libavfilter/vsrc_buffer.c:133: error: Integer Overflow L2
  ([0, +oo] - 1):unsigned32 by call to `avfilter_unref_buffer`.

libavfilter/vsrc_buffer.c:129:5: Assignment
127.     picref->video->pixel_aspect    = c->pixel_aspect;
128.     picref->video->interlaced      = c->frame.interlaced_frame;
129.     picref->video->top_field_first = c->frame.top_field_first;
         ^
130.     avfilter_start_frame(link, avfilter_ref_buffer(picref, ~0));
131.     avfilter_draw_slice(link, 0, link->h, 1);

libavfilter/vsrc_buffer.c:130:5: Call
128.     picref->video->interlaced      = c->frame.interlaced_frame;
129.     picref->video->top_field_first = c->frame.top_field_first;
130.     avfilter_start_frame(link, avfilter_ref_buffer(picref, ~0));
         ^
131.     avfilter_draw_slice(link, 0, link->h, 1);
132.     avfilter_end_frame(link);

libavfilter/avfilter.c:286:1: Parameter `picref->type`
  284. /* XXX: should we do the duplicating of the picture ref here, instead of
  285.  * forcing the source filter to do it? */
  286. void avfilter_start_frame(AVFilterLink *link, AVFilterBufferRef *picref)
       ^
  287. {
  288.     void (*start_frame)(AVFilterLink *, AVFilterBufferRef *);

libavfilter/vsrc_buffer.c:131:5: Call
129.     picref->video->top_field_first = c->frame.top_field_first;
130.     avfilter_start_frame(link, avfilter_ref_buffer(picref, ~0));
131.     avfilter_draw_slice(link, 0, link->h, 1);
         ^
132.     avfilter_end_frame(link);
133.     avfilter_unref_buffer(picref);

libavfilter/avfilter.c:331:1: Parameter `link->cur_buf->linesize[*]`
  329. }
  330. 
  331. void avfilter_draw_slice(AVFilterLink *link, int y, int h, int slice_dir)
       ^
  332. {
  333.     uint8_t *src[4], *dst[4];

libavfilter/vsrc_buffer.c:133:5: Call
131.     avfilter_draw_slice(link, 0, link->h, 1);
132.     avfilter_end_frame(link);
133.     avfilter_unref_buffer(picref);
         ^
134. 
135.     c->has_frame = 0;

libavfilter/avfilter.c:75:1: <LHS trace>
73. }
74. 
75. void avfilter_unref_buffer(AVFilterBufferRef *ref)
    ^
76. {
77.     if (!(--ref->buf->refcount))

libavfilter/avfilter.c:75:1: Parameter `ref->buf->refcount`
  73. }
  74. 
  75. void avfilter_unref_buffer(AVFilterBufferRef *ref)
      ^
  76. {
  77.     if (!(--ref->buf->refcount))

libavfilter/avfilter.c:77:11: Binary operation: ([0, +oo] - 1):unsigned32 by call to `avfilter_unref_buffer` 
  75. void avfilter_unref_buffer(AVFilterBufferRef *ref)
  76. {
  77.     if (!(--ref->buf->refcount))
                ^
  78.         ref->buf->free(ref->buf);
  79.     av_free(ref->video);
