Android 7.0 Audio ：通话中的音频调用接口
对于Audio在通话中的处理，根据不同的功能，有不同的调用路径，
1) 通话中 打开speaker 流程 enableSpeaker
对于在通话中打开扬声器，走图示1的调用路径，
在telephony部分，调用流程如下，
InCallAudioManager. enableSpeaker--telecomAdapter.setAudioRoute(CallAudioState.ROUTE_SPEAKER)/binderIPC-- mInCallService.setAudioRoute(route);-- mPhone.setAudioRoute(route);-- mInCallAdapter.setAudioRoute(route);--mAdapter.setAudioRoute(route);/binder IPC--…--CallsManager.
setAudioRoute --mCallAudioManager.setAudioRoute(route)--CallAudioRouteStateMachine.sendMessageWithSessionInfo / CallAudioRouteStateMachine.USER_SWITCH_SPEAKER/--通过ActiveSpeakerRoute向下..—setSpeakerphoneOn-- mAudioManager.setSpeakerphoneOn(on)
这样，就到了Audio系统了，根据之前的章节，就知道接下来就是AM/AService/ASystem了，
AudioManager.setSpeakerphoneOn/ binder IPC--setSpeakerphoneOn --/ mForcedUseForComm = AudioSystem.FORCE_SPEAKER / sendMsg(mAudioHandler,MSG_SET_FORCE_USE, SENDMSG_QUEUE,
AudioSystem.FOR_COMMUNICATION, mForcedUseForComm, null, 0) /内部handler--setForceUse --setForceUseInt_SyncDevices -- AudioSystem.setForceUse/jni-AudioSystem::setForceUse
在native部分的调用流程如下，
AudioSystem::setForceUse--AudioPolicyService::setForceUse（AudioPolicyInterfaceImpl.cpp）--AudioPolicyManager::setForceUse
APM处理部分如下，
| //////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// void AudioPolicyManager::setForceUse(audio_policy_force_use_t usage, audio_policy_forced_cfg_t config) {
if (mEngine->setForceUse(usage, config) != NO_ERROR) { ALOGW("setForceUse() could not set force cfg %d for usage %d", config, usage); return; }
checkA2dpSuspend(); checkOutputForAllStrategies(); updateDevicesAndOutputs();
if (mEngine->getPhoneState() == AUDIO_MODE_IN_CALL && hasPrimaryOutput()) { audio_devices_t newDevice = getNewOutputDevice(mPrimaryOutput, true /*fromCache*/); updateCallRouting(newDevice); } for (size_t i = 0; i < mOutputs.size(); i++) { sp audio_devices_t newDevice = getNewOutputDevice(outputDesc, true /*fromCache*/); if ((mEngine->getPhoneState() != AUDIO_MODE_IN_CALL) || (outputDesc != mPrimaryOutput)) { setOutputDevice(outputDesc, newDevice, (newDevice != AUDIO_DEVICE_NONE)); } if (forceVolumeReeval && (newDevice != AUDIO_DEVICE_NONE)) { applyStreamVolumes(outputDesc, newDevice, 0, true); } }
audio_io_handle_t activeInput = mInputs.getActiveInput(); if (activeInput != 0) { sp audio_devices_t newDevice = getNewInputDevice(activeInput); // Force new input selection if the new device can not be reached via current input if (activeDesc->mProfile->getSupportedDevices().types() & (newDevice & ~AUDIO_DEVICE_BIT_IN)) { setInputDevice(activeInput, newDevice); } else { closeInput(activeInput); } } }
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a）mEngine->setForceUse
实现在Engine.cpp里面，主要是判断当前对设备设置是否合逻辑，并给mForceUse的成员赋值。
| //////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// status_t Engine::setForceUse(audio_policy_force_use_t usage, audio_policy_forced_cfg_t config) { switch(usage) { case AUDIO_POLICY_FORCE_FOR_COMMUNICATION: if (config != AUDIO_POLICY_FORCE_SPEAKER && config != AUDIO_POLICY_FORCE_BT_SCO && config != AUDIO_POLICY_FORCE_NONE) { ALOGW("setForceUse() invalid config %d for FOR_COMMUNICATION", config); return BAD_VALUE; } mForceUse[usage] = config; break; |
b）checkA2dpSuspend
checkA2dpSuspend--AudioPolicyService::AudioPolicyClient::suspendOutput--AudioFlinger::suspendOutput--thread->suspend
| /////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// void suspend() { (void) android_atomic_inc(&mSuspended); } |
最终是给&mSuspended赋值。
c）checkOutputForStrategy 根据策略类型和当前设置获取设备类型，并最input和output进行处理，最后invalidateStream。
其中，
AudioPolicyManager::checkOutputForStrategy--audio_devices_tAudioPolicyManager::getDeviceForStrategy--mEngine->getDeviceForStrategy，
Engine.cpp里，
根据strategy为STRATEGY_PHONE，以及刚刚设置的mForceUse[AUDIO_POLICY_FORCE_FOR_COMMUNICATION]为AUDIO_POLICY_FORCE_SPEAKER，匹配到正确的设备类型，刚好为AUDIO_DEVICE_OUT_SPEAKER，
| //////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// audio_devices_t Engine::getDeviceForStrategyInt(routing_strategy strategy, DeviceVector availableOutputDevices, DeviceVector availableInputDevices, const SwAudioOutputCollection &outputs) const { uint32_t device = AUDIO_DEVICE_NONE; uint32_t availableOutputDevicesType = availableOutputDevices.types();
switch (strategy) { case STRATEGY_PHONE:
switch (mForceUse[AUDIO_POLICY_FORCE_FOR_COMMUNICATION]) {
case AUDIO_POLICY_FORCE_SPEAKER: // when not in a phone call, phone strategy should route STREAM_VOICE_CALL to // A2DP speaker when forcing to speaker output
device = availableOutputDevicesType & AUDIO_DEVICE_OUT_SPEAKER; break; } break; |
d)之后是updateCallRouting，设置device的操作。
2）dtmf音
在telephony模块，调用流程（这里只分析了声音播放，并不包含信令处理）
CallsManager.playDtmfTone --DtmfLocalTonePlayer .playTone--mToneGenerator.startTone
在Audio模块，调用流程
ToneGenerator.startTone--jni--android_media_ToneGenerator_startTone--ToneGenerator::startTone
ToneGenerator则直接使用了AT，先initAudioTrack创建AT实例，prepareWave生成PCM数据，再mpAudioTrack->start()开始，
| //////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// bool ToneGenerator::startTone(tone_type toneType, int durationMs) {
toneType = getToneForRegion(toneType);
if (mState == TONE_IDLE) { ALOGV("startTone: try to re-init AudioTrack"); if (!initAudioTrack()) { return lResult; } }
if (mState == TONE_INIT) { if (prepareWave()) { ALOGV("Immediate start, time %d", (unsigned int)(systemTime()/1000000)); lResult = true; mState = TONE_STARTING; if (clock_gettime(CLOCK_MONOTONIC, &mStartTime) != 0) { mStartTime.tv_sec = 0; } mLock.unlock(); mpAudioTrack->start(); … } mLock.unlock(); }
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可以看到，initAudioTrack创建AT实例时，使用了AUDIO_OUTPUT_FLAG_FAST的方式播放，通过audioCallback回调完成数据填充。
| //////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// bool ToneGenerator::initAudioTrack() {
// Open audio track in mono, PCM 16bit, default sampling rate, default buffer size mpAudioTrack = new AudioTrack(); ALOGV("Create Track: %p", mpAudioTrack.get());
mpAudioTrack->set(mStreamType, 0, // sampleRate AUDIO_FORMAT_PCM_16_BIT, AUDIO_CHANNEL_OUT_MONO, 0, // frameCount AUDIO_OUTPUT_FLAG_FAST, audioCallback, this, // user 0, // notificationFrames 0, // sharedBuffer mThreadCanCallJava, AUDIO_SESSION_ALLOCATE, AudioTrack::TRANSFER_CALLBACK);
if (mpAudioTrack->initCheck() != NO_ERROR) { ALOGE("AudioTrack->initCheck failed"); goto initAudioTrack_exit; }
mpAudioTrack->setVolume(mVolume);
mState = TONE_INIT;
return true;
initAudioTrack_exit:
ALOGV("Init failed: %p", mpAudioTrack.get());
// Cleanup mpAudioTrack.clear();
return false; } |
这条通道走的是AF的路径，并不在上图的三个path之中。
3）标记3的场景有，Telephony向Audio设置当前是通话状态，这个会用setMode (MODE_INCALL)；向Audio设置当前是VOICE通话还是LTE通话，这个会用AudioSystem::setParameters()，
vendor\qcom\proprietary\qcril\qcril_qmi\qcril_am.cc