This is, afaik, the only real remaining potential issue from https://code.mythtv.org/trac/ticket/10602

If, for example, the current VideoDisplayProfile uses FFmpeg decoding for SD content and VAAPI for HD content, when the stream switches from SD to HD, FFmpeg is still used.

Note: this is purely an issue for in stream changes - it does not relate to switching channels etc - and as such is a pretty rare occurrence (I think).

Furthermore, I'm not sure how feasible it is to switch decoders mid-stream - some investigation is needed.