static int decode_frame(AVCodecContext *avctx, void *data, int *data_size,
                        AVPacket *avpkt)
{
    V210DecContext *s = avctx->priv_data;

    int h, w, stride, aligned_input;
    AVFrame *pic = avctx->coded_frame;
    const uint8_t *psrc = avpkt->data;
    uint16_t *y, *u, *v;

    if (s->custom_stride )
        stride = s->custom_stride;
    else {
        int aligned_width = ((avctx->width + 47) / 48) * 48;
        stride = aligned_width * 8 / 3;
    }

    aligned_input = !((uintptr_t)psrc & 0xf) && !(stride & 0xf);
    if (aligned_input != s->aligned_input) {
        s->aligned_input = aligned_input;
        if (HAVE_MMX)
            v210_x86_init(s);
    }

    if (pic->data[0])
        avctx->release_buffer(avctx, pic);

    if (avpkt->size < stride * avctx->height) {
        av_log(avctx, AV_LOG_ERROR, "packet too small\n");
        return -1;
    }

    pic->reference = 0;
    if (avctx->get_buffer(avctx, pic) < 0)
        return -1;

    y = (uint16_t*)pic->data[0];
    u = (uint16_t*)pic->data[1];
    v = (uint16_t*)pic->data[2];
    pic->pict_type = AV_PICTURE_TYPE_I;
    pic->key_frame = 1;

    for (h = 0; h < avctx->height; h++) {
        const uint32_t *src = (const uint32_t*)psrc;
        uint32_t val;

        w = (avctx->width / 6) * 6;
        s->unpack_frame(src, y, u, v, w);

        y += w;
        u += w >> 1;
        v += w >> 1;
        src += (w << 1) / 3;

        if (w < avctx->width - 1) {
            READ_PIXELS(u, y, v);

            val  = av_le2ne32(*src++);
            *y++ =  val & 0x3FF;
            if (w < avctx->width - 3) {
                *u++ = (val >> 10) & 0x3FF;
                *y++ = (val >> 20) & 0x3FF;

                val  = av_le2ne32(*src++);
                *v++ =  val & 0x3FF;
                *y++ = (val >> 10) & 0x3FF;
            }
        }

        psrc += stride;
        y += pic->linesize[0] / 2 - avctx->width;
        u += pic->linesize[1] / 2 - avctx->width / 2;
        v += pic->linesize[2] / 2 - avctx->width / 2;
    }

    *data_size = sizeof(AVFrame);
    *(AVFrame*)data = *avctx->coded_frame;

    return avpkt->size;
}