static int v210_read_packet(AVFormatContext *s, AVPacket *pkt)
{
    int packet_size, ret, width, height;
    AVStream *st = s->streams[0];

    width = st->codec->width;
    height = st->codec->height;

    packet_size = GET_PACKET_SIZE(width, height);
    if (packet_size < 0)
        return -1;

    ret = av_get_packet(s->pb, pkt, packet_size);
    pkt->pts = pkt->dts = pkt->pos / packet_size;

    pkt->stream_index = 0;
    if (ret < 0)
        return ret;
    return 0;
}