Prime 4+ / StageLinQ: identifying Deck 1/3 and Deck 2/4 layers

Prime 4+ / StageLinQ: identifying Deck 1/3 and Deck 2/4 layers

I’m experimenting with the StageLinQ protocol on a Denon Prime 4+ to read deck state externally.

Discovery and StateMap communication are working. The device reports DeckCount = 4, and I can read mixer state for all four channels (CH1–CH4).

However, the Engine StateMap appears to expose only:

/Engine/Deck1/... /Engine/Deck2/...

I don’t see /Engine/Deck3/... or /Engine/Deck4/....

When switching the physical layers 1↔3 and 2↔4, I receive StageLinQ activity, including Play/PlayState changes, but so far I haven’t found a StateMap value that explicitly identifies whether the left player is currently controlling Deck 1 or Deck 3, or whether the right player is controlling Deck 2 or Deck 4.

The capture is unfiltered, so this does not appear to be caused by filtering the StateMap messages.

Questions:

  1. Does the Prime 4+ expose the active 1/3 and 2/4 layer through StageLinQ?
  2. If so, which service/path/message contains this information?
  3. Are Deck 3/4 represented as layers of /Engine/Deck1 and /Engine/Deck2, rather than separate Engine deck objects?
  4. Is this information perhaps available through another StageLinQ service rather than StateMap?

I’m currently testing with PyStageLinQ, but information about the protocol itself would also be very helpful.

Ultimately I’d like to reliably map track/play state to the four physical mixer channels.