commit 9c2d0a78b39cd5cff4c36c9e321454c6de48c117
author Fyodor Kyslov <kyslov@google.com> Mon Nov 30 18:37:06 2020 -0800
committer Fyodor Kyslov <kyslov@google.com> Tue Dec 01 20:51:06 2020 +0000
tree 9a7aab727698a618f91be58b845d8f14163b40b2
parent 351401731c9c4793c7a8bcc3cb49d1cc05a31050

AV1 RT: Refine 32x32 block split on min-max var diff

Split 32x32 block on min-max variance condition for noisy content only.
~2% speed up on lowres speed 8 (no noise estimation) with neutral
BDrate. ~1.3% BDRate gain on RTC testset on speed 8 (on 720p clips where
noise estimation is on)

Change-Id: Icce2925f7c425a38934cac37d741745eb38ec8d3

av1/encoder/var_based_part.c

diff --git a/av1/encoder/var_based_part.c b/av1/encoder/var_based_part.c
index c6d0f05..c22dc10 100644
--- a/av1/encoder/var_based_part.c
+++ b/av1/encoder/var_based_part.c
@@ -847,6 +847,7 @@
   const uint8_t *d;
   int sp;
   int dp;
+  NOISE_LEVEL noise_level = kLow;
 
   int is_key_frame =
       (frame_is_intra_only(cm) ||
@@ -923,6 +924,8 @@
     d = AV1_VAR_OFFS;
     dp = 0;
   }
+  if (cpi->noise_estimate.enabled)
+    noise_level = av1_noise_estimate_extract_level(&cpi->noise_estimate);
 
   if (low_res && threshold_4x4avg < INT64_MAX)
     CHECK_MEM_ERROR(cm, vt2, aom_malloc(sizeof(*vt2)));
@@ -996,14 +999,18 @@
       var_64x64 = vt->split[m].part_variances.none.variance;
       max_var_64x64 = AOMMAX(var_64x64, max_var_64x64);
       min_var_64x64 = AOMMIN(var_64x64, min_var_64x64);
-      // If variance of this 64x64 block is above (some threshold of) the
-      // average variance over the sub-32x32 blocks, then force this block to
-      // split. Only checking this for noise level >= medium for now.
+      // If the difference of the max-min variances of sub-blocks or max
+      // variance of a sub-block is above some threshold of then force this
+      // block to split. Only checking this for noise level >= medium or if
+      // encoder is in SVC.
 
       if (!is_key_frame &&
           (max_var_32x32[m] - min_var_32x32[m]) > 3 * (thresholds[1] >> 3) &&
-          max_var_32x32[m] > thresholds[1] >> 1)
+          max_var_32x32[m] > thresholds[1] >> 1 &&
+          (noise_level >= kMedium || cpi->use_svc)) {
         force_split[1 + m] = 1;
+        force_split[0] = 1;
+      }
       avg_64x64 += var_64x64;
     }
     if (is_small_sb) force_split[0] = 1;