modules/audio_device/android/audio_record_jni.h

/*
 *  Copyright (c) 2013 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 MODULES_AUDIO_DEVICE_ANDROID_AUDIO_RECORD_JNI_H_
#define MODULES_AUDIO_DEVICE_ANDROID_AUDIO_RECORD_JNI_H_

#include <memory>

#include <jni.h>

#include "modules/audio_device/android/audio_manager.h"
#include "modules/audio_device/audio_device_generic.h"
#include "modules/audio_device/include/audio_device_defines.h"
#include "modules/utility/include/helpers_android.h"
#include "modules/utility/include/jvm_android.h"
#include "rtc_base/thread_checker.h"

namespace webrtc {

// Implements 16-bit mono PCM audio input support for Android using the Java
// AudioRecord interface. Most of the work is done by its Java counterpart in
// WebRtcAudioRecord.java. This class is created and lives on a thread in
// C++-land, but recorded audio buffers are delivered on a high-priority
// thread managed by the Java class.
//
// The Java class makes use of AudioEffect features (mainly AEC) which are
// first available in Jelly Bean. If it is instantiated running against earlier
// SDKs, the AEC provided by the APM in WebRTC must be used and enabled
// separately instead.
//
// 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 RTC_DCHECK if any method is called on an invalid thread.
//
// This class uses JvmThreadConnector to attach to a Java VM if needed
// and detach when the object goes out of scope. Additional thread checking
// guarantees that no other (possibly non attached) thread is used.
class AudioRecordJni {
 public:
  // Wraps the Java specific parts of the AudioRecordJni into one helper class.
  class JavaAudioRecord {
   public:
    JavaAudioRecord(NativeRegistration* native_registration,
                    std::unique_ptr<GlobalRef> audio_track);
    ~JavaAudioRecord();

    int InitRecording(int sample_rate, size_t channels);
    bool StartRecording();
    bool StopRecording();
    bool EnableBuiltInAEC(bool enable);
    bool EnableBuiltInNS(bool enable);

   private:
    std::unique_ptr<GlobalRef> audio_record_;
    jmethodID init_recording_;
    jmethodID start_recording_;
    jmethodID stop_recording_;
    jmethodID enable_built_in_aec_;
    jmethodID enable_built_in_ns_;
  };

  explicit AudioRecordJni(AudioManager* audio_manager);
  ~AudioRecordJni();

  int32_t Init();
  int32_t Terminate();

  int32_t InitRecording();
  bool RecordingIsInitialized() const { return initialized_; }

  int32_t StartRecording();
  int32_t StopRecording();
  bool Recording() const { return recording_; }

  void AttachAudioBuffer(AudioDeviceBuffer* audioBuffer);

  int32_t EnableBuiltInAEC(bool enable);
  int32_t EnableBuiltInAGC(bool enable);
  int32_t EnableBuiltInNS(bool enable);

 private:
  // Called from Java side so we can cache the address of the Java-manged
  // |byte_buffer| in |direct_buffer_address_|. The size of the buffer
  // is also stored in |direct_buffer_capacity_in_bytes_|.
  // This method will be called by the WebRtcAudioRecord constructor, i.e.,
  // on the same thread that this object is created on.
  static void JNICALL CacheDirectBufferAddress(JNIEnv* env,
                                               jobject obj,
                                               jobject byte_buffer,
                                               jlong nativeAudioRecord);
  void OnCacheDirectBufferAddress(JNIEnv* env, jobject byte_buffer);

  // Called periodically by the Java based WebRtcAudioRecord object when
  // recording has started. Each call indicates that there are |length| new
  // bytes recorded in the memory area |direct_buffer_address_| and it is
  // now time to send these to the consumer.
  // This method is called on a high-priority thread from Java. The name of
  // the thread is 'AudioRecordThread'.
  static void JNICALL DataIsRecorded(JNIEnv* env,
                                     jobject obj,
                                     jint length,
                                     jlong nativeAudioRecord);
  void OnDataIsRecorded(int length);

  // Stores thread ID in constructor.
  rtc::ThreadChecker thread_checker_;

  // Stores thread ID in first call to OnDataIsRecorded() from high-priority
  // thread in Java. Detached during construction of this object.
  rtc::ThreadChecker thread_checker_java_;

  // Calls JavaVM::AttachCurrentThread() if this thread is not attached at
  // construction.
  // Also ensures that DetachCurrentThread() is called at destruction.
  JvmThreadConnector attach_thread_if_needed_;

  // Wraps the JNI interface pointer and methods associated with it.
  std::unique_ptr<JNIEnvironment> j_environment_;

  // Contains factory method for creating the Java object.
  std::unique_ptr<NativeRegistration> j_native_registration_;

  // Wraps the Java specific parts of the AudioRecordJni class.
  std::unique_ptr<AudioRecordJni::JavaAudioRecord> j_audio_record_;

  // Raw pointer to the audio manger.
  const AudioManager* audio_manager_;

  // Contains audio parameters provided to this class at construction by the
  // AudioManager.
  const AudioParameters audio_parameters_;

  // Delay estimate of the total round-trip delay (input + output).
  // Fixed value set once in AttachAudioBuffer() and it can take one out of two
  // possible values. See audio_common.h for details.
  int total_delay_in_milliseconds_;

  // Cached copy of address to direct audio buffer owned by |j_audio_record_|.
  void* direct_buffer_address_;

  // Number of bytes in the direct audio buffer owned by |j_audio_record_|.
  size_t direct_buffer_capacity_in_bytes_;

  // Number audio frames per audio buffer. Each audio frame corresponds to
  // one sample of PCM mono data at 16 bits per sample. Hence, each audio
  // frame contains 2 bytes (given that the Java layer only supports mono).
  // Example: 480 for 48000 Hz or 441 for 44100 Hz.
  size_t frames_per_buffer_;

  bool initialized_;

  bool recording_;

  // Raw pointer handle provided to us in AttachAudioBuffer(). Owned by the
  // AudioDeviceModuleImpl class and called by AudioDeviceModule::Create().
  AudioDeviceBuffer* audio_device_buffer_;
};

}  // namespace webrtc

#endif  // MODULES_AUDIO_DEVICE_ANDROID_AUDIO_RECORD_JNI_H_