Looking at this again, I think the solution is the other way around – the uploads:migrate_to_s3 task should be if !FileHelper.is_supported_media?(name). It doesn’t make sense to put the content-disposition: attachment; filename=X header on videos and audio. You are streaming those files from within a Discourse post, not downloading them?
So what we would want is:
No content-disposition attachment header
- Image
- Video
- Audio
Yes content-disposition attachment header with original filename
- All other attachments/uploads (PDF, TXT, CSV, etc.)
If I’m not seeing something here please feel free to add more information / examples.