preferredAudioBackend property
Backend for the AUDIO encoder, independent of preferredBackend. Null
lets the engine choose, as for preferredVisionBackend, and the native
LiteRT-LM engine reports it in InferenceModel.activeAudioBackend. Set
one only where the section allows it: the published Gemma 4 and Gemma 3n
audio encoders declare backend_constraint cpu, so
PreferredBackend.gpu is refused for them
(readLiteRtLmBundleInfo(path).audioEncoder?.backendConstraint shows
it). Ignored by MediaPipe.
Implementation
final PreferredBackend? preferredAudioBackend;