ffmpeg.c:1780: error: Integer Overflow L2
  ([0, +oo] - 1):unsigned32 by call to `avfilter_unref_buffer`.

ffmpeg.c:1780:17: Call
1778.                               ist->out_video_filter && avfilter_poll_frame(ist->out_video_filter->inputs[0]);
1779.             if(ist->picref)
1780.                 avfilter_unref_buffer(ist->picref);
                      ^
1781.         }
1782. #endif

libavfilter/avfilter.c:57:1: Parameter `ref->buf->refcount`
  55. }
  56. 
  57. void avfilter_unref_buffer(AVFilterBufferRef *ref)
      ^
  58. {
  59.     if(!(--ref->buf->refcount))

libavfilter/avfilter.c:59:10: Assignment
  57. void avfilter_unref_buffer(AVFilterBufferRef *ref)
  58. {
  59.     if(!(--ref->buf->refcount))
               ^
  60.         ref->buf->free(ref->buf);
  61.     av_free(ref);

ffmpeg.c:1780:17: Call
1778.                               ist->out_video_filter && avfilter_poll_frame(ist->out_video_filter->inputs[0]);
1779.             if(ist->picref)
1780.                 avfilter_unref_buffer(ist->picref);
                      ^
1781.         }
1782. #endif

libavfilter/avfilter.c:57:1: <LHS trace>
55. }
56. 
57. void avfilter_unref_buffer(AVFilterBufferRef *ref)
    ^
58. {
59.     if(!(--ref->buf->refcount))

libavfilter/avfilter.c:57:1: Parameter `ref->buf->refcount`
  55. }
  56. 
  57. void avfilter_unref_buffer(AVFilterBufferRef *ref)
      ^
  58. {
  59.     if(!(--ref->buf->refcount))

libavfilter/avfilter.c:59:10: Binary operation: ([0, +oo] - 1):unsigned32 by call to `avfilter_unref_buffer` 
  57. void avfilter_unref_buffer(AVFilterBufferRef *ref)
  58. {
  59.     if(!(--ref->buf->refcount))
               ^
  60.         ref->buf->free(ref->buf);
  61.     av_free(ref);
