1/*
2 *  Copyright (c) 2013 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// Android APIs used to access Java functionality needed to enable low latency
12// audio.
13
14#ifndef WEBRTC_MODULES_AUDIO_DEVICE_ANDROID_AUDIO_MANAGER_JNI_H_
15#define WEBRTC_MODULES_AUDIO_DEVICE_ANDROID_AUDIO_MANAGER_JNI_H_
16
17#include <jni.h>
18
19namespace webrtc {
20
21class AudioManagerJni {
22 public:
23  AudioManagerJni();
24  ~AudioManagerJni() {}
25
26  // SetAndroidAudioDeviceObjects must only be called once unless there has
27  // been a successive call to ClearAndroidAudioDeviceObjects. For each
28  // call to ClearAndroidAudioDeviceObjects, SetAndroidAudioDeviceObjects may be
29  // called once.
30  // This function must be called by a Java thread as calling it from a thread
31  // created by the native application will prevent FindClass from working. See
32  // http://developer.android.com/training/articles/perf-jni.html#faq_FindClass
33  // for more details.
34  // It has to be called for this class' APIs to be successful. Calling
35  // ClearAndroidAudioDeviceObjects will prevent this class' APIs to be called
36  // successfully if SetAndroidAudioDeviceObjects is not called after it.
37  static void SetAndroidAudioDeviceObjects(void* jvm, void* env,
38                                           void* context);
39  // This function must be called when the AudioManagerJni class is no
40  // longer needed. It frees up the global references acquired in
41  // SetAndroidAudioDeviceObjects.
42  static void ClearAndroidAudioDeviceObjects();
43
44  bool low_latency_supported() const { return low_latency_supported_; }
45  int native_output_sample_rate() const { return native_output_sample_rate_; }
46  int native_buffer_size() const { return native_buffer_size_; }
47
48 private:
49  bool HasDeviceObjects();
50
51  // Following functions assume that the calling thread has been attached.
52  void SetLowLatencySupported(JNIEnv* env);
53  void SetNativeOutputSampleRate(JNIEnv* env);
54  void SetNativeFrameSize(JNIEnv* env);
55
56  jmethodID LookUpMethodId(JNIEnv* env, const char* method_name,
57                           const char* method_signature);
58
59  void CreateInstance(JNIEnv* env);
60
61  // Whether or not low latency audio is supported, the native output sample
62  // rate and the audio buffer size do not change. I.e the values might as well
63  // just be cached when initializing.
64  bool low_latency_supported_;
65  int native_output_sample_rate_;
66  int native_buffer_size_;
67};
68
69}  // namespace webrtc
70
71#endif  // WEBRTC_MODULES_AUDIO_DEVICE_ANDROID_AUDIO_MANAGER_JNI_H_
72