On-the-fly Video Transcoding for Broader Browser Playback

Problem:
As someone who is not particularly experienced with video codecs or service side media processing, I'm encountering a common issue: When I serve video files, especially MKV files, through copyparty, they often don't play directly in my web browser. I am aware that this happens because browsers don't natively support containers like MKV (and corresponding codecs).

Solution:
I'd like to suggest adding an optional feature for on-the-fly video transcoding. Since copyparty already uses ffmpeg for things like audio processing and thumbnails, it seems like ffmpeg could be used to convert unsupported video containers into browser friendly formats in real-time.

Pros: improved user experience and copyparty as an even better media server.
Cons: performance and battery, especially on mobile devices running Termux and maybe security concerns with untrusted video files.
Therefore, this feature should be optional and highly configurable, allowing users to enable it only when needed and adjust quality settings.

Thank you for considering this suggestion!