commit 60a35f2e125a0eff1a6dee58dafc615debe37939
author Paul Wilkins <paulwilkins@google.com> Mon Feb 24 17:09:59 2020 +0000
committer Paul Wilkins <paulwilkins@google.com> Thu Mar 19 17:58:36 2020 +0000
tree 7cf1b0b26e712519602a13f3de2e51ff1c9bceb1
parent f84f7c47ce8c55f310c307ddc97803e270fb8ec4

Tighten up recode tolerance for very low rate frames.

This small change reduces the recode tolerance by a small amount.
The main impact is for very low rate frames where previously the
rate error threshold was (target rate * X%) + 200 it is now
max ((target rate x X%), 100).

This will not have much impact at all at higher rates and will mainly
affect leaf frames where the target rate may only be a few hundred
bits.

STATS_CHANGED

Change-Id: I2ec9f031904d9430fae3dc78dedeaae26cc67e18

av1/encoder/ratectrl.c

diff --git a/av1/encoder/ratectrl.c b/av1/encoder/ratectrl.c
index f0a107d..7a895ca 100644
--- a/av1/encoder/ratectrl.c
+++ b/av1/encoder/ratectrl.c
@@ -1486,10 +1486,11 @@
   } else {
     // For very small rate targets where the fractional adjustment
     // may be tiny make sure there is at least a minimum range.
-    const int tolerance = (cpi->sf.hl_sf.recode_tolerance * frame_target) / 100;
-    *frame_under_shoot_limit = AOMMAX(frame_target - tolerance - 200, 0);
+    const int tolerance =
+        AOMMAX(100, (cpi->sf.hl_sf.recode_tolerance * frame_target) / 100);
+    *frame_under_shoot_limit = AOMMAX(frame_target - tolerance, 0);
     *frame_over_shoot_limit =
-        AOMMIN(frame_target + tolerance + 200, cpi->rc.max_frame_bandwidth);
+        AOMMIN(frame_target + tolerance, cpi->rc.max_frame_bandwidth);
   }
 }