total == 0 seems like it should be valid (based upon patch by Steve Lhomme | slhomme divxcorp com)

Originally committed as revision 4745 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavformat/matroska.c

@@ -796,9 +796,6 @@ matroska_ebmlnum_uint (uint8_t  *data,
         n++;
     }
 
-    if (!total)
-        return AVERROR_INVALIDDATA;
-
     if (read == num_ffs)
         *num = (uint64_t)-1;
     else