commit 1f7f0d0a99fd9f2cf0d47f40f245ac0e3ed126e0
author Debargha Mukherjee <debargha@google.com> Fri Sep 21 13:26:34 2018 -0700
committer Debargha Mukherjee <debargha@google.com> Tue Sep 25 01:05:06 2018 +0000
tree 1d0c1555e0af134677ce5666c971ed99067c3c76
parent 5737825b176f33fe2564fa011f74399c25e8c648

Tune vbr bit-allocation among various pyr levels

lowres (30 frames, vbr):
-0.253% Av PSNR, +0.017% Glb PSNR, -0.415% SSIM

Also does not seem to be slower.

STATS_CHANGED

Change-Id: I059b19c4afc09082e037870fb789427b6d57a26e

av1/encoder/firstpass.c

diff --git a/av1/encoder/firstpass.c b/av1/encoder/firstpass.c
index e8ef07e..e1ab9ff 100644
--- a/av1/encoder/firstpass.c
+++ b/av1/encoder/firstpass.c
@@ -2128,22 +2128,14 @@
 }
 
 #if USE_SYMM_MULTI_LAYER
-// TODO(debargha): Temporarily disable the allocation startegy that
-// uses the macros below, since it seems to cause a slowdown.
-// INvestigate and either re-enable or remove.
-#define NEW_MULTI_LVL_BOOST_VBR_ALLOC 0
+#define NEW_MULTI_LVL_BOOST_VBR_ALLOC 1
 
 #if NEW_MULTI_LVL_BOOST_VBR_ALLOC
-#define LEAF_REDUCTION_FACTOR 0.75f
-#define LVL_3_BOOST_FACTOR 0.8f
-#define LVL_2_BOOST_FACTOR 0.3f
-
-static float_t lvl_budget_factor[MAX_PYRAMID_LVL][MAX_PYRAMID_LVL - 1] = {
-  { 0, 0, 0 },
-  { 1, 0, 0 },
-  { LVL_3_BOOST_FACTOR, 0, 0 },  // Leaking budget works better
-  { LVL_3_BOOST_FACTOR, (1 - LVL_3_BOOST_FACTOR) * LVL_2_BOOST_FACTOR,
-    (1 - LVL_3_BOOST_FACTOR) * (1 - LVL_2_BOOST_FACTOR) }
+#define LEAF_REDUCTION_FACTOR 0.75
+static double lvl_budget_factor[MAX_PYRAMID_LVL - 1][MAX_PYRAMID_LVL - 1] = {
+  { 1.0, 0.0, 0.0 },
+  { 1.0, 0.5, 0.0 },
+  { 1.0, 0.5, 0.25 },
 };
 #endif  // NEW_MULTI_LVL_BOOST_VBR_ALLOC
 #endif  // USE_SYMM_MULTI_LAYER
@@ -2247,11 +2239,12 @@
       const int this_lvl = gf_group->pyramid_level[arf_pos];
       const int dist2top = gf_group->pyramid_height - 1 - this_lvl;
 #if NEW_MULTI_LVL_BOOST_VBR_ALLOC
-      const float_t budget =
-          LEAF_REDUCTION_FACTOR * gf_group->pyramid_lvl_nodes[0];
-      const float_t lvl_boost =
-          budget * lvl_budget_factor[gf_group->pyramid_height - 1][dist2top] /
-          gf_group->pyramid_lvl_nodes[this_lvl];
+      const double lvl_ratio = LEAF_REDUCTION_FACTOR *
+                               (double)gf_group->pyramid_lvl_nodes[0] /
+                               (double)gf_group->pyramid_lvl_nodes[this_lvl];
+      const double lvl_boost =
+          AOMMIN(lvl_ratio, 3.0) *
+          lvl_budget_factor[gf_group->pyramid_height - 2][dist2top];
       gf_group->bit_allocation[arf_pos] += (int)(target_frame_size * lvl_boost);
 #else
       gf_group->bit_allocation[arf_pos] += (target_frame_size >> dist2top);