libavfilter/vf_fieldorder.c:213: error: Integer Overflow L2
  ([0, +oo] - 1):unsigned32 by call to `avfilter_unref_buffer`.

libavfilter/vf_fieldorder.c:213:5: Call
211. 
212.     avfilter_end_frame(outlink);
213.     avfilter_unref_buffer(inpicref);
         ^
214. }
215. 

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);
