libavfilter/vsrc_color.c:152: error: Integer Overflow L2
  ([0, +oo] - 1):unsigned32 by call to `avfilter_unref_buffer`.

libavfilter/vsrc_color.c:147:5: Call
145. 
146.     avfilter_start_frame(link, avfilter_ref_buffer(picref, ~0));
147.     ff_draw_rectangle(picref->data, picref->linesize,
         ^
148.                       color->line, color->line_step, color->hsub, color->vsub,
149.                       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:150:5: Call
148.                       color->line, color->line_step, color->hsub, color->vsub,
149.                       0, 0, color->w, color->h);
150.     avfilter_draw_slice(link, 0, color->h, 1);
         ^
151.     avfilter_end_frame(link);
152.     avfilter_unref_buffer(picref);

libavfilter/avfilter.c:534:1: Parameter `link->cur_buf->linesize[*]`
  532. }
  533. 
  534. void avfilter_draw_slice(AVFilterLink *link, int y, int h, int slice_dir)
       ^
  535. {
  536.     uint8_t *src[4], *dst[4];

libavfilter/vsrc_color.c:152:5: Call
150.     avfilter_draw_slice(link, 0, color->h, 1);
151.     avfilter_end_frame(link);
152.     avfilter_unref_buffer(picref);
         ^
153. 
154.     return 0;

libavfilter/avfilter.c:87:1: <LHS trace>
85. }
86. 
87. void avfilter_unref_buffer(AVFilterBufferRef *ref)
    ^
88. {
89.     if (!ref)

libavfilter/avfilter.c:87:1: Parameter `ref->buf->refcount`
  85. }
  86. 
  87. void avfilter_unref_buffer(AVFilterBufferRef *ref)
      ^
  88. {
  89.     if (!ref)

libavfilter/avfilter.c:91:11: Binary operation: ([0, +oo] - 1):unsigned32 by call to `avfilter_unref_buffer` 
  89.     if (!ref)
  90.         return;
  91.     if (!(--ref->buf->refcount))
                ^
  92.         ref->buf->free(ref->buf);
  93.     if (ref->extended_data != ref->data)
