说明：  linux音频系统架构问题由来已久……远远比你想像的复杂。如果你想理清从读取音频文件到最终从你的扬声器中播放出来这一过程中所用到的技术之间的关系的话，纸上的结构图足以像炸酱面一样混乱，而你根本找不到任何头绪。 这是因为，音频系统本身就比其他架构更加复杂。OSI模型每一层都有自己的作用域和功能，每一层几乎不会有任何交集，所以你绝对不会碰到任何混乱情况。但是，在linux音频系统上，却上演着这样的事情：没有明确的底层，各种音频技术各自为政。linux的音频系统架构有点像地壳构造，偶尔就地震一下，要不就火山爆发一下，上层结构则要使劲遮掩发生的一切。
(Linux audio system architecture has a long history... It's much more complicated than you think. If you want to clarify the relationship between the technologies used in the process from reading audio files to eventually playing them out from your speaker, the paper structure is as chaotic as fried noodles, and you can't find any clues at all. This is because the audio system itself is more complex than other architectures. Each layer of the OSI model has its own scope and function, and there is hardly any intersection in each layer, so you will never encounter any confusion. However, on the Linux audio system, there is such a thing: there is no clear bottom, all kinds of audio technology are independent. Linux's audio system architecture is a bit like the crustal structure, with occasional earthquakes or volcanic eruptions, and the superstructure trying to hide everything that happens.)