cavs: initialize various context tables to 0

Avoids crashes with corrupted files.

CC:libav-stable@libav.org

libavcodec/cavs.c

@@ -708,17 +708,17 @@ void ff_cavs_init_pic(AVSContext *h) {
  */
 void ff_cavs_init_top_lines(AVSContext *h) {
     /* alloc top line of predictors */
-    h->top_qp       = av_malloc( h->mb_width);
-    h->top_mv[0]    = av_malloc((h->mb_width*2+1)*sizeof(cavs_vector));
-    h->top_mv[1]    = av_malloc((h->mb_width*2+1)*sizeof(cavs_vector));
-    h->top_pred_Y   = av_malloc( h->mb_width*2*sizeof(*h->top_pred_Y));
-    h->top_border_y = av_malloc((h->mb_width+1)*16);
-    h->top_border_u = av_malloc( h->mb_width * 10);
-    h->top_border_v = av_malloc( h->mb_width * 10);
+    h->top_qp       = av_mallocz( h->mb_width);
+    h->top_mv[0]    = av_mallocz((h->mb_width*2+1)*sizeof(cavs_vector));
+    h->top_mv[1]    = av_mallocz((h->mb_width*2+1)*sizeof(cavs_vector));
+    h->top_pred_Y   = av_mallocz( h->mb_width*2*sizeof(*h->top_pred_Y));
+    h->top_border_y = av_mallocz((h->mb_width+1)*16);
+    h->top_border_u = av_mallocz( h->mb_width * 10);
+    h->top_border_v = av_mallocz( h->mb_width * 10);
 
     /* alloc space for co-located MVs and types */
-    h->col_mv       = av_malloc( h->mb_width*h->mb_height*4*sizeof(cavs_vector));
-    h->col_type_base = av_malloc(h->mb_width*h->mb_height);
+    h->col_mv       = av_mallocz( h->mb_width*h->mb_height*4*sizeof(cavs_vector));
+    h->col_type_base = av_mallocz(h->mb_width*h->mb_height);
     h->block        = av_mallocz(64*sizeof(int16_t));
 }