diff -ur libgdither-0.6/gdither.c libgdither/gdither.c
--- libgdither-0.6/gdither.c 2005-07-24 22:19:30.000000000 +0200
+++ libgdither/gdither.c 2008-04-20 13:43:33.000000000 +0200
@@ -342,7 +342,7 @@
for (i=0; (i + pos) < length && i < GDITHER_CONV_BLOCK; i++) {
conv[i] = x[pos + i];
}
- gdither_runf(s, channel, i, conv, ycast + s->channels * step);
+ gdither_runf(s, channel, i, conv, ycast + pos * step);
pos += i;
}
}