GrantXTV wrote:...or do I need design my standards convert to do this job?
Considering the options you have, I suspect this is going to be the outcome. The YUV matrixing is comparatively easy. If you keep it YUV and not composite (PAL/NTSC) there's little difference from monochrome.
Having done a full 625 monochrome SPG (Sync Pulse Generator) for 625/50 in a PIC micro this should be a little bit easier. Though many might choose the Arduino/R-Pi route instead.
It was a standards convertor 'of sorts', but not on this scale. (It was SSTV-625).
The problem with a device like this is it isn't really commercially viable. The returns on time and resources required and the projected sales don't justify the outlay. The WC-01 and the like must have been a labour of love. I have looked into this thoroughly in the past with a view to doing something similar. My conclusion - don't bother.
There are exceptions where the application has a wide appeal, an example is here...I wish I thought of it...
https://www.dos4ever.com/uTracer3/uTracer3_pag0.html...and also...though 'on hold' at the moment....
https://oscilloclock.com/Steve A.