Merge commit 'c8e135ea'

* commit 'c8e135ea':
  vaapi_encode: Allocate slice structures and parameter buffers dynamically

Already present as e4a6eb70, one minor
fix for libav merged.
Merged-by: Mark Thompson <sw@jkqxz.net>

libavcodec/vaapi_encode.c

@@ -321,11 +321,13 @@ static int vaapi_encode_issue(AVCodecContext *avctx,
         }
     }
 
+    if (pic->nb_slices > 0) {
         pic->slices = av_mallocz_array(pic->nb_slices, sizeof(*pic->slices));
         if (!pic->slices) {
             err = AVERROR(ENOMEM);
             goto fail;
         }
+    }
     for (i = 0; i < pic->nb_slices; i++) {
         slice = &pic->slices[i];
         slice->index = i;