libavfilter/vsrc_color.c:145: error: Integer Overflow L2
  ([0, +oo] - 1):unsigned32 by call to `avfilter_unref_buffer`.

libavfilter/vsrc_color.c:140:5: Call
138. 
139.     avfilter_start_frame(link, avfilter_ref_buffer(picref, ~0));
140.     ff_draw_rectangle(picref->data, picref->linesize,
         ^
141.                       color->line, color->line_step, color->hsub, color->vsub,
142.                       0, 0, color->w, color->h);

libavfilter/drawutils.c:79:1: Parameter `**dst`
  77. }
  78. 
  79. void ff_draw_rectangle(uint8_t *dst[4], int dst_linesize[4],
      ^
  80.                        uint8_t *src[4], int pixelstep[4],
  81.                        int hsub, int vsub, int x, int y, int w, int h)

libavfilter/vsrc_color.c:143:5: Call
141.                       color->line, color->line_step, color->hsub, color->vsub,
142.                       0, 0, color->w, color->h);
143.     avfilter_draw_slice(link, 0, color->h, 1);
         ^
144.     avfilter_end_frame(link);
145.     avfilter_unref_buffer(picref);

libavfilter/avfilter.c:442:1: Parameter `link->cur_buf->linesize[*]`
  440. }
  441. 
  442. void avfilter_draw_slice(AVFilterLink *link, int y, int h, int slice_dir)
       ^
  443. {
  444.     uint8_t *src[4], *dst[4];

libavfilter/vsrc_color.c:145:5: Call
143.     avfilter_draw_slice(link, 0, color->h, 1);
144.     avfilter_end_frame(link);
145.     avfilter_unref_buffer(picref);
         ^
146. 
147.     return 0;

libavfilter/avfilter.c:72:1: <LHS trace>
70. }
71. 
72. void avfilter_unref_buffer(AVFilterBufferRef *ref)
    ^
73. {
74.     if (!ref)

libavfilter/avfilter.c:72:1: Parameter `ref->buf->refcount`
  70. }
  71. 
  72. void avfilter_unref_buffer(AVFilterBufferRef *ref)
      ^
  73. {
  74.     if (!ref)

libavfilter/avfilter.c:76:11: Binary operation: ([0, +oo] - 1):unsigned32 by call to `avfilter_unref_buffer` 
  74.     if (!ref)
  75.         return;
  76.     if (!(--ref->buf->refcount))
                ^
  77.         ref->buf->free(ref->buf);
  78.     av_free(ref->video);
