h264: skip chroma edges at the picture boundary while deblocking 4:4:4

This handles macroblock edges for the chroma components in the same way
as for the luma compoment for 4:4:4 streams. The Spec explicitly states
that the deblocking filter is not applied to edges at the boundary of
the picture.
Signed-off-by: Janne Grunau <janne-libav@jannau.net>

libavcodec/h264.c

@@ -2361,17 +2361,19 @@ static av_always_inline void xchg_mb_border(H264Context *h, uint8_t *src_y,
     }
     if (simple || !CONFIG_GRAY || !(h->flags & CODEC_FLAG_GRAY)) {
         if (chroma444) {
-            if (deblock_topleft) {
-                XCHG(top_border_m1 + (24 << pixel_shift), src_cb - (7 << pixel_shift), 1);
-                XCHG(top_border_m1 + (40 << pixel_shift), src_cr - (7 << pixel_shift), 1);
-            }
-            XCHG(top_border + (16 << pixel_shift), src_cb + (1 << pixel_shift), xchg);
-            XCHG(top_border + (24 << pixel_shift), src_cb + (9 << pixel_shift), 1);
-            XCHG(top_border + (32 << pixel_shift), src_cr + (1 << pixel_shift), xchg);
-            XCHG(top_border + (40 << pixel_shift), src_cr + (9 << pixel_shift), 1);
-            if (h->mb_x + 1 < h->mb_width) {
-                XCHG(h->top_borders[top_idx][h->mb_x + 1] + (16 << pixel_shift), src_cb + (17 << pixel_shift), 1);
-                XCHG(h->top_borders[top_idx][h->mb_x + 1] + (32 << pixel_shift), src_cr + (17 << pixel_shift), 1);
+            if (deblock_top) {
+                if (deblock_topleft) {
+                    XCHG(top_border_m1 + (24 << pixel_shift), src_cb - (7 << pixel_shift), 1);
+                    XCHG(top_border_m1 + (40 << pixel_shift), src_cr - (7 << pixel_shift), 1);
+                }
+                XCHG(top_border + (16 << pixel_shift), src_cb + (1 << pixel_shift), xchg);
+                XCHG(top_border + (24 << pixel_shift), src_cb + (9 << pixel_shift), 1);
+                XCHG(top_border + (32 << pixel_shift), src_cr + (1 << pixel_shift), xchg);
+                XCHG(top_border + (40 << pixel_shift), src_cr + (9 << pixel_shift), 1);
+                if (h->mb_x + 1 < h->mb_width) {
+                    XCHG(h->top_borders[top_idx][h->mb_x + 1] + (16 << pixel_shift), src_cb + (17 << pixel_shift), 1);
+                    XCHG(h->top_borders[top_idx][h->mb_x + 1] + (32 << pixel_shift), src_cr + (17 << pixel_shift), 1);
+                }
             }
         } else {
             if (deblock_top) {