Hello!
Once again I have a livestream in two languages. One language is the original language of the caller (vMix Call) and the other language is from the simultaneous translator. My external sound card is a MOTU UltraLite Mk4.
I send the original sound of the caller via a vMix audio bus to my sound card and from there from the output to the translator's headphones. Together with the translator's microphone input, I make a submix in the sound card mixer (translator loud, original sound muted) and take that back into vMix via an audio input.
Unfortunately, I then have a significant delay in the original sound compared to the image of the caller. Not quite as bad, because the original sound is anyway lower in the stream with translation compared to the translation, but still annoying.
My vMix is set to 1080p25. Through the audio routing to the translator and back, I get an audio delay of about 4 frames, so at 25 fps about 160 ms. I would have explained this by the processing of the sound card buffers, etc. But first of all this is too much delay and secondly I did another test.
If the sound card is not involved at all. I send the original sound to an audio bus and take this bus directly as input again into vMix, so purely vMix internally, then I have a delay of about 3 frames, at 25 fps so about 120 ms. For me it is clear that most of the audio delay comes from vMix and not from the audio card.

Now my question, can't the way vMix processes the audio be sped up a bit?