- HEVC playback is slow? Try hevc first
- Check if you are transcoding
- It shouldn't be transcoded
- Check if your codec combination is supported
- Ah darn, how do I transcode?
- Check if your browser supports playback
- Enable Websockets support in your site page
https://mlohr.com/websockets-for-synology-dsm/ is a good writeup for enabling websockets
Check the docs for the most up-to-date configurations
- Don't use CF Tunnels