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Adds experimental libvpx VP9 speed settings.
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Using the field trial WebRTC-VP9-PerformanceFlags, this CL allows you to
configure the libvpx VP9 encoder with a list of flags to affect the
quality vs speed tradeoff. This CL adds support for:

* Speed (effort), for the temporal base layer frames
* Speed for higher (non-base) layer frames
* De-blocking (as part of the loopfilter) enabled for:
  0 = all frames
  1 = all but frames from the highest temporal layer
  2 = no frames

Each entry in the list has a threshold in min number of pixels needed
for settings in the entry to apply.

Example: Two spatial layers (180p, 360p) with three temporal
layers are configured. Field trial "WebRTC-VP9-PerformanceFlags" set to:
"min_pixel_count:0|129600,base_layer_speed:5|8,high_layer_speed:7|8,deblock_mode:1|2"
This translates to:
S0:
  - TL0: Speed 5, deblocked
  - TL1: Speed 8, deblocked
  - TL2: Speed 8, not deblocked
S1:
  - TL0: Speed 7, not deblocked
  - TL1: Speed 8, not deblocked
  - TL2: Speed 8, not deblocked

Bug: webrtc:11551
Change-Id: Ieef6816d3e0831ff53348ecc4a90260e2ef10422
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/188461
Reviewed-by: Michael Horowitz <mhoro@webrtc.org>
Reviewed-by: Sergey Silkin <ssilkin@webrtc.org>
Commit-Queue: Erik Språng <sprang@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#32749}
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Erik Språng authored and Commit Bot committed Dec 2, 2020
1 parent 6efb031 commit 6e71674
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Showing 2 changed files with 137 additions and 58 deletions.
167 changes: 115 additions & 52 deletions modules/video_coding/codecs/vp9/vp9_impl.cc
View file
Original file line number Diff line number Diff line change
Expand Up @@ -32,6 +32,7 @@
#include "modules/video_coding/svc/scalable_video_controller_no_layering.h"
#include "modules/video_coding/utility/vp9_uncompressed_header_parser.h"
#include "rtc_base/checks.h"
#include "rtc_base/experiments/field_trial_list.h"
#include "rtc_base/experiments/field_trial_parser.h"
#include "rtc_base/experiments/rate_control_settings.h"
#include "rtc_base/keep_ref_until_done.h"
Expand Down Expand Up @@ -65,20 +66,6 @@ const int kMaxAllowedPidDiff = 30;
constexpr int kLowVp9QpThreshold = 149;
constexpr int kHighVp9QpThreshold = 205;

// Only positive speeds, range for real-time coding currently is: 5 - 8.
// Lower means slower/better quality, higher means fastest/lower quality.
int GetCpuSpeed(int width, int height) {
#if defined(WEBRTC_ARCH_ARM) || defined(WEBRTC_ARCH_ARM64) || defined(ANDROID)
return 8;
#else
// For smaller resolutions, use lower speed setting (get some coding gain at
// the cost of increased encoding complexity).
if (width * height <= 352 * 288)
return 5;
else
return 7;
#endif
}
// Helper class for extracting VP9 colorspace.
ColorSpace ExtractVP9ColorSpace(vpx_color_space_t space_t,
vpx_color_range_t range_t,
Expand Down Expand Up @@ -281,7 +268,6 @@ VP9EncoderImpl::VP9EncoderImpl(const cricket::VideoCodec& codec,
ParseSdpForVP9Profile(codec.params).value_or(VP9Profile::kProfile0)),
inited_(false),
timestamp_(0),
cpu_speed_(3),
rc_max_intra_target_(0),
encoder_(nullptr),
config_(nullptr),
Expand Down Expand Up @@ -318,7 +304,7 @@ VP9EncoderImpl::VP9EncoderImpl(const cricket::VideoCodec& codec,
external_ref_ctrl_(
!absl::StartsWith(trials.Lookup("WebRTC-Vp9ExternalRefCtrl"),
"Disabled")),
per_layer_speed_(ParsePerLayerSpeed(trials)),
performance_flags_(ParsePerformanceFlagsFromTrials(trials)),
num_steady_state_frames_(0),
config_changed_(true) {
codec_ = {};
Expand Down Expand Up @@ -455,8 +441,6 @@ bool VP9EncoderImpl::SetSvcRates(
first_active_layer_ = 0;
bool seen_active_layer = false;
bool expect_no_more_active_layers = false;
int highest_active_width = 0;
int highest_active_height = 0;
for (int i = 0; i < num_spatial_layers_; ++i) {
if (config_->ss_target_bitrate[i] > 0) {
RTC_DCHECK(!expect_no_more_active_layers) << "Only middle layer is "
Expand All @@ -466,12 +450,6 @@ bool VP9EncoderImpl::SetSvcRates(
}
num_active_spatial_layers_ = i + 1;
seen_active_layer = true;
highest_active_width =
(svc_params_.scaling_factor_num[i] * config_->g_w) /
svc_params_.scaling_factor_den[i];
highest_active_height =
(svc_params_.scaling_factor_num[i] * config_->g_h) /
svc_params_.scaling_factor_den[i];
} else {
expect_no_more_active_layers = seen_active_layer;
}
Expand Down Expand Up @@ -499,7 +477,6 @@ bool VP9EncoderImpl::SetSvcRates(
svc_controller_->OnRatesUpdated(allocation);
}
current_bitrate_allocation_ = bitrate_allocation;
cpu_speed_ = GetCpuSpeed(highest_active_width, highest_active_height);
config_changed_ = true;
return true;
}
Expand Down Expand Up @@ -665,8 +642,6 @@ int VP9EncoderImpl::InitEncode(const VideoCodec* inst,
config_->g_threads =
NumberOfThreads(config_->g_w, config_->g_h, settings.number_of_cores);

cpu_speed_ = GetCpuSpeed(config_->g_w, config_->g_h);

is_flexible_mode_ = inst->VP9().flexibleMode;

inter_layer_pred_ = inst->VP9().interLayerPred;
Expand Down Expand Up @@ -827,22 +802,16 @@ int VP9EncoderImpl::InitAndSetControlSettings(const VideoCodec* inst) {
return WEBRTC_VIDEO_CODEC_UNINITIALIZED;
}

if (per_layer_speed_.enabled) {
for (int i = 0; i < num_spatial_layers_; ++i) {
if (codec_.spatialLayers[i].active) {
continue;
}

if (per_layer_speed_.layers[i] != -1) {
svc_params_.speed_per_layer[i] = per_layer_speed_.layers[i];
} else {
svc_params_.speed_per_layer[i] = GetCpuSpeed(
codec_.spatialLayers[i].width, codec_.spatialLayers[i].height);
}
}
UpdatePerformanceFlags();
RTC_DCHECK_EQ(performance_flags_by_spatial_index_.size(),
static_cast<size_t>(num_spatial_layers_));
for (int si = 0; si < std::min<int>(num_spatial_layers_, 1); ++si) {
svc_params_.speed_per_layer[si] =
performance_flags_by_spatial_index_[si].base_layer_speed;
svc_params_.loopfilter_ctrl[si] =
performance_flags_by_spatial_index_[si].deblock_mode;
}

vpx_codec_control(encoder_, VP8E_SET_CPUUSED, cpu_speed_);
vpx_codec_control(encoder_, VP8E_SET_MAX_INTRA_BITRATE_PCT,
rc_max_intra_target_);
vpx_codec_control(encoder_, VP9E_SET_AQ_MODE,
Expand All @@ -854,6 +823,9 @@ int VP9EncoderImpl::InitAndSetControlSettings(const VideoCodec* inst) {
if (is_svc_) {
vpx_codec_control(encoder_, VP9E_SET_SVC, 1);
vpx_codec_control(encoder_, VP9E_SET_SVC_PARAMETERS, &svc_params_);
} else {
vpx_codec_control(encoder_, VP8E_SET_CPUUSED,
performance_flags_by_spatial_index_[0].base_layer_speed);
}

if (num_spatial_layers_ > 1) {
Expand Down Expand Up @@ -1068,6 +1040,24 @@ int VP9EncoderImpl::Encode(const VideoFrame& input_image,
}
}

if (is_svc_) {
// Update speed settings that might depend on temporal index.
bool speed_updated = false;
for (int sl_idx = 0; sl_idx < num_spatial_layers_; ++sl_idx) {
const int target_speed =
layer_id.temporal_layer_id_per_spatial[sl_idx] == 0
? performance_flags_by_spatial_index_[sl_idx].base_layer_speed
: performance_flags_by_spatial_index_[sl_idx].high_layer_speed;
if (svc_params_.speed_per_layer[sl_idx] != target_speed) {
svc_params_.speed_per_layer[sl_idx] = target_speed;
speed_updated = true;
}
}
if (speed_updated) {
vpx_codec_control(encoder_, VP9E_SET_SVC_PARAMETERS, &svc_params_);
}
}

vpx_codec_control(encoder_, VP9E_SET_SVC_LAYER_ID, &layer_id);

if (num_spatial_layers_ > 1) {
Expand All @@ -1080,7 +1070,6 @@ int VP9EncoderImpl::Encode(const VideoFrame& input_image,
if (vpx_codec_enc_config_set(encoder_, config_)) {
return WEBRTC_VIDEO_CODEC_ERROR;
}
vpx_codec_control(encoder_, VP8E_SET_CPUUSED, cpu_speed_);
config_changed_ = false;
}

Expand Down Expand Up @@ -1826,18 +1815,92 @@ VP9EncoderImpl::ParseQualityScalerConfig(const WebRtcKeyValueConfig& trials) {
return config;
}

void VP9EncoderImpl::UpdatePerformanceFlags() {
const auto find_speed = [&](int min_pixel_count) {
auto it = std::lower_bound(
performance_flags_.begin(), performance_flags_.end(), min_pixel_count,
[](const PerformanceFlags& lhs, int min_pixel_count) {
return lhs.min_pixel_count < min_pixel_count;
});
return it == performance_flags_.begin() ? *it : *std::prev(it);
};

performance_flags_by_spatial_index_.clear();
if (is_svc_) {
for (int si = 0; si < num_spatial_layers_; ++si) {
performance_flags_by_spatial_index_.push_back(find_speed(
codec_.spatialLayers[si].width * codec_.spatialLayers[si].height));
}
} else {
performance_flags_by_spatial_index_.push_back(
find_speed(codec_.width * codec_.height));
}
}

// static
VP9EncoderImpl::SpeedSettings VP9EncoderImpl::ParsePerLayerSpeed(
std::vector<VP9EncoderImpl::PerformanceFlags>
VP9EncoderImpl::ParsePerformanceFlagsFromTrials(
const WebRtcKeyValueConfig& trials) {
FieldTrialFlag enabled("enabled");
FieldTrialParameter<int> speeds[kMaxSpatialLayers]{
{"s0", -1}, {"s1", -1}, {"s2", -1}, {"s3", -1}, {"s4", -1}};
ParseFieldTrial(
{&enabled, &speeds[0], &speeds[1], &speeds[2], &speeds[3], &speeds[4]},
trials.Lookup("WebRTC-VP9-PerLayerSpeed"));
return SpeedSettings{enabled.Get(),
{speeds[0].Get(), speeds[1].Get(), speeds[2].Get(),
speeds[3].Get(), speeds[4].Get()}};
FieldTrialStructList<PerformanceFlags> trials_list(
{FieldTrialStructMember(
"min_pixel_count",
[](PerformanceFlags* c) { return &c->min_pixel_count; }),
FieldTrialStructMember(
"high_layer_speed",
[](PerformanceFlags* c) { return &c->high_layer_speed; }),
FieldTrialStructMember(
"base_layer_speed",
[](PerformanceFlags* c) { return &c->base_layer_speed; }),
FieldTrialStructMember(
"deblock_mode",
[](PerformanceFlags* c) { return &c->deblock_mode; })},
{});

ParseFieldTrial({&trials_list}, trials.Lookup("WebRTC-VP9-PerformanceFlags"));
std::vector<VP9EncoderImpl::PerformanceFlags> configs;
constexpr int kMinSpeed = 1;
constexpr int kMaxSpeed = 9;
for (auto& f : trials_list.Get()) {
if (f.base_layer_speed < kMinSpeed || f.base_layer_speed > kMaxSpeed ||
f.high_layer_speed < kMinSpeed || f.high_layer_speed > kMaxSpeed ||
f.deblock_mode < 0 || f.deblock_mode > 2) {
RTC_LOG(LS_WARNING) << "Ignoring invalid performance flags: "
<< "min_pixel_count = " << f.min_pixel_count
<< ", high_layer_speed = " << f.high_layer_speed
<< ", base_layer_speed = " << f.base_layer_speed
<< ", deblock_mode = " << f.deblock_mode;
continue;
}
configs.push_back(f);
}

if (configs.empty()) {
return GetDefaultPerformanceFlags();
}

std::sort(configs.begin(), configs.end(),
[](const PerformanceFlags& lhs, const PerformanceFlags& rhs) {
return lhs.min_pixel_count < rhs.min_pixel_count;
});
return configs;
}

// static
std::vector<VP9EncoderImpl::PerformanceFlags>
VP9EncoderImpl::GetDefaultPerformanceFlags() {
std::vector<VP9EncoderImpl::PerformanceFlags> default_config;
#if defined(WEBRTC_ARCH_ARM) || defined(WEBRTC_ARCH_ARM64) || defined(ANDROID)
// Speed 8 on all layers for all resolutions.
default_config.push_back({0, 8, 8, 0});
#else
// For smaller resolutions, use lower speed setting (get some coding gain at
// the cost of increased encoding complexity).
default_config.push_back({0, 5, 5, 0});

// Use speed 7 for QCIF and above.
default_config.push_back({352 * 288, 7, 7, 0});
#endif
return default_config;
}

void VP9EncoderImpl::MaybeRewrapRawWithFormat(const vpx_img_fmt fmt) {
Expand Down
28 changes: 22 additions & 6 deletions modules/video_coding/codecs/vp9/vp9_impl.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -112,7 +112,6 @@ class VP9EncoderImpl : public VP9Encoder {
const VP9Profile profile_;
bool inited_;
int64_t timestamp_;
int cpu_speed_;
uint32_t rc_max_intra_target_;
vpx_codec_ctx_t* encoder_;
vpx_codec_enc_cfg_t* config_;
Expand Down Expand Up @@ -194,11 +193,28 @@ class VP9EncoderImpl : public VP9Encoder {
const WebRtcKeyValueConfig& trials);
const bool external_ref_ctrl_;

const struct SpeedSettings {
bool enabled;
int layers[kMaxSpatialLayers];
} per_layer_speed_;
static SpeedSettings ParsePerLayerSpeed(const WebRtcKeyValueConfig& trials);
// Flags that can affect speed vs quality tradeoff, and are configureable per
// resolution ranges.
struct PerformanceFlags {
// Min number of pixels needed for this config to be valid.
int min_pixel_count = 0;

int base_layer_speed = -1; // Speed setting for TL0.
int high_layer_speed = -1; // Speed setting for TL1-TL3.
// 0 = deblock all temporal layers (TL)
// 1 = disable deblock for top-most TL
// 2 = disable deblock for all TLs
int deblock_mode = 0;
};
// Performance flags, ordered by |min_pixel_count|.
const std::vector<PerformanceFlags> performance_flags_;
// Caching of of |speed_configs_|, where index i maps to the resolution as
// specified in |codec_.spatialLayer[i]|.
std::vector<PerformanceFlags> performance_flags_by_spatial_index_;
void UpdatePerformanceFlags();
static std::vector<PerformanceFlags> ParsePerformanceFlagsFromTrials(
const WebRtcKeyValueConfig& trials);
static std::vector<PerformanceFlags> GetDefaultPerformanceFlags();

int num_steady_state_frames_;
// Only set config when this flag is set.
Expand Down

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