vp56: Release old pictures after a resolution changes

Signed-off-by: Janne Grunau <janne-libav@jannau.net>

libavcodec/vp56.c

@@ -467,6 +467,7 @@ static int vp56_size_changed(AVCodecContext *avctx)
     s->mb_height = (avctx->coded_height+15) / 16;
 
     if (s->mb_width > 1000 || s->mb_height > 1000) {
+        avcodec_set_dimensions(avctx, 0, 0);
         av_log(avctx, AV_LOG_ERROR, "picture too big\n");
         return -1;
     }
@@ -515,6 +516,18 @@ int ff_vp56_decode_frame(AVCodecContext *avctx, void *data, int *data_size,
         if (!res)
             return -1;
 
+        if (res == 2) {
+            int i;
+            for (i = 0; i < 4; i++) {
+                if (s->frames[i].data[0])
+                    avctx->release_buffer(avctx, &s->frames[i]);
+            }
+            if (is_alpha) {
+                avcodec_set_dimensions(avctx, 0, 0);
+                return -1;
+            }
+        }
+
         if (!is_alpha) {
             p->reference = 1;
             if (avctx->get_buffer(avctx, p) < 0) {