static int v410_encode_frame(AVCodecContext *avctx, uint8_t *buf,
                             int buf_size, void *data)
{
    AVFrame *pic = data;
    uint8_t *dst = buf;
    uint16_t *y, *u, *v;
    uint32_t val;
    int i, j;
    int output_size = 0;

    if (buf_size < avctx->width * avctx->height * 4) {
        av_log(avctx, AV_LOG_ERROR, "Out buffer is too small.\n");
        return AVERROR(ENOMEM);
    }

    avctx->coded_frame->reference = 0;
    avctx->coded_frame->key_frame = 1;
    avctx->coded_frame->pict_type = FF_I_TYPE;

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

    for (i = 0; i < avctx->height; i++) {
        for (j = 0; j < avctx->width; j++) {
            val  = u[j] << 2;
            val |= y[j] << 12;
            val |= v[j] << 22;
            AV_WL32(dst, val);
            dst += 4;
            output_size += 4;
        }
        y += pic->linesize[0] >> 1;
        u += pic->linesize[1] >> 1;
        v += pic->linesize[2] >> 1;
    }

    return output_size;
}