Helium is adding videos with mp4 to the database.
Helium creates a new unknown artists and is adding the videos to it.
If the video matches a valid MP4 audio container it will be added, creating "unknown artists" is most likely a side effect because you are adding a video.
Can you share one video that you can add to the database?
Update: We will add a more safe way to check this.
Please try this version:
This version checks an mp4/m4a file in it's binary structure if it is a video or not.
Great to hear, thanks for the update.