livekit uses libwebrtc that doesn't seem to have an API to input encoded data

(I may be wrong on this btw), but the API is pretty high-level, I don't think you can input already-encoded frames

but if you feel like going into a world of pain, what you could potentially do would be to inject fake frames into libwebrtc, intercept them with the

SetEncoderToPacketizerFrameTransformer

api, and replace them with your already-encoded frames

you would be wasting compute encoding fake frames, but hey, it would work

there could be problems related to keyframe generation - webrtc can ask the encoder in the other end for keyframes when it deems necessary, but as you are providing an already-encoded stream it wouldn't be able to fulfill that