Basic knowledge of audio coding and decoding

PCM Basic knowledge of

PCM It refers to the uncompressed original sound pulse signal data , It is mainly through the sampling rate 、 Sampling format ( For example, each sampling point is 8 position 、16 position 、32 I'm waiting for you )、 The number of channels to describe .
stay FFmpeg There are two expressions in PCM Packet mode , Namely planer and packed Pattern , So what's the difference between them ？ among packed Also known as interleaving pattern , and planer Also known as plane mode , The so-called interleaving or plane is the way in which the sound signals of different channels are arranged and stored , For example, for a two channel PCM In terms of data , use packed The pattern representation is like this ：

use L Indicates left channel data , use R Represents right channel data

LRLRLRLRLRLRLRLR

While using laner Pattern representation , It's like this ：
use L Indicates left channel data , use R Represents right channel data

LLLLLLLL RRRRRRRR

stay FFmpeg in ,packed The format of the pattern is ：

AV_SAMPLE_FMT_U8,          ///< unsigned 8 bits