shithub: libvpx

Download patch

ref: cea5e1c1e362ea37612346ed1585ae28089c1f45
parent: 449e46958cd8d644f7713dd8312636f7aa72b139
author: paulwilkins <paulwilkins@google.com>
date: Tue Dec 15 05:27:51 EST 2015

1 pass VBR mode bug fix.

The one pass VBR mode selects a Q range based on a
moving average of recent Q values. This calculation
should have been excluding arf overlay frames as these
are usually coded at the highest allowed value. Their
inclusion skews the average and can cause it to drift
upwards even when the clip as a whole is undershooting.

As such it can undermine correct adaptation of the allowed
Q range especially for easy content.

Change-Id: I7d10fe4227262376aa2dc2a7aec0f1fd82bf11f9

--- a/vp9/encoder/vp9_ratectrl.c

+++ b/vp9/encoder/vp9_ratectrl.c

@@ -1313,9 +1313,9 @@

       }

     }

   } else {

-    if (rc->is_src_frame_alt_ref ||

-        !(cpi->refresh_golden_frame || cpi->refresh_alt_ref_frame) ||

-        (cpi->use_svc && oxcf->rc_mode == VPX_CBR)) {

+    if ((cpi->use_svc && oxcf->rc_mode == VPX_CBR) ||

+        (!rc->is_src_frame_alt_ref &&

+         !(cpi->refresh_golden_frame || cpi->refresh_alt_ref_frame))) {

       rc->last_q[INTER_FRAME] = qindex;

       rc->avg_frame_qindex[INTER_FRAME] =

         ROUND_POWER_OF_TWO(3 * rc->avg_frame_qindex[INTER_FRAME] + qindex, 2);