a0d7827b16
BUG=3712 R=marpan@google.com, stefan@webrtc.org Review URL: https://webrtc-codereview.appspot.com/18169004 git-svn-id: http://webrtc.googlecode.com/svn/trunk@7164 4adac7df-926f-26a2-2b94-8c16560cd09d
138 lines
3.5 KiB
C++
138 lines
3.5 KiB
C++
/*
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* Copyright (c) 2014 The WebRTC project authors. All Rights Reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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#include "webrtc/modules/video_coding/utility/quality_scaler.h"
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namespace webrtc {
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static const int kMinFps = 10;
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static const int kMeasureSeconds = 5;
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static const int kFramedropPercentThreshold = 60;
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static const int kLowQpThresholdDenominator = 3;
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QualityScaler::QualityScaler()
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: num_samples_(0), low_qp_threshold_(-1), downscale_shift_(0) {
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}
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void QualityScaler::Init(int max_qp) {
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ClearSamples();
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downscale_shift_ = 0;
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low_qp_threshold_ = max_qp / kLowQpThresholdDenominator ;
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}
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void QualityScaler::ReportFramerate(int framerate) {
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num_samples_ = static_cast<size_t>(
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kMeasureSeconds * (framerate < kMinFps ? kMinFps : framerate));
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}
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void QualityScaler::ReportEncodedFrame(int qp) {
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average_qp_.AddSample(qp);
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framedrop_percent_.AddSample(0);
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}
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void QualityScaler::ReportDroppedFrame() {
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framedrop_percent_.AddSample(100);
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}
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QualityScaler::Resolution QualityScaler::GetScaledResolution(
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const I420VideoFrame& frame) {
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// Both of these should be set through InitEncode -> Should be set by now.
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assert(low_qp_threshold_ >= 0);
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assert(num_samples_ > 0);
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// Update scale factor.
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int avg;
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if (framedrop_percent_.GetAverage(num_samples_, &avg) &&
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avg >= kFramedropPercentThreshold) {
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AdjustScale(false);
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} else if (average_qp_.GetAverage(num_samples_, &avg) &&
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avg <= low_qp_threshold_) {
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AdjustScale(true);
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}
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Resolution res;
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res.width = frame.width();
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res.height = frame.height();
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assert(downscale_shift_ >= 0);
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for (int shift = downscale_shift_;
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shift > 0 && res.width > 1 && res.height > 1;
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--shift) {
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res.width >>= 1;
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res.height >>= 1;
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}
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return res;
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}
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const I420VideoFrame& QualityScaler::GetScaledFrame(
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const I420VideoFrame& frame) {
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Resolution res = GetScaledResolution(frame);
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if (res.width == frame.width())
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return frame;
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scaler_.Set(frame.width(),
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frame.height(),
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res.width,
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res.height,
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kI420,
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kI420,
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kScaleBox);
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if (scaler_.Scale(frame, &scaled_frame_) != 0)
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return frame;
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scaled_frame_.set_ntp_time_ms(frame.ntp_time_ms());
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scaled_frame_.set_timestamp(frame.timestamp());
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scaled_frame_.set_render_time_ms(frame.render_time_ms());
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return scaled_frame_;
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}
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QualityScaler::MovingAverage::MovingAverage() : sum_(0) {
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}
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void QualityScaler::MovingAverage::AddSample(int sample) {
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samples_.push_back(sample);
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sum_ += sample;
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}
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bool QualityScaler::MovingAverage::GetAverage(size_t num_samples, int* avg) {
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assert(num_samples > 0);
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if (num_samples > samples_.size())
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return false;
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// Remove old samples.
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while (num_samples < samples_.size()) {
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sum_ -= samples_.front();
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samples_.pop_front();
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}
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*avg = sum_ / static_cast<int>(num_samples);
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return true;
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}
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void QualityScaler::MovingAverage::Reset() {
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sum_ = 0;
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samples_.clear();
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}
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void QualityScaler::ClearSamples() {
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average_qp_.Reset();
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framedrop_percent_.Reset();
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}
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void QualityScaler::AdjustScale(bool up) {
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downscale_shift_ += up ? -1 : 1;
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if (downscale_shift_ < 0)
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downscale_shift_ = 0;
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ClearSamples();
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}
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} // namespace webrtc
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