libavfilter/defaults.c:100: error: Integer Overflow L2
  ([0, +oo] - 1):unsigned32 by call to `avfilter_unref_buffer`.

libavfilter/defaults.c:100:5: Call
 98.         out = link->dst->outputs[0];
 99. 
100.     avfilter_unref_buffer(link->cur_buf);
         ^
101.     link->cur_buf = NULL;
102. 

libavfilter/avfilter.c:57:1: <LHS trace>
55. }
56. 
57. void avfilter_unref_buffer(AVFilterBufferRef *ref)
    ^
58. {
59.     if(!(--ref->buf->refcount))

libavfilter/avfilter.c:57:1: Parameter `ref->buf->refcount`
  55. }
  56. 
  57. void avfilter_unref_buffer(AVFilterBufferRef *ref)
      ^
  58. {
  59.     if(!(--ref->buf->refcount))

libavfilter/avfilter.c:59:10: Binary operation: ([0, +oo] - 1):unsigned32 by call to `avfilter_unref_buffer` 
  57. void avfilter_unref_buffer(AVFilterBufferRef *ref)
  58. {
  59.     if(!(--ref->buf->refcount))
               ^
  60.         ref->buf->free(ref->buf);
  61.     av_free(ref);

void avfilter_unref_buffer(AVFilterBufferRef *ref)
{
    if(!(--ref->buf->refcount))
        ref->buf->free(ref->buf);
    av_free(ref);
}
['void avfilter_default_end_frame(AVFilterLink *link)\n{\n    AVFilterLink *out = NULL;\n    if(link->dst->output_count)\n        out = link->dst->outputs[0];\n    avfilter_unref_buffer(link->cur_buf);\n    link->cur_buf = NULL;\n    if(out) {\n        if(out->out_buf) {\n            avfilter_unref_buffer(out->out_buf);\n            out->out_buf = NULL;\n        }\n        avfilter_end_frame(out);\n    }\n}', 'void avfilter_unref_buffer(AVFilterBufferRef *ref)\n{\n    if(!(--ref->buf->refcount))\n        ref->buf->free(ref->buf);\n    av_free(ref);\n}']