libavcodec/dvdsubenc.c:115: error: Uninitialized Value
  The value read from hist[_] was never initialized.

libavcodec/dvdsubenc.c:115:13: 
113.             // only count non-transparent pixels
114.             alpha = h->rects[object_id].rgba_palette[color] >> 24;
115.             hist[color] += alpha;
                 ^
116.         }
117.     for (color=3;; --color) {
