shithub: libvpx

Download patch

ref: bbfc3290a4da45f0166bc81a7d0da0e097f3f9b3
parent: 49434a1201f821c67f8602328470df441cc67353
author: Paul Wilkins <paulwilkins@google.com>
date: Tue Jul 24 05:56:25 EDT 2018

Limit min Q for normal frames.

This patch limits the active min Q for normal frames based on the previous
KF/GF/ARF. In a few cases, especially at the end of a clip where there
has been systemic underspend, (as is often the case with slide shows),
this prevents the encoder rapidly dropping Q on normal frames (just to
try and use up bits), such that they end up with a lower Q than the key
frame / GF / ARF off which they key.

Change-Id: Ic8def5c0d1e37ca2202e007ec1d13e501c0a91dd

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

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

@@ -1329,6 +1329,14 @@

     }

   }

+  // For normal frames do not allow an active minq lower than the q used for

+  // the last boosted frame.

+  if (!frame_is_intra_only(cm) &&

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

+       rc->is_src_frame_alt_ref)) {

+    active_best_quality = VPXMAX(active_best_quality, rc->last_boosted_qindex);

+  }

+

 #if LIMIT_QRANGE_FOR_ALTREF_AND_KEY

   vpx_clear_system_state();

   // Static forced key frames Q restrictions dealt with elsewhere.