libavcodec/h264_refs.c:156: error: Uninitialized Value
  The value read from lens[_] was never initialized.

libavcodec/h264_refs.c:156:17: 
154.                         sl->ref_list[0][i].parent->f->buf[0]->buffer ==
155.                         sl->ref_list[1][i].parent->f->buf[0]->buffer; i++);
156.             if (i == lens[0]) {
                     ^
157.                 FFSWAP(H264Ref, sl->ref_list[1][0], sl->ref_list[1][1]);
158.             }
