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 19 namespace webrtc { 20 21 class AudioManagerJni { 22 public: 23 AudioManagerJni(); ~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 low_latency_supported()44 bool low_latency_supported() const { return low_latency_supported_; } native_output_sample_rate()45 int native_output_sample_rate() const { return native_output_sample_rate_; } native_buffer_size()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