libavformat/oggdec.c

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/*
 * Ogg bitstream support
 * Luca Barbato <lu_zero@gentoo.org>
 * Based on tcvp implementation
 *
 */

#include <stdio.h>
#include "oggdec.h"
#include "avformat.h"
#include "vorbiscomment.h"

#define MAX_PAGE_SIZE 65307
#define DECODER_BUFFER_SIZE MAX_PAGE_SIZE

static const struct ogg_codec * const ogg_codecs[] = {
    &ff_skeleton_codec,
    &ff_dirac_codec,
    &ff_speex_codec,
    &ff_vorbis_codec,
    &ff_theora_codec,
    &ff_flac_codec,
    &ff_celt_codec,
    &ff_old_dirac_codec,
    &ff_old_flac_codec,
    &ff_ogm_video_codec,
    &ff_ogm_audio_codec,
    &ff_ogm_text_codec,
    &ff_ogm_old_codec,
    NULL
};

//FIXME We could avoid some structure duplication
static int ogg_save(AVFormatContext *s)
{
    struct ogg *ogg = s->priv_data;
    struct ogg_state *ost =
        av_malloc(sizeof (*ost) + (ogg->nstreams-1) * sizeof (*ogg->streams));
    int i;
    ost->pos = avio_tell (s->pb);
    ost->curidx = ogg->curidx;
    ost->next = ogg->state;
    ost->nstreams = ogg->nstreams;
    memcpy(ost->streams, ogg->streams, ogg->nstreams * sizeof(*ogg->streams));

    for (i = 0; i < ogg->nstreams; i++){
        struct ogg_stream *os = ogg->streams + i;
        os->buf = av_malloc (os->bufsize);
        memset (os->buf, 0, os->bufsize);
        memcpy (os->buf, ost->streams[i].buf, os->bufpos);
    }

    ogg->state = ost;

    return 0;
}

static int ogg_restore(AVFormatContext *s, int discard)
{
    struct ogg *ogg = s->priv_data;
    AVIOContext *bc = s->pb;
    struct ogg_state *ost = ogg->state;
    int i;

    if (!ost)
        return 0;

    ogg->state = ost->next;

    if (!discard){
        struct ogg_stream *old_streams = ogg->streams;

        for (i = 0; i < ogg->nstreams; i++)
            av_free (ogg->streams[i].buf);

        avio_seek (bc, ost->pos, SEEK_SET);
        ogg->curidx = ost->curidx;
        ogg->nstreams = ost->nstreams;
        ogg->streams = av_realloc (ogg->streams,
                                   ogg->nstreams * sizeof (*ogg->streams));

        if (ogg->streams) {
            memcpy(ogg->streams, ost->streams,
                   ost->nstreams * sizeof(*ogg->streams));
        } else {
            av_free(old_streams);
            ogg->nstreams = 0;
        }
    }

    av_free (ost);

    return 0;
}

static int ogg_reset(struct ogg *ogg)
{
    int i;

    for (i = 0; i < ogg->nstreams; i++){
        struct ogg_stream *os = ogg->streams + i;
        os->bufpos = 0;
        os->pstart = 0;
        os->psize = 0;
        os->granule = -1;
        os->lastpts = AV_NOPTS_VALUE;
        os->lastdts = AV_NOPTS_VALUE;
        os->sync_pos = -1;
        os->page_pos = 0;
        os->nsegs = 0;
        os->segp = 0;
        os->incomplete = 0;
    }

    ogg->curidx = -1;

    return 0;
}

static const struct ogg_codec *ogg_find_codec(uint8_t *buf, int size)
{
    int i;

    for (i = 0; ogg_codecs[i]; i++)
        if (size >= ogg_codecs[i]->magicsize &&
            !memcmp (buf, ogg_codecs[i]->magic, ogg_codecs[i]->magicsize))
            return ogg_codecs[i];

    return NULL;
}

static int ogg_new_stream(AVFormatContext *s, uint32_t serial, int new_avstream)
{

    struct ogg *ogg = s->priv_data;
    int idx = ogg->nstreams++;
    AVStream *st;
    struct ogg_stream *os;

    ogg->streams = av_realloc (ogg->streams,
                               ogg->nstreams * sizeof (*ogg->streams));
    memset (ogg->streams + idx, 0, sizeof (*ogg->streams));
    os = ogg->streams + idx;
    os->serial = serial;
    os->bufsize = DECODER_BUFFER_SIZE;
    os->buf = av_malloc(os->bufsize);
    os->header = -1;

    if (new_avstream) {
        st = av_new_stream(s, idx);
        if (!st)
            return AVERROR(ENOMEM);

        av_set_pts_info(st, 64, 1, 1000000);
    }

    return idx;
}

static int ogg_new_buf(struct ogg *ogg, int idx)
{
    struct ogg_stream *os = ogg->streams + idx;
    uint8_t *nb = av_malloc(os->bufsize);
    int size = os->bufpos - os->pstart;
    if(os->buf){
        memcpy(nb, os->buf + os->pstart, size);
        av_free(os->buf);
    }
    os->buf = nb;
    os->bufpos = size;
    os->pstart = 0;

    return 0;
}

static int ogg_read_page(AVFormatContext *s, int *str)
{
    AVIOContext *bc = s->pb;
    struct ogg *ogg = s->priv_data;
    struct ogg_stream *os;
    int ret, i = 0;
    int flags, nsegs;
    uint64_t gp;
    uint32_t serial;
    int size, idx;
    uint8_t sync[4];
    int sp = 0;

    ret = avio_read (bc, sync, 4);
    if (ret < 4)
        return ret < 0 ? ret : AVERROR_EOF;

    do{
        int c;

        if (sync[sp & 3] == 'O' &&
            sync[(sp + 1) & 3] == 'g' &&
            sync[(sp + 2) & 3] == 'g' && sync[(sp + 3) & 3] == 'S')
            break;

        c = avio_r8(bc);
        if (url_feof(bc))
            return AVERROR_EOF;
        sync[sp++ & 3] = c;
    }while (i++ < MAX_PAGE_SIZE);

    if (i >= MAX_PAGE_SIZE){
        av_log (s, AV_LOG_INFO, "ogg, can't find sync word\n");
        return AVERROR_INVALIDDATA;
    }

    if (avio_r8(bc) != 0)      /* version */
        return AVERROR_INVALIDDATA;

    flags = avio_r8(bc);
    gp = avio_rl64 (bc);
    serial = avio_rl32 (bc);
    avio_skip(bc, 8); /* seq, crc */
    nsegs = avio_r8(bc);

    idx = ogg_find_stream (ogg, serial);
    if (idx < 0){
        if (ogg->headers) {
            int n;

            for (n = 0; n < ogg->nstreams; n++) {
                av_freep(&ogg->streams[n].buf);
                if (!ogg->state || ogg->state->streams[n].private != ogg->streams[n].private)
                    av_freep(&ogg->streams[n].private);
            }
            ogg->curidx   = -1;
            ogg->nstreams = 0;
            idx = ogg_new_stream(s, serial, 0);
        } else {
            idx = ogg_new_stream(s, serial, 1);
        }
        if (idx < 0)
            return idx;
    }

    os = ogg->streams + idx;
    os->page_pos = avio_tell(bc) - 27;

    if(os->psize > 0)
        ogg_new_buf(ogg, idx);

    ret = avio_read (bc, os->segments, nsegs);
    if (ret < nsegs)
        return ret < 0 ? ret : AVERROR_EOF;

    os->nsegs = nsegs;
    os->segp = 0;

    size = 0;
    for (i = 0; i < nsegs; i++)
        size += os->segments[i];

    if (flags & OGG_FLAG_CONT || os->incomplete){
        if (!os->psize){
            while (os->segp < os->nsegs){
                int seg = os->segments[os->segp++];
                os->pstart += seg;
                if (seg < 255)
                    break;
            }
            os->sync_pos = os->page_pos;
        }
    }else{
        os->psize = 0;
        os->sync_pos = os->page_pos;
    }

    if (os->bufsize - os->bufpos < size){
        uint8_t *nb = av_malloc (os->bufsize *= 2);
        memcpy (nb, os->buf, os->bufpos);
        av_free (os->buf);
        os->buf = nb;
    }

    ret = avio_read (bc, os->buf + os->bufpos, size);
    if (ret < size)
        return ret < 0 ? ret : AVERROR_EOF;

    os->bufpos += size;
    os->granule = gp;
    os->flags = flags;

    if (str)
        *str = idx;

    return 0;
}

static int ogg_packet(AVFormatContext *s, int *str, int *dstart, int *dsize,
                      int64_t *fpos)
{
    struct ogg *ogg = s->priv_data;
    int idx, i, ret;
    struct ogg_stream *os;
    int complete = 0;
    int segp = 0, psize = 0;

    av_dlog(s, "ogg_packet: curidx=%i\n", ogg->curidx);

    do{
        idx = ogg->curidx;

        while (idx < 0){
            ret = ogg_read_page (s, &idx);
            if (ret < 0)
                return ret;
        }

        os = ogg->streams + idx;

        av_dlog(s, "ogg_packet: idx=%d pstart=%d psize=%d segp=%d nsegs=%d\n",
                idx, os->pstart, os->psize, os->segp, os->nsegs);

        if (!os->codec){
            if (os->header < 0){
                os->codec = ogg_find_codec (os->buf, os->bufpos);
                if (!os->codec){
                    av_log(s, AV_LOG_WARNING, "Codec not found\n");
                    os->header = 0;
                    return 0;
                }
            }else{
                return 0;
            }
        }

        segp = os->segp;
        psize = os->psize;

        while (os->segp < os->nsegs){
            int ss = os->segments[os->segp++];
            os->psize += ss;
            if (ss < 255){
                complete = 1;
                break;
            }
        }

        if (!complete && os->segp == os->nsegs){
            ogg->curidx = -1;
            os->incomplete = 1;
        }
    }while (!complete);


    if (os->granule == -1)
        av_log(s, AV_LOG_WARNING, "Page at %"PRId64" is missing granule\n", os->page_pos);

    ogg->curidx = idx;
    os->incomplete = 0;

    if (os->header) {
        os->header = os->codec->header (s, idx);
        if (!os->header){
            os->segp = segp;
            os->psize = psize;

            // We have reached the first non-header packet in this stream.
            // Unfortunately more header packets may still follow for others,
            // but if we continue with header parsing we may lose data packets.
            ogg->headers = 1;

            // Update the header state for all streams and
            // compute the data_offset.
            if (!s->data_offset)
                s->data_offset = os->sync_pos;
            for (i = 0; i < ogg->nstreams; i++) {
                struct ogg_stream *cur_os = ogg->streams + i;

                // if we have a partial non-header packet, its start is
                // obviously at or after the data start
                if (cur_os->incomplete)
                    s->data_offset = FFMIN(s->data_offset, cur_os->sync_pos);
            }
        }else{
            os->pstart += os->psize;
            os->psize = 0;
        }
    } else {
        os->pflags = 0;
        os->pduration = 0;
        if (os->codec && os->codec->packet)
            os->codec->packet (s, idx);
        if (str)
            *str = idx;
        if (dstart)
            *dstart = os->pstart;
        if (dsize)
            *dsize = os->psize;
        if (fpos)
            *fpos = os->sync_pos;
        os->pstart += os->psize;
        os->psize = 0;
        if(os->pstart == os->bufpos)
            os->bufpos = os->pstart = 0;
        os->sync_pos = os->page_pos;
    }

    // determine whether there are more complete packets in this page
    // if not, the page's granule will apply to this packet
    os->page_end = 1;
    for (i = os->segp; i < os->nsegs; i++)
        if (os->segments[i] < 255) {
            os->page_end = 0;
            break;
        }

    if (os->segp == os->nsegs)
        ogg->curidx = -1;

    return 0;
}

static int ogg_get_headers(AVFormatContext *s)
{
    struct ogg *ogg = s->priv_data;
    int ret;

    do{
        ret = ogg_packet (s, NULL, NULL, NULL, NULL);
        if (ret < 0)
            return ret;
    }while (!ogg->headers);

    av_dlog(s, "found headers\n");

    return 0;
}

static int ogg_get_length(AVFormatContext *s)
{
    struct ogg *ogg = s->priv_data;
    int i;
    int64_t size, end;

    if(!s->pb->seekable)
        return 0;

// already set
    if (s->duration != AV_NOPTS_VALUE)
        return 0;

    size = avio_size(s->pb);
    if(size < 0)
        return 0;
    end = size > MAX_PAGE_SIZE? size - MAX_PAGE_SIZE: 0;

    ogg_save (s);
    avio_seek (s->pb, end, SEEK_SET);

    while (!ogg_read_page (s, &i)){
        if (ogg->streams[i].granule != -1 && ogg->streams[i].granule != 0 &&
            ogg->streams[i].codec) {
            s->streams[i]->duration =
                ogg_gptopts (s, i, ogg->streams[i].granule, NULL);
            if (s->streams[i]->start_time != AV_NOPTS_VALUE)
                s->streams[i]->duration -= s->streams[i]->start_time;
        }
    }

    ogg_restore (s, 0);

    ogg_save (s);
    avio_seek (s->pb, 0, SEEK_SET);
    while (!ogg_read_page (s, &i)){
        if (ogg->streams[i].granule != -1 && ogg->streams[i].granule != 0 &&
            ogg->streams[i].codec) {
            s->streams[i]->duration -=
                ogg_gptopts (s, i, ogg->streams[i].granule, NULL);
            break;
        }
    }
    ogg_restore (s, 0);

    return 0;
}

static int ogg_read_header(AVFormatContext *s, AVFormatParameters *ap)
{
    struct ogg *ogg = s->priv_data;
    int ret, i;
    ogg->curidx = -1;
    //linear headers seek from start
    ret = ogg_get_headers (s);
    if (ret < 0){
        return ret;
    }

    for (i = 0; i < ogg->nstreams; i++)
        if (ogg->streams[i].header < 0)
            ogg->streams[i].codec = NULL;

    //linear granulepos seek from end
    ogg_get_length (s);

    //fill the extradata in the per codec callbacks
    return 0;
}

static int64_t ogg_calc_pts(AVFormatContext *s, int idx, int64_t *dts)
{
    struct ogg *ogg = s->priv_data;
    struct ogg_stream *os = ogg->streams + idx;
    int64_t pts = AV_NOPTS_VALUE;

    if (dts)
        *dts = AV_NOPTS_VALUE;

    if (os->lastpts != AV_NOPTS_VALUE) {
        pts = os->lastpts;
        os->lastpts = AV_NOPTS_VALUE;
    }
    if (os->lastdts != AV_NOPTS_VALUE) {
        if (dts)
            *dts = os->lastdts;
        os->lastdts = AV_NOPTS_VALUE;
    }
    if (os->page_end) {
        if (os->granule != -1LL) {
            if (os->codec && os->codec->granule_is_start)
                pts = ogg_gptopts(s, idx, os->granule, dts);
            else
                os->lastpts = ogg_gptopts(s, idx, os->granule, &os->lastdts);
            os->granule = -1LL;
        }
    }
    return pts;
}

static int ogg_read_packet(AVFormatContext *s, AVPacket *pkt)
{
    struct ogg *ogg;
    struct ogg_stream *os;
    int idx = -1;
    int pstart, psize;
    int64_t fpos, pts, dts;

    //Get an ogg packet
retry:
    do{
        if (ogg_packet (s, &idx, &pstart, &psize, &fpos) < 0)
            return AVERROR(EIO);
    }while (idx < 0 || !s->streams[idx]);

    ogg = s->priv_data;
    os = ogg->streams + idx;

    // pflags might not be set until after this
    pts = ogg_calc_pts(s, idx, &dts);

    if (os->keyframe_seek && !(os->pflags & AV_PKT_FLAG_KEY))
        goto retry;
    os->keyframe_seek = 0;

    //Alloc a pkt
    if (av_new_packet (pkt, psize) < 0)
        return AVERROR(EIO);
    pkt->stream_index = idx;
    memcpy (pkt->data, os->buf + pstart, psize);

    pkt->pts = pts;
    pkt->dts = dts;
    pkt->flags = os->pflags;
    pkt->duration = os->pduration;
    pkt->pos = fpos;

    return psize;
}

static int ogg_read_close(AVFormatContext *s)
{
    struct ogg *ogg = s->priv_data;
    int i;

    for (i = 0; i < ogg->nstreams; i++){
        av_free (ogg->streams[i].buf);
        av_free (ogg->streams[i].private);
    }
    av_free (ogg->streams);
    return 0;
}

static int64_t ogg_read_timestamp(AVFormatContext *s, int stream_index,
                                  int64_t *pos_arg, int64_t pos_limit)
{
    struct ogg *ogg = s->priv_data;
    AVIOContext *bc = s->pb;
    int64_t pts = AV_NOPTS_VALUE;
    int i = -1;
    avio_seek(bc, *pos_arg, SEEK_SET);
    ogg_reset(ogg);

    while (avio_tell(bc) < pos_limit && !ogg_packet(s, &i, NULL, NULL, pos_arg)) {
        if (i == stream_index) {
            struct ogg_stream *os = ogg->streams + stream_index;
            pts = ogg_calc_pts(s, i, NULL);
            if (os->keyframe_seek && !(os->pflags & AV_PKT_FLAG_KEY))
                pts = AV_NOPTS_VALUE;
        }
        if (pts != AV_NOPTS_VALUE)
            break;
    }
    ogg_reset(ogg);
    return pts;
}

static int ogg_read_seek(AVFormatContext *s, int stream_index,
                         int64_t timestamp, int flags)
{
    struct ogg *ogg = s->priv_data;
    struct ogg_stream *os = ogg->streams + stream_index;
    int ret;

    // Try seeking to a keyframe first. If this fails (very possible),
    // av_seek_frame will fall back to ignoring keyframes
    if (s->streams[stream_index]->codec->codec_type == AVMEDIA_TYPE_VIDEO
        && !(flags & AVSEEK_FLAG_ANY))
        os->keyframe_seek = 1;

    ret = av_seek_frame_binary(s, stream_index, timestamp, flags);
    os = ogg->streams + stream_index;
    if (ret < 0)
        os->keyframe_seek = 0;
    return ret;
}

static int ogg_probe(AVProbeData *p)
{
    if (!memcmp("OggS", p->buf, 5) && p->buf[5] <= 0x7)
        return AVPROBE_SCORE_MAX;
    return 0;
}

AVInputFormat ff_ogg_demuxer = {
    .name           = "ogg",
    .long_name      = NULL_IF_CONFIG_SMALL("Ogg"),
    .priv_data_size = sizeof(struct ogg),
    .read_probe     = ogg_probe,
    .read_header    = ogg_read_header,
    .read_packet    = ogg_read_packet,
    .read_close     = ogg_read_close,
    .read_seek      = ogg_read_seek,
    .read_timestamp = ogg_read_timestamp,
    .extensions     = "ogg",
    .flags          = AVFMT_GENERIC_INDEX,
};

---