yuv2422_1_c_template(SwsContext *c, const int16_t *buf0,
                     const int16_t *ubuf[2], const int16_t *vbuf[2],
                     const int16_t *abuf0, uint8_t *dest, int dstW,
                     int uvalpha, int y, enum PixelFormat target)
{
    const int16_t *ubuf0 = ubuf[0], *vbuf0 = vbuf[0];
    int i;
    if (uvalpha < 2048) {
        for (i = 0; i < (dstW >> 1); i++) {
            int Y1 = buf0[i * 2]     >> 7;
            int Y2 = buf0[i * 2 + 1] >> 7;
            int U  = ubuf0[i]        >> 7;
            int V  = vbuf0[i]        >> 7;
            output_pixels(i * 4, Y1, U, Y2, V);
        }
    } else {
        const int16_t *ubuf1 = ubuf[1], *vbuf1 = vbuf[1];
        for (i = 0; i < (dstW >> 1); i++) {
            int Y1 =  buf0[i * 2]          >> 7;
            int Y2 =  buf0[i * 2 + 1]      >> 7;
            int U  = (ubuf0[i] + ubuf1[i]) >> 8;
            int V  = (vbuf0[i] + vbuf1[i]) >> 8;
            output_pixels(i * 4, Y1, U, Y2, V);
        }
    }
}