blob: 9e9182aed849ab0a71b5b34a4f06dd2b76a8b549 [file] [log] [blame]
* Copyright (c) 2018 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.
#include <aaudio/AAudio.h>
#include <memory>
#include "api/sequence_checker.h"
#include "modules/audio_device/android/aaudio_wrapper.h"
#include "modules/audio_device/include/audio_device_defines.h"
#include "rtc_base/message_handler.h"
#include "rtc_base/thread.h"
#include "rtc_base/thread_annotations.h"
namespace webrtc {
class AudioDeviceBuffer;
class FineAudioBuffer;
class AudioManager;
// Implements low-latency 16-bit mono PCM audio output support for Android
// using the C based AAudio API.
// An instance must be created and destroyed on one and the same thread.
// All public methods must also be called on the same thread. A thread checker
// will DCHECK if any method is called on an invalid thread. Audio buffers
// are requested on a dedicated high-priority thread owned by AAudio.
// The existing design forces the user to call InitPlayout() after StopPlayout()
// to be able to call StartPlayout() again. This is in line with how the Java-
// based implementation works.
// An audio stream can be disconnected, e.g. when an audio device is removed.
// This implementation will restart the audio stream using the new preferred
// device if such an event happens.
// Also supports automatic buffer-size adjustment based on underrun detections
// where the internal AAudio buffer can be increased when needed. It will
// reduce the risk of underruns (~glitches) at the expense of an increased
// latency.
class AAudioPlayer final : public AAudioObserverInterface,
public rtc::MessageHandler {
explicit AAudioPlayer(AudioManager* audio_manager);
int Init();
int Terminate();
int InitPlayout();
bool PlayoutIsInitialized() const;
int StartPlayout();
int StopPlayout();
bool Playing() const;
void AttachAudioBuffer(AudioDeviceBuffer* audioBuffer);
// Not implemented in AAudio.
int SpeakerVolumeIsAvailable(bool& available); // NOLINT
int SetSpeakerVolume(uint32_t volume) { return -1; }
int SpeakerVolume(uint32_t& volume) const { return -1; } // NOLINT
int MaxSpeakerVolume(uint32_t& maxVolume) const { return -1; } // NOLINT
int MinSpeakerVolume(uint32_t& minVolume) const { return -1; } // NOLINT
// AAudioObserverInterface implementation.
// For an output stream, this function should render and write |num_frames|
// of data in the streams current data format to the |audio_data| buffer.
// Called on a real-time thread owned by AAudio.
aaudio_data_callback_result_t OnDataCallback(void* audio_data,
int32_t num_frames) override;
// AAudio calls this functions if any error occurs on a callback thread.
// Called on a real-time thread owned by AAudio.
void OnErrorCallback(aaudio_result_t error) override;
// rtc::MessageHandler used for restart messages from the error-callback
// thread to the main (creating) thread.
void OnMessage(rtc::Message* msg) override;
// Closes the existing stream and starts a new stream.
void HandleStreamDisconnected();
// Ensures that methods are called from the same thread as this object is
// created on.
SequenceChecker main_thread_checker_;
// Stores thread ID in first call to AAudioPlayer::OnDataCallback from a
// real-time thread owned by AAudio. Detached during construction of this
// object.
SequenceChecker thread_checker_aaudio_;
// The thread on which this object is created on.
rtc::Thread* main_thread_;
// Wraps all AAudio resources. Contains an output stream using the default
// output audio device. Can be accessed on both the main thread and the
// real-time thread owned by AAudio. See separate AAudio documentation about
// thread safety.
AAudioWrapper aaudio_;
// FineAudioBuffer takes an AudioDeviceBuffer which delivers audio data
// in chunks of 10ms. It then allows for this data to be pulled in
// a finer or coarser granularity. I.e. interacting with this class instead
// of directly with the AudioDeviceBuffer one can ask for any number of
// audio data samples.
// Example: native buffer size can be 192 audio frames at 48kHz sample rate.
// WebRTC will provide 480 audio frames per 10ms but AAudio asks for 192
// in each callback (once every 4th ms). This class can then ask for 192 and
// the FineAudioBuffer will ask WebRTC for new data approximately only every
// second callback and also cache non-utilized audio.
std::unique_ptr<FineAudioBuffer> fine_audio_buffer_;
// Counts number of detected underrun events reported by AAudio.
int32_t underrun_count_ = 0;
// True only for the first data callback in each audio session.
bool first_data_callback_ = true;
// Raw pointer handle provided to us in AttachAudioBuffer(). Owned by the
// AudioDeviceModuleImpl class and set by AudioDeviceModule::Create().
AudioDeviceBuffer* audio_device_buffer_ RTC_GUARDED_BY(main_thread_checker_) =
bool initialized_ RTC_GUARDED_BY(main_thread_checker_) = false;
bool playing_ RTC_GUARDED_BY(main_thread_checker_) = false;
// Estimated latency between writing an audio frame to the output stream and
// the time that same frame is played out on the output audio device.
double latency_millis_ RTC_GUARDED_BY(thread_checker_aaudio_) = 0;
} // namespace webrtc