libavfilter/buffersrc.c:135: error: Integer Overflow L2
  ([0, +oo] - 1):unsigned32 by call to `avfilter_unref_buffer`.

libavfilter/buffersrc.c:135:5: Call
133. {
134.     AVFilterBufferRef *buf = opaque;
135.     avfilter_unref_buffer(buf);
         ^
136. }
137. 

libavfilter/buffer.c:75:1: <LHS trace>
73. }
74. 
75. void avfilter_unref_buffer(AVFilterBufferRef *ref)
    ^
76. {
77.     if (!ref)

libavfilter/buffer.c:75:1: Parameter `ref->buf->refcount`
  73. }
  74. 
  75. void avfilter_unref_buffer(AVFilterBufferRef *ref)
      ^
  76. {
  77.     if (!ref)

libavfilter/buffer.c:79:11: Binary operation: ([0, +oo] - 1):unsigned32 by call to `avfilter_unref_buffer` 
  77.     if (!ref)
  78.         return;
  79.     if (!(--ref->buf->refcount))
                ^
  80.         ref->buf->free(ref->buf);
  81.     if (ref->extended_data != ref->data)
