I put in a feedback request with Arcsoft:
"I have heard that Arcsoft will remove HD-DVD support from TMT. I am concerned by this, for that means you will be removing something which you sold with the product.
Is this information true? If it is true, will it be taken from the current release via an update?"
I will post their reply.
My personal feeling is they will simply not add it to the next version of their TMT software. I do not think they can simply remove it from software which was purchased already - since it was sold with the ability to do HD-DVD. In other words, they will have to follow PDVD's path or face tons of refunds.