[FFmpeg-devel] [PATCH 1/3] avcodec/h264_cabac: Fix CABAC+8x8dct in 4:4:4

[Ronald S. Bultje]

From: Anton Mitrofanov <BugMaster at narod.ru>

Use the correct ctxIdxInc calculation for coded_block_flag.
Keep old behavior for old versions of x264 for backward compatibility.

Signed-off-by: Ronald S. Bultje <rsbultje at gmail.com>
---
 libavcodec/h264_cabac.c | 47 +++++++++++++++++++++++++++++++++--------------
 1 file changed, 33 insertions(+), 14 deletions(-)

diff --git a/libavcodec/h264_cabac.c b/libavcodec/h264_cabac.c
index 11ff3a0..28aacc5 100644
--- a/libavcodec/h264_cabac.c
+++ b/libavcodec/h264_cabac.c
@@ -2347,21 +2347,40 @@ decode_intra_mb:
     if (CHROMA444(h) && IS_8x8DCT(mb_type)){
         int i;
         uint8_t *nnz_cache = sl->non_zero_count_cache;
-        for (i = 0; i < 2; i++){
-            if (sl->left_type[LEFT(i)] && !IS_8x8DCT(sl->left_type[LEFT(i)])) {
-                nnz_cache[3+8* 1 + 2*8*i]=
-                nnz_cache[3+8* 2 + 2*8*i]=
-                nnz_cache[3+8* 6 + 2*8*i]=
-                nnz_cache[3+8* 7 + 2*8*i]=
-                nnz_cache[3+8*11 + 2*8*i]=
-                nnz_cache[3+8*12 + 2*8*i]= IS_INTRA(mb_type) ? 64 : 0;
+        if (h->sei.unregistered.x264_build < 151U) {
+            for (i = 0; i < 2; i++){
+                if (sl->left_type[LEFT(i)] && !IS_8x8DCT(sl->left_type[LEFT(i)])) {
+                    nnz_cache[3+8* 1 + 2*8*i]=
+                    nnz_cache[3+8* 2 + 2*8*i]=
+                    nnz_cache[3+8* 6 + 2*8*i]=
+                    nnz_cache[3+8* 7 + 2*8*i]=
+                    nnz_cache[3+8*11 + 2*8*i]=
+                    nnz_cache[3+8*12 + 2*8*i]= IS_INTRA(mb_type) ? 64 : 0;
+                }
+            }
+            if (sl->top_type && !IS_8x8DCT(sl->top_type)){
+                uint32_t top_empty = !IS_INTRA(mb_type) ? 0 : 0x40404040;
+                AV_WN32A(&nnz_cache[4+8* 0], top_empty);
+                AV_WN32A(&nnz_cache[4+8* 5], top_empty);
+                AV_WN32A(&nnz_cache[4+8*10], top_empty);
+            }
+        } else {
+            for (i = 0; i < 2; i++){
+                if (sl->left_type[LEFT(i)] && !IS_8x8DCT(sl->left_type[LEFT(i)])) {
+                    nnz_cache[3+8* 1 + 2*8*i]=
+                    nnz_cache[3+8* 2 + 2*8*i]=
+                    nnz_cache[3+8* 6 + 2*8*i]=
+                    nnz_cache[3+8* 7 + 2*8*i]=
+                    nnz_cache[3+8*11 + 2*8*i]=
+                    nnz_cache[3+8*12 + 2*8*i]= !IS_INTRA_PCM(sl->left_type[LEFT(i)]) ? 0 : 64;
+                }
+            }
+            if (sl->top_type && !IS_8x8DCT(sl->top_type)){
+                uint32_t top_empty = !IS_INTRA_PCM(sl->top_type) ? 0 : 0x40404040;
+                AV_WN32A(&nnz_cache[4+8* 0], top_empty);
+                AV_WN32A(&nnz_cache[4+8* 5], top_empty);
+                AV_WN32A(&nnz_cache[4+8*10], top_empty);
             }
-        }
-        if (sl->top_type && !IS_8x8DCT(sl->top_type)){
-            uint32_t top_empty = !IS_INTRA(mb_type) ? 0 : 0x40404040;
-            AV_WN32A(&nnz_cache[4+8* 0], top_empty);
-            AV_WN32A(&nnz_cache[4+8* 5], top_empty);
-            AV_WN32A(&nnz_cache[4+8*10], top_empty);
         }
     }
     h->cur_pic.mb_type[mb_xy] = mb_type;
-- 
2.8.1