h264: fix intra 16x16 mode check when using mbaff and constrained_intra_pred.

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
(cherry picked from commit a4fd95b5d511384ed3ce388d8d20a16b1c4c0530)

1 files changed, 20 insertions, 6 deletions

diff --git a/libavcodec/h264.c b/libavcodec/h264.c
index dcca6bd73c..bab032b300 100644
--- a/libavcodec/h264.c
+++ b/libavcodec/h264.c
@@ -106,12 +106,9 @@ int ff_h264_check_intra4x4_pred_mode(H264Context *h){
     }
 
     return 0;
-} //FIXME cleanup like ff_h264_check_intra_pred_mode
+} //FIXME cleanup like check_intra_pred_mode
 
-/**
- * checks if the top & left blocks are available if needed & changes the dc mode so it only uses the available blocks.
- */
-int ff_h264_check_intra_pred_mode(H264Context *h, int mode){
+static int check_intra_pred_mode(H264Context *h, int mode, int is_chroma){
     MpegEncContext * const s = &h->s;
     static const int8_t top [7]= {LEFT_DC_PRED8x8, 1,-1,-1};
     static const int8_t left[7]= { TOP_DC_PRED8x8,-1, 2,-1,DC_128_PRED8x8};
@@ -131,7 +128,7 @@ int ff_h264_check_intra_pred_mode(H264Context *h, int mode){
 
     if((h->left_samples_available&0x8080) != 0x8080){
         mode= left[ mode ];
-        if(h->left_samples_available&0x8080){ //mad cow disease mode, aka MBAFF + constrained_intra_pred
+        if(is_chroma && (h->left_samples_available&0x8080)){ //mad cow disease mode, aka MBAFF + constrained_intra_pred
             mode= ALZHEIMER_DC_L0T_PRED8x8 + (!(h->left_samples_available&0x8000)) + 2*(mode == DC_128_PRED8x8);
         }
         if(mode<0){
@@ -143,6 +140,23 @@ int ff_h264_check_intra_pred_mode(H264Context *h, int mode){
     return mode;
 }
 
+/**
+ * checks if the top & left blocks are available if needed & changes the dc mode so it only uses the available blocks.
+ */
+int ff_h264_check_intra16x16_pred_mode(H264Context *h, int mode)
+{
+    return check_intra_pred_mode(h, mode, 0);
+}
+
+/**
+ * checks if the top & left blocks are available if needed & changes the dc mode so it only uses the available blocks.
+ */
+int ff_h264_check_intra_chroma_pred_mode(H264Context *h, int mode)
+{
+    return check_intra_pred_mode(h, mode, 1);
+}
+
+
 const uint8_t *ff_h264_decode_nal(H264Context *h, const uint8_t *src, int *dst_length, int *consumed, int length){
     int i, si, di;
     uint8_t *dst;