Repo created

TMessagesProj/jni/voip/webrtc/video/encoder_bitrate_adjuster.h

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+/*
+ *  Copyright (c) 2019 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.
+ */
+
+#ifndef VIDEO_ENCODER_BITRATE_ADJUSTER_H_
+#define VIDEO_ENCODER_BITRATE_ADJUSTER_H_
+
+#include <memory>
+
+#include "api/field_trials_view.h"
+#include "api/video/encoded_image.h"
+#include "api/video/video_bitrate_allocation.h"
+#include "api/video_codecs/video_encoder.h"
+#include "video/encoder_overshoot_detector.h"
+
+namespace webrtc {
+
+class EncoderBitrateAdjuster {
+ public:
+  // Size of sliding window used to track overshoot rate.
+  static constexpr int64_t kWindowSizeMs = 3000;
+  // Minimum number of frames since last layout change required to trust the
+  // overshoot statistics. Otherwise falls back to default utilization.
+  // By layout change, we mean any simulcast/spatial/temporal layer being either
+  // enabled or disabled.
+  static constexpr size_t kMinFramesSinceLayoutChange = 30;
+  // Default utilization, before reliable metrics are available, is set to 20%
+  // overshoot. This is conservative so that badly misbehaving encoders don't
+  // build too much queue at the very start.
+  static constexpr double kDefaultUtilizationFactor = 1.2;
+
+  EncoderBitrateAdjuster(const VideoCodec& codec_settings,
+                         const FieldTrialsView& field_trials);
+  ~EncoderBitrateAdjuster();
+
+  // Adjusts the given rate allocation to make it paceable within the target
+  // rates.
+  VideoBitrateAllocation AdjustRateAllocation(
+      const VideoEncoder::RateControlParameters& rates);
+
+  // Updated overuse detectors with data about the encoder, specifically about
+  // the temporal layer frame rate allocation.
+  void OnEncoderInfo(const VideoEncoder::EncoderInfo& encoder_info);
+
+  // Updates the overuse detectors according to the encoded image size.
+  // `stream_index` is the spatial or simulcast index.
+  // TODO(https://crbug.com/webrtc/14891): If we want to support a mix of
+  // simulcast and SVC we'll also need to consider the case where we have both
+  // simulcast and spatial indices.
+  void OnEncodedFrame(DataSize size, int stream_index, int temporal_index);
+
+  void Reset();
+
+ private:
+  const bool utilize_bandwidth_headroom_;
+
+  VideoEncoder::RateControlParameters current_rate_control_parameters_;
+  // FPS allocation of temporal layers, per simulcast/spatial layer. Represented
+  // as a Q8 fraction; 0 = 0%, 255 = 100%. See
+  // VideoEncoder::EncoderInfo.fps_allocation.
+  absl::InlinedVector<uint8_t, kMaxTemporalStreams>
+      current_fps_allocation_[kMaxSpatialLayers];
+
+  // Frames since layout was changed, mean that any simulcast, spatial or
+  // temporal layer was either disabled or enabled.
+  size_t frames_since_layout_change_;
+  std::unique_ptr<EncoderOvershootDetector>
+      overshoot_detectors_[kMaxSpatialLayers][kMaxTemporalStreams];
+
+  // Minimum bitrates allowed, per spatial layer.
+  uint32_t min_bitrates_bps_[kMaxSpatialLayers];
+
+  // Size in pixels of each spatial layer.
+  uint32_t frame_size_pixels_[kMaxSpatialLayers];
+
+  // Codec type used for encoding.
+  VideoCodecType codec_;
+
+  // Codec mode: { kRealtimeVideo, kScreensharing }.
+  VideoCodecMode codec_mode_;
+};
+
+}  // namespace webrtc
+
+#endif  // VIDEO_ENCODER_BITRATE_ADJUSTER_H_