libavfilter/vsrc_color.c:175: error: Integer Overflow L1
  (0 - 1):unsigned32 by call to `avfilter_unref_buffer`.

libavfilter/vsrc_color.c:153:5: Assignment
151.     picref->video->pixel_aspect = (AVRational) {1, 1};
152.     picref->pts                 = color->pts++;
153.     picref->pos                 = -1;
         ^
154. 
155.     buf_out = avfilter_ref_buffer(picref, ~0);

libavfilter/vsrc_color.c:175:5: Call
173. 
174. fail:
175.     avfilter_unref_buffer(picref);
         ^
176. 
177.     return ret;

libavfilter/buffer.c:74:1: <LHS trace>
72. }
73. 
74. void avfilter_unref_buffer(AVFilterBufferRef *ref)
    ^
75. {
76.     if (!ref)

libavfilter/buffer.c:74:1: Parameter `ref->buf->refcount`
  72. }
  73. 
  74. void avfilter_unref_buffer(AVFilterBufferRef *ref)
      ^
  75. {
  76.     if (!ref)

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