shithub: libvpx

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Adapt ARNR filter length and strength.

Adjust the filter length and strength for each
ARF group based on a measure of difficulty (the boost)
and the active q range.

Remove lower limit on RDMULT value.

Average gains on the different sets in range 0.4%-0.9%.
However the ARNR changes give a very big boost on a
few clips.

Eg. Soccer ~5%, in derf set and Cyclist ~ 10% in the std-hd set

Change-Id: I2078d78798e27ad2bcc2b32d703ea37b67412ec4

--- a/vp9/encoder/vp9_firstpass.c

+++ b/vp9/encoder/vp9_firstpass.c

@@ -1428,11 +1428,14 @@

   return arf_boost;

 }

-static void configure_arnr_filter(VP9_COMP *cpi, FIRSTPASS_STATS *this_frame) {

+static void configure_arnr_filter(VP9_COMP *cpi,

+                                  FIRSTPASS_STATS *this_frame,

+                                  int group_boost) {

   int half_gf_int;

   int frames_after_arf;

   int frames_bwd = cpi->oxcf.arnr_max_frames - 1;

   int frames_fwd = cpi->oxcf.arnr_max_frames - 1;

+  int q;

   // Define the arnr filter width for this group of frames:

   // We only filter frames that lie within a distance of half

@@ -1477,6 +1480,25 @@

   }

   cpi->active_arnr_frames = frames_bwd + 1 + frames_fwd;

+

+  // Adjust the strength based on active max q

+  q = ((int)vp9_convert_qindex_to_q(cpi->active_worst_quality) >> 1);

+  if (q > 8) {

+    cpi->active_arnr_strength = cpi->oxcf.arnr_strength;

+  } else {

+    cpi->active_arnr_strength = cpi->oxcf.arnr_strength - (8 - q);

+    if (cpi->active_arnr_strength < 0)

+      cpi->active_arnr_strength = 0;

+  }

+

+  // Adjust number of frames in filter and strength based on gf boost level.

+  if (cpi->active_arnr_frames > (group_boost / 150)) {

+    cpi->active_arnr_frames = (group_boost / 150);

+    cpi->active_arnr_frames += !(cpi->active_arnr_frames & 1);

+  }

+  if (cpi->active_arnr_strength > (group_boost / 300)) {

+    cpi->active_arnr_strength = (group_boost / 300);

+  }

 }

 // Analyse and define a gf/arf group .

@@ -1655,7 +1677,7 @@

     cpi->gfu_boost = calc_arf_boost(cpi, 0, (i - 1), (i - 1), &f_boost, &b_boost);

     cpi->source_alt_ref_pending = TRUE;

-    configure_arnr_filter(cpi, this_frame);

+    configure_arnr_filter(cpi, this_frame, cpi->gfu_boost);

   } else {

     cpi->gfu_boost = (int)boost_score;

     cpi->source_alt_ref_pending = FALSE;

--- a/vp9/encoder/vp9_onyx_if.c

+++ b/vp9/encoder/vp9_onyx_if.c

@@ -2727,10 +2727,6 @@

   else

     cpi->zbin_mode_boost_enabled = TRUE;

-  if (cpi->gfu_boost <= 400) {

-    cpi->zbin_mode_boost_enabled = FALSE;

-  }

-

   // Current default encoder behaviour for the altref sign bias

   if (cpi->source_alt_ref_active)

     cpi->common.ref_frame_sign_bias[ALTREF_FRAME] = 1;

--- a/vp9/encoder/vp9_onyx_int.h

+++ b/vp9/encoder/vp9_onyx_int.h

@@ -416,6 +416,7 @@

   int max_gf_interval;

   int baseline_gf_interval;

   int active_arnr_frames;           // <= cpi->oxcf.arnr_max_frames

+  int active_arnr_strength;         // <= cpi->oxcf.arnr_max_strength

   int64_t key_frame_count;

   int prior_key_frame_distance[KEY_FRAME_CONTEXT];

--- a/vp9/encoder/vp9_rdopt.c

+++ b/vp9/encoder/vp9_rdopt.c

@@ -284,9 +284,6 @@

           (cpi->RDMULT * rd_iifactor[cpi->twopass.next_iiratio]) >> 4;

   }

-  if (cpi->RDMULT < 7)

-    cpi->RDMULT = 7;

-

   cpi->mb.errorperbit = (cpi->RDMULT / 110);

   cpi->mb.errorperbit += (cpi->mb.errorperbit == 0);

--- a/vp9/encoder/vp9_temporal_filter.c

+++ b/vp9/encoder/vp9_temporal_filter.c

@@ -381,10 +381,8 @@

   int frames_to_blur = 0;

   int start_frame = 0;

-  int strength = cpi->oxcf.arnr_strength;

-

+  int strength = cpi->active_arnr_strength;

   int blur_type = cpi->oxcf.arnr_type;

-

   int max_frames = cpi->active_arnr_frames;

   num_frames_backward = distance;

-- 

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