avformat.c

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/*
 * Various functions used by both muxers and demuxers
 * Copyright (c) 2000, 2001, 2002 Fabrice Bellard
 *
 * 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 "config_components.h"
 
#include <math.h>
#include "libavutil/avassert.h"
#include "libavutil/avstring.h"
#include "libavutil/channel_layout.h"
#include "libavutil/frame.h"
#include "libavutil/iamf.h"
#include "libavutil/mem.h"
#include "libavutil/opt.h"
#include "libavutil/pixfmt.h"
#include "libavutil/samplefmt.h"
#include "libavcodec/avcodec.h"
#include "libavcodec/codec.h"
#include "libavcodec/bsf.h"
#include "libavcodec/codec_desc.h"
#include "packet_internal.h"
#include "avformat.h"
#include "avformat_internal.h"
#include "avio.h"
#include "demux.h"
#include "mux.h"
#include "internal.h"
#include "url.h"
 
void ff_free_stream(AVStream **pst)
{
    AVStream *st = *pst;
    FFStream *const sti = ffstream(st);
 
    if (!st)
        return;
 
    if (st->attached_pic.data)
        av_packet_unref(&st->attached_pic);
 
    av_parser_close(sti->parser);
    avcodec_free_context(&sti->avctx);
    av_bsf_free(&sti->bsfc);
    av_freep(&sti->index_entries);
    av_freep(&sti->probe_data.buf);
 
    av_packet_free(&sti->parse_pkt);
 
    av_bsf_free(&sti->extract_extradata.bsf);
 
    if (sti->info) {
        av_freep(&sti->info->duration_error);
        av_freep(&sti->info);
    }
 
    av_dict_free(&st->metadata);
    avcodec_parameters_free(&st->codecpar);
    av_freep(&st->priv_data);
 
    av_freep(pst);
}
 
void ff_free_stream_group(AVStreamGroup **pstg)
{
    AVStreamGroup *stg = *pstg;
 
    if (!stg)
        return;
 
#if FF_API_STREAM_GROUP_ENTRIES
FF_DISABLE_DEPRECATION_WARNINGS
    av_freep(&stg->streams);
FF_ENABLE_DEPRECATION_WARNINGS
#endif
    for (int i = 0; i < stg->nb_entries; i++)
        av_freep(&stg->entries[i]);
    av_freep(&stg->entries);
    av_packet_side_data_free(&stg->coded_side_data,
                             &stg->nb_coded_side_data);
    av_dict_free(&stg->metadata);
    av_freep(&stg->priv_data);
    switch (stg->type) {
    case AV_STREAM_GROUP_PARAMS_IAMF_AUDIO_ELEMENT: {
        av_iamf_audio_element_free(&stg->params.iamf_audio_element);
        break;
    }
    case AV_STREAM_GROUP_PARAMS_IAMF_MIX_PRESENTATION: {
        av_iamf_mix_presentation_free(&stg->params.iamf_mix_presentation);
        break;
    }
    case AV_STREAM_GROUP_PARAMS_TILE_GRID:
        av_opt_free(stg->params.tile_grid);
        av_freep(&stg->params.tile_grid->offsets);
#if FF_API_STREAM_GROUP_ENTRIES
FF_DISABLE_DEPRECATION_WARNINGS
        av_packet_side_data_free(&stg->params.tile_grid->coded_side_data,
                                 &stg->params.tile_grid->nb_coded_side_data);
FF_ENABLE_DEPRECATION_WARNINGS
#endif
        av_freep(&stg->params.tile_grid);
        break;
    case AV_STREAM_GROUP_PARAMS_TREF:
        av_opt_free(stg->params.tref);
        av_freep(&stg->params.tref);
        break;
    case AV_STREAM_GROUP_PARAMS_LCEVC:
    case AV_STREAM_GROUP_PARAMS_DOLBY_VISION:
    case AV_STREAM_GROUP_PARAMS_GAIN_MAP:
    case AV_STREAM_GROUP_PARAMS_ALPHA:
        av_opt_free(stg->params.layered_video);
        av_freep(&stg->params.layered_video);
        break;
    default:
        break;
    }
 
    av_freep(pstg);
}
 
void ff_remove_stream(AVFormatContext *s, AVStream *st)
{
    av_assert0(s->nb_streams>0);
    av_assert0(s->streams[ s->nb_streams - 1 ] == st);
 
    ff_free_stream(&s->streams[ --s->nb_streams ]);
}
 
void ff_remove_stream_group(AVFormatContext *s, AVStreamGroup *stg)
{
    av_assert0(s->nb_stream_groups > 0);
    av_assert0(s->stream_groups[ s->nb_stream_groups - 1 ] == stg);
 
    ff_free_stream_group(&s->stream_groups[ --s->nb_stream_groups ]);
}
 
/* XXX: suppress the packet queue */
void ff_flush_packet_queue(AVFormatContext *s)
{
    FormatContextInternal *const fci = ff_fc_internal(s);
    FFFormatContext *const si = &fci->fc;
    ff_packet_list_free(&fci->parse_queue);
    ff_packet_list_free(&si->packet_buffer);
    ff_packet_list_free(&fci->raw_packet_buffer);
 
    fci->raw_packet_buffer_size = 0;
}
 
void avformat_free_context(AVFormatContext *s)
{
    FormatContextInternal *fci;
    FFFormatContext *si;
 
    if (!s)
        return;
    fci = ff_fc_internal(s);
    si  = &fci->fc;
 
    if (s->oformat && ffofmt(s->oformat)->deinit && fci->initialized)
        ffofmt(s->oformat)->deinit(s);
 
    av_opt_free(s);
    if (s->iformat && s->iformat->priv_class && s->priv_data)
        av_opt_free(s->priv_data);
    if (s->oformat && s->oformat->priv_class && s->priv_data)
        av_opt_free(s->priv_data);
 
    for (unsigned i = 0; i < s->nb_streams; i++)
        ff_free_stream(&s->streams[i]);
    for (unsigned i = 0; i < s->nb_stream_groups; i++)
        ff_free_stream_group(&s->stream_groups[i]);
    s->nb_stream_groups = 0;
    s->nb_streams = 0;
 
    for (unsigned i = 0; i < s->nb_programs; i++) {
        av_dict_free(&s->programs[i]->metadata);
        av_freep(&s->programs[i]->stream_index);
        av_freep(&s->programs[i]);
    }
    s->nb_programs = 0;
 
    av_freep(&s->programs);
    av_freep(&s->priv_data);
    while (s->nb_chapters--) {
        av_dict_free(&s->chapters[s->nb_chapters]->metadata);
        av_freep(&s->chapters[s->nb_chapters]);
    }
    av_freep(&s->chapters);
    av_dict_free(&s->metadata);
    av_dict_free(&si->id3v2_meta);
#if CONFIG_LIBCURL_PROTOCOL
    ff_curl_loop_free(&si->curl_loop);
#endif
    av_packet_free(&si->pkt);
    av_packet_free(&si->parse_pkt);
    ff_packet_list_free(&si->packet_buffer);
    av_freep(&s->streams);
    av_freep(&s->stream_groups);
    if (s->iformat)
        ff_flush_packet_queue(s);
    av_freep(&s->url);
    av_freep(&s->name);
    av_free(s);
}
 
/**
 * Copy all stream parameters from source to destination stream, with the
 * exception of the index field, which is usually set by avformat_new_stream().
 *
 * @param dst pointer to destination AVStream
 * @param src pointer to source AVStream
 * @return >=0 on success, AVERROR code on error
 */
static int stream_params_copy(AVStream *dst, const AVStream *src)
{
    int ret;
 
    dst->id                  = src->id;
    dst->time_base           = src->time_base;
    dst->start_time          = src->start_time;
    dst->duration            = src->duration;
    dst->nb_frames           = src->nb_frames;
    dst->disposition         = src->disposition;
    dst->discard             = src->discard;
    dst->sample_aspect_ratio = src->sample_aspect_ratio;
    dst->avg_frame_rate      = src->avg_frame_rate;
    dst->event_flags         = src->event_flags;
    dst->r_frame_rate        = src->r_frame_rate;
    dst->pts_wrap_bits       = src->pts_wrap_bits;
 
    av_dict_free(&dst->metadata);
    ret = av_dict_copy(&dst->metadata, src->metadata, 0);
    if (ret < 0)
        return ret;
 
    ret = avcodec_parameters_copy(dst->codecpar, src->codecpar);
    if (ret < 0)
        return ret;
 
    av_packet_unref(&dst->attached_pic);
    if (src->attached_pic.data) {
        ret = av_packet_ref(&dst->attached_pic, &src->attached_pic);
        if (ret < 0)
            return ret;
    }
 
    return 0;
}
 
AVStream *ff_stream_clone(AVFormatContext *dst_ctx, const AVStream *src)
{
    AVStream *st;
    int ret;
 
    st = avformat_new_stream(dst_ctx, NULL);
    if (!st)
        return NULL;
 
    ret = stream_params_copy(st, src);
    if (ret < 0) {
        ff_remove_stream(dst_ctx, st);
        return NULL;
    }
 
    return st;
}
 
const char *avformat_stream_group_name(enum AVStreamGroupParamsType type)
{
    switch(type) {
    case AV_STREAM_GROUP_PARAMS_IAMF_AUDIO_ELEMENT:        return "IAMF Audio Element";
    case AV_STREAM_GROUP_PARAMS_IAMF_MIX_PRESENTATION:     return "IAMF Mix Presentation";
    case AV_STREAM_GROUP_PARAMS_TILE_GRID:                 return "Tile Grid";
    case AV_STREAM_GROUP_PARAMS_LCEVC:                     return "LCEVC (Split video and enhancement)";
    case AV_STREAM_GROUP_PARAMS_TREF:                      return "Track Reference";
    case AV_STREAM_GROUP_PARAMS_DOLBY_VISION:              return "Dolby Vision (Split base and enhancement layer)";
    case AV_STREAM_GROUP_PARAMS_GAIN_MAP:                  return "Gain Map (Split base rendition and gain map)";
    case AV_STREAM_GROUP_PARAMS_ALPHA:                     return "Alpha (Split color and alpha channels)";
    }
    return NULL;
}
 
AVProgram *av_new_program(AVFormatContext *ac, int id)
{
    FFFormatContext *const si = ffformatcontext(ac);
    AVProgram *program = NULL;
    int ret;
 
    av_log(ac, AV_LOG_TRACE, "new_program: id=0x%04x\n", id);
 
    if (!ac->nb_programs) {
        si->program_ids_monotonic = 1;
    } else if (!si->program_ids_monotonic || ac->programs[ac->nb_programs - 1]->id >= id) {
        for (unsigned i = 0; i < ac->nb_programs; i++)
            if (ac->programs[i]->id == id)
                program = ac->programs[i];
        if (!program)
            si->program_ids_monotonic = 0;
    }
 
    if (!program) {
        program = av_mallocz(sizeof(*program));
        if (!program)
            return NULL;
        ret = av_dynarray_add_nofree(&ac->programs, &ac->nb_programs, program);
        if (ret < 0) {
            av_free(program);
            return NULL;
        }
        program->discard = AVDISCARD_NONE;
        program->pmt_version = -1;
        program->id = id;
        program->pts_wrap_reference = AV_NOPTS_VALUE;
        program->pts_wrap_behavior = AV_PTS_WRAP_IGNORE;
        program->start_time =
        program->end_time   = AV_NOPTS_VALUE;
    }
    return program;
}
 
int av_program_add_stream_index2(AVFormatContext *ac, int progid, unsigned idx)
{
    AVProgram *program = NULL;
    void *tmp;
 
    if (idx >= ac->nb_streams) {
        av_log(ac, AV_LOG_ERROR, "stream index %d is greater than stream count %d\n", idx, ac->nb_streams);
        return AVERROR(EINVAL);
    }
 
    for (unsigned i = 0; i < ac->nb_programs; i++) {
        if (ac->programs[i]->id != progid)
            continue;
        program = ac->programs[i];
        for (unsigned j = 0; j < program->nb_stream_indexes; j++)
            if (program->stream_index[j] == idx)
                return 0;
 
        tmp = av_realloc_array(program->stream_index, program->nb_stream_indexes+1, sizeof(unsigned int));
        if (!tmp)
            return AVERROR(ENOMEM);
        program->stream_index = tmp;
        program->stream_index[program->nb_stream_indexes++] = idx;
        return 0;
    }
 
    av_log(ac, AV_LOG_ERROR, "no program with id %d found\n", progid);
    return AVERROR(EINVAL);
}
 
void av_program_add_stream_index(AVFormatContext *ac, int progid, unsigned idx)
{
    av_program_add_stream_index2(ac, progid, idx);
    return;
}
 
int av_program_copy(AVFormatContext *dst, const AVFormatContext *src, int progid, int flags)
{
    const AVProgram *src_prog = NULL;
    AVProgram *dst_prog = NULL;
    int ret, idx = -1, match = -1;
    int overwrite = flags & AVFMT_PROGCOPY_OVERWRITE;
 
    if ((flags & AVFMT_PROGCOPY_MATCH_BY_ID) && (flags & AVFMT_PROGCOPY_MATCH_BY_INDEX))
        return AVERROR(EINVAL);
    else if (flags & AVFMT_PROGCOPY_MATCH_BY_ID)
        match = 0;
    else if (flags & AVFMT_PROGCOPY_MATCH_BY_INDEX)
        match = 1;
 
    for (unsigned i = 0; i < src->nb_programs; i++) {
        if (src->programs[i]->id == progid) {
            if (src_prog) {
                av_log(dst, AV_LOG_ERROR, "multiple programs found in source with same id 0x%04x. Not copying.\n", progid);
                return AVERROR(EINVAL);
            } else {
                src_prog = src->programs[i];
            }
        }
    }
 
    if (!src_prog) {
        av_log(dst, AV_LOG_ERROR, "source program not found: id=0x%04x\n", progid);
        return AVERROR(EINVAL);
    }
 
    for (unsigned i = 0; i < dst->nb_programs; i++) {
        if (dst->programs[i]->id == progid) {
            if (idx > -1) {
                av_log(dst, AV_LOG_ERROR, "multiple programs found in target with same id 0x%04x. Not copying.\n", progid);
                return AVERROR(EINVAL);
            } else {
                idx = i;
            }
        }
    }
 
    if (idx >= 0 && !overwrite)
        return AVERROR(EEXIST);
 
    av_log(dst, AV_LOG_TRACE, "%s program: id=0x%04x\n", idx >= 0 ? "overwriting" : "copying", progid);
 
    if (idx >= 0) {
        dst_prog = dst->programs[idx];
        av_dict_free(&dst_prog->metadata);
        av_freep(&dst_prog->stream_index);
        dst_prog->nb_stream_indexes = 0;
    } else {
        dst_prog = av_new_program(dst, progid);
        if (!dst_prog)
            return AVERROR(ENOMEM);
    }
 
    /* public fields */
    dst_prog->id          = src_prog->id;
    dst_prog->flags       = src_prog->flags;
    dst_prog->discard     = src_prog->discard;
    dst_prog->program_num = src_prog->program_num;
    dst_prog->pmt_pid     = src_prog->pmt_pid;
    dst_prog->pcr_pid     = src_prog->pcr_pid;
    dst_prog->pmt_version = src_prog->pmt_version;
 
    if (match == -1 && src->nb_streams) {
        match = 0;
        for (unsigned i = 0; i < src->nb_streams && !match; i++) {
            int src_id = src->streams[i]->id;
            if (!src_id) {
                match = 1;
                break;
            }
            for (unsigned j=i+1; j < src->nb_streams; j++) {
                int sib_id = src->streams[j]->id;
                if (src_id == sib_id) {
                    match = 1;
                    break;
                }
            }
        }
    }
 
    for (unsigned i = 0; i < dst->nb_streams; i++) {
        int dst_val = match ? i : dst->streams[i]->id;
 
        for (unsigned j = 0; j < src_prog->nb_stream_indexes; j++) {
            int src_val = match ? src_prog->stream_index[j] : src->streams[src_prog->stream_index[j]]->id;
 
            if (dst_val == src_val) {
                ret = av_program_add_stream_index2(dst, dst_prog->id, i);
                if (ret < 0)
                    return ret;
            }
        }
    }
 
    ret = av_dict_copy(&dst_prog->metadata, src_prog->metadata, 0);
    if (ret < 0)
        return ret;
 
    return 0;
}
 
AVProgram *av_find_program_from_stream(AVFormatContext *ic, AVProgram *last, int s)
{
    for (unsigned i = 0; i < ic->nb_programs; i++) {
        if (ic->programs[i] == last) {
            last = NULL;
        } else {
            if (!last)
                for (unsigned j = 0; j < ic->programs[i]->nb_stream_indexes; j++)
                    if (ic->programs[i]->stream_index[j] == s)
                        return ic->programs[i];
        }
    }
    return NULL;
}
 
int av_find_default_stream_index(AVFormatContext *s)
{
    int best_stream = 0;
    int best_score = INT_MIN;
 
    if (s->nb_streams <= 0)
        return -1;
    for (unsigned i = 0; i < s->nb_streams; i++) {
        const AVStream *const st = s->streams[i];
        const FFStream *const sti = cffstream(st);
        int score = 0;
        if (st->codecpar->codec_type == AVMEDIA_TYPE_VIDEO) {
            if (st->disposition & AV_DISPOSITION_ATTACHED_PIC)
                score -= 400;
            if (st->codecpar->width && st->codecpar->height)
                score += 50;
            score+= 25;
        }
        if (st->codecpar->codec_type == AVMEDIA_TYPE_AUDIO) {
            if (st->codecpar->sample_rate)
                score += 50;
        }
        if (sti->codec_info_nb_frames)
            score += 12;
 
        if (st->discard != AVDISCARD_ALL)
            score += 200;
 
        if (score > best_score) {
            best_score = score;
            best_stream = i;
        }
    }
    return best_stream;
}
 
int av_find_best_stream(AVFormatContext *ic, enum AVMediaType type,
                        int wanted_stream_nb, int related_stream,
                        const AVCodec **decoder_ret, int flags)
{
    int nb_streams = ic->nb_streams;
    int ret = AVERROR_STREAM_NOT_FOUND;
    int best_count = -1, best_multiframe = -1, best_disposition = -1;
    int count, multiframe, disposition;
    int64_t best_bitrate = -1;
    int64_t bitrate;
    unsigned *program = NULL;
    const AVCodec *decoder = NULL, *best_decoder = NULL;
 
    if (related_stream >= 0 && wanted_stream_nb < 0) {
        AVProgram *p = av_find_program_from_stream(ic, NULL, related_stream);
        if (p) {
            program    = p->stream_index;
            nb_streams = p->nb_stream_indexes;
        }
    }
    for (unsigned i = 0; i < nb_streams; i++) {
        int real_stream_index = program ? program[i] : i;
        AVStream *st          = ic->streams[real_stream_index];
        AVCodecParameters *par = st->codecpar;
        const AVCodecDescriptor *desc = avcodec_descriptor_get(par->codec_id);
        if (par->codec_type != type)
            continue;
        if (desc && (desc->props & AV_CODEC_PROP_ENHANCEMENT))
            continue;
        if (wanted_stream_nb >= 0 && real_stream_index != wanted_stream_nb)
            continue;
        if (type == AVMEDIA_TYPE_AUDIO && !(par->ch_layout.nb_channels && par->sample_rate))
            continue;
        if (decoder_ret) {
            decoder = ff_find_decoder(ic, st, par->codec_id);
            if (!decoder) {
                if (ret < 0)
                    ret = AVERROR_DECODER_NOT_FOUND;
                continue;
            }
        }
        disposition = !(st->disposition & (AV_DISPOSITION_HEARING_IMPAIRED | AV_DISPOSITION_VISUAL_IMPAIRED))
                      + !! (st->disposition & AV_DISPOSITION_DEFAULT);
        count = ffstream(st)->codec_info_nb_frames;
        bitrate = par->bit_rate;
        multiframe = FFMIN(5, count);
        if ((best_disposition >  disposition) ||
            (best_disposition == disposition && best_multiframe >  multiframe) ||
            (best_disposition == disposition && best_multiframe == multiframe && best_bitrate >  bitrate) ||
            (best_disposition == disposition && best_multiframe == multiframe && best_bitrate == bitrate && best_count >= count))
            continue;
        best_disposition = disposition;
        best_count   = count;
        best_bitrate = bitrate;
        best_multiframe = multiframe;
        ret          = real_stream_index;
        best_decoder = decoder;
        if (program && i == nb_streams - 1 && ret < 0) {
            program    = NULL;
            nb_streams = ic->nb_streams;
            /* no related stream found, try again with everything */
            i = 0;
        }
    }
    if (decoder_ret)
        *decoder_ret = best_decoder;
    return ret;
}
 
/**
 * Matches a stream specifier (but ignores requested index).
 *
 * @param indexptr set to point to the requested stream index if there is one
 *
 * @return <0 on error
 *         0  if st is NOT a matching stream
 *         >0 if st is a matching stream
 */
static int match_stream_specifier(const AVFormatContext *s, const AVStream *st,
                                  const char *spec, const char **indexptr,
                                  const AVStreamGroup **g, const AVProgram **p)
{
    int match = 1;                      /* Stores if the specifier matches so far. */
    while (*spec) {
        if (*spec <= '9' && *spec >= '0') { /* opt:index */
            if (indexptr)
                *indexptr = spec;
            return match;
        } else if (*spec == 'v' || *spec == 'a' || *spec == 's' || *spec == 'd' ||
                   *spec == 't' || *spec == 'V') { /* opt:[vasdtV] */
            enum AVMediaType type;
            int nopic = 0;
 
            switch (*spec++) {
            case 'v': type = AVMEDIA_TYPE_VIDEO;      break;
            case 'a': type = AVMEDIA_TYPE_AUDIO;      break;
            case 's': type = AVMEDIA_TYPE_SUBTITLE;   break;
            case 'd': type = AVMEDIA_TYPE_DATA;       break;
            case 't': type = AVMEDIA_TYPE_ATTACHMENT; break;
            case 'V': type = AVMEDIA_TYPE_VIDEO; nopic = 1; break;
            default:  av_assert0(0);
            }
            if (*spec && *spec++ != ':')         /* If we are not at the end, then another specifier must follow. */
                return AVERROR(EINVAL);
 
            if (type != st->codecpar->codec_type)
                match = 0;
            if (nopic && (st->disposition & AV_DISPOSITION_ATTACHED_PIC))
                match = 0;
        } else if (*spec == 'g' && *(spec + 1) == ':') {
            int64_t group_idx = -1, group_id = -1;
            int found = 0;
            char *endptr;
            spec += 2;
            if (*spec == '#' || (*spec == 'i' && *(spec + 1) == ':')) {
                spec += 1 + (*spec == 'i');
                group_id = strtol(spec, &endptr, 0);
                if (spec == endptr || (*endptr && *endptr++ != ':'))
                    return AVERROR(EINVAL);
                spec = endptr;
            } else {
                group_idx = strtol(spec, &endptr, 0);
                /* Disallow empty id and make sure that if we are not at the end, then another specifier must follow. */
                if (spec == endptr || (*endptr && *endptr++ != ':'))
                    return AVERROR(EINVAL);
                spec = endptr;
            }
            if (match) {
                if (group_id > 0) {
                    for (unsigned i = 0; i < s->nb_stream_groups; i++) {
                        if (group_id == s->stream_groups[i]->id) {
                            group_idx = i;
                            break;
                        }
                    }
                }
                if (group_idx < 0 || group_idx >= s->nb_stream_groups)
                    return AVERROR(EINVAL);
                for (unsigned j = 0; j < s->stream_groups[group_idx]->nb_entries; j++) {
                    if (s->stream_groups[group_idx]->entries[j]->type != AV_STREAM_GROUP_ENTRY_STREAM)
                        continue;
                    if (st->index == s->stream_groups[group_idx]->entries[j]->stream->index) {
                        found = 1;
                        if (g)
                            *g = s->stream_groups[group_idx];
                        break;
                    }
                }
            }
            if (!found)
                match = 0;
        } else if (*spec == 'p' && *(spec + 1) == ':') {
            int prog_id;
            int found = 0;
            char *endptr;
            spec += 2;
            prog_id = strtol(spec, &endptr, 0);
            /* Disallow empty id and make sure that if we are not at the end, then another specifier must follow. */
            if (spec == endptr || (*endptr && *endptr++ != ':'))
                return AVERROR(EINVAL);
            spec = endptr;
            if (match) {
                for (unsigned i = 0; i < s->nb_programs; i++) {
                    if (s->programs[i]->id != prog_id)
                        continue;
 
                    for (unsigned j = 0; j < s->programs[i]->nb_stream_indexes; j++) {
                        if (st->index == s->programs[i]->stream_index[j]) {
                            found = 1;
                            if (p)
                                *p = s->programs[i];
                            i = s->nb_programs;
                            break;
                        }
                    }
                }
            }
            if (!found)
                match = 0;
        } else if (*spec == '#' ||
                   (*spec == 'i' && *(spec + 1) == ':')) {
            int stream_id;
            char *endptr;
            spec += 1 + (*spec == 'i');
            stream_id = strtol(spec, &endptr, 0);
            if (spec == endptr || *endptr)                /* Disallow empty id and make sure we are at the end. */
                return AVERROR(EINVAL);
            return match && (stream_id == st->id);
        } else if (*spec == 'm' && *(spec + 1) == ':') {
            const AVDictionaryEntry *tag;
            int ret;
 
            if (match) {
                spec += 2;
                const char *val = strchr(spec, ':');
 
                char *key = val ? av_strndup(spec, val - spec) : av_strdup(spec);
                if (!key)
                    return AVERROR(ENOMEM);
 
                tag = av_dict_get(st->metadata, key, NULL, 0);
                if (tag) {
                    if (!val || !strcmp(tag->value, val + 1))
                        ret = 1;
                    else
                        ret = 0;
                } else
                    ret = 0;
 
                av_freep(&key);
            }
            return match && ret;
        } else if (*spec == 'u' && *(spec + 1) == '\0') {
            const AVCodecParameters *par = st->codecpar;
            int val;
            switch (par->codec_type) {
            case AVMEDIA_TYPE_AUDIO:
                val = par->sample_rate && par->ch_layout.nb_channels;
                if (par->format == AV_SAMPLE_FMT_NONE)
                    return 0;
                break;
            case AVMEDIA_TYPE_VIDEO:
                val = par->width && par->height;
                if (par->format == AV_PIX_FMT_NONE)
                    return 0;
                break;
            case AVMEDIA_TYPE_UNKNOWN:
                val = 0;
                break;
            default:
                val = 1;
                break;
            }
            return match && (par->codec_id != AV_CODEC_ID_NONE && val != 0);
        } else {
            return AVERROR(EINVAL);
        }
    }
 
    return match;
}
 
int avformat_match_stream_specifier(AVFormatContext *s, AVStream *st,
                                    const char *spec)
{
    int ret, index;
    char *endptr;
    const char *indexptr = NULL;
    const AVStreamGroup *g = NULL;
    const AVProgram *p = NULL;
    int nb_streams;
 
    ret = match_stream_specifier(s, st, spec, &indexptr, &g, &p);
    if (ret < 0)
        goto error;
 
    if (!indexptr)
        return ret;
 
    index = strtol(indexptr, &endptr, 0);
    if (*endptr) {                  /* We can't have anything after the requested index. */
        ret = AVERROR(EINVAL);
        goto error;
    }
 
    /* This is not really needed but saves us a loop for simple stream index specifiers. */
    if (spec == indexptr)
        return (index == st->index);
 
    /* If we requested a matching stream index, we have to ensure st is that. */
    nb_streams = g ? g->nb_entries : (p ? p->nb_stream_indexes : s->nb_streams);
    for (int i = 0; i < nb_streams && index >= 0; i++) {
        if (g && g->entries[i]->type != AV_STREAM_GROUP_ENTRY_STREAM)
            continue;
        unsigned idx = g ? g->entries[i]->stream->index : (p ? p->stream_index[i] : i);
        const AVStream *candidate = s->streams[idx];
        ret = match_stream_specifier(s, candidate, spec, NULL, NULL, NULL);
        if (ret < 0)
            goto error;
        if (ret > 0 && index-- == 0 && st == candidate)
            return 1;
    }
    return 0;
 
error:
    if (ret == AVERROR(EINVAL))
        av_log(s, AV_LOG_ERROR, "Invalid stream specifier: %s.\n", spec);
    return ret;
}
 
AVRational av_guess_sample_aspect_ratio(AVFormatContext *format, AVStream *stream, AVFrame *frame)
{
    AVRational undef = {0, 1};
    AVRational stream_sample_aspect_ratio = stream ? stream->sample_aspect_ratio : undef;
    AVRational codec_sample_aspect_ratio  = stream && stream->codecpar ? stream->codecpar->sample_aspect_ratio : undef;
    AVRational frame_sample_aspect_ratio  = frame  ? frame->sample_aspect_ratio  : codec_sample_aspect_ratio;
 
    av_reduce(&stream_sample_aspect_ratio.num, &stream_sample_aspect_ratio.den,
               stream_sample_aspect_ratio.num,  stream_sample_aspect_ratio.den, INT_MAX);
    if (stream_sample_aspect_ratio.num <= 0 || stream_sample_aspect_ratio.den <= 0)
        stream_sample_aspect_ratio = undef;
 
    av_reduce(&frame_sample_aspect_ratio.num, &frame_sample_aspect_ratio.den,
               frame_sample_aspect_ratio.num,  frame_sample_aspect_ratio.den, INT_MAX);
    if (frame_sample_aspect_ratio.num <= 0 || frame_sample_aspect_ratio.den <= 0)
        frame_sample_aspect_ratio = undef;
 
    if (stream_sample_aspect_ratio.num)
        return stream_sample_aspect_ratio;
    else
        return frame_sample_aspect_ratio;
}
 
AVRational av_guess_frame_rate(AVFormatContext *format, AVStream *st, AVFrame *frame)
{
    AVRational fr = st->r_frame_rate;
    const AVCodecDescriptor *desc = cffstream(st)->codec_desc;
    AVRational   avg_fr = st->avg_frame_rate;
 
    if (avg_fr.num > 0 && avg_fr.den > 0 && fr.num > 0 && fr.den > 0 &&
        av_q2d(avg_fr) < 70 && av_q2d(fr) > 210) {
        fr = avg_fr;
    }
 
    if (desc && (desc->props & AV_CODEC_PROP_FIELDS)) {
        const AVCodecContext *const avctx = ffstream(st)->avctx;
        AVRational codec_fr = avctx->framerate;
 
        if (   codec_fr.num > 0 && codec_fr.den > 0 &&
            (fr.num == 0 || av_q2d(codec_fr) < av_q2d(fr)*0.7 && fabs(1.0 - av_q2d(av_div_q(avg_fr, fr))) > 0.1))
            fr = codec_fr;
    }
 
    return fr;
}
 
void avpriv_set_pts_info(AVStream *st, int pts_wrap_bits,
                         unsigned int pts_num, unsigned int pts_den)
{
    FFStream *const sti = ffstream(st);
    AVRational new_tb;
    if (av_reduce(&new_tb.num, &new_tb.den, pts_num, pts_den, INT_MAX)) {
        if (new_tb.num != pts_num)
            av_log(NULL, AV_LOG_DEBUG,
                   "st:%d removing common factor %d from timebase\n",
                   st->index, pts_num / new_tb.num);
    } else
        av_log(NULL, AV_LOG_WARNING,
               "st:%d has too large timebase, reducing\n", st->index);
 
    if (new_tb.num <= 0 || new_tb.den <= 0) {
        av_log(NULL, AV_LOG_ERROR,
               "Ignoring attempt to set invalid timebase %d/%d for st:%d\n",
               new_tb.num, new_tb.den,
               st->index);
        return;
    }
    st->time_base     = new_tb;
    if (sti->avctx)
        sti->avctx->pkt_timebase = new_tb;
    st->pts_wrap_bits = pts_wrap_bits;
}
 
const AVCodec *ff_find_decoder(AVFormatContext *s, const AVStream *st,
                               enum AVCodecID codec_id)
{
    switch (st->codecpar->codec_type) {
    case AVMEDIA_TYPE_VIDEO:
        if (s->video_codec)    return s->video_codec;
        break;
    case AVMEDIA_TYPE_AUDIO:
        if (s->audio_codec)    return s->audio_codec;
        break;
    case AVMEDIA_TYPE_SUBTITLE:
        if (s->subtitle_codec) return s->subtitle_codec;
        break;
    }
 
    return avcodec_find_decoder(codec_id);
}
 
int ff_copy_whiteblacklists(AVFormatContext *dst, const AVFormatContext *src)
{
#define OFF(field) offsetof(AVFormatContext, field)
    static const unsigned offsets[] = {
        OFF(codec_whitelist),    OFF(format_whitelist),
        OFF(protocol_whitelist), OFF(protocol_blacklist),
    };
#undef OFF
    av_assert0(!dst->codec_whitelist &&
               !dst->format_whitelist &&
               !dst->protocol_whitelist &&
               !dst->protocol_blacklist);
    for (unsigned i = 0; i < FF_ARRAY_ELEMS(offsets); i++) {
        const char *src_str = *(char *const*)((const char*)src + offsets[i]);
 
        if (src_str) {
            char *dst_str = av_strdup(src_str);
            if (!dst_str) {
                av_log(dst, AV_LOG_ERROR, "Failed to duplicate black/whitelist\n");
                return AVERROR(ENOMEM);
            }
 
            *(char **)((char*)dst + offsets[i]) = dst_str;
        }
    }
    if (src->recursion_limit <= 0) {
        av_log(dst, AV_LOG_ERROR, "Too deep recursion\n");
        return AVERROR_INVALIDDATA;
    }
    dst->recursion_limit = src->recursion_limit - 1;
    return 0;
}
 
int ff_is_intra_only(enum AVCodecID id)
{
    const AVCodecDescriptor *d = avcodec_descriptor_get(id);
    if (!d)
        return 0;
    if ((d->type == AVMEDIA_TYPE_VIDEO || d->type == AVMEDIA_TYPE_AUDIO) &&
        !(d->props & AV_CODEC_PROP_INTRA_ONLY))
        return 0;
    return 1;
}
 
void ff_format_set_url(AVFormatContext *s, char *url)
{
    av_assert0(url);
    av_freep(&s->url);
    s->url = url;
}
 
int ff_format_check_set_url(AVFormatContext *s, const char *url)
{
    URLComponents uc;
    av_assert0(url);
    char proto[64];
 
    int ret = ff_url_decompose(&uc, url, NULL);
    if (ret < 0)
        return ret;
    av_strlcpy(proto, uc.scheme, FFMIN(sizeof(proto), uc.url_component_end_scheme - uc.scheme));
 
    if (s->protocol_whitelist && av_match_list(proto, s->protocol_whitelist, ',') <= 0) {
        av_log(s, AV_LOG_ERROR, "Protocol '%s' not on whitelist '%s'!\n", proto, s->protocol_whitelist);
        return AVERROR(EINVAL);
    }
 
    if (s->protocol_blacklist && av_match_list(proto, s->protocol_blacklist, ',') > 0) {
        av_log(s, AV_LOG_ERROR, "Protocol '%s' on blacklist '%s'!\n", proto, s->protocol_blacklist);
        return AVERROR(EINVAL);
    }
 
    char *urldup = av_strdup(url);
    if (!urldup)
        return AVERROR(ENOMEM);
 
    av_freep(&s->url);
    s->url = urldup;
    return 0;
}
 
 
int ff_format_io_close(AVFormatContext *s, AVIOContext **pb)
{
    int ret = 0;
    if (*pb)
        ret = s->io_close2(s, *pb);
    *pb = NULL;
    return ret;
}