Open HMT File
The HMT file is used by High Performance Media Access Technology (HighMAT), and that's where the extension comes from.
HighMAT is a technology jointly developed by Microsoft and Panasonic that is used to store and play digital media on physical pastes such as CD's, DVD's, etc.
This HMT file contains images, audio and video saved in a proprietary format.
The HMT format, itself, is not a video file, instead it represents a type of multi-media file that is used solely for the purpose of recording on physical media.
It is important to know that the HMT format is no longer supported, therefore the HighMAT application was discontinued, by Microsoft's decision.
The HighMAT (HMT) extension is only available for the Windows XP CD Writing Assistant.
Software to open HMT files
As mentioned above, the HMT format is no longer supported, however, if you still use this format, you can use the Windows XP operating system.