note

https://blog.youkuaiyun.com/weixin_33863087/article/details/85968023

https://blog.youkuaiyun.com/qq_33750826/article/details/82455026

https://blog.youkuaiyun.com/lin20044140410/article/details/78542066

https://blog.youkuaiyun.com/weixin_42082222/article/details/83653194

https://blog.youkuaiyun.com/u013377887/article/details/81255707

https://blog.youkuaiyun.com/u011006622/article/details/77884418

https://blog.youkuaiyun.com/wangjun7121/article/details/88199085

https://blog.youkuaiyun.com/bberdong/article/details/79910736

https://blog.youkuaiyun.com/QQ839787886/article/details/85237372

https://blog.youkuaiyun.com/bhj1119/article/details/78223281

https://blog.youkuaiyun.com/u012188065/article/details/84104275

https://blog.youkuaiyun.com/liangtianmeng/article/details/83957777

https://blog.youkuaiyun.com/xiangzaixiansheng/article/details/88858755

https://blog.youkuaiyun.com/Tommy_wxie/article/details/77256619

http://www.xuehuile.com/blog/23b1d66e9a114ab0b9ac6570b004b877.html

http://forum.vipersaudio.com/forum.php?mod=viewthread&tid=915

https://blog.youkuaiyun.com/zhuyong006/article/details/79634843

https://cloud.tencent.com/developer/article/1351968

https://www.cnblogs.com/scue/archive/2013/06/17/3141327.html

https://www.cnblogs.com/wulizhi/p/8179067.html

https://blog.youkuaiyun.com/lininglive/article/details/41675427

https://blog.youkuaiyun.com/u013377887/article/details/81255707

https://blog.youkuaiyun.com/michaelcao1980/article/details/42426169

open so 文件时会构造 audio_hw_device，这个结构体里有一堆函数，set,get ,唯独没有 read write 函数，open_output_stream, open_input_stream ;
操作硬件都用到厂价提供的AudioHardware 可是现在已经没有了。

厂家的实现函数是什么？
录音是audio_stream_in()

https://blog.youkuaiyun.com/weixin_33919941/article/details/86970980

https://blog.youkuaiyun.com/u010481276/article/details/88864554

https://www.cnblogs.com/helloworldtoyou/p/8404925.html

https://blog.youkuaiyun.com/weijory/article/details/62422869

https://blog.youkuaiyun.com/ly601579033/article/details/85112365