Tool: EDIUS

The operation steps are as follows:

1. First, open the video file to be edited in EDIUS.

2. After importing, drag the material into the timeline and preview the video to see if it is completely imported.

3. press ALT+Y or right click "link"-"unlock" to separate audio and video.

4. delete the video part and only keep the audio part. Cut the audio with the scissors tool, leaving only the parts that need to be kept.

5. Render and output the sound, and select the audio format when outputting.

6. The export was successful.