Also centralizes backend listing in constants.py, and simplifies code that shouldn't have an explicit dependency on backend names in the first place.
Note that this is untested with the node backend, which uses a lot of separate codepaths, so it wouldn't be surprising if this introduces unnoticed issues for node-based playback.
Also centralizes backend listing in constants.py, and simplifies code that shouldn't have an explicit dependency on backend names in the first place.
Note that this is untested with the node backend, which uses a lot of separate codepaths, so it wouldn't be surprising if this introduces unnoticed issues for node-based playback.