Recommendations for video transcoding settings?

[Qhilm]

What settings do you use?

My server users have firefox mostly, and the mobile app for iOS.

What would be the recommended setting for this particular clients?

And is there a settings that has a good ratio between bandwidth efficiency and compatibility? (I don't care so much for CPU efficiency at the moment)

[krypton9208]

I'm thinking about buy some GPU, to help transcoding, but, i don't find any list of with graphic cards immich handled.
Can someone give me examples with compatible cards?