From a5f895a366a97e1c22c142e83c1f34d0c899a92b Mon Sep 17 00:00:00 2001
From: Danil Chapovalov <danilchap@webrtc.org>
Date: Tue, 16 Apr 2024 11:41:56 +0200
Subject: [PATCH] Delete field trial WebRTC-UseShortVP8TL2Pattern as unused
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Bug: webrtc:9477, webrtc:11503
Change-Id: I65551a00c394aa39b0d30ecd343616e8142d1df1
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/347522
Reviewed-by: Erik Språng <sprang@webrtc.org>
Commit-Queue: Danil Chapovalov <danilchap@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#42082}
---
 experiments/field_trials.py                   |  5 +--
 .../codecs/vp8/default_temporal_layers.cc     | 36 +++++--------------
 2 files changed, 9 insertions(+), 32 deletions(-)

diff --git a/experiments/field_trials.py b/experiments/field_trials.py
index 43e2e73039..5e3521c8ca 100755
--- a/experiments/field_trials.py
+++ b/experiments/field_trials.py
@@ -781,9 +781,6 @@ POLICY_EXEMPT_FIELD_TRIALS: FrozenSet[FieldTrial] = frozenset([
     FieldTrial('WebRTC-UseDifferentiatedCellularCosts',
                'webrtc:11473',
                date(2024, 4, 1)),
-    FieldTrial('WebRTC-UseShortVP8TL2Pattern',
-               'webrtc:9477',
-               INDEFINITE),
     FieldTrial('WebRTC-UseShortVP8TL3Pattern',
                'webrtc:8162',
                INDEFINITE),
@@ -908,7 +905,7 @@ POLICY_EXEMPT_FIELD_TRIALS: FrozenSet[FieldTrial] = frozenset([
 ])  # yapf: disable
 
 POLICY_EXEMPT_FIELD_TRIALS_DIGEST: str = \
-    '2387f9c58686fb4e4f9baa69b9323ef857255d6a'
+    'c8a81e2e8f6e55640a1093bddb8efdf668341e2a'
 
 REGISTERED_FIELD_TRIALS: FrozenSet[FieldTrial] = ACTIVE_FIELD_TRIALS.union(
     POLICY_EXEMPT_FIELD_TRIALS)
diff --git a/modules/video_coding/codecs/vp8/default_temporal_layers.cc b/modules/video_coding/codecs/vp8/default_temporal_layers.cc
index 94860da1b6..8ad30f044c 100644
--- a/modules/video_coding/codecs/vp8/default_temporal_layers.cc
+++ b/modules/video_coding/codecs/vp8/default_temporal_layers.cc
@@ -141,29 +141,13 @@ DefaultTemporalLayers::GetDependencyInfo(size_t num_layers) {
       // that the 'alt' buffer reference is effectively the last keyframe.
       // TL0 also references and updates the 'last' buffer.
       // TL1 also references 'last' and references and updates 'golden'.
-      if (!field_trial::IsDisabled("WebRTC-UseShortVP8TL2Pattern")) {
-        // Shortened 4-frame pattern:
-        //   1---1   1---1 ...
-        //  /   /   /   /
-        // 0---0---0---0 ...
-        return {{"SS", {kReferenceAndUpdate, kNone, kNone}},
-                {"-S", {kReference, kUpdate, kNone}},
-                {"SR", {kReferenceAndUpdate, kNone, kNone}},
-                {"-D", {kReference, kReference, kNone, kFreezeEntropy}}};
-      } else {
-        // "Default" 8-frame pattern:
-        //   1---1---1---1   1---1---1---1 ...
-        //  /   /   /   /   /   /   /   /
-        // 0---0---0---0---0---0---0---0 ...
-        return {{"SS", {kReferenceAndUpdate, kNone, kNone}},
-                {"-S", {kReference, kUpdate, kNone}},
-                {"SR", {kReferenceAndUpdate, kNone, kNone}},
-                {"-R", {kReference, kReferenceAndUpdate, kNone}},
-                {"SR", {kReferenceAndUpdate, kNone, kNone}},
-                {"-R", {kReference, kReferenceAndUpdate, kNone}},
-                {"SR", {kReferenceAndUpdate, kNone, kNone}},
-                {"-D", {kReference, kReference, kNone, kFreezeEntropy}}};
-      }
+      //   1---1   1---1 ...
+      //  /   /   /   /
+      // 0---0---0---0 ...
+      return {{"SS", {kReferenceAndUpdate, kNone, kNone}},
+              {"-S", {kReference, kUpdate, kNone}},
+              {"SR", {kReferenceAndUpdate, kNone, kNone}},
+              {"-D", {kReference, kReference, kNone, kFreezeEntropy}}};
     case 3:
       if (field_trial::IsEnabled("WebRTC-UseShortVP8TL3Pattern")) {
         // This field trial is intended to check if it is worth using a shorter
@@ -708,11 +692,7 @@ std::vector<std::set<uint8_t>> GetTemporalDependencies(
     case 1:
       return {{0}};
     case 2:
-      if (!field_trial::IsDisabled("WebRTC-UseShortVP8TL2Pattern")) {
-        return {{2}, {0}, {0}, {1, 2}};
-      } else {
-        return {{6}, {0}, {0}, {1, 2}, {2}, {3, 4}, {4}, {5, 6}};
-      }
+      return {{2}, {0}, {0}, {1, 2}};
     case 3:
       if (field_trial::IsEnabled("WebRTC-UseShortVP8TL3Pattern")) {
         return {{0}, {0}, {0}, {0, 1, 2}};