1. Recording: This is the simplest and rudest method. No matter the video on the computer or the video on the mobile phone, you can record the background music by recording. However, computers and mobile phones are not professional recording equipment after all, and the recorded audio quality can not be compared with the original audio, and there are still many noises;

2. modify the suffix: find the video file in the mobile phone file manager and modify the suffix to ".mp3". The same is true of the operation method of the computer. In this way, you can directly convert video files into audio files. However, it should be noted that the file may be damaged or cannot be played by this method;