commit aeac045cca685c72cf0522df14379a478c474ea6
author Sergey Silkin <ssilkin@webrtc.org> Fri May 23 07:34:44 2025
committer WebRTC LUCI CQ <webrtc-scoped@luci-project-accounts.iam.gserviceaccount.com> Fri May 23 10:54:48 2025
tree ec84564e064e632d49b1649e780cc3fc3965dae7
parent 14ab61e4dfa3b73a3bebbd431a177c8f39dd4506

Disable "follow preferred order for codec fallback" by default

The feature causes "no video" issue in M135+. See webrtc:416659453 for
details.

Bug: webrtc:416659453
Change-Id: Id7509b5e9c8f99c5914f74911878daf83459d5da
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/393180
Reviewed-by: Erik Språng <sprang@webrtc.org>
Commit-Queue: Sergey Silkin <ssilkin@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#44742}

media/engine/webrtc_video_engine_unittest.cc

diff --git a/media/engine/webrtc_video_engine_unittest.cc b/media/engine/webrtc_video_engine_unittest.cc
index 31b9b4f..596c555 100644
--- a/media/engine/webrtc_video_engine_unittest.cc
+++ b/media/engine/webrtc_video_engine_unittest.cc
@@ -2556,6 +2556,8 @@
 
 TEST_F(WebRtcVideoChannelBaseTest,
        RequestEncoderFallbackNextCodecFollowNegotiatedOrder) {
+  webrtc::test::ScopedKeyValueConfig field_trials(
+      field_trials_, "WebRTC-SwitchEncoderFollowCodecPreferenceOrder/Enabled/");
   VideoSenderParameters parameters;
   parameters.codecs.push_back(GetEngineCodec("VP9"));
   parameters.codecs.push_back(GetEngineCodec("AV1"));

video/video_stream_encoder.cc

diff --git a/video/video_stream_encoder.cc b/video/video_stream_encoder.cc
index 212108e..53125ff 100644
--- a/video/video_stream_encoder.cc
+++ b/video/video_stream_encoder.cc
@@ -1530,7 +1530,7 @@
   }
 
   if (!preferred_fallback_encoder) {
-    if (!env_.field_trials().IsDisabled(
+    if (env_.field_trials().IsEnabled(
             kSwitchEncoderFollowCodecPreferenceOrderFieldTrial)) {
       encoder_fallback_requested_ = true;
       settings_.encoder_switch_request_callback->RequestEncoderFallback();

video/video_stream_encoder_unittest.cc

diff --git a/video/video_stream_encoder_unittest.cc b/video/video_stream_encoder_unittest.cc
index ea47223..bbae05d 100644
--- a/video/video_stream_encoder_unittest.cc
+++ b/video/video_stream_encoder_unittest.cc
@@ -8314,7 +8314,9 @@
       .WillByDefault(Return(WEBRTC_VIDEO_CODEC_ENCODER_FAILURE));
 
   Event encode_attempted;
-  EXPECT_CALL(switch_callback, RequestEncoderFallback())
+  EXPECT_CALL(switch_callback,
+              RequestEncoderSwitch(Field(&SdpVideoFormat::name, "VP8"),
+                                   /*allow_default_fallback=*/true))
       .WillOnce([&encode_attempted]() { encode_attempted.Set(); });
 
   video_source_.IncomingCapturedFrame(CreateFrame(1, nullptr));
@@ -8387,6 +8389,9 @@
   constexpr int kDontCare = 100;
   constexpr int kNumFrames = 8;
 
+  webrtc::test::ScopedKeyValueConfig field_trials(
+      field_trials_, "WebRTC-SwitchEncoderFollowCodecPreferenceOrder/Enabled/");
+
   NiceMock<MockVideoEncoder> video_encoder;
   StrictMock<MockEncoderSwitchRequestCallback> switch_callback;
   video_send_config_.encoder_settings.encoder_switch_request_callback =
@@ -8444,10 +8449,6 @@
   constexpr int kSufficientBitrateToNotDrop = 1000;
   constexpr int kDontCare = 100;
 
-  webrtc::test::ScopedKeyValueConfig field_trials(
-      field_trials_,
-      "WebRTC-SwitchEncoderFollowCodecPreferenceOrder/Disabled/");
-
   NiceMock<MockVideoEncoder> video_encoder;
   StrictMock<MockEncoderSwitchRequestCallback> switch_callback;
   video_send_config_.encoder_settings.encoder_switch_request_callback =