Field trial to control SVC frame dropping mode in libvpx VP9 encoder
Example: "WebRTC-LibvpxVp9Encoder-SvcFrameDropConfig/Enabled,layer_drop_mode:1,max_consec_drop:7/"
It is only possible to enable LAYER_DROP (layer_drop_mode=1) for now. All other modes are ignored. Max consecutive frame drops (max_consec_drop) value from the field is always applied if the field trial is enabled.
LAYER_DROP requires flexible mode (is_flexible_mode_=true) which can be enabled by means of WebRTC-Vp9InterLayerPred: https://source.chromium.org/chromium/chromium/src/+/main:third_party/webrtc/media/engine/webrtc_video_engine.cc;l=976
Bug: webrtc:15827, b/320629637
Change-Id: I9c4d4838b11547e608d863198b109cb1485902d6
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/335041
Commit-Queue: Sergey Silkin <ssilkin@webrtc.org>
Reviewed-by: Erik Språng <sprang@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#41755}
diff --git a/experiments/field_trials.py b/experiments/field_trials.py
index 86066ec..0273f89 100755
--- a/experiments/field_trials.py
+++ b/experiments/field_trials.py
@@ -95,6 +95,9 @@
FieldTrial('WebRTC-LibaomAv1Encoder-MaxConsecFrameDrop',
'webrtc:15821',
date(2024, 4, 1)),
+ FieldTrial('WebRTC-LibvpxVp9Encoder-SvcFrameDropConfig',
+ 'webrtc:15827',
+ date(2024, 9, 1)),
FieldTrial('WebRTC-Pacer-FastRetransmissions',
'chromium:1354491',
date(2024, 4, 1)),
diff --git a/modules/video_coding/codecs/vp9/libvpx_vp9_encoder.cc b/modules/video_coding/codecs/vp9/libvpx_vp9_encoder.cc
index b73fd10..20c29ab 100644
--- a/modules/video_coding/codecs/vp9/libvpx_vp9_encoder.cc
+++ b/modules/video_coding/codecs/vp9/libvpx_vp9_encoder.cc
@@ -266,7 +266,8 @@
"Disabled")),
performance_flags_(ParsePerformanceFlagsFromTrials(trials)),
num_steady_state_frames_(0),
- config_changed_(true) {
+ config_changed_(true),
+ svc_frame_drop_config_(ParseSvcFrameDropConfig(trials)) {
codec_ = {};
memset(&svc_params_, 0, sizeof(vpx_svc_extra_cfg_t));
}
@@ -924,11 +925,24 @@
svc_drop_frame_.framedrop_thresh[i] = config_->rc_dropframe_thresh;
}
} else {
- // Configure encoder to drop entire superframe whenever it needs to drop
- // a layer. This mode is preferred over per-layer dropping which causes
- // quality flickering and is not compatible with RTP non-flexible mode.
- svc_drop_frame_.framedrop_mode = FULL_SUPERFRAME_DROP;
- svc_drop_frame_.max_consec_drop = std::numeric_limits<int>::max();
+ if (svc_frame_drop_config_.enabled &&
+ svc_frame_drop_config_.layer_drop_mode == LAYER_DROP &&
+ is_flexible_mode_ && svc_controller_ &&
+ (inter_layer_pred_ == InterLayerPredMode::kOff ||
+ inter_layer_pred_ == InterLayerPredMode::kOnKeyPic)) {
+ // SVC controller is required since it properly accounts for dropped
+ // refs (unlike SetReferences(), which assumes full superframe drop).
+ svc_drop_frame_.framedrop_mode = LAYER_DROP;
+ } else {
+ // Configure encoder to drop entire superframe whenever it needs to drop
+ // a layer. This mode is preferred over per-layer dropping which causes
+ // quality flickering and is not compatible with RTP non-flexible mode.
+ svc_drop_frame_.framedrop_mode = FULL_SUPERFRAME_DROP;
+ }
+ svc_drop_frame_.max_consec_drop =
+ svc_frame_drop_config_.enabled
+ ? svc_frame_drop_config_.max_consec_drop
+ : std::numeric_limits<int>::max();
for (size_t i = 0; i < num_spatial_layers_; ++i) {
svc_drop_frame_.framedrop_thresh[i] = config_->rc_dropframe_thresh;
}
@@ -1910,6 +1924,26 @@
return config;
}
+LibvpxVp9Encoder::SvcFrameDropConfig LibvpxVp9Encoder::ParseSvcFrameDropConfig(
+ const FieldTrialsView& trials) {
+ FieldTrialFlag enabled = FieldTrialFlag("Enabled");
+ FieldTrialParameter<int> layer_drop_mode("layer_drop_mode",
+ FULL_SUPERFRAME_DROP);
+ FieldTrialParameter<int> max_consec_drop("max_consec_drop",
+ std::numeric_limits<int>::max());
+ ParseFieldTrial({&enabled, &layer_drop_mode, &max_consec_drop},
+ trials.Lookup("WebRTC-LibvpxVp9Encoder-SvcFrameDropConfig"));
+ SvcFrameDropConfig config;
+ config.enabled = enabled.Get();
+ config.layer_drop_mode = layer_drop_mode.Get();
+ config.max_consec_drop = max_consec_drop.Get();
+ RTC_LOG(LS_INFO) << "Libvpx VP9 encoder SVC frame drop config: "
+ << (config.enabled ? "enabled" : "disabled")
+ << " layer_drop_mode " << config.layer_drop_mode
+ << " max_consec_drop " << config.max_consec_drop;
+ return config;
+}
+
void LibvpxVp9Encoder::UpdatePerformanceFlags() {
flat_map<int, PerformanceFlags::ParameterSet> params_by_resolution;
if (codec_.GetVideoEncoderComplexity() ==
diff --git a/modules/video_coding/codecs/vp9/libvpx_vp9_encoder.h b/modules/video_coding/codecs/vp9/libvpx_vp9_encoder.h
index 0474e7b..3ccaa5f 100644
--- a/modules/video_coding/codecs/vp9/libvpx_vp9_encoder.h
+++ b/modules/video_coding/codecs/vp9/libvpx_vp9_encoder.h
@@ -236,6 +236,14 @@
bool config_changed_;
const LibvpxVp9EncoderInfoSettings encoder_info_override_;
+
+ const struct SvcFrameDropConfig {
+ bool enabled;
+ int layer_drop_mode; // SVC_LAYER_DROP_MODE
+ int max_consec_drop;
+ } svc_frame_drop_config_;
+ static SvcFrameDropConfig ParseSvcFrameDropConfig(
+ const FieldTrialsView& trials);
};
} // namespace webrtc
diff --git a/modules/video_coding/codecs/vp9/test/vp9_impl_unittest.cc b/modules/video_coding/codecs/vp9/test/vp9_impl_unittest.cc
index 993fd24..50e9cf2 100644
--- a/modules/video_coding/codecs/vp9/test/vp9_impl_unittest.cc
+++ b/modules/video_coding/codecs/vp9/test/vp9_impl_unittest.cc
@@ -2459,4 +2459,113 @@
}
}
+struct SvcFrameDropConfigTestParameters {
+ bool flexible_mode;
+ absl::optional<ScalabilityMode> scalability_mode;
+ std::string field_trial;
+ int expected_framedrop_mode;
+ int expected_max_consec_drop;
+};
+
+class TestVp9ImplSvcFrameDropConfig
+ : public ::testing::TestWithParam<SvcFrameDropConfigTestParameters> {};
+
+TEST_P(TestVp9ImplSvcFrameDropConfig, SvcFrameDropConfig) {
+ SvcFrameDropConfigTestParameters test_params = GetParam();
+ auto* const vpx = new NiceMock<MockLibvpxInterface>();
+ LibvpxVp9Encoder encoder(
+ cricket::CreateVideoCodec(cricket::kVp9CodecName),
+ absl::WrapUnique<LibvpxInterface>(vpx),
+ test::ExplicitKeyValueConfig(test_params.field_trial));
+
+ vpx_image_t img;
+ ON_CALL(*vpx, img_wrap).WillByDefault(GetWrapImageFunction(&img));
+
+ EXPECT_CALL(*vpx,
+ codec_control(_, VP9E_SET_SVC_FRAME_DROP_LAYER,
+ SafeMatcherCast<vpx_svc_frame_drop_t*>(AllOf(
+ Field(&vpx_svc_frame_drop_t::framedrop_mode,
+ test_params.expected_framedrop_mode),
+ Field(&vpx_svc_frame_drop_t::max_consec_drop,
+ test_params.expected_max_consec_drop)))));
+
+ VideoCodec settings = DefaultCodecSettings();
+ settings.VP9()->flexibleMode = test_params.flexible_mode;
+ if (test_params.scalability_mode.has_value()) {
+ settings.SetScalabilityMode(*test_params.scalability_mode);
+ }
+ settings.VP9()->numberOfSpatialLayers =
+ 3; // to execute SVC code paths even when scalability_mode is not set.
+
+ EXPECT_EQ(WEBRTC_VIDEO_CODEC_OK, encoder.InitEncode(&settings, kSettings));
+}
+
+INSTANTIATE_TEST_SUITE_P(
+ All,
+ TestVp9ImplSvcFrameDropConfig,
+ ::testing::Values(
+ // Flexible mode is disabled. Layer drop is not allowed. Ignore
+ // layer_drop_mode from field trial.
+ SvcFrameDropConfigTestParameters{
+ .flexible_mode = false,
+ .scalability_mode = ScalabilityMode::kL3T3_KEY,
+ .field_trial = "WebRTC-LibvpxVp9Encoder-SvcFrameDropConfig/"
+ "Enabled,layer_drop_mode:1,max_consec_drop:7/",
+ .expected_framedrop_mode = FULL_SUPERFRAME_DROP,
+ .expected_max_consec_drop = 7},
+ // Flexible mode is enabled but the field trial is not set. Use default
+ // settings.
+ SvcFrameDropConfigTestParameters{
+ .flexible_mode = true,
+ .scalability_mode = ScalabilityMode::kL3T3_KEY,
+ .field_trial = "",
+ .expected_framedrop_mode = FULL_SUPERFRAME_DROP,
+ .expected_max_consec_drop = std::numeric_limits<int>::max()},
+ // Flexible mode is enabled but the field trial is disabled. Use default
+ // settings.
+ SvcFrameDropConfigTestParameters{
+ .flexible_mode = true,
+ .scalability_mode = ScalabilityMode::kL3T3_KEY,
+ .field_trial = "WebRTC-LibvpxVp9Encoder-SvcFrameDropConfig/"
+ "Disabled,layer_drop_mode:1,max_consec_drop:7/",
+ .expected_framedrop_mode = FULL_SUPERFRAME_DROP,
+ .expected_max_consec_drop = std::numeric_limits<int>::max()},
+ // Flexible mode is enabled, layer drop is enabled, KSVC. Apply config
+ // from field trial.
+ SvcFrameDropConfigTestParameters{
+ .flexible_mode = true,
+ .scalability_mode = ScalabilityMode::kL3T3_KEY,
+ .field_trial = "WebRTC-LibvpxVp9Encoder-SvcFrameDropConfig/"
+ "Enabled,layer_drop_mode:1,max_consec_drop:7/",
+ .expected_framedrop_mode = LAYER_DROP,
+ .expected_max_consec_drop = 7},
+ // Flexible mode is enabled, layer drop is enabled, simulcast. Apply
+ // config from field trial.
+ SvcFrameDropConfigTestParameters{
+ .flexible_mode = true,
+ .scalability_mode = ScalabilityMode::kS3T3,
+ .field_trial = "WebRTC-LibvpxVp9Encoder-SvcFrameDropConfig/"
+ "Enabled,layer_drop_mode:1,max_consec_drop:7/",
+ .expected_framedrop_mode = LAYER_DROP,
+ .expected_max_consec_drop = 7},
+ // Flexible mode is enabled, layer drop is enabled, full SVC. Apply
+ // config from field trial.
+ SvcFrameDropConfigTestParameters{
+ .flexible_mode = false,
+ .scalability_mode = ScalabilityMode::kL3T3,
+ .field_trial = "WebRTC-LibvpxVp9Encoder-SvcFrameDropConfig/"
+ "Enabled,layer_drop_mode:1,max_consec_drop:7/",
+ .expected_framedrop_mode = FULL_SUPERFRAME_DROP,
+ .expected_max_consec_drop = 7},
+ // Flexible mode is enabled, layer-drop is enabled, scalability mode is
+ // not set (i.e., SVC controller is not enabled). Ignore layer_drop_mode
+ // from field trial.
+ SvcFrameDropConfigTestParameters{
+ .flexible_mode = true,
+ .scalability_mode = absl::nullopt,
+ .field_trial = "WebRTC-LibvpxVp9Encoder-SvcFrameDropConfig/"
+ "Enabled,layer_drop_mode:1,max_consec_drop:7/",
+ .expected_framedrop_mode = FULL_SUPERFRAME_DROP,
+ .expected_max_consec_drop = 7}));
+
} // namespace webrtc
