1. Receive Bilibili video URL or BV number and save directory.
2. Validate the URL/BV number format.
3. Check if the video exists and is accessible.
4. Extract video and audio streams.
5. Download the video stream as `{BV号}_video.mp4`.
6. Download the audio stream as `{BV号}_audio.mp4`.
7. Save the files to the specified directory.
8. Report any errors encountered during the process.
SynapticSkills