| /* |
| * Copyright 2016 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 COMMON_VIDEO_INCLUDE_BITRATE_ADJUSTER_H_ |
| #define COMMON_VIDEO_INCLUDE_BITRATE_ADJUSTER_H_ |
| |
| #include <stddef.h> |
| #include <stdint.h> |
| |
| #include "absl/types/optional.h" |
| #include "rtc_base/criticalsection.h" |
| #include "rtc_base/rate_statistics.h" |
| #include "rtc_base/thread_annotations.h" |
| |
| namespace webrtc { |
| |
| // Certain hardware encoders tend to consistently overshoot the bitrate that |
| // they are configured to encode at. This class estimates an adjusted bitrate |
| // that when set on the encoder will produce the desired bitrate. |
| class BitrateAdjuster { |
| public: |
| // min_adjusted_bitrate_pct and max_adjusted_bitrate_pct are the lower and |
| // upper bound outputted adjusted bitrates as a percentage of the target |
| // bitrate. |
| BitrateAdjuster(float min_adjusted_bitrate_pct, |
| float max_adjusted_bitrate_pct); |
| virtual ~BitrateAdjuster() {} |
| |
| static const uint32_t kBitrateUpdateIntervalMs; |
| static const uint32_t kBitrateUpdateFrameInterval; |
| static const float kBitrateTolerancePct; |
| static const float kBytesPerMsToBitsPerSecond; |
| |
| // Sets the desired bitrate in bps (bits per second). |
| // Should be called at least once before Update. |
| void SetTargetBitrateBps(uint32_t bitrate_bps); |
| uint32_t GetTargetBitrateBps() const; |
| |
| // Returns the adjusted bitrate in bps. |
| uint32_t GetAdjustedBitrateBps() const; |
| |
| // Returns what we think the current bitrate is. |
| absl::optional<uint32_t> GetEstimatedBitrateBps(); |
| |
| // This should be called after each frame is encoded. The timestamp at which |
| // it is called is used to estimate the output bitrate of the encoder. |
| // Should be called from only one thread. |
| void Update(size_t frame_size); |
| |
| private: |
| // Returns true if the bitrate is within kBitrateTolerancePct of bitrate_bps. |
| bool IsWithinTolerance(uint32_t bitrate_bps, uint32_t target_bitrate_bps); |
| |
| // Returns smallest possible adjusted value. |
| uint32_t GetMinAdjustedBitrateBps() const RTC_EXCLUSIVE_LOCKS_REQUIRED(crit_); |
| // Returns largest possible adjusted value. |
| uint32_t GetMaxAdjustedBitrateBps() const RTC_EXCLUSIVE_LOCKS_REQUIRED(crit_); |
| |
| void Reset(); |
| void UpdateBitrate(uint32_t current_time_ms) |
| RTC_EXCLUSIVE_LOCKS_REQUIRED(crit_); |
| |
| rtc::CriticalSection crit_; |
| const float min_adjusted_bitrate_pct_; |
| const float max_adjusted_bitrate_pct_; |
| // The bitrate we want. |
| volatile uint32_t target_bitrate_bps_ RTC_GUARDED_BY(crit_); |
| // The bitrate we use to get what we want. |
| volatile uint32_t adjusted_bitrate_bps_ RTC_GUARDED_BY(crit_); |
| // The target bitrate that the adjusted bitrate was computed from. |
| volatile uint32_t last_adjusted_target_bitrate_bps_ RTC_GUARDED_BY(crit_); |
| // Used to estimate bitrate. |
| RateStatistics bitrate_tracker_ RTC_GUARDED_BY(crit_); |
| // The last time we tried to adjust the bitrate. |
| uint32_t last_bitrate_update_time_ms_ RTC_GUARDED_BY(crit_); |
| // The number of frames since the last time we tried to adjust the bitrate. |
| uint32_t frames_since_last_update_ RTC_GUARDED_BY(crit_); |
| }; |
| |
| } // namespace webrtc |
| |
| #endif // COMMON_VIDEO_INCLUDE_BITRATE_ADJUSTER_H_ |