avconv.c:1572: error: Integer Overflow L2
  ([0, +oo] - 1):unsigned32 by call to `avfilter_unref_buffer`.

avconv.c:1564:39: Call
1562.             avfilter_copy_buf_props(filtered_frame, picref);
1563.             if (picref->pts != AV_NOPTS_VALUE) {
1564.                 filtered_frame->pts = av_rescale_q(picref->pts,
                                            ^
1565.                                                    ost->filter->filter->inputs[0]->time_base,
1566.                                                    ost->st->codec->time_base) -

libavutil/mathematics.c:143:12: Call
  141. int64_t av_rescale_q(int64_t a, AVRational bq, AVRational cq)
  142. {
  143.     return av_rescale_q_rnd(a, bq, cq, AV_ROUND_NEAR_INF);
                  ^
  144. }
  145. 

libavutil/mathematics.c:138:12: Call
    136.     int64_t b= bq.num * (int64_t)cq.den;
    137.     int64_t c= cq.num * (int64_t)bq.den;
    138.     return av_rescale_rnd(a, b, c, rnd);
                    ^
    139. }
    140. 

libavutil/mathematics.c:83:39: Unknown value from: av_rescale_rnd
      81.     assert((unsigned)rnd<=5 && rnd!=4);
      82. 
      83.     if(a<0 && a != INT64_MIN) return -av_rescale_rnd(-a, b, c, rnd ^ ((rnd>>1)&1));
                                                ^
      84. 
      85.     if(rnd==AV_ROUND_NEAR_INF) r= c/2;

libavutil/mathematics.c:83:31: Assignment
      81.     assert((unsigned)rnd<=5 && rnd!=4);
      82. 
      83.     if(a<0 && a != INT64_MIN) return -av_rescale_rnd(-a, b, c, rnd ^ ((rnd>>1)&1));
                                        ^
      84. 
      85.     if(rnd==AV_ROUND_NEAR_INF) r= c/2;

libavutil/mathematics.c:138:5: Assignment
    136.     int64_t b= bq.num * (int64_t)cq.den;
    137.     int64_t c= cq.num * (int64_t)bq.den;
    138.     return av_rescale_rnd(a, b, c, rnd);
             ^
    139. }
    140. 

libavutil/mathematics.c:143:5: Assignment
  141. int64_t av_rescale_q(int64_t a, AVRational bq, AVRational cq)
  142. {
  143.     return av_rescale_q_rnd(a, bq, cq, AV_ROUND_NEAR_INF);
           ^
  144. }
  145. 

avconv.c:1564:17: Assignment
1562.             avfilter_copy_buf_props(filtered_frame, picref);
1563.             if (picref->pts != AV_NOPTS_VALUE) {
1564.                 filtered_frame->pts = av_rescale_q(picref->pts,
                      ^
1565.                                                    ost->filter->filter->inputs[0]->time_base,
1566.                                                    ost->st->codec->time_base) -

avconv.c:1572:21: Call
1570. 
1571.                 if (of->start_time && filtered_frame->pts < 0) {
1572.                     avfilter_unref_buffer(picref);
                          ^
1573.                     continue;
1574.                 }

libavfilter/buffer.c:74:1: <LHS trace>
72. }
73. 
74. void avfilter_unref_buffer(AVFilterBufferRef *ref)
    ^
75. {
76.     if (!ref)

libavfilter/buffer.c:74:1: Parameter `ref->buf->refcount`
  72. }
  73. 
  74. void avfilter_unref_buffer(AVFilterBufferRef *ref)
      ^
  75. {
  76.     if (!ref)

libavfilter/buffer.c:78:11: Binary operation: ([0, +oo] - 1):unsigned32 by call to `avfilter_unref_buffer` 
  76.     if (!ref)
  77.         return;
  78.     if (!(--ref->buf->refcount))
                ^
  79.         ref->buf->free(ref->buf);
  80.     if (ref->extended_data != ref->data)
