音频基础

https://blog.csdn.net/u010664697/article/details/105428055(基本概念)
https://blog.csdn.net/qq_41824928/article/details/108124382

基本概念

• 采样率
  常用
  44,100 Hz - 音频 CD, 也常用于 MPEG-1 音频（VCD, SVCD, MP3）所用采样率
  https://zhuanlan.zhihu.com/p/459608749
• 位深
• 码率
• 压缩算法（编码算法）
• 声道
  https://blog.csdn.net/yinshipin007/article/details/131334183
  双声道，stereo，最常见的类型，包含左声道以及右声道
• 采样格式
  https://blog.csdn.net/qq_21438461/article/details/131036433
  分pcm(整型)与fltp(浮点)

enum AVSampleFormat {
    AV_SAMPLE_FMT_NONE = -1,
    AV_SAMPLE_FMT_U8, ///< unsigned 8 bits
    AV_SAMPLE_FMT_S16, ///< signed 16 bits
    AV_SAMPLE_FMT_S32, ///< signed 32 bits
    AV_SAMPLE_FMT_FLT, ///< float
    AV_SAMPLE_FMT_DBL, ///< double
    AV_SAMPLE_FMT_U8P, ///< unsigned 8 bits, planar
    AV_SAMPLE_FMT_S16P, ///< signed 16 bits, planar
    AV_SAMPLE_FMT_S32P, ///< signed 32 bits, planar
    AV_SAMPLE_FMT_FLTP, ///< float, planar
    AV_SAMPLE_FMT_DBLP, ///< double, planar
    AV_SAMPLE_FMT_S64, ///< signed 64 bits
    AV_SAMPLE_FMT_S64P, ///< signed 64 bits, planar
    AV_SAMPLE_FMT_NB ///< Number of sample formats. DO NOT USE if linking dynamically
};

1.从物理学角度说音频和编码的概念

https://www.jianshu.com/p/13c651cfb0a4

2.编码算法

https://www.jianshu.com/p/e2a63dfcff1a

压缩编码类型：
有损编码与无损编码

常用压缩编码格式：
https://www.jianshu.com/p/e2a63dfcff1a

WAV编码
MP3编码
AAC编码
https://blog.csdn.net/dodod2012/article/details/80474446
Ogg编码