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