Hi Mark,
The ability to skip commercials and fast forward are both limited by MythTV's streaming implementation. Both would require arbitrary skipping within a stream, which at present MythTV cannot do. It starts transcoding the program at the beginning and does so as quickly as possible based on your hardware. So at any given time you can only jump within the transcoded portion.
There was a time where people were talking about adding support for commercial skip (while transcoding) and potentially the ability to seek within the untranscoded portions (which would require a rework on the MythTV streaming to pre-write the playlist and only start transcoding a segment when it was requested), but neither seem to have been implemented. Because of these limitations of the backend, Torc also is limited to the current streaming functionality.
Thanks,
Robert