 
    // copy estimated duration as a hint to the muxer
    if (ost->ist && ost->ist->st->duration > 0) {
        ms->stream_duration    = ist->st->duration;
        ms->stream_duration_tb = ist->st->time_base;
    }
 
    if (post)
        *post = ost;
 
    ret = 0;
 
fail:
    av_dict_free(&encoder_opts);
 
    return ret;
}
 
static int map_auto_video(Muxer *mux, const OptionsContext *o)
{
    AVFormatContext *oc = mux->fc;
    InputStream *best_ist = NULL;
    int best_score = 0;
    int qcr;
 
    /* video: highest resolution */
    if (av_guess_codec(oc->oformat, NULL, oc->url, NULL, AVMEDIA_TYPE_VIDEO) == AV_CODEC_ID_NONE)
        return 0;
 
    qcr = avformat_query_codec(oc->oformat, oc->oformat->video_codec, 0);
    for (int j = 0; j < nb_input_files; j++) {
        InputFile *ifile = input_files[j];
        InputStream *file_best_ist = NULL;
        int file_best_score = 0;
        for (int i = 0; i < ifile->nb_streams; i++) {
            InputStream *ist = ifile->streams[i];
            int score;
 
            if (ist->user_set_discard == AVDISCARD_ALL ||
                ist->st->codecpar->codec_type != AVMEDIA_TYPE_VIDEO)
                continue;
 
            score = ist->st->codecpar->width * ist->st->codecpar->height
                       + 100000000 * !!(ist->st->event_flags & AVSTREAM_EVENT_FLAG_NEW_PACKETS)
                       + 5000000*!!(ist->st->disposition & AV_DISPOSITION_DEFAULT);
            if((qcr!=MKTAG('A', 'P', 'I', 'C')) && (ist->st->disposition & AV_DISPOSITION_ATTACHED_PIC))
                score = 1;
 
            if (score > file_best_score) {
                if((qcr==MKTAG('A', 'P', 'I', 'C')) && !(ist->st->disposition & AV_DISPOSITION_ATTACHED_PIC))
                    continue;
                file_best_score = score;
                file_best_ist   = ist;
            }
        }
        if (file_best_ist) {
            if((qcr == MKTAG('A', 'P', 'I', 'C')) ||
               !(file_best_ist->st->disposition & AV_DISPOSITION_ATTACHED_PIC))
                file_best_score -= 5000000*!!(file_best_ist->st->disposition & AV_DISPOSITION_DEFAULT);
            if (file_best_score > best_score) {
                best_score = file_best_score;
                best_ist = file_best_ist;
            }
       }
    }
    if (best_ist)
        return ost_add(mux, o, AVMEDIA_TYPE_VIDEO, best_ist, NULL, NULL, NULL);
 
    return 0;
}
 
static int map_auto_audio(Muxer *mux, const OptionsContext *o)
{
    AVFormatContext *oc = mux->fc;
    InputStream *best_ist = NULL;
    int best_score = 0;
 
        /* audio: most channels */
    if (av_guess_codec(oc->oformat, NULL, oc->url, NULL, AVMEDIA_TYPE_AUDIO) == AV_CODEC_ID_NONE)
        return 0;
 
    for (int j = 0; j < nb_input_files; j++) {
        InputFile *ifile = input_files[j];
        InputStream *file_best_ist = NULL;
        int file_best_score = 0;
        for (int i = 0; i < ifile->nb_streams; i++) {
            InputStream *ist = ifile->streams[i];
            int score;
 
            if (ist->user_set_discard == AVDISCARD_ALL ||
                ist->st->codecpar->codec_type != AVMEDIA_TYPE_AUDIO)
                continue;
 
            score = ist->st->codecpar->ch_layout.nb_channels
                    + 100000000 * !!(ist->st->event_flags & AVSTREAM_EVENT_FLAG_NEW_PACKETS)
                    + 5000000*!!(ist->st->disposition & AV_DISPOSITION_DEFAULT);
            if (score > file_best_score) {
                file_best_score = score;
                file_best_ist   = ist;
            }
        }
        if (file_best_ist) {
            file_best_score -= 5000000*!!(file_best_ist->st->disposition & AV_DISPOSITION_DEFAULT);
            if (file_best_score > best_score) {
                best_score = file_best_score;
                best_ist   = file_best_ist;
            }
       }
    }
    if (best_ist)
        return ost_add(mux, o, AVMEDIA_TYPE_AUDIO, best_ist, NULL, NULL, NULL);
 
    return 0;
}
 
static int map_auto_subtitle(Muxer *mux, const OptionsContext *o)
{
    AVFormatContext *oc = mux->fc;
    const char *subtitle_codec_name = NULL;
 
        /* subtitles: pick first */
    subtitle_codec_name = opt_match_per_type_str(&o->codec_names, 's');
    if (!avcodec_find_encoder(oc->oformat->subtitle_codec) && !subtitle_codec_name)
        return 0;
 
    for (InputStream *ist = ist_iter(NULL); ist; ist = ist_iter(ist))
        if (ist->st->codecpar->codec_type == AVMEDIA_TYPE_SUBTITLE) {
            AVCodecDescriptor const *input_descriptor =
                avcodec_descriptor_get(ist->st->codecpar->codec_id);
            AVCodecDescriptor const *output_descriptor = NULL;
            AVCodec const *output_codec =
                avcodec_find_encoder(oc->oformat->subtitle_codec);
            int input_props = 0, output_props = 0;
            if (ist->user_set_discard == AVDISCARD_ALL)
                continue;
            if (output_codec)
                output_descriptor = avcodec_descriptor_get(output_codec->id);
            if (input_descriptor)
                input_props = input_descriptor->props & (AV_CODEC_PROP_TEXT_SUB | AV_CODEC_PROP_BITMAP_SUB);
            if (output_descriptor)
                output_props = output_descriptor->props & (AV_CODEC_PROP_TEXT_SUB | AV_CODEC_PROP_BITMAP_SUB);
            if (subtitle_codec_name ||
                input_props & output_props ||
                // Map dvb teletext which has neither property to any output subtitle encoder
                input_descriptor && output_descriptor &&
                (!input_descriptor->props ||
                 !output_descriptor->props)) {
                return ost_add(mux, o, AVMEDIA_TYPE_SUBTITLE, ist, NULL, NULL, NULL);
            }
        }
 
    return 0;
}
 
static int map_auto_data(Muxer *mux, const OptionsContext *o)
{
    AVFormatContext *oc = mux->fc;
    /* Data only if codec id match */
    enum AVCodecID codec_id = av_guess_codec(oc->oformat, NULL, oc->url, NULL, AVMEDIA_TYPE_DATA);
 
    if (codec_id == AV_CODEC_ID_NONE)
        return 0;
 
    for (InputStream *ist = ist_iter(NULL); ist; ist = ist_iter(ist)) {
        if (ist->user_set_discard == AVDISCARD_ALL)
            continue;
        if (ist->st->codecpar->codec_type == AVMEDIA_TYPE_DATA &&
            ist->st->codecpar->codec_id == codec_id) {
            int ret = ost_add(mux, o, AVMEDIA_TYPE_DATA, ist, NULL, NULL, NULL);
            if (ret < 0)
                return ret;
        }
    }
 
    return 0;
}
 
static int map_manual(Muxer *mux, const OptionsContext *o, const StreamMap *map)
{
    InputStream *ist;
    int ret;
 
    if (map->disabled)
        return 0;
 
    if (map->linklabel) {
        FilterGraph *fg;
        OutputFilter *ofilter = NULL;
        int j, k;
 
        for (j = 0; j < nb_filtergraphs; j++) {
            fg = filtergraphs[j];
            for (k = 0; k < fg->nb_outputs; k++) {
                const char *linklabel = fg->outputs[k]->linklabel;
                if (linklabel && !strcmp(linklabel, map->linklabel)) {
                    ofilter = fg->outputs[k];
                    goto loop_end;
                }
            }
        }
loop_end:
        if (!ofilter) {
            av_log(mux, AV_LOG_FATAL, "Output with label '%s' does not exist "
                   "in any defined filter graph, or was already used elsewhere.\n", map->linklabel);
            return AVERROR(EINVAL);
        }
 
        av_log(mux, AV_LOG_VERBOSE, "Creating output stream from an explicitly "
               "mapped complex filtergraph %d, output [%s]\n", fg->index, map->linklabel);
 
        ret = ost_add(mux, o, ofilter->type, NULL, ofilter, NULL, NULL);
        if (ret < 0)
            return ret;
    } else {
        const ViewSpecifier *vs = map->vs.type == VIEW_SPECIFIER_TYPE_NONE ?
                                  NULL : &map->vs;
 
        ist = input_files[map->file_index]->streams[map->stream_index];
        if (ist->user_set_discard == AVDISCARD_ALL) {
            av_log(mux, AV_LOG_FATAL, "Stream #%d:%d is disabled and cannot be mapped.\n",
                   map->file_index, map->stream_index);
            return AVERROR(EINVAL);
        }
        if(o->subtitle_disable && ist->st->codecpar->codec_type == AVMEDIA_TYPE_SUBTITLE)
            return 0;
        if(o->   audio_disable && ist->st->codecpar->codec_type == AVMEDIA_TYPE_AUDIO)
            return 0;
        if(o->   video_disable && ist->st->codecpar->codec_type == AVMEDIA_TYPE_VIDEO)
            return 0;
        if(o->    data_disable && ist->st->codecpar->codec_type == AVMEDIA_TYPE_DATA)
            return 0;
 
        if (ist->st->codecpar->codec_type == AVMEDIA_TYPE_UNKNOWN &&
            !copy_unknown_streams) {
            av_log(mux, ignore_unknown_streams ? AV_LOG_WARNING : AV_LOG_FATAL,
                   "Cannot map stream #%d:%d - unsupported type.\n",
                   map->file_index, map->stream_index);
            if (!ignore_unknown_streams) {
                av_log(mux, AV_LOG_FATAL,
                       "If you want unsupported types ignored instead "
                       "of failing, please use the -ignore_unknown option\n"
                       "If you want them copied, please use -copy_unknown\n");
                return AVERROR(EINVAL);
            }
            return 0;
        }
 
        if (vs && ist->st->codecpar->codec_type != AVMEDIA_TYPE_VIDEO) {
            av_log(mux, AV_LOG_ERROR,
                   "View specifier given for mapping a %s input stream\n",
                   av_get_media_type_string(ist->st->codecpar->codec_type));
            return AVERROR(EINVAL);
        }
 
        ret = ost_add(mux, o, ist->st->codecpar->codec_type, ist, NULL, vs, NULL);
        if (ret < 0)
            return ret;
    }
 
    return 0;
}
 
static int of_add_attachments(Muxer *mux, const OptionsContext *o)
{
    OutputStream *ost;
    int err;
 
    for (int i = 0; i < o->nb_attachments; i++) {
        AVIOContext *pb;
        uint8_t *attachment;
        char *attachment_filename;
        const char *p;
        int64_t len;
 
        if ((err = avio_open2(&pb, o->attachments[i], AVIO_FLAG_READ, &int_cb, NULL)) < 0) {
            av_log(mux, AV_LOG_FATAL, "Could not open attachment file %s.\n",
                   o->attachments[i]);
            return err;
        }
        if ((len = avio_size(pb)) <= 0) {
            av_log(mux, AV_LOG_FATAL, "Could not get size of the attachment %s.\n",
                   o->attachments[i]);
            err = len ? len : AVERROR_INVALIDDATA;
            goto read_fail;
        }
        if (len > INT_MAX - AV_INPUT_BUFFER_PADDING_SIZE) {
            av_log(mux, AV_LOG_FATAL, "Attachment %s too large.\n",
                   o->attachments[i]);
            err = AVERROR(ERANGE);
            goto read_fail;
        }
 
        attachment = av_malloc(len + AV_INPUT_BUFFER_PADDING_SIZE);
        if (!attachment) {
            err = AVERROR(ENOMEM);
            goto read_fail;
        }
 
        err = avio_read(pb, attachment, len);
        if (err < 0)
            av_log(mux, AV_LOG_FATAL, "Error reading attachment file %s: %s\n",
                   o->attachments[i], av_err2str(err));
        else if (err != len) {
            av_log(mux, AV_LOG_FATAL, "Could not read all %"PRId64" bytes for "
                   "attachment file %s\n", len, o->attachments[i]);
            err = AVERROR(EIO);
        }
 
read_fail:
        avio_closep(&pb);
        if (err < 0)
            return err;
 
        memset(attachment + len, 0, AV_INPUT_BUFFER_PADDING_SIZE);
 
        av_log(mux, AV_LOG_VERBOSE, "Creating attachment stream from file %s\n",
               o->attachments[i]);
 
        attachment_filename = av_strdup(o->attachments[i]);
        if (!attachment_filename) {
            av_free(attachment);
            return AVERROR(ENOMEM);
        }
 
        err = ost_add(mux, o, AVMEDIA_TYPE_ATTACHMENT, NULL, NULL, NULL, &ost);
        if (err < 0) {
            av_free(attachment_filename);
            av_freep(&attachment);
            return err;
        }
 
        ost->attachment_filename       = attachment_filename;
        ost->par_in->extradata         = attachment;
        ost->par_in->extradata_size    = len;
 
        p = strrchr(o->attachments[i], '/');
        av_dict_set(&ost->st->metadata, "filename", (p && *p) ? p + 1 : o->attachments[i], AV_DICT_DONT_OVERWRITE);
    }
 
    return 0;
}
 
static int create_streams(Muxer *mux, const OptionsContext *o)
{
    static int (* const map_func[])(Muxer *mux, const OptionsContext *o) = {
        [AVMEDIA_TYPE_VIDEO]    = map_auto_video,
        [AVMEDIA_TYPE_AUDIO]    = map_auto_audio,
        [AVMEDIA_TYPE_SUBTITLE] = map_auto_subtitle,
        [AVMEDIA_TYPE_DATA]     = map_auto_data,
    };
 
    AVFormatContext *oc = mux->fc;
 
    int auto_disable =
        o->video_disable    * (1 << AVMEDIA_TYPE_VIDEO)    |
        o->audio_disable    * (1 << AVMEDIA_TYPE_AUDIO)    |
        o->subtitle_disable * (1 << AVMEDIA_TYPE_SUBTITLE) |
        o->data_disable     * (1 << AVMEDIA_TYPE_DATA);
 
    int ret;
 
    /* create streams for all unlabeled output pads */
    for (int i = 0; i < nb_filtergraphs; i++) {
        FilterGraph *fg = filtergraphs[i];
        for (int j = 0; j < fg->nb_outputs; j++) {
            OutputFilter *ofilter = fg->outputs[j];
 
            if (ofilter->linklabel || ofilter->bound)
                continue;
 
            auto_disable |= 1 << ofilter->type;
 
            av_log(mux, AV_LOG_VERBOSE, "Creating output stream from unlabeled "
                   "output of complex filtergraph %d.", fg->index);
            if (!o->nb_stream_maps)
                av_log(mux, AV_LOG_VERBOSE, " This overrides automatic %s mapping.",
                       av_get_media_type_string(ofilter->type));
            av_log(mux, AV_LOG_VERBOSE, "\n");
 
            ret = ost_add(mux, o, ofilter->type, NULL, ofilter, NULL, NULL);
            if (ret < 0)
                return ret;
        }
    }
 
    if (!o->nb_stream_maps) {
        av_log(mux, AV_LOG_VERBOSE, "No explicit maps, mapping streams automatically...\n");
 
        /* pick the "best" stream of each type */
        for (int i = 0; i < FF_ARRAY_ELEMS(map_func); i++) {
            if (!map_func[i] || auto_disable & (1 << i))
                continue;
            ret = map_func[i](mux, o);
            if (ret < 0)
                return ret;
        }
    } else {
        av_log(mux, AV_LOG_VERBOSE, "Adding streams from explicit maps...\n");
 
        for (int i = 0; i < o->nb_stream_maps; i++) {
            ret = map_manual(mux, o, &o->stream_maps[i]);
            if (ret < 0)
                return ret;
        }
    }
 
    ret = of_add_attachments(mux, o);
    if (ret < 0)
        return ret;
 
    // setup fix_sub_duration_heartbeat mappings
    for (unsigned i = 0; i < oc->nb_streams; i++) {
        MuxStream *src = ms_from_ost(mux->of.streams[i]);
 
        if (!src->ost.fix_sub_duration_heartbeat)
            continue;
 
        for (unsigned j = 0; j < oc->nb_streams; j++) {
            MuxStream *dst = ms_from_ost(mux->of.streams[j]);
 
            if (src == dst || dst->ost.type != AVMEDIA_TYPE_SUBTITLE ||
                !dst->ost.enc || !dst->ost.ist || !dst->ost.ist->fix_sub_duration)
                continue;
 
            ret = sch_mux_sub_heartbeat_add(mux->sch, mux->sch_idx, src->sch_idx,
                                            dst->sch_idx_src);
 
        }
    }
 
    // handle -apad
    if (o->shortest) {
        int have_video = 0;
 
        for (unsigned i = 0; i < mux->of.nb_streams; i++)
            if (mux->of.streams[i]->type == AVMEDIA_TYPE_VIDEO) {
                have_video = 1;
                break;
            }
 
        for (unsigned i = 0; have_video && i < mux->of.nb_streams; i++) {
            MuxStream         *ms = ms_from_ost(mux->of.streams[i]);
            OutputFilter *ofilter = ms->ost.filter;
 
            if (ms->ost.type != AVMEDIA_TYPE_AUDIO || !ms->apad || !ofilter)
                continue;
 
            ofilter->apad = av_strdup(ms->apad);
            if (!ofilter->apad)
                return AVERROR(ENOMEM);
        }
    }
    for (unsigned i = 0; i < mux->of.nb_streams; i++) {
        MuxStream *ms = ms_from_ost(mux->of.streams[i]);
        ms->apad = NULL;
    }
 
    if (!oc->nb_streams && !(oc->oformat->flags & AVFMT_NOSTREAMS)) {
        av_dump_format(oc, nb_output_files - 1, oc->url, 1);
        av_log(mux, AV_LOG_ERROR, "Output file does not contain any stream\n");
        return AVERROR(EINVAL);
    }
 
    return 0;
}
 
static int setup_sync_queues(Muxer *mux, AVFormatContext *oc,
                             int64_t buf_size_us, int shortest)
{
    OutputFile *of = &mux->of;
    int nb_av_enc = 0, nb_audio_fs = 0, nb_interleaved = 0;
    int limit_frames = 0, limit_frames_av_enc = 0;
 
#define IS_AV_ENC(ost, type)  \
    (ost->enc_ctx && (type == AVMEDIA_TYPE_VIDEO || type == AVMEDIA_TYPE_AUDIO))
#define IS_INTERLEAVED(type) (type != AVMEDIA_TYPE_ATTACHMENT)
 
    for (int i = 0; i < oc->nb_streams; i++) {
        OutputStream *ost = of->streams[i];
        MuxStream     *ms = ms_from_ost(ost);
        enum AVMediaType type = ost->type;
 
        ms->sq_idx_mux  = -1;
 
        nb_interleaved += IS_INTERLEAVED(type);
        nb_av_enc      += IS_AV_ENC(ost, type);
        nb_audio_fs    += (ost->enc_ctx && type == AVMEDIA_TYPE_AUDIO &&
                           !(ost->enc_ctx->codec->capabilities & AV_CODEC_CAP_VARIABLE_FRAME_SIZE));
 
        limit_frames        |=  ms->max_frames < INT64_MAX;
        limit_frames_av_enc |= (ms->max_frames < INT64_MAX) && IS_AV_ENC(ost, type);
    }
 
    if (!((nb_interleaved > 1 && shortest) ||
          (nb_interleaved > 0 && limit_frames) ||
          nb_audio_fs))
        return 0;
 
    /* we use a sync queue before encoding when:
     * - 'shortest' is in effect and we have two or more encoded audio/video
     *   streams
     * - at least one encoded audio/video stream is frame-limited, since
     *   that has similar semantics to 'shortest'
     * - at least one audio encoder requires constant frame sizes
     *
     * Note that encoding sync queues are handled in the scheduler, because
     * different encoders run in different threads and need external
     * synchronization, while muxer sync queues can be handled inside the muxer
     */
    if ((shortest && nb_av_enc > 1) || limit_frames_av_enc || nb_audio_fs) {
        int sq_idx, ret;
 
        sq_idx = sch_add_sq_enc(mux->sch, buf_size_us, mux);
        if (sq_idx < 0)
            return sq_idx;
 
        for (int i = 0; i < oc->nb_streams; i++) {
            OutputStream *ost = of->streams[i];
            MuxStream     *ms = ms_from_ost(ost);
            enum AVMediaType type = ost->type;
 
            if (!IS_AV_ENC(ost, type))
                continue;
 
            ret = sch_sq_add_enc(mux->sch, sq_idx, ms->sch_idx_enc,
                                 shortest || ms->max_frames < INT64_MAX,
                                 ms->max_frames);
            if (ret < 0)
                return ret;
        }
    }
 
    /* if there are any additional interleaved streams, then ALL the streams
     * are also synchronized before sending them to the muxer */
    if (nb_interleaved > nb_av_enc) {
        mux->sq_mux = sq_alloc(SYNC_QUEUE_PACKETS, buf_size_us, mux);
        if (!mux->sq_mux)
            return AVERROR(ENOMEM);
 
        mux->sq_pkt = av_packet_alloc();
        if (!mux->sq_pkt)
            return AVERROR(ENOMEM);
 
        for (int i = 0; i < oc->nb_streams; i++) {
            OutputStream *ost = of->streams[i];
            MuxStream     *ms = ms_from_ost(ost);
            enum AVMediaType type = ost->type;
 
            if (!IS_INTERLEAVED(type))
                continue;
 
            ms->sq_idx_mux = sq_add_stream(mux->sq_mux,
                                           shortest || ms->max_frames < INT64_MAX);
            if (ms->sq_idx_mux < 0)
                return ms->sq_idx_mux;
 
            if (ms->max_frames != INT64_MAX)
                sq_limit_frames(mux->sq_mux, ms->sq_idx_mux, ms->max_frames);
        }
    }
 
#undef IS_AV_ENC
#undef IS_INTERLEAVED
 
    return 0;
}
 
static int of_parse_iamf_audio_element_layers(Muxer *mux, AVStreamGroup *stg, char *ptr)
{
    AVIAMFAudioElement *audio_element = stg->params.iamf_audio_element;
    AVDictionary *dict = NULL;
    const char *token;
    int ret = 0;
 
    audio_element->demixing_info =
        av_iamf_param_definition_alloc(AV_IAMF_PARAMETER_DEFINITION_DEMIXING, 1, NULL);
    audio_element->recon_gain_info =
        av_iamf_param_definition_alloc(AV_IAMF_PARAMETER_DEFINITION_RECON_GAIN, 1, NULL);
 
    if (!audio_element->demixing_info ||
        !audio_element->recon_gain_info)
        return AVERROR(ENOMEM);
 
    /* process manually set layers and parameters */
    token = av_strtok(NULL, ",", &ptr);
    while (token) {
        const AVDictionaryEntry *e;
        int demixing = 0, recon_gain = 0;
        int layer = 0;
 
        if (ptr)
            ptr += strspn(ptr, " \n\t\r");
        if (av_strstart(token, "layer=", &token))
            layer = 1;
        else if (av_strstart(token, "demixing=", &token))
            demixing = 1;
        else if (av_strstart(token, "recon_gain=", &token))
            recon_gain = 1;
 
        av_dict_free(&dict);
        ret = av_dict_parse_string(&dict, token, "=", ":", 0);
        if (ret < 0) {
            av_log(mux, AV_LOG_ERROR, "Error parsing audio element specification %s\n", token);
            goto fail;
        }
 
        if (layer) {
            AVIAMFLayer *audio_layer = av_iamf_audio_element_add_layer(audio_element);
            if (!audio_layer) {
                av_log(mux, AV_LOG_ERROR, "Error adding layer to stream group %d\n", stg->index);
                ret = AVERROR(ENOMEM);
                goto fail;
            }
            av_opt_set_dict(audio_layer, &dict);
        } else if (demixing || recon_gain) {
            AVIAMFParamDefinition *param = demixing ? audio_element->demixing_info
                                                    : audio_element->recon_gain_info;
            void *subblock = av_iamf_param_definition_get_subblock(param, 0);
 
            av_opt_set_dict(param, &dict);
            av_opt_set_dict(subblock, &dict);
        }
 
        // make sure that no entries are left in the dict
        e = NULL;
        if (e = av_dict_iterate(dict, e)) {
            av_log(mux, AV_LOG_FATAL, "Unknown layer key %s.\n", e->key);
            ret = AVERROR(EINVAL);
            goto fail;
        }
        token = av_strtok(NULL, ",", &ptr);
    }
 
fail:
    av_dict_free(&dict);
    if (!ret && !audio_element->nb_layers) {
        av_log(mux, AV_LOG_ERROR, "No layer in audio element specification\n");
        ret = AVERROR(EINVAL);
    }
 
    return ret;
}
 
static int of_parse_iamf_submixes(Muxer *mux, AVStreamGroup *stg, char *ptr)
{
    AVFormatContext *oc = mux->fc;
    AVIAMFMixPresentation *mix = stg->params.iamf_mix_presentation;
    AVDictionary *dict = NULL;
    const char *token;
    char *submix_str = NULL;
    int ret = 0;
 
    /* process manually set submixes */
    token = av_strtok(NULL, ",", &ptr);
    while (token) {
        AVIAMFSubmix *submix = NULL;
        const char *subtoken;
        char *subptr = NULL;
 
        if (ptr)
            ptr += strspn(ptr, " \n\t\r");
        if (!av_strstart(token, "submix=", &token)) {
            av_log(mux, AV_LOG_ERROR, "No submix in mix presentation specification \"%s\"\n", token);
            goto fail;
        }
 
        submix_str = av_strdup(token);
        if (!submix_str)
            goto fail;
 
        submix = av_iamf_mix_presentation_add_submix(mix);
        if (!submix) {
            av_log(mux, AV_LOG_ERROR, "Error adding submix to stream group %d\n", stg->index);
            ret = AVERROR(ENOMEM);
            goto fail;
        }
        submix->output_mix_config =
            av_iamf_param_definition_alloc(AV_IAMF_PARAMETER_DEFINITION_MIX_GAIN, 0, NULL);
        if (!submix->output_mix_config) {
            ret = AVERROR(ENOMEM);
            goto fail;
        }
 
        subptr = NULL;
        subtoken = av_strtok(submix_str, "|", &subptr);
        while (subtoken) {
            const AVDictionaryEntry *e;
            int element = 0, layout = 0;
 
            if (subptr)
                subptr += strspn(subptr, " \n\t\r");
            if (av_strstart(subtoken, "element=", &subtoken))
                element = 1;
            else if (av_strstart(subtoken, "layout=", &subtoken))
                layout = 1;
 
            av_dict_free(&dict);
            ret = av_dict_parse_string(&dict, subtoken, "=", ":", 0);
            if (ret < 0) {
                av_log(mux, AV_LOG_ERROR, "Error parsing submix specification \"%s\"\n", subtoken);
                goto fail;
            }
 
            if (element) {
                AVIAMFSubmixElement *submix_element;
                char *endptr = NULL;
                int64_t idx = -1;
 
                if (e = av_dict_get(dict, "stg", NULL, 0))
                    idx = strtoll(e->value, &endptr, 0);
                if (!endptr || *endptr || idx < 0 || idx >= oc->nb_stream_groups - 1 ||
                    oc->stream_groups[idx]->type != AV_STREAM_GROUP_PARAMS_IAMF_AUDIO_ELEMENT) {
                    av_log(mux, AV_LOG_ERROR, "Invalid or missing stream group index in "
                                              "submix element specification \"%s\"\n", subtoken);
                    ret = AVERROR(EINVAL);
                    goto fail;
                }
                submix_element = av_iamf_submix_add_element(submix);
                if (!submix_element) {
                    av_log(mux, AV_LOG_ERROR, "Error adding element to submix\n");
                    ret = AVERROR(ENOMEM);
                    goto fail;
                }
 
                submix_element->audio_element_id = oc->stream_groups[idx]->id;
 
                submix_element->element_mix_config =
                    av_iamf_param_definition_alloc(AV_IAMF_PARAMETER_DEFINITION_MIX_GAIN, 0, NULL);
                if (!submix_element->element_mix_config)
                    ret = AVERROR(ENOMEM);
                av_dict_set(&dict, "stg", NULL, 0);
                av_opt_set_dict2(submix_element, &dict, AV_OPT_SEARCH_CHILDREN);
            } else if (layout) {
                AVIAMFSubmixLayout *submix_layout = av_iamf_submix_add_layout(submix);
                if (!submix_layout) {
                    av_log(mux, AV_LOG_ERROR, "Error adding layout to submix\n");
                    ret = AVERROR(ENOMEM);
                    goto fail;
                }
                av_opt_set_dict(submix_layout, &dict);
            } else
                av_opt_set_dict2(submix, &dict, AV_OPT_SEARCH_CHILDREN);
 
            if (ret < 0) {
                goto fail;
            }
 
            // make sure that no entries are left in the dict
            e = NULL;
            while (e = av_dict_iterate(dict, e)) {
                av_log(mux, AV_LOG_FATAL, "Unknown submix key %s.\n", e->key);
                ret = AVERROR(EINVAL);
                goto fail;
            }
            subtoken = av_strtok(NULL, "|", &subptr);
        }
        av_freep(&submix_str);
 
        if (!submix->nb_elements) {
            av_log(mux, AV_LOG_ERROR, "No audio elements in submix specification \"%s\"\n", token);
            ret = AVERROR(EINVAL);
        }
        token = av_strtok(NULL, ",", &ptr);
    }
 
fail:
    av_dict_free(&dict);
    av_free(submix_str);
 
    return ret;
}
 
static int of_serialize_options(Muxer *mux, void *obj, AVBPrint *bp)
{
    char *ptr;
    int ret;
 
    ret = av_opt_serialize(obj, 0, AV_OPT_SERIALIZE_SKIP_DEFAULTS | AV_OPT_SERIALIZE_SEARCH_CHILDREN,
                           &ptr, '=', ':');
    if (ret < 0) {
        av_log(mux, AV_LOG_ERROR, "Failed to serialize group\n");
        return ret;
    }
 
    av_bprintf(bp, "%s", ptr);
    ret = strlen(ptr);
    av_free(ptr);
 
    return ret;
}
 
#define SERIALIZE(parent, child) do {                   \
    ret = of_serialize_options(mux, parent->child, bp); \
    if (ret < 0)                                        \
        return ret;                                     \
} while (0)
 
#define SERIALIZE_LOOP_SUBBLOCK(obj) do {                                \
    for (int k = 0; k < obj->nb_subblocks; k++) {                        \
        ret = of_serialize_options(mux,                                  \
                  av_iamf_param_definition_get_subblock(obj, k), bp);    \
        if (ret < 0)                                                     \
            return ret;                                                  \
    }                                                                    \
} while (0)
 
#define SERIALIZE_LOOP(parent, child, suffix, separator) do {            \
    for (int j = 0; j < parent->nb_## child ## suffix; j++) {            \
        av_bprintf(bp, separator#child "=");                             \
        SERIALIZE(parent, child ## suffix[j]);                           \
    }                                                                    \
} while (0)
 
static int64_t get_stream_group_index_from_id(Muxer *mux, int64_t id)
{
    AVFormatContext *oc = mux->fc;
 
    for (unsigned i = 0; i < oc->nb_stream_groups; i++)
        if (oc->stream_groups[i]->id == id)
            return oc->stream_groups[i]->index;
 
    return AVERROR(EINVAL);
}
 
static int of_map_group(Muxer *mux, AVDictionary **dict, AVBPrint *bp, const char *map)
{
    AVStreamGroup *stg;
    int ret, file_idx, stream_idx;
    char *ptr;
 
    file_idx = strtol(map, &ptr, 0);
    if (file_idx >= nb_input_files || file_idx < 0 || map == ptr) {
        av_log(mux, AV_LOG_ERROR, "Invalid input file index: %d.\n", file_idx);
        return AVERROR(EINVAL);
    }
 
    stream_idx = strtol(*ptr == '=' ? ptr + 1 : ptr, &ptr, 0);
    if (*ptr || stream_idx >= input_files[file_idx]->ctx->nb_stream_groups || stream_idx < 0) {
        av_log(mux, AV_LOG_ERROR, "Invalid input stream group index: %d.\n", stream_idx);
        return AVERROR(EINVAL);
    }
 
    stg = input_files[file_idx]->ctx->stream_groups[stream_idx];
    ret = of_serialize_options(mux, stg, bp);
    if (ret < 0)
       return ret;
 
    ret = av_dict_parse_string(dict, bp->str, "=", ":", 0);
    if (ret < 0)
        av_log(mux, AV_LOG_ERROR, "Error parsing mapped group specification %s\n", ptr);
    av_dict_set_int(dict, "type", stg->type, 0);
 
    av_bprint_clear(bp);
    switch(stg->type) {
    case AV_STREAM_GROUP_PARAMS_IAMF_AUDIO_ELEMENT: {
        AVIAMFAudioElement *audio_element = stg->params.iamf_audio_element;
 
        if (audio_element->demixing_info) {
            AVIAMFParamDefinition *demixing_info = audio_element->demixing_info;
            av_bprintf(bp, ",demixing=");
            SERIALIZE(audio_element, demixing_info);
            if (ret && demixing_info->nb_subblocks)
                av_bprintf(bp, ":");
            SERIALIZE_LOOP_SUBBLOCK(demixing_info);
        }
        if (audio_element->recon_gain_info) {
            AVIAMFParamDefinition *recon_gain_info = audio_element->recon_gain_info;
            av_bprintf(bp, ",recon_gain=");
            SERIALIZE(audio_element, recon_gain_info);
            if (ret && recon_gain_info->nb_subblocks)
                av_bprintf(bp, ":");
            SERIALIZE_LOOP_SUBBLOCK(recon_gain_info);
        }
        SERIALIZE_LOOP(audio_element, layer, s, ",");
        break;
    }
    case AV_STREAM_GROUP_PARAMS_IAMF_MIX_PRESENTATION: {
        AVIAMFMixPresentation *mix = stg->params.iamf_mix_presentation;
 
        for (int i = 0; i < mix->nb_submixes; i++) {
            AVIAMFSubmix *submix = mix->submixes[i];
            AVIAMFParamDefinition *output_mix_config = submix->output_mix_config;
 
            av_bprintf(bp, ",submix=");
            SERIALIZE(mix, submixes[i]);
            if (ret && output_mix_config->nb_subblocks)
                av_bprintf(bp, ":");
            SERIALIZE_LOOP_SUBBLOCK(output_mix_config);
            for (int j = 0; j < submix->nb_elements; j++) {
                AVIAMFSubmixElement *element = submix->elements[j];
                AVIAMFParamDefinition *element_mix_config = element->element_mix_config;
                int64_t id = get_stream_group_index_from_id(mux, element->audio_element_id);
 
                if (id < 0) {
                    av_log(mux, AV_LOG_ERROR, "Invalid or missing stream group index in"
                                              "submix element");
                    return id;
                }
 
                av_bprintf(bp, "|element=");
                SERIALIZE(submix, elements[j]);
                if (ret && element_mix_config->nb_subblocks)
                    av_bprintf(bp, ":");
                SERIALIZE_LOOP_SUBBLOCK(element_mix_config);
                if (ret)
                    av_bprintf(bp, ":");
                av_bprintf(bp, "stg=%"PRId64, id);
            }
            SERIALIZE_LOOP(submix, layout, s, "|");
        }
        break;
    }
    default:
        av_log(mux, AV_LOG_ERROR, "Unsupported mapped group type %d.\n", stg->type);
        ret = AVERROR(EINVAL);
        break;
    }
    return 0;
}
 
static int of_parse_group_token(Muxer *mux, const char *token, char *ptr)
{
    AVFormatContext *oc = mux->fc;
    AVStreamGroup *stg;
    AVDictionary *dict = NULL, *tmp = NULL;
    char *mapped_string = NULL;
    const AVDictionaryEntry *e;
    const AVOption opts[] = {
        { "type", "Set group type", offsetof(AVStreamGroup, type), AV_OPT_TYPE_INT,
                { .i64 = 0 }, 0, INT_MAX, AV_OPT_FLAG_ENCODING_PARAM, .unit = "type" },
            { "iamf_audio_element",    NULL, 0, AV_OPT_TYPE_CONST,
                { .i64 = AV_STREAM_GROUP_PARAMS_IAMF_AUDIO_ELEMENT },    .unit = "type" },
            { "iamf_mix_presentation", NULL, 0, AV_OPT_TYPE_CONST,
                { .i64 = AV_STREAM_GROUP_PARAMS_IAMF_MIX_PRESENTATION }, .unit = "type" },
        { NULL },
    };
    const AVClass class = {
        .class_name = "StreamGroupType",
        .item_name  = av_default_item_name,
        .option     = opts,
        .version    = LIBAVUTIL_VERSION_INT,
    };
    const AVClass *pclass = &class;
    int type, ret;
 
    ret = av_dict_parse_string(&dict, token, "=", ":", AV_DICT_MULTIKEY);
    if (ret < 0) {
        av_log(mux, AV_LOG_ERROR, "Error parsing group specification %s\n", token);
        return ret;
    }
 
    av_dict_copy(&tmp, dict, 0);
    e = av_dict_get(dict, "map", NULL, 0);
    if (e) {
        AVBPrint bp;
 
        if (ptr) {
            av_log(mux, AV_LOG_ERROR, "Unexpected extra parameters when mapping a"
                                      " stream group\n");
            ret = AVERROR(EINVAL);
            goto end;
        }
 
        av_bprint_init(&bp, 0, AV_BPRINT_SIZE_AUTOMATIC);
        ret = of_map_group(mux, &tmp, &bp, e->value);
        if (ret < 0) {
            av_bprint_finalize(&bp, NULL);
            goto end;
        }
 
        av_bprint_finalize(&bp, &mapped_string);
        ptr = mapped_string;
    }
 
    // "type" is not a user settable AVOption in AVStreamGroup, so handle it here
    e = av_dict_get(tmp, "type", NULL, 0);
    if (!e) {
        av_log(mux, AV_LOG_ERROR, "No type specified for Stream Group in \"%s\"\n", token);
        ret = AVERROR(EINVAL);
        goto end;
    }
 
    ret = av_opt_eval_int(&pclass, opts, e->value, &type);
    if (!ret && type == AV_STREAM_GROUP_PARAMS_NONE)
        ret = AVERROR(EINVAL);
    if (ret < 0) {
        av_log(mux, AV_LOG_ERROR, "Invalid group type \"%s\"\n", e->value);
        goto end;
    }
 
    stg = avformat_stream_group_create(oc, type, &tmp);
    if (!stg) {
        ret = AVERROR(ENOMEM);
        goto end;
    }
 
    e = NULL;
    while (e = av_dict_get(dict, "st", e, 0)) {
        char *endptr;
        int64_t idx = strtoll(e->value, &endptr, 0);
        if (*endptr || idx < 0 || idx >= oc->nb_streams) {
            av_log(mux, AV_LOG_ERROR, "Invalid stream index %"PRId64"\n", idx);
            ret = AVERROR(EINVAL);
            goto end;
        }
        ret = avformat_stream_group_add_stream(stg, oc->streams[idx]);
        if (ret < 0)
            goto end;
    }
    while (e = av_dict_get(dict, "stg", e, 0)) {
        char *endptr;
        int64_t idx = strtoll(e->value, &endptr, 0);
        if (*endptr || idx < 0 || idx >= oc->nb_stream_groups - 1) {
            av_log(mux, AV_LOG_ERROR, "Invalid stream group index %"PRId64"\n", idx);
            ret = AVERROR(EINVAL);
            goto end;
        }
        for (unsigned i = 0; i < oc->stream_groups[idx]->nb_streams; i++) {
            ret = avformat_stream_group_add_stream(stg, oc->stream_groups[idx]->streams[i]);
            if (ret < 0)
                goto end;
        }
    }
 
    switch(type) {
    case AV_STREAM_GROUP_PARAMS_IAMF_AUDIO_ELEMENT:
        ret = of_parse_iamf_audio_element_layers(mux, stg, ptr);
        break;
    case AV_STREAM_GROUP_PARAMS_IAMF_MIX_PRESENTATION:
        ret = of_parse_iamf_submixes(mux, stg, ptr);
        break;
    default:
        av_log(mux, AV_LOG_FATAL, "Unknown group type %d.\n", type);
        ret = AVERROR(EINVAL);
        break;
    }
 
    if (ret < 0)
        goto end;
 
    // make sure that nothing but "st" and "stg" entries are left in the dict
    e = NULL;
    av_dict_set(&tmp, "map", NULL, 0);
    av_dict_set(&tmp, "type", NULL, 0);
    while (e = av_dict_iterate(tmp, e)) {
        if (!strcmp(e->key, "st") || !strcmp(e->key, "stg"))
            continue;
 
        av_log(mux, AV_LOG_FATAL, "Unknown group key %s.\n", e->key);
        ret = AVERROR(EINVAL);
        goto end;
    }
 
    ret = 0;
end:
    av_free(mapped_string);
    av_dict_free(&dict);
    av_dict_free(&tmp);
 
    return ret;
}
 
static int of_add_groups(Muxer *mux, const OptionsContext *o)
{
    /* process manually set groups */
    for (int i = 0; i < o->stream_groups.nb_opt; i++) {
        const char *token;
        char *str, *ptr = NULL;
        int ret = 0;
 
        str = av_strdup(o->stream_groups.opt[i].u.str);
        if (!str)
            return ret;
 
        token = av_strtok(str, ",", &ptr);
        if (token) {
            if (ptr)
                ptr += strspn(ptr, " \n\t\r");
            ret = of_parse_group_token(mux, token, ptr);
        }
 
        av_free(str);
        if (ret < 0)
            return ret;
    }
 
    return 0;
}
 
static int of_add_programs(Muxer *mux, const OptionsContext *o)
{
    AVFormatContext *oc = mux->fc;
    /* process manually set programs */
    for (int i = 0; i < o->program.nb_opt; i++) {
        AVDictionary *dict = NULL;
        const AVDictionaryEntry *e;
        AVProgram *program;
        int ret, progid = i + 1;
 
        ret = av_dict_parse_string(&dict, o->program.opt[i].u.str, "=", ":",
                                   AV_DICT_MULTIKEY);
        if (ret < 0) {
            av_log(mux, AV_LOG_ERROR, "Error parsing program specification %s\n",
                   o->program.opt[i].u.str);
            return ret;
        }
 
        e = av_dict_get(dict, "program_num", NULL, 0);
        if (e) {
            progid = strtol(e->value, NULL, 0);
            av_dict_set(&dict, e->key, NULL, 0);
        }
 
        program = av_new_program(oc, progid);
        if (!program) {
            ret = AVERROR(ENOMEM);
            goto fail;
        }
 
        e = av_dict_get(dict, "title", NULL, 0);
        if (e) {
            av_dict_set(&program->metadata, e->key, e->value, 0);
            av_dict_set(&dict, e->key, NULL, 0);
        }
 
        e = NULL;
        while (e = av_dict_get(dict, "st", e, 0)) {
            int st_num = strtol(e->value, NULL, 0);
            av_program_add_stream_index(oc, progid, st_num);
        }
 
        // make sure that nothing but "st" entries are left in the dict
        e = NULL;
        while (e = av_dict_iterate(dict, e)) {
            if (!strcmp(e->key, "st"))
                continue;
 
            av_log(mux, AV_LOG_FATAL, "Unknown program key %s.\n", e->key);
            ret = AVERROR(EINVAL);
            goto fail;
        }
 
fail:
        av_dict_free(&dict);
        if (ret < 0)
            return ret;
    }
 
    return 0;
}
 
/**
 * Parse a metadata specifier passed as 'arg' parameter.
 * @param arg  metadata string to parse
 * @param type metadata type is written here -- g(lobal)/s(tream)/c(hapter)/p(rogram)
 * @param index for type c/p, chapter/program index is written here
 * @param stream_spec for type s, the stream specifier is written here
 */
static int parse_meta_type(void *logctx, const char *arg,
                           char *type, int *index, const char **stream_spec)
{
    if (*arg) {
        *type = *arg;
        switch (*arg) {
        case 'g':
            break;
        case 's':
            if (*(++arg) && *arg != ':') {
                av_log(logctx, AV_LOG_FATAL, "Invalid metadata specifier %s.\n", arg);
                return AVERROR(EINVAL);
            }
            *stream_spec = *arg == ':' ? arg + 1 : "";
            break;
        case 'c':
        case 'p':
            if (*(++arg) == ':')
                *index = strtol(++arg, NULL, 0);
            break;
        default:
            av_log(logctx, AV_LOG_FATAL, "Invalid metadata type %c.\n", *arg);
            return AVERROR(EINVAL);
        }
    } else
        *type = 'g';
 
    return 0;
}
 
static int of_add_metadata(OutputFile *of, AVFormatContext *oc,
                           const OptionsContext *o)
{
    for (int i = 0; i < o->metadata.nb_opt; i++) {
        AVDictionary **m;
        char type, *val;
        const char *stream_spec;
        int index = 0, ret = 0;
 
        val = strchr(o->metadata.opt[i].u.str, '=');
        if (!val) {
            av_log(of, AV_LOG_FATAL, "No '=' character in metadata string %s.\n",
                   o->metadata.opt[i].u.str);
            return AVERROR(EINVAL);
        }
        *val++ = 0;
 
        ret = parse_meta_type(of, o->metadata.opt[i].specifier, &type, &index, &stream_spec);
        if (ret < 0)
            return ret;
 
        if (type == 's') {
            for (int j = 0; j < oc->nb_streams; j++) {
                if ((ret = check_stream_specifier(oc, oc->streams[j], stream_spec)) > 0) {
                    av_dict_set(&oc->streams[j]->metadata, o->metadata.opt[i].u.str, *val ? val : NULL, 0);
                } else if (ret < 0)
                    return ret;
            }
        } else {
            switch (type) {
            case 'g':
                m = &oc->metadata;
                break;
            case 'c':
                if (index < 0 || index >= oc->nb_chapters) {
                    av_log(of, AV_LOG_FATAL, "Invalid chapter index %d in metadata specifier.\n", index);
                    return AVERROR(EINVAL);
                }
                m = &oc->chapters[index]->metadata;
                break;
            case 'p':
                if (index < 0 || index >= oc->nb_programs) {
                    av_log(of, AV_LOG_FATAL, "Invalid program index %d in metadata specifier.\n", index);
                    return AVERROR(EINVAL);
                }
                m = &oc->programs[index]->metadata;
                break;
            default:
                av_log(of, AV_LOG_FATAL, "Invalid metadata specifier %s.\n", o->metadata.opt[i].specifier);
                return AVERROR(EINVAL);
            }
            av_dict_set(m, o->metadata.opt[i].u.str, *val ? val : NULL, 0);
        }
    }
 
    return 0;
}
 
static int copy_chapters(InputFile *ifile, OutputFile *ofile, AVFormatContext *os,
                         int copy_metadata)
{
    AVFormatContext *is = ifile->ctx;
    AVChapter **tmp;
 
    tmp = av_realloc_f(os->chapters, is->nb_chapters + os->nb_chapters, sizeof(*os->chapters));
    if (!tmp)
        return AVERROR(ENOMEM);
    os->chapters = tmp;
 
    for (int i = 0; i < is->nb_chapters; i++) {
        AVChapter *in_ch = is->chapters[i], *out_ch;
        int64_t start_time = (ofile->start_time == AV_NOPTS_VALUE) ? 0 : ofile->start_time;
        int64_t ts_off   = av_rescale_q(start_time - ifile->ts_offset,
                                       AV_TIME_BASE_Q, in_ch->time_base);
        int64_t rt       = (ofile->recording_time == INT64_MAX) ? INT64_MAX :
                           av_rescale_q(ofile->recording_time, AV_TIME_BASE_Q, in_ch->time_base);
 
 
        if (in_ch->end < ts_off)
            continue;
        if (rt != INT64_MAX && in_ch->start > rt + ts_off)
            break;
 
        out_ch = av_mallocz(sizeof(AVChapter));
        if (!out_ch)
            return AVERROR(ENOMEM);
 
        out_ch->id        = in_ch->id;
        out_ch->time_base = in_ch->time_base;
        out_ch->start     = FFMAX(0,  in_ch->start - ts_off);
        out_ch->end       = FFMIN(rt, in_ch->end   - ts_off);
 
        if (copy_metadata)
            av_dict_copy(&out_ch->metadata, in_ch->metadata, 0);
 
        os->chapters[os->nb_chapters++] = out_ch;
    }
    return 0;
}
 
static int copy_metadata(Muxer *mux, AVFormatContext *ic,
                         const char *outspec, const char *inspec,
                         int *metadata_global_manual, int *metadata_streams_manual,
                         int *metadata_chapters_manual)
{
    AVFormatContext *oc = mux->fc;
    AVDictionary **meta_in = NULL;
    AVDictionary **meta_out = NULL;
    int i, ret = 0;
    char type_in, type_out;
    const char *istream_spec = NULL, *ostream_spec = NULL;
    int idx_in = 0, idx_out = 0;
 
    ret     = parse_meta_type(mux, inspec,  &type_in,  &idx_in,  &istream_spec);
    if (ret >= 0)
        ret = parse_meta_type(mux, outspec, &type_out, &idx_out, &ostream_spec);
    if (ret < 0)
        return ret;
 
    if (type_in == 'g' || type_out == 'g' || (!*outspec && !ic))
        *metadata_global_manual = 1;
    if (type_in == 's' || type_out == 's' || (!*outspec && !ic))
        *metadata_streams_manual = 1;
    if (type_in == 'c' || type_out == 'c' || (!*outspec && !ic))
        *metadata_chapters_manual = 1;
 
    /* ic is NULL when just disabling automatic mappings */
    if (!ic)
        return 0;
 
#define METADATA_CHECK_INDEX(index, nb_elems, desc)\
    if ((index) < 0 || (index) >= (nb_elems)) {\
        av_log(mux, AV_LOG_FATAL, "Invalid %s index %d while processing metadata maps.\n",\
                (desc), (index));\
        return AVERROR(EINVAL);\
    }
 
#define SET_DICT(type, meta, context, index)\
        switch (type) {\
        case 'g':\
            meta = &context->metadata;\
            break;\
        case 'c':\
            METADATA_CHECK_INDEX(index, context->nb_chapters, "chapter")\
            meta = &context->chapters[index]->metadata;\
            break;\
        case 'p':\
            METADATA_CHECK_INDEX(index, context->nb_programs, "program")\
            meta = &context->programs[index]->metadata;\
            break;\
        case 's':\
            break; /* handled separately below */ \
        default: av_assert0(0);\
        }\
 
    SET_DICT(type_in, meta_in, ic, idx_in);
    SET_DICT(type_out, meta_out, oc, idx_out);
 
    /* for input streams choose first matching stream */
    if (type_in == 's') {
        for (i = 0; i < ic->nb_streams; i++) {
            if ((ret = check_stream_specifier(ic, ic->streams[i], istream_spec)) > 0) {
                meta_in = &ic->streams[i]->metadata;
                break;
            } else if (ret < 0)
                return ret;
        }
        if (!meta_in) {
            av_log(mux, AV_LOG_FATAL, "Stream specifier %s does not match  any streams.\n", istream_spec);
            return AVERROR(EINVAL);
        }
    }
 
    if (type_out == 's') {
        for (i = 0; i < oc->nb_streams; i++) {
            if ((ret = check_stream_specifier(oc, oc->streams[i], ostream_spec)) > 0) {
                meta_out = &oc->streams[i]->metadata;
                av_dict_copy(meta_out, *meta_in, AV_DICT_DONT_OVERWRITE);
            } else if (ret < 0)
                return ret;
        }
    } else
        av_dict_copy(meta_out, *meta_in, AV_DICT_DONT_OVERWRITE);
 
    return 0;
}
 
static int copy_meta(Muxer *mux, const OptionsContext *o)
{
    OutputFile      *of = &mux->of;
    AVFormatContext *oc = mux->fc;
    int chapters_input_file = o->chapters_input_file;
    int metadata_global_manual   = 0;
    int metadata_streams_manual  = 0;
    int metadata_chapters_manual = 0;
    int ret;
 
    /* copy metadata */
    for (int i = 0; i < o->metadata_map.nb_opt; i++) {
        char *p;
        int in_file_index = strtol(o->metadata_map.opt[i].u.str, &p, 0);
 
        if (in_file_index >= nb_input_files) {
            av_log(mux, AV_LOG_FATAL, "Invalid input file index %d while "
                   "processing metadata maps\n", in_file_index);
            return AVERROR(EINVAL);
        }
        ret = copy_metadata(mux,
                            in_file_index >= 0 ? input_files[in_file_index]->ctx : NULL,
                            o->metadata_map.opt[i].specifier, *p ? p + 1 : p,
                            &metadata_global_manual, &metadata_streams_manual,
                            &metadata_chapters_manual);
        if (ret < 0)
            return ret;
    }
 
    /* copy chapters */
    if (chapters_input_file >= nb_input_files) {
        if (chapters_input_file == INT_MAX) {
            /* copy chapters from the first input file that has them*/
            chapters_input_file = -1;
            for (int i = 0; i < nb_input_files; i++)
                if (input_files[i]->ctx->nb_chapters) {
                    chapters_input_file = i;
                    break;
                }
        } else {
            av_log(mux, AV_LOG_FATAL, "Invalid input file index %d in chapter mapping.\n",
                   chapters_input_file);
            return AVERROR(EINVAL);
        }
    }
    if (chapters_input_file >= 0)
        copy_chapters(input_files[chapters_input_file], of, oc,
                      !metadata_chapters_manual);
 
    /* copy global metadata by default */
    if (!metadata_global_manual && nb_input_files){
        av_dict_copy(&oc->metadata, input_files[0]->ctx->metadata,
                     AV_DICT_DONT_OVERWRITE);
        if (of->recording_time != INT64_MAX)
            av_dict_set(&oc->metadata, "duration", NULL, 0);
        av_dict_set(&oc->metadata, "creation_time", NULL, 0);
        av_dict_set(&oc->metadata, "company_name", NULL, 0);
        av_dict_set(&oc->metadata, "product_name", NULL, 0);
        av_dict_set(&oc->metadata, "product_version", NULL, 0);
    }
    if (!metadata_streams_manual)
        for (int i = 0; i < of->nb_streams; i++) {
            OutputStream *ost = of->streams[i];
 
            if (!ost->ist)         /* this is true e.g. for attached files */
                continue;
            av_dict_copy(&ost->st->metadata, ost->ist->st->metadata, AV_DICT_DONT_OVERWRITE);
            if (ost->enc_ctx) {
                av_dict_set(&ost->st->metadata, "encoder", NULL, 0);
            }
        }
 
    return 0;
}
 
static int set_dispositions(Muxer *mux, const OptionsContext *o)
{
    OutputFile                    *of = &mux->of;
    AVFormatContext              *ctx = mux->fc;
 
    // indexed by type+1, because AVMEDIA_TYPE_UNKNOWN=-1
    int nb_streams[AVMEDIA_TYPE_NB + 1]   = { 0 };
    int have_default[AVMEDIA_TYPE_NB + 1] = { 0 };
    int have_manual = 0;
    int ret = 0;
 
    const char **dispositions;
 
    dispositions = av_calloc(ctx->nb_streams, sizeof(*dispositions));
    if (!dispositions)
        return AVERROR(ENOMEM);
 
    // first, copy the input dispositions
    for (int i = 0; i < ctx->nb_streams; i++) {
        OutputStream *ost = of->streams[i];
 
        nb_streams[ost->type + 1]++;
 
        opt_match_per_stream_str(ost, &o->disposition, ctx, ost->st, &dispositions[i]);
 
        have_manual |= !!dispositions[i];
 
        if (ost->ist) {
            ost->st->disposition = ost->ist->st->disposition;
 
            if (ost->st->disposition & AV_DISPOSITION_DEFAULT)
                have_default[ost->type + 1] = 1;
        }
    }
 
    if (have_manual) {
        // process manually set dispositions - they override the above copy
        for (int i = 0; i < ctx->nb_streams; i++) {
            OutputStream *ost = of->streams[i];
            const char  *disp = dispositions[i];
 
            if (!disp)
                continue;
 
            ret = av_opt_set(ost->st, "disposition", disp, 0);
            if (ret < 0)
                goto finish;
        }
    } else {
        // For each media type with more than one stream, find a suitable stream to
        // mark as default, unless one is already marked default.
        // "Suitable" means the first of that type, skipping attached pictures.
        for (int i = 0; i < ctx->nb_streams; i++) {
            OutputStream *ost = of->streams[i];
            enum AVMediaType type = ost->type;
 
            if (nb_streams[type + 1] < 2 || have_default[type + 1] ||
                ost->st->disposition & AV_DISPOSITION_ATTACHED_PIC)
                continue;
 
            ost->st->disposition |= AV_DISPOSITION_DEFAULT;
            have_default[type + 1] = 1;
        }
    }
 
finish:
    av_freep(&dispositions);
 
    return ret;
}
 
const char *const forced_keyframes_const_names[] = {
    "n",
    "n_forced",
    "prev_forced_n",
    "prev_forced_t",
    "t",
    NULL
};
 
static int compare_int64(const void *a, const void *b)
{
    return FFDIFFSIGN(*(const int64_t *)a, *(const int64_t *)b);
}
 
static int parse_forced_key_frames(void *log, KeyframeForceCtx *kf,
                                   const Muxer *mux, const char *spec)
{
    const char *p;
    int n = 1, i, ret, size, index = 0;
    int64_t t, *pts;
 
    for (p = spec; *p; p++)
        if (*p == ',')
            n++;
    size = n;
    pts = av_malloc_array(size, sizeof(*pts));
    if (!pts)
        return AVERROR(ENOMEM);
 
    p = spec;
    for (i = 0; i < n; i++) {
        char *next = strchr(p, ',');
 
        if (next)
            *next++ = 0;
 
        if (strstr(p, "chapters") == p) {
            AVChapter * const *ch = mux->fc->chapters;
            unsigned int    nb_ch = mux->fc->nb_chapters;
            int j;
 
            if (nb_ch > INT_MAX - size) {
                ret = AVERROR(ERANGE);
                goto fail;
            }
            size += nb_ch - 1;
            pts = av_realloc_f(pts, size, sizeof(*pts));
            if (!pts)
                return AVERROR(ENOMEM);
 
            if (p[8]) {
                ret = av_parse_time(&t, p + 8, 1);
                if (ret < 0) {
                    av_log(log, AV_LOG_ERROR,
                           "Invalid chapter time offset: %s\n", p + 8);
                    goto fail;
                }
            } else
                t = 0;
 
            for (j = 0; j < nb_ch; j++) {
                const AVChapter *c = ch[j];
                av_assert1(index < size);
                pts[index++] = av_rescale_q(c->start, c->time_base,
                                            AV_TIME_BASE_Q) + t;
            }
 
        } else {
            av_assert1(index < size);
            ret = av_parse_time(&t, p, 1);
            if (ret < 0) {
                av_log(log, AV_LOG_ERROR, "Invalid keyframe time: %s\n", p);
                goto fail;
            }
 
            pts[index++] = t;
        }
 
        p = next;
    }
 
    av_assert0(index == size);
    qsort(pts, size, sizeof(*pts), compare_int64);
    kf->nb_pts = size;
    kf->pts    = pts;
 
    return 0;
fail:
    av_freep(&pts);
    return ret;
}
 
static int process_forced_keyframes(Muxer *mux, const OptionsContext *o)
{
    for (int i = 0; i < mux->of.nb_streams; i++) {
        OutputStream *ost = mux->of.streams[i];
        const char *forced_keyframes = NULL;
 
        opt_match_per_stream_str(ost, &o->forced_key_frames,
                                 mux->fc, ost->st, &forced_keyframes);
 
        if (!(ost->type == AVMEDIA_TYPE_VIDEO &&
              ost->enc_ctx && forced_keyframes))
            continue;
 
        if (!strncmp(forced_keyframes, "expr:", 5)) {
            int ret = av_expr_parse(&ost->kf.pexpr, forced_keyframes + 5,
                                    forced_keyframes_const_names, NULL, NULL, NULL, NULL, 0, NULL);
            if (ret < 0) {
                av_log(ost, AV_LOG_ERROR,
                       "Invalid force_key_frames expression '%s'\n", forced_keyframes + 5);
                return ret;
            }
            ost->kf.expr_const_values[FKF_N]             = 0;
            ost->kf.expr_const_values[FKF_N_FORCED]      = 0;
            ost->kf.expr_const_values[FKF_PREV_FORCED_N] = NAN;
            ost->kf.expr_const_values[FKF_PREV_FORCED_T] = NAN;
 
            // Don't parse the 'forced_keyframes' in case of 'keep-source-keyframes',
            // parse it only for static kf timings
        } else if (!strcmp(forced_keyframes, "source")) {
            ost->kf.type = KF_FORCE_SOURCE;
#if FFMPEG_OPT_FORCE_KF_SOURCE_NO_DROP
        } else if (!strcmp(forced_keyframes, "source_no_drop")) {
            av_log(ost, AV_LOG_WARNING, "The 'source_no_drop' value for "
                   "-force_key_frames is deprecated, use just 'source'\n");
            ost->kf.type = KF_FORCE_SOURCE;
#endif
        } else {
            int ret = parse_forced_key_frames(ost, &ost->kf, mux, forced_keyframes);
            if (ret < 0)
                return ret;
        }
    }
 
    return 0;
}
 
static const char *output_file_item_name(void *obj)
{
    const Muxer *mux = obj;
 
    return mux->log_name;
}
 
static const AVClass output_file_class = {
    .class_name = "OutputFile",
    .version    = LIBAVUTIL_VERSION_INT,
    .item_name  = output_file_item_name,
    .category   = AV_CLASS_CATEGORY_MUXER,
};
 
static Muxer *mux_alloc(void)
{
    Muxer *mux = allocate_array_elem(&output_files, sizeof(*mux), &nb_output_files);
 
    if (!mux)
        return NULL;
 
    mux->of.class = &output_file_class;
    mux->of.index = nb_output_files - 1;
 
    snprintf(mux->log_name, sizeof(mux->log_name), "out#%d", mux->of.index);
 
    return mux;
}
 
int of_open(const OptionsContext *o, const char *filename, Scheduler *sch)
{
    Muxer *mux;
    AVFormatContext *oc;
    int err;
    OutputFile *of;
 
    int64_t recording_time = o->recording_time;
    int64_t stop_time      = o->stop_time;
 
    mux = mux_alloc();
    if (!mux)
        return AVERROR(ENOMEM);
 
    of  = &mux->of;
 
    if (stop_time != INT64_MAX && recording_time != INT64_MAX) {
        stop_time = INT64_MAX;
        av_log(mux, AV_LOG_WARNING, "-t and -to cannot be used together; using -t.\n");
    }
 
    if (stop_time != INT64_MAX && recording_time == INT64_MAX) {
        int64_t start_time = o->start_time == AV_NOPTS_VALUE ? 0 : o->start_time;
        if (stop_time <= start_time) {
            av_log(mux, AV_LOG_ERROR, "-to value smaller than -ss; aborting.\n");
            return AVERROR(EINVAL);
        } else {
            recording_time = stop_time - start_time;
        }
    }
 
    of->recording_time = recording_time;
    of->start_time     = o->start_time;
 
    mux->limit_filesize    = o->limit_filesize;
    av_dict_copy(&mux->opts, o->g->format_opts, 0);
 
    if (!strcmp(filename, "-"))
        filename = "pipe:";
 
    err = avformat_alloc_output_context2(&oc, NULL, o->format, filename);
    if (!oc) {
        av_log(mux, AV_LOG_FATAL, "Error initializing the muxer for %s: %s\n",
               filename, av_err2str(err));
        return err;
    }
    mux->fc = oc;
 
    av_strlcat(mux->log_name, "/",               sizeof(mux->log_name));
    av_strlcat(mux->log_name, oc->oformat->name, sizeof(mux->log_name));
 
 
    if (recording_time != INT64_MAX)
        oc->duration = recording_time;
 
    oc->interrupt_callback = int_cb;
 
    if (o->bitexact) {
        oc->flags    |= AVFMT_FLAG_BITEXACT;
        of->bitexact  = 1;
    } else {
        of->bitexact  = check_opt_bitexact(oc, mux->opts, "fflags",
                                           AVFMT_FLAG_BITEXACT);
    }
 
    err = sch_add_mux(sch, muxer_thread, mux_check_init, mux,
                      !strcmp(oc->oformat->name, "rtp"), o->thread_queue_size);
    if (err < 0)
        return err;
    mux->sch     = sch;
    mux->sch_idx = err;
 
    /* create all output streams for this file */
    err = create_streams(mux, o);
    if (err < 0)
        return err;
 
    /* check if all codec options have been used */
    err = check_avoptions_used(o->g->codec_opts, mux->enc_opts_used, mux, 0);
    av_dict_free(&mux->enc_opts_used);
    if (err < 0)
        return err;
 
    /* check filename in case of an image number is expected */
    if (oc->oformat->flags & AVFMT_NEEDNUMBER && !av_filename_number_test(oc->url)) {
        av_log(mux, AV_LOG_FATAL,
               "Output filename '%s' does not contain a numeric pattern like "
               "'%%d', which is required by output format '%s'.\n",
               oc->url, oc->oformat->name);
        return AVERROR(EINVAL);
    }
 
    if (!(oc->oformat->flags & AVFMT_NOFILE)) {
        /* test if it already exists to avoid losing precious files */
        err = assert_file_overwrite(filename);
        if (err < 0)
            return err;
 
        /* open the file */
        if ((err = avio_open2(&oc->pb, filename, AVIO_FLAG_WRITE,
                              &oc->interrupt_callback,
                              &mux->opts)) < 0) {
            av_log(mux, AV_LOG_FATAL, "Error opening output %s: %s\n",
                   filename, av_err2str(err));
            return err;
        }
    } else if (strcmp(oc->oformat->name, "image2")==0 && !av_filename_number_test(filename)) {
        err = assert_file_overwrite(filename);
        if (err < 0)
            return err;
    }
 
    if (o->mux_preload) {
        av_dict_set_int(&mux->opts, "preload", o->mux_preload*AV_TIME_BASE, 0);
    }
    oc->max_delay = (int)(o->mux_max_delay * AV_TIME_BASE);
 
    /* copy metadata and chapters from input files */
    err = copy_meta(mux, o);
    if (err < 0)
        return err;
 
    err = of_add_groups(mux, o);
    if (err < 0)
        return err;
 
    err = of_add_programs(mux, o);
    if (err < 0)
        return err;
 
    err = of_add_metadata(of, oc, o);
    if (err < 0)
        return err;
 
    err = set_dispositions(mux, o);
    if (err < 0) {
        av_log(mux, AV_LOG_FATAL, "Error setting output stream dispositions\n");
        return err;
    }
 
    // parse forced keyframe specifications;
    // must be done after chapters are created
    err = process_forced_keyframes(mux, o);
    if (err < 0) {
        av_log(mux, AV_LOG_FATAL, "Error processing forced keyframes\n");
        return err;
    }
 
    err = setup_sync_queues(mux, oc, o->shortest_buf_duration * AV_TIME_BASE,
                            o->shortest);
    if (err < 0) {
        av_log(mux, AV_LOG_FATAL, "Error setting up output sync queues\n");
        return err;
    }
 
    of->url        = filename;
 
    /* initialize streamcopy streams. */
    for (int i = 0; i < of->nb_streams; i++) {
        OutputStream *ost = of->streams[i];
 
        if (!ost->enc) {
            err = of_stream_init(of, ost);
            if (err < 0)
                return err;
        }
    }
 
    return 0;
}