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Field trial to control SVC frame dropping mode in libvpx VP9 encoder

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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}
This commit is contained in:
Sergey Silkin 2024-02-16 11:42:33 +01:00 committed by WebRTC LUCI CQ
parent 54d9cd002c
commit 052bc3af92
4 changed files with 160 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
experiments/field_trials.py
View File

@ -95,6 +95,9 @@ ACTIVE_FIELD_TRIALS: FrozenSet[FieldTrial] = frozenset([
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)),

46
modules/video_coding/codecs/vp9/libvpx_vp9_encoder.cc
View File

@ -266,7 +266,8 @@ LibvpxVp9Encoder::LibvpxVp9Encoder(const cricket::VideoCodec& codec,
"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 @@ int LibvpxVp9Encoder::InitAndSetControlSettings(const VideoCodec* inst) {
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 @@ LibvpxVp9Encoder::ParseQualityScalerConfig(const FieldTrialsView& trials) {
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() ==

8
modules/video_coding/codecs/vp9/libvpx_vp9_encoder.h
View File

@ -236,6 +236,14 @@ class LibvpxVp9Encoder : public VP9Encoder {
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

109
modules/video_coding/codecs/vp9/test/vp9_impl_unittest.cc
View File

@ -2459,4 +2459,113 @@ TEST(Vp9SpeedSettingsTrialsTest, DefaultPerLayerFlagsWithSvc) {
}
}
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