libavfilter/defaults.c:199: error: Integer Overflow L2
  ([0, +oo] - 1):unsigned32 by call to `avfilter_unref_buffer`.

libavfilter/defaults.c:199:13: Call
197.     if (outlink) {
198.         if (outlink->out_buf) {
199.             avfilter_unref_buffer(outlink->out_buf);
                 ^
200.             outlink->out_buf = NULL;
201.         }

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

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

libavfilter/avfilter.c:74:11: Binary operation: ([0, +oo] - 1):unsigned32 by call to `avfilter_unref_buffer` 
  72. void avfilter_unref_buffer(AVFilterBufferRef *ref)
  73. {
  74.     if (!(--ref->buf->refcount))
                ^
  75.         ref->buf->free(ref->buf);
  76.     av_free(ref->video);

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