Option to bypass VHS chroma upconvert

[jbshelton]

I have a sneaking suspicion that some of the rainbowing effect I'm getting when exporting .tbc captures is due to the VHS chroma carrier being upconverted by a non-integer amount, and/or being affected by the luma channel after the upconversion. Would it be possible to add the option to skip chroma upconversion and just output the decoded 629KHz chroma signal into the chroma .tbc file? (Rather, the raw non-upconverted chroma signal from any color-under tape format.)

If it's just bypassing the upconvert function in the code (I looked at it,) I probably will make the change myself and submit a pull request, but I'm pretty rusty coding-wise, especially with Python, so some pointers are appreciated.

Getting tbc-video-export to work with the non-upconverted chroma signal data I assume is a separate issue.