libavfilter/vsrc_color.c:154: error: Integer Overflow L2
  ([0, +oo] - 1):unsigned32 by call to `avfilter_unref_buffer`.

libavfilter/vsrc_color.c:149:5: Call
147. 
148.     ff_start_frame(link, avfilter_ref_buffer(picref, ~0));
149.     ff_draw_rectangle(picref->data, picref->linesize,
         ^
150.                       color->line, color->line_step, color->hsub, color->vsub,
151.                       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:152:5: Call
150.                       color->line, color->line_step, color->hsub, color->vsub,
151.                       0, 0, color->w, color->h);
152.     ff_draw_slice(link, 0, color->h, 1);
         ^
153.     ff_end_frame(link);
154.     avfilter_unref_buffer(picref);

libavfilter/video.c:271:1: Parameter `link->cur_buf->linesize[*]`
  269. }
  270. 
  271. void ff_draw_slice(AVFilterLink *link, int y, int h, int slice_dir)
       ^
  272. {
  273.     uint8_t *src[4], *dst[4];

libavfilter/vsrc_color.c:154:5: Call
152.     ff_draw_slice(link, 0, color->h, 1);
153.     ff_end_frame(link);
154.     avfilter_unref_buffer(picref);
         ^
155. 
156.     return 0;

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, +oo] - 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)
