static int matroska_read_seek(AVFormatContext *s, int stream_index,

                              int64_t timestamp, int flags)

{

    MatroskaDemuxContext *matroska = s->priv_data;

    MatroskaTrack *tracks = matroska->tracks.elem;

    AVStream *st = s->streams[stream_index];

    int i, index, index_sub, index_min;



    /* Parse the CUES now since we need the index data to seek. */

    if (matroska->cues_parsing_deferred) {

        matroska_parse_cues(matroska);

        matroska->cues_parsing_deferred = 0;

    }



    if (!st->nb_index_entries)

        return 0;

    timestamp = FFMAX(timestamp, st->index_entries[0].timestamp);



    if ((index = av_index_search_timestamp(st, timestamp, flags)) < 0) {

        avio_seek(s->pb, st->index_entries[st->nb_index_entries-1].pos, SEEK_SET);

        matroska->current_id = 0;

        while ((index = av_index_search_timestamp(st, timestamp, flags)) < 0) {


            matroska_clear_queue(matroska);

            if (matroska_parse_cluster(matroska) < 0)

                break;

        }

    }



    matroska_clear_queue(matroska);

    if (index < 0)

        return 0;



    index_min = index;

    for (i=0; i < matroska->tracks.nb_elem; i++) {

        tracks[i].audio.pkt_cnt = 0;

        tracks[i].audio.sub_packet_cnt = 0;

        tracks[i].audio.buf_timecode = AV_NOPTS_VALUE;

        tracks[i].end_timecode = 0;

        if (tracks[i].type == MATROSKA_TRACK_TYPE_SUBTITLE

            && !tracks[i].stream->discard != AVDISCARD_ALL) {

            index_sub = av_index_search_timestamp(tracks[i].stream, st->index_entries[index].timestamp, AVSEEK_FLAG_BACKWARD);

            if (index_sub >= 0

                && st->index_entries[index_sub].pos < st->index_entries[index_min].pos

                && st->index_entries[index].timestamp - st->index_entries[index_sub].timestamp < 30000000000/matroska->time_scale)

                index_min = index_sub;

        }

    }



    avio_seek(s->pb, st->index_entries[index_min].pos, SEEK_SET);

    matroska->current_id = 0;

    matroska->skip_to_keyframe = !(flags & AVSEEK_FLAG_ANY);

    matroska->skip_to_timecode = st->index_entries[index].timestamp;

    matroska->done = 0;

    ff_update_cur_dts(s, st, st->index_entries[index].timestamp);

    return 0;

}