audio框架学习-Audio_Flinger分析

最新推荐文章于 2025-09-28 16:31:16 发布

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最新推荐文章于 2025-09-28 16:31:16 发布 · 2k 阅读

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#cocos2d #游戏引擎

本文详细介绍了Android系统中AudioFlinger组件的工作原理，包括其代码结构、服务启动过程和服务接口等内容。通过对AudioFlinger核心功能的解析，帮助读者理解音频处理流程。

文章目录

一、代码位置
二、audio服务启动

之前记录过audioTrack的笔记，这次继续参考audioFlinger相关的代码并做笔记；
参考文档： https://www.cnblogs.com/innost/archive/2011/01/15/1936425.html和 https://blog.youkuaiyun.com/zyuanyun/article/details/60890534?spm=1001.2014.3001.5501#t4

一、代码位置

frameworks/av/services/audioflinger/
├── Android.mk
├── AudioFlinger.cpp
├── AudioFlinger.h
├── AudioHwDevice.cpp
├── AudioHwDevice.h
├── AudioMixer.cpp
├── AudioMixer.h
├── AudioMixerOps.h
├── audio-resampler
│   ├── Android.mk
│   ├── AudioResamplerCoefficients.cpp
│   └── filter_coefficients.h
├── AudioResampler.cpp
├── AudioResamplerCubic.cpp
├── AudioResamplerCubic.h
├── AudioResamplerDyn.cpp
├── AudioResamplerDyn.h
├── AudioResamplerFirGen.h
├── AudioResamplerFirOps.h
├── AudioResamplerFirProcess.h
├── AudioResamplerFirProcessNeon.h
├── AudioResampler.h
├── AudioResamplerSinc.cpp
├── AudioResamplerSincDown.h
├── AudioResamplerSinc.h
├── AudioResamplerSincUp.h
├── AudioStreamOut.cpp
├── AudioStreamOut.h
├── AudioWatchdog.cpp
├── AudioWatchdog.h
├── BufferProviders.cpp
├── BufferProviders.h
├── Configuration.h
├── Effects.cpp
├── Effects.h
├── FastCapture.cpp
├── FastCaptureDumpState.cpp
├── FastCaptureDumpState.h
├── FastCapture.h
├── FastCaptureState.cpp
├── FastCaptureState.h
├── FastMixer.cpp
├── FastMixerDumpState.cpp
├── FastMixerDumpState.h
├── FastMixer.h
├── FastMixerState.cpp
├── FastMixerState.h
├── FastThread.cpp
├── FastThreadDumpState.cpp
├── FastThreadDumpState.h
├── FastThread.h
├── FastThreadState.cpp
├── FastThreadState.h
├── MODULE_LICENSE_APACHE2
├── NOTICE
├── PatchPanel.cpp
├── PatchPanel.h
├── PlaybackTracks.h
├── RecordTracks.h
├── ServiceUtilities.cpp
├── ServiceUtilities.h
├── SpdifStreamOut.cpp
├── SpdifStreamOut.h
├── StateQueue.cpp
├── StateQueue.h
├── StateQueueInstantiations.cpp
├── test-resample.cpp
├── tests
│   ├── Android.mk
│   ├── build_and_run_all_unit_tests.sh
│   ├── mixer_to_wav_tests.sh
│   ├── resampler_tests.cpp
│   ├── run_all_unit_tests.sh
│   ├── test-mixer.cpp
│   └── test_utils.h
├── Threads.cpp
├── Threads.h
├── TrackBase.h
└── Tracks.cpp

大概文件讲解：

AudioResampler.cpp：重采样处理类，可进行采样率转换和声道转换；由录制线程 AudioFlinger::RecordThread 直接使用
AudioMixer.cpp：混音处理类，包括重采样、音量调节、声道转换等，其中的重采样复用了 AudioResampler；由回放线程 AudioFlinger::MixerThread 直接使用
Effects.cpp：音效处理类
Tracks.cpp：音频流管理类，可控制音频流的状态，如 start、stop、pause
Threads.cpp：回放线程和录制线程类；回放线程从 FIFO 读取回放数据并混音处理，然后写数据到输出流设备；录制线程从输入流设备读取录音数据并重采样处理，然后写数据到 FIFO
AudioFlinger.cpp：AudioFlinger 对外提供的服务接口
还有一些相关文件不再这目录下，但是基本都在frameworks这个目录下，所以到时候只需要找一找就行。