M之前版本在一个进程中创建media相关所有服务

av/media/mediaserver/main_mediaserver.cpp        

        sp<IServiceManager> sm = defaultServiceManager();
        ALOGI("ServiceManager: %p", sm.get());
        AudioFlinger::instantiate();
        MediaPlayerService::instantiate();
        ResourceManagerService::instantiate();
        CameraService::instantiate();
        AudioPolicyService::instantiate();
        SoundTriggerHwService::instantiate();
        RadioService::instantiate();
        registerExtensions();
        ProcessState::self()->startThreadPool();
        IPCThreadState::self()->joinThreadPool();

N版本将各个服务转移到不同进程中进行创建

media/audioserver/main_audioserver.cpp:        AudioPolicyService::instantiate();
camera/cameraserver/main_cameraserver.cpp:    CameraService::instantiate();
media/mediaserver/main_mediaserver.cpp:    MediaPlayerService::instantiate();