static void mpc8_parse_seektable(AVFormatContext *s, int64_t off)
{
    MPCContext *c = s->priv_data;
    int tag;
    int64_t size, pos, ppos[2];
    uint8_t *buf;
    int i, t, seekd;
    GetBitContext gb;

    avio_seek(s->pb, off, SEEK_SET);
    mpc8_get_chunk_header(s->pb, &tag, &size);
    if(tag != TAG_SEEKTABLE){
        av_log(s, AV_LOG_ERROR, "No seek table at given position\n");
        return;
    }
    if (size > INT_MAX/10 || size<=0) {
        av_log(s, AV_LOG_ERROR, "Seek table size is invalid\n");
        return;
    }
    if(!(buf = av_malloc(size + FF_INPUT_BUFFER_PADDING_SIZE)))
        return;
    avio_read(s->pb, buf, size);
    init_get_bits(&gb, buf, size * 8);
    size = gb_get_v(&gb);
    if(size > UINT_MAX/4 || size > c->samples/1152){
        av_log(s, AV_LOG_ERROR, "Seek table is too big\n");
        return;
    }
    seekd = get_bits(&gb, 4);
    for(i = 0; i < 2; i++){
        pos = gb_get_v(&gb) + c->header_pos;
        ppos[1 - i] = pos;
        av_add_index_entry(s->streams[0], pos, i, 0, 0, AVINDEX_KEYFRAME);
    }
    for(; i < size; i++){
        t = get_unary(&gb, 1, 33) << 12;
        t += get_bits(&gb, 12);
        if(t & 1)
            t = -(t & ~1);
        pos = (t >> 1) + ppos[0]*2 - ppos[1];
        av_add_index_entry(s->streams[0], pos, i << seekd, 0, 0, AVINDEX_KEYFRAME);
        ppos[1] = ppos[0];
        ppos[0] = pos;
    }
    av_free(buf);
}