avcodec/mpegpicture: Decrease size of encoding_error array

The current size is AV_NUM_DATA_POINTERS (i.e. eight).
This number is chosen in order to minimize the amount of allocations
for AVFrame.extended_(data|buf) for audio; it is meaningless
for video for which four is sufficient. So decrease this array
in order to minimize what is copied in ff_mpeg_ref_picture()
and at the places that copy a whole MpegEncContext.

Also do the same for snowenc.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>

1 files changed, 3 insertions, 1 deletions

diff --git a/libavcodec/snow.h b/libavcodec/snow.h
index 8795491cf3..f5beca66e9 100644
--- a/libavcodec/snow.h
+++ b/libavcodec/snow.h
@@ -35,6 +35,8 @@
 #include "mpegvideo.h"
 #include "h264qpel.h"
 
+#define SNOW_MAX_PLANES 4
+
 #define FF_ME_ITER 3
 
 #define MID_STATE 128
@@ -188,7 +190,7 @@ typedef struct SnowContext{
     AVMotionVector *avmv;
     unsigned avmv_size;
     int avmv_index;
-    uint64_t encoding_error[AV_NUM_DATA_POINTERS];
+    uint64_t encoding_error[SNOW_MAX_PLANES];
 
     int pred;
 }SnowContext;