swscale/yuv2rgb: fix width % 8 != 0 and rgb/bgr8 output

Fixes Ticket2570
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libswscale/yuv2rgb.c

@@ -504,7 +504,27 @@ YUV2RGBFUNC(yuv2rgb_c_8_ordered_dither, uint8_t, 0)
     LOADCHROMA(3);
     PUTRGB8(dst_2, py_2, 3, 6 + 8);
     PUTRGB8(dst_1, py_1, 3, 6);
-CLOSEYUV2RGBFUNC(8)
+
+ENDYUV2RGBLINE(8, 0)
+    const uint8_t *d32 = ff_dither_8x8_32[y & 7];
+    const uint8_t *d64 = ff_dither_8x8_73[y & 7];
+    LOADCHROMA(0);
+    PUTRGB8(dst_1, py_1, 0, 0);
+    PUTRGB8(dst_2, py_2, 0, 0 + 8);
+
+    LOADCHROMA(1);
+    PUTRGB8(dst_2, py_2, 1, 2 + 8);
+    PUTRGB8(dst_1, py_1, 1, 2);
+
+ENDYUV2RGBLINE(8, 1)
+    const uint8_t *d32 = ff_dither_8x8_32[y & 7];
+    const uint8_t *d64 = ff_dither_8x8_73[y & 7];
+    LOADCHROMA(0);
+    PUTRGB8(dst_1, py_1, 0, 0);
+    PUTRGB8(dst_2, py_2, 0, 0 + 8);
+
+ENDYUV2RGBFUNC()
+
 
 YUV2RGBFUNC(yuv2rgb_c_4_ordered_dither, uint8_t, 0)
     const uint8_t * d64 = ff_dither_8x8_73[y & 7];