shithub: libvpx

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vp9-svc: Fix to frames_since_golden update for SVC.

When the second (gf) temporal reference is used in SVC:
the reference is refreshed on base TL superframes, and so
the rc->frames_since_golden counter was also only updated on
base TL frames. But this was disabling the golden reference
from being used as a temporal reference for TL > 0 frames
(since frames_since_golden was 0/not updated on TL > 0 frames).

Fix is to copy the update of rc->frames_since_golden to all
upper temporal layers. This allows TL > 0 frames to test the
golden inter mode.

Gain on RTC set: ~2%, ~8% on desktop_vga clip.
Encode time increase ~5-8% on linux, 3SL-3TL run with 1 thread.

For now keep this off for TL > 0 frames in speed features, so
this change does not change current behavior for speed >= 7.

Change-Id: I405708f3f80039ae47bd64ec53e66f92160acd9e

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

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

@@ -1601,6 +1601,8 @@

   // update the golden frame counter, only for base temporal layer.

   if (cpi->use_svc && cpi->svc.use_gf_temporal_ref_current_layer &&

       cpi->svc.temporal_layer_id == 0) {

+    int i = 0;

+    SVC *const svc = &cpi->svc;

     if (cpi->refresh_golden_frame)

       rc->frames_since_golden = 0;

     else

@@ -1607,6 +1609,14 @@

       rc->frames_since_golden++;

     // Decrement count down till next gf

     if (rc->frames_till_gf_update_due > 0) rc->frames_till_gf_update_due--;

+    // Update the frames_since_golden for all upper temporal layers.

+    for (i = 1; i < svc->number_temporal_layers; ++i) {

+      const int layer = LAYER_IDS_TO_IDX(svc->spatial_layer_id, i,

+                                         svc->number_temporal_layers);

+      LAYER_CONTEXT *const lc = &svc->layer_context[layer];

+      RATE_CONTROL *const lrc = &lc->rc;

+      lrc->frames_since_golden = rc->frames_since_golden;

+    }

   }

   if (cm->frame_type == KEY_FRAME) rc->frames_since_key = 0;

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

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

@@ -629,6 +629,12 @@

         cpi->svc.number_spatial_layers == 3 && cpi->svc.temporal_layer_id > 0 &&

         cpi->oxcf.width * cpi->oxcf.height > 640 * 480)

       sf->svc_use_lowres_part = 1;

+    // For SVC when golden is used as second temporal reference: to avoid

+    // encode time increase only use this feature on base temporal layer.

+    // (i.e remove golden flag from frame_flags for temporal_layer_id > 0).

+    if (cpi->use_svc && cpi->svc.use_gf_temporal_ref_current_layer &&

+        cpi->svc.temporal_layer_id > 0)

+      cpi->ref_frame_flags &= (~VP9_GOLD_FLAG);

   }

   if (speed >= 8) {