lavc: initialize AVFrame.extended_data in avcodec_get_frame_defaults()

libavcodec/utils.c

@@ -635,12 +635,16 @@ enum PixelFormat avcodec_default_get_format(struct AVCodecContext *s, const enum
 
 void avcodec_get_frame_defaults(AVFrame *frame)
 {
+    if (frame->extended_data != frame->data)
+        av_freep(&frame->extended_data);
+
     memset(frame, 0, sizeof(AVFrame));
 
     frame->pts                 = AV_NOPTS_VALUE;
     frame->key_frame           = 1;
     frame->sample_aspect_ratio = (AVRational) {0, 1 };
     frame->format              = -1; /* unknown */
+    frame->extended_data       = frame->data;
 }
 
 AVFrame *avcodec_alloc_frame(void)