76 lines
2.8 KiB
C++
76 lines
2.8 KiB
C++
/*
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* Copyright (c) 2019 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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#ifndef VIDEO_ENCODER_BITRATE_ADJUSTER_H_
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#define VIDEO_ENCODER_BITRATE_ADJUSTER_H_
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#include <memory>
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#include "api/video/encoded_image.h"
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#include "api/video/video_bitrate_allocation.h"
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#include "api/video_codecs/video_encoder.h"
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#include "video/encoder_overshoot_detector.h"
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namespace webrtc {
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class EncoderBitrateAdjuster {
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public:
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// Size of sliding window used to track overshoot rate.
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static constexpr int64_t kWindowSizeMs = 3000;
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// Minimum number of frames since last layout change required to trust the
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// overshoot statistics. Otherwise falls back to default utilization.
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// By layout change, we mean any spatial/temporal layer being either enabled
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// or disabled.
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static constexpr size_t kMinFramesSinceLayoutChange = 30;
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// Default utilization, before reliable metrics are available, is set to 20%
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// overshoot. This is conservative so that badly misbehaving encoders don't
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// build too much queue at the very start.
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static constexpr double kDefaultUtilizationFactor = 1.2;
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explicit EncoderBitrateAdjuster(const VideoCodec& codec_settings);
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~EncoderBitrateAdjuster();
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// Adjusts the given rate allocation to make it paceable within the target
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// rates.
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VideoBitrateAllocation AdjustRateAllocation(
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const VideoEncoder::RateControlParameters& rates);
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// Updated overuse detectors with data about the encoder, specifically about
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// the temporal layer frame rate allocation.
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void OnEncoderInfo(const VideoEncoder::EncoderInfo& encoder_info);
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// Updates the overuse detectors according to the encoded image size.
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void OnEncodedFrame(const EncodedImage& encoded_image, int temporal_index);
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void Reset();
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private:
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const bool utilize_bandwidth_headroom_;
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VideoEncoder::RateControlParameters current_rate_control_parameters_;
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// FPS allocation of temporal layers, per spatial layer. Represented as a Q8
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// fraction; 0 = 0%, 255 = 100%. See VideoEncoder::EncoderInfo.fps_allocation.
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absl::InlinedVector<uint8_t, kMaxTemporalStreams>
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current_fps_allocation_[kMaxSpatialLayers];
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// Frames since layout was changed, mean that any spatial or temporal layer
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// was either disabled or enabled.
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size_t frames_since_layout_change_;
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std::unique_ptr<EncoderOvershootDetector>
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overshoot_detectors_[kMaxSpatialLayers][kMaxTemporalStreams];
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// Minimum bitrates allowed, per spatial layer.
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uint32_t min_bitrates_bps_[kMaxSpatialLayers];
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};
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} // namespace webrtc
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#endif // VIDEO_ENCODER_BITRATE_ADJUSTER_H_
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