学习路线

https://zhuanlan.zhihu.com/p/144769222
https://blog.csdn.net/dev_csdn/article/details/78738806

转码篇

使用 iOS AudioConverterFillComplexBuffer 进行转码
https://juejin.cn/post/6844903503966502925

iOS 内部库的结构
https://medium.com/chameleon-podcast/creating-an-advanced-streaming-audio-engine-for-ios-9fbc7aef4115
https://developer.apple.com/library/archive/documentation/MusicAudio/Conceptual/AudioUnitHostingGuide_iOS/Introduction/Introduction.html#//apple_ref/doc/uid/TP40009492-CH1-SW1

参数介绍
https://blog.51cto.com/metoo/1314560

iOS Audio Service
https://developer.apple.com/library/archive/documentation/MusicAudio/Conceptual/AudioQueueProgrammingGuide/AboutAudioQueues/AboutAudioQueues.html#//apple_ref/doc/uid/TP40005343-CH5-SW1

AAC 的ADTS 头的含义
https://blog.csdn.net/tantion/article/details/82743942

音频调试工具
https://www.fosshub.com/Audacity.html

Audio Unit 简单介绍
https://www.jianshu.com/p/8ce865c9bbac
https://developer.apple.com/library/archive/documentation/MusicAudio/Conceptual/AudioUnitHostingGuide_iOS/Introduction/Introduction.html#//apple_ref/doc/uid/TP40009492
介绍的比较明白的
https://blog.csdn.net/gamereborn/article/details/80232453?utm_medium=distribute.pc_relevant.none-task-blog-searchFromBaidu-1.control&depth_1-utm_source=distribute.pc_relevant.none-task-blog-searchFromBaidu-1.control

G711 编解码文章
http://dystopiancode.blogspot.com/2012/02/pcm-law-and-u-law-companding-algorithms.html

降噪

https://www.infoq.cn/article/qop4ioao_djj6ensioxp
https://juejin.cn/post/6844904190322409486
https://github.com/KeenTeam1990/KTNoiseReduction
https://tw511.com/a/01/6594.html

回音消除

https://weiyimu.vip/article/6914629614606385159
https://github.com/mumble-voip/mumblekit/blob/master/src/MKVoiceProcessingDevice.m

自动增益

人声放大

RTMP 篇

RTMP 使用的音视频流为 FLV
FLV 的格式 https://www.adobe.com/content/dam/acom/en/devnet/flv/video_file_format_spec_v10.pdf
RTMP 协议
http://wwwimages.adobe.com/www.adobe.com/content/dam/acom/en/devnet/rtmp/pdf/rtmp_specification_1.0.pdf