- Open IDM and click on the options under the download bar
- Click on "Edit" next to "IDM download floating bar in custom browser"
- Click on "Add"
- Add "M4S" and "XS" file types one by one (representing video and audio file types) and save
- Open the browser and install the IDM Integration Module plugin
- Reopen the desired Bilibili video
- The download button in the top right corner of the Bilibili video will reappear
- If the video and audio are separate after downloading, you can use ffmpeg to merge them together
- You can also merge them online into mp4 format from https://www.online-convert.com/ or https://bilitool.lie.moe/