I've seen Ch mouths with: Ah, D, Ee, F, K, L, M, Oh, R, S, Th, Uh, W-Oo, smile, neutral, and surprised.
Is there a list of standard mouth positions approved by you guys? And are the unused letters (G, P, etc) usable?
The ones listed in the tags area are the official ones.
When CH hears something, it tries to translate it into one of those sounds. So for sounds other than that, CH tries its best to match them with the closest mouth shape. So when you right-click a recorded viseme you'll see some suggested alternatives, like how "b" and p" will get changed into "m".
You can make as many custom mouths as you want and key trigger them instead. In the future we may allow users a way to go even deeper here (since lip sync is so important to a compelling animated performance).
Thank you. This is helpful.