commit de71d1429f9135006a5c1500a74ec2e3059bfd24
author Urvang Joshi <urvang@google.com> Thu Oct 05 12:12:15 2017 -0700
committer Urvang Joshi <urvang@google.com> Sat Oct 07 04:44:19 2017 +0000
tree 78af8f43ce245e86d7264d62cb0f77e7e3884961
parent e61923faeac2415dc709ab092661a4ab527f6113

FRAME_SUPERRES: Rework to use scale factor of 8/D

Earlier, the superres scale was in the form of:
N/16, where N ranged from 8 to 16.

We change this to the form:
8/D, where D ranges from 8 to 16.

This helps on the decoder side, by making it possible to work on 8x8
blocks at a time.

Change-Id: I6c72d4b3e8d1c830e61d4bb8d7f6337a100c3064

av1/encoder/bitstream.c

diff --git a/av1/encoder/bitstream.c b/av1/encoder/bitstream.c
index 799ee81..302b56c 100644
--- a/av1/encoder/bitstream.c
+++ b/av1/encoder/bitstream.c
@@ -4249,12 +4249,12 @@
 static void write_superres_scale(const AV1_COMMON *const cm,
                                  struct aom_write_bit_buffer *wb) {
   // First bit is whether to to scale or not
-  if (cm->superres_scale_numerator == SCALE_DENOMINATOR) {
+  if (cm->superres_scale_denominator == SCALE_NUMERATOR) {
     aom_wb_write_bit(wb, 0);  // no scaling
   } else {
     aom_wb_write_bit(wb, 1);  // scaling, write scale factor
     aom_wb_write_literal(
-        wb, cm->superres_scale_numerator - SUPERRES_SCALE_NUMERATOR_MIN,
+        wb, cm->superres_scale_denominator - SUPERRES_SCALE_DENOMINATOR_MIN,
         SUPERRES_SCALE_BITS);
   }
 }