Need help understanding the affect bitrate has on quality

[TheDreadPirate]

1) There will be quality loss in both scenarios. Is that quality loss noticeable? Depends on a lot of factors. Specifically what encoder you are using, like Quick Sync or NVENC or just your CPU, and what settings you're using. With the default settings in Jellyfin, modern iterations of both Intel Quick Sync and Nvidia NVENC will produce very close to original quality at both bit rates for 4K video. You'd have to pause and A/B compare to notice the differences.

2) Again, yes. At a minimum, you lose HDR since Jellyfin does not currently support HDR to HDR transcoding. Whenever you are re-encoding a lossy codec/lossy configuration, there will be quality degregation. Again, probably not noticeable if the bit rate is sufficiently high.