avidec.c

static int avi_read_seek(AVFormatContext *s, int stream_index, int64_t timestamp, int flags)
{
    AVIContext *avi = s->priv_data;
    AVStream *st;
    int i, index;
    int64_t pos;

    if (!avi->index_loaded) {
        /* we only load the index on demand */
        avi_load_index(s);
        avi->index_loaded = 1;
    }
    assert(stream_index>= 0);

    st = s->streams[stream_index];
    index= av_index_search_timestamp(st, timestamp, flags);
    if(index<0)
        return -1;

    /* find the position */
    pos = st->index_entries[index].pos;
    timestamp = st->index_entries[index].timestamp;

//    av_log(s, AV_LOG_DEBUG, "XX %"PRId64" %d %"PRId64"\n", timestamp, index, st->index_entries[index].timestamp);

    if (CONFIG_DV_DEMUXER && avi->dv_demux) {
        /* One and only one real stream for DV in AVI, and it has video  */
        /* offsets. Calling with other stream indexes should have failed */
        /* the av_index_search_timestamp call above.                     */
        assert(stream_index == 0);

        /* Feed the DV video stream version of the timestamp to the */
        /* DV demux so it can synthesize correct timestamps.        */
        dv_offset_reset(avi->dv_demux, timestamp);

        url_fseek(s->pb, pos, SEEK_SET);
        avi->stream_index= -1;
        return 0;
    }

    for(i = 0; i < s->nb_streams; i++) {
        AVStream *st2 = s->streams[i];
        AVIStream *ast2 = st2->priv_data;

        ast2->packet_size=
        ast2->remaining= 0;

        if (st2->nb_index_entries <= 0)
            continue;

//        assert(st2->codec->block_align);
        assert((int64_t)st2->time_base.num*ast2->rate == (int64_t)st2->time_base.den*ast2->scale);
        index = av_index_search_timestamp(
                st2,
                av_rescale(timestamp, st2->time_base.den*(int64_t)st->time_base.num, st->time_base.den * (int64_t)st2->time_base.num),
                flags | AVSEEK_FLAG_BACKWARD);
        if(index<0)
            index=0;

        if(!avi->non_interleaved){
            while(index>0 && st2->index_entries[index].pos > pos)
                index--;
            while(index+1 < st2->nb_index_entries && st2->index_entries[index].pos < pos)
                index++;
        }

//        av_log(s, AV_LOG_DEBUG, "%"PRId64" %d %"PRId64"\n", timestamp, index, st2->index_entries[index].timestamp);
        /* extract the current frame number */
        ast2->frame_offset = st2->index_entries[index].timestamp;
        if(ast2->sample_size)
            ast2->frame_offset *=ast2->sample_size;
    }

    /* do the seek */
    url_fseek(s->pb, pos, SEEK_SET);
    avi->stream_index= -1;
    return 0;
}

static int avi_read_close(AVFormatContext *s)
{
    int i;
    AVIContext *avi = s->priv_data;

    for(i=0;i<s->nb_streams;i++) {
        AVStream *st = s->streams[i];
        av_free(st->codec->palctrl);
    }

    if (avi->dv_demux)
        av_free(avi->dv_demux);

    return 0;
}

static int avi_probe(AVProbeData *p)
{
    int i;

    /* check file header */
    for(i=0; avi_headers[i][0]; i++)
        if(!memcmp(p->buf  , avi_headers[i]  , 4) &&
           !memcmp(p->buf+8, avi_headers[i]+4, 4))
            return AVPROBE_SCORE_MAX;

    return 0;
}

AVInputFormat avi_demuxer = {
    "avi",
    NULL_IF_CONFIG_SMALL("AVI format"),
    sizeof(AVIContext),
    avi_probe,
    avi_read_header,
    avi_read_packet,
    avi_read_close,
    avi_read_seek,
};