Centos does not support mp3 format voice conversion through yum install sox, so you must install sox by compiling. Download the two tar.gz packages in the attachment.
If you have installed sox through yum, you need to remove it first, yum remove sox
tar -zxvf lame-3.99.5.tar.gz
cd lame-3.99.5
./configure
make install
tar -zxvf sox-14.4.2.tar.gz
cd sox-14.4.2
./configure
make install
In this way, sox supports the conversion of mp3 format.