[AchimTuran]

But - correct me if i'm wrong - adsp.basic is set up at movie level and retains different settings on a per-movie basis (as opposed to a global Kodi-wide setting like adsp.biquad) ?

If adsp.basic does indeed allow to be set on a per-movie basis then center channel downmixing functionality with a similar behaviour would be awesome : movies aren't all affected the same way by this lack of center channel volume. As an example, the harry Potter blu-ray saga is extremely affected, Matrix blu-ray saga to a lesser degree and some other 5.1 movies are not affected at all. It depends on choices made by the director's sound staff, so having the ability to set boost levels on a per-movie basis would be awesome.

No adsp.basic currently doesn't support gain levels for a specific movies.

Would you really use specific settigns for every movie? So fat I can think of that we store a config file in the same directory as the movie and use this settings if available. But I don't know how much work it will require. Is the a common feature or only for one user?