1 /* 2 * Copyright (c) 2012 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 MODULES_AUDIO_MIXER_AUDIO_MIXER_IMPL_H_ 12 #define MODULES_AUDIO_MIXER_AUDIO_MIXER_IMPL_H_ 13 14 #include <stddef.h> 15 16 #include <memory> 17 #include <vector> 18 19 #include "api/audio/audio_frame.h" 20 #include "api/audio/audio_mixer.h" 21 #include "api/scoped_refptr.h" 22 #include "modules/audio_mixer/frame_combiner.h" 23 #include "modules/audio_mixer/output_rate_calculator.h" 24 #include "rtc_base/constructor_magic.h" 25 #include "rtc_base/race_checker.h" 26 #include "rtc_base/synchronization/mutex.h" 27 #include "rtc_base/thread_annotations.h" 28 29 namespace webrtc { 30 31 typedef std::vector<AudioFrame*> AudioFrameList; 32 33 class AudioMixerImpl : public AudioMixer { 34 public: 35 struct SourceStatus { SourceStatusSourceStatus36 SourceStatus(Source* audio_source, bool is_mixed, float gain) 37 : audio_source(audio_source), is_mixed(is_mixed), gain(gain) {} 38 Source* audio_source = nullptr; 39 bool is_mixed = false; 40 float gain = 0.0f; 41 42 // A frame that will be passed to audio_source->GetAudioFrameWithInfo. 43 AudioFrame audio_frame; 44 }; 45 46 using SourceStatusList = std::vector<std::unique_ptr<SourceStatus>>; 47 48 // AudioProcessing only accepts 10 ms frames. 49 static const int kFrameDurationInMs = 10; 50 enum : int { kMaximumAmountOfMixedAudioSources = 3 }; 51 52 static rtc::scoped_refptr<AudioMixerImpl> Create(); 53 54 static rtc::scoped_refptr<AudioMixerImpl> Create( 55 std::unique_ptr<OutputRateCalculator> output_rate_calculator, 56 bool use_limiter); 57 58 ~AudioMixerImpl() override; 59 60 // AudioMixer functions 61 bool AddSource(Source* audio_source) override; 62 void RemoveSource(Source* audio_source) override; 63 64 void Mix(size_t number_of_channels, 65 AudioFrame* audio_frame_for_mixing) override 66 RTC_LOCKS_EXCLUDED(mutex_); 67 68 // Returns true if the source was mixed last round. Returns 69 // false and logs an error if the source was never added to the 70 // mixer. 71 bool GetAudioSourceMixabilityStatusForTest(Source* audio_source) const; 72 73 protected: 74 AudioMixerImpl(std::unique_ptr<OutputRateCalculator> output_rate_calculator, 75 bool use_limiter); 76 77 private: 78 // Set mixing frequency through OutputFrequencyCalculator. 79 void CalculateOutputFrequency(); 80 // Get mixing frequency. 81 int OutputFrequency() const; 82 83 // Compute what audio sources to mix from audio_source_list_. Ramp 84 // in and out. Update mixed status. Mixes up to 85 // kMaximumAmountOfMixedAudioSources audio sources. 86 AudioFrameList GetAudioFromSources() RTC_EXCLUSIVE_LOCKS_REQUIRED(mutex_); 87 88 // The critical section lock guards audio source insertion and 89 // removal, which can be done from any thread. The race checker 90 // checks that mixing is done sequentially. 91 mutable Mutex mutex_; 92 rtc::RaceChecker race_checker_; 93 94 std::unique_ptr<OutputRateCalculator> output_rate_calculator_; 95 // The current sample frequency and sample size when mixing. 96 int output_frequency_ RTC_GUARDED_BY(race_checker_); 97 size_t sample_size_ RTC_GUARDED_BY(race_checker_); 98 99 // List of all audio sources. Note all lists are disjunct 100 SourceStatusList audio_source_list_ RTC_GUARDED_BY(mutex_); // May be mixed. 101 102 // Component that handles actual adding of audio frames. 103 FrameCombiner frame_combiner_ RTC_GUARDED_BY(race_checker_); 104 105 RTC_DISALLOW_COPY_AND_ASSIGN(AudioMixerImpl); 106 }; 107 } // namespace webrtc 108 109 #endif // MODULES_AUDIO_MIXER_AUDIO_MIXER_IMPL_H_ 110