Erik Språng | 7ca375c | 2019-02-06 16:20:17 +0100 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright (c) 2019 The WebRTC project authors. All Rights Reserved. |
| 3 | * |
| 4 | * Use of this source code is governed by a BSD-style license |
| 5 | * that can be found in the LICENSE file in the root of the source |
| 6 | * tree. An additional intellectual property rights grant can be found |
| 7 | * in the file PATENTS. All contributing project authors may |
| 8 | * be found in the AUTHORS file in the root of the source tree. |
| 9 | */ |
| 10 | |
| 11 | #ifndef VIDEO_ENCODER_BITRATE_ADJUSTER_H_ |
| 12 | #define VIDEO_ENCODER_BITRATE_ADJUSTER_H_ |
| 13 | |
| 14 | #include <memory> |
| 15 | |
| 16 | #include "api/video/encoded_image.h" |
| 17 | #include "api/video/video_bitrate_allocation.h" |
| 18 | #include "api/video_codecs/video_encoder.h" |
| 19 | #include "video/encoder_overshoot_detector.h" |
| 20 | |
| 21 | namespace webrtc { |
| 22 | |
| 23 | class EncoderBitrateAdjuster { |
| 24 | public: |
| 25 | // Size of sliding window used to track overshoot rate. |
| 26 | static constexpr int64_t kWindowSizeMs = 3000; |
| 27 | // Minimum number of frames since last layout change required to trust the |
| 28 | // overshoot statistics. Otherwise falls back to default utilization. |
| 29 | // By layout change, we mean any spatial/temporal layer being either enabled |
| 30 | // or disabled. |
| 31 | static constexpr size_t kMinFramesSinceLayoutChange = 30; |
| 32 | // Default utilization, before reliable metrics are available, is set to 20% |
| 33 | // overshoot. This is conservative so that badly misbehaving encoders don't |
| 34 | // build too much queue at the very start. |
| 35 | static constexpr double kDefaultUtilizationFactor = 1.2; |
| 36 | |
| 37 | explicit EncoderBitrateAdjuster(const VideoCodec& codec_settings); |
| 38 | ~EncoderBitrateAdjuster(); |
| 39 | |
| 40 | // Adjusts the given rate allocation to make it paceable within the target |
| 41 | // rates. |
| 42 | VideoBitrateAllocation AdjustRateAllocation( |
| 43 | const VideoBitrateAllocation& bitrate_allocation, |
| 44 | int framerate_fps); |
| 45 | |
| 46 | // Updated overuse detectors with data about the encoder, specifically about |
| 47 | // the temporal layer frame rate allocation. |
| 48 | void OnEncoderInfo(const VideoEncoder::EncoderInfo& encoder_info); |
| 49 | |
| 50 | // Updates the overuse detectors according to the encoded image size. |
| 51 | void OnEncodedFrame(const EncodedImage& encoded_image, int temporal_index); |
| 52 | |
| 53 | void Reset(); |
| 54 | |
| 55 | private: |
| 56 | VideoBitrateAllocation current_bitrate_allocation_; |
| 57 | int current_total_framerate_fps_; |
| 58 | // FPS allocation of temporal layers, per spatial layer. Represented as a Q8 |
| 59 | // fraction; 0 = 0%, 255 = 100%. See VideoEncoder::EncoderInfo.fps_allocation. |
| 60 | absl::InlinedVector<uint8_t, kMaxTemporalStreams> |
| 61 | current_fps_allocation_[kMaxSpatialLayers]; |
| 62 | |
| 63 | // Frames since layout was changed, mean that any spatial or temporal layer |
| 64 | // was either disabled or enabled. |
| 65 | size_t frames_since_layout_change_; |
| 66 | std::unique_ptr<EncoderOvershootDetector> |
| 67 | overshoot_detectors_[kMaxSpatialLayers][kMaxTemporalStreams]; |
| 68 | |
| 69 | // Minimum bitrates allowed, per spatial layer. |
| 70 | uint32_t min_bitrates_bps_[kMaxSpatialLayers]; |
| 71 | }; |
| 72 | |
| 73 | } // namespace webrtc |
| 74 | |
| 75 | #endif // VIDEO_ENCODER_BITRATE_ADJUSTER_H_ |