Function pdv_read_header

libavformat/pdvdec.c:43–100

}

static int pdv_read_header(AVFormatContext *s)
{
    PDVDemuxContext *p = s->priv_data;
    AVIOContext *pb = s->pb;
    AVCodecParameters *par;
    AVStream *st;
    uint64_t start;
    uint32_t fps;

    avio_skip(pb, 16);

    st = avformat_new_stream(s, NULL);
    if (!st)
        return AVERROR(ENOMEM);

    par              = st->codecpar;
    par->codec_type  = AVMEDIA_TYPE_VIDEO;
    par->codec_id    = AV_CODEC_ID_PDV;
    st->start_time   = 0;
    st->duration     =
    st->nb_frames    = avio_rl16(pb);
    avio_skip(pb, 2);
    fps = avio_rl32(pb);
    st->avg_frame_rate = av_d2q(av_int2float(fps), INT_MAX);
    par->width       = avio_rl16(pb);
    par->height      = avio_rl16(pb);

    avpriv_set_pts_info(st, 64, st->avg_frame_rate.den, st->avg_frame_rate.num);

    p->current_frame = 0;
    p->frame_flags = av_calloc(st->nb_frames + 1, sizeof(*p->frame_flags));
    p->frame_offsets = av_calloc(st->nb_frames + 1, sizeof(*p->frame_offsets));

    if (!p->frame_flags || !p->frame_offsets)
        return AVERROR(ENOMEM);

    for (int n = 0; n <= st->nb_frames; n++) {
        const uint32_t entry = avio_rl32(pb);

        p->frame_flags[n] = entry & 3;
        p->frame_offsets[n] = entry >> 2;
    }

    start = avio_tell(pb);

    for (int n = 0; n < st->nb_frames; n++) {
        const uint64_t pos = start + p->frame_offsets[n];
        const int32_t size = p->frame_offsets[n+1] - p->frame_offsets[n];
        const int flags = p->frame_flags[n] & 1 ? AVINDEX_KEYFRAME : 0;

        if (p->frame_flags[n] == 0 || size <= 0 ||
            ((pb->seekable & AVIO_SEEKABLE_NORMAL) && pos + size > avio_size(pb)))
            break;
        av_add_index_entry(st, pos, n, size, 0, flags);
    }

    return 0;
}