shithub: libvpx

Info  •  Files  •  Log  •  Branches

Use small transform size in non-rd real-time mode

In non-rd real-time mode, choosing smaller transform size in
encoding gives better video quality and good speed gain than
choosing larger transform size. This patch set tx size search
method to ALLOW_8X8, which is better than using 4x4 or other
larger sizes.

Borg tests on rtc set at speed 6 showed significant gain on quality.
PSNR gain: 11.034% and SSIM gain: 15.466%.

The speed gain is 5% - 12% for <720p clips, and 2% - 7% for
720p clips.

Change-Id: If4dc74ed2df359346b059f47fb73b4a0193ec548

--- a/vp9/encoder/vp9_encodeframe.c

+++ b/vp9/encoder/vp9_encodeframe.c

@@ -2418,6 +2418,8 @@

       return rd_opt->tx_select_threshes[frame_type][ALLOW_32X32] >

                  rd_opt->tx_select_threshes[frame_type][TX_MODE_SELECT] ?

                      ALLOW_32X32 : TX_MODE_SELECT;

+    } else if (cpi->sf.tx_size_search_method == USE_TX_8X8) {

+      return ALLOW_8X8;

     } else {

       unsigned int total = 0;

       int i;

--- a/vp9/encoder/vp9_speed_features.c

+++ b/vp9/encoder/vp9_speed_features.c

@@ -269,6 +269,8 @@

     sf->partition_search_type = SOURCE_VAR_BASED_PARTITION;

     sf->search_type_check_frequency = 50;

     sf->source_var_thresh = 360;

+

+    sf->tx_size_search_method = USE_TX_8X8;

   }

   if (speed >= 7) {

--- a/vp9/encoder/vp9_speed_features.h

+++ b/vp9/encoder/vp9_speed_features.h

@@ -58,7 +58,8 @@

   USE_FULL_RD = 0,

   USE_LARGESTINTRA,

   USE_LARGESTINTRA_MODELINTER,

-  USE_LARGESTALL

+  USE_LARGESTALL,

+  USE_TX_8X8

 } TX_SIZE_SEARCH_METHOD;

 typedef enum {