I’ve been successfully using Tracktion Engine to prepare and render an edit to a single output file. However, I’m having problems rendering multiple tracks in an edit to multiple output files simultaneously.
You need to include send and return tracks in the tracksToDo.
Also, I’m not sure it’s wise to render the same Edit concurrently, I’m surprised if that would work at all as there’s probably a lot of state in there that is shared.
If you user the “renderMultipleTracks” option, it will just render each track that you’ve passed it separately. Obviously if you’ve got sub mixes/aux busses etc that’s not what you want.
For these cases I’d just create the tracks you want to render together and render each of them in turn with different passes.