Scope of support
The Topfield REC profile writes the MPEG transport-stream representation validated by SmartCut64's editor, Batch and Joiner gates. It is intended for workflows that accept that transport-stream form.
Recorder-specific headers
Some recorder generations add proprietary header or device metadata outside the transport stream. SmartCut64 does not claim universal generation of every hardware-specific variant without a corresponding fixture. Test the actual target recorder/player before using the profile operationally.
Fallback
If the receiving device rejects .rec, export a standard .ts with the same selected streams and compare its documented requirements. Keep the export report and a device-generated sample for support.