Merge commit 'd07b51bf'

* commit 'd07b51bf':
  aviobuf: Handle a NULL buffer in avio_close_dyn_buf
Merged-by: Michael Niedermayer <michaelni@gmx.at>

libavformat/aviobuf.c

@@ -1034,6 +1034,11 @@ int avio_close_dyn_buf(AVIOContext *s, uint8_t **pbuffer)
     static const char padbuf[FF_INPUT_BUFFER_PADDING_SIZE] = {0};
     int padding = 0;
 
+    if (!s) {
+        *pbuffer = NULL;
+        return 0;
+    }
+
     /* don't attempt to pad fixed-size packet buffers */
     if (!s->max_packet_size) {
         avio_write(s, padbuf, sizeof(padbuf));