Use stable sort with PVQ.
Cherry-pick Daala 85433214
Fully order the pvq search candidates
For portable and stable sorting, break ties.
Large differences in output were observed between AWCY and an OS X
machine because of the platform qsort implementation.
Change-Id: I294dd2e167c1e0464c7f61f32d60ab478341446e
diff --git a/av1/encoder/pvq_encoder.c b/av1/encoder/pvq_encoder.c
index b72e7ba..284b807 100644
--- a/av1/encoder/pvq_encoder.c
+++ b/av1/encoder/pvq_encoder.c
@@ -286,7 +286,9 @@
} pvq_search_item;
int items_compare(pvq_search_item *a, pvq_search_item *b) {
- return a->k - b->k;
+ /* Break ties in K with gain to ensure a stable sort.
+ Otherwise, the order depends on qsort implementation. */
+ return a->k == b->k ? a->gain - b->gain : a->k - b->k;
}
/** Perform PVQ quantization with prediction, trying several
