Kindred souls. About three years ago, I did the same, but with NTSC. In my case I actually built a digitization board that sampled the signal from a composite cable and dumped the raw samples over USB using the Cypress EZ-USB2 chip. I didn't want to "cheat" with a chip that did the synchronization etc. :)

I never really finished it, but I threw a little bit of it on GitHub: https://github.com/gabesk/tv_python is the prototyping version (the raw data is a picture of Lena on a Raspberry Pi composite output).

Also as an aside, if anyone ever wants an example of how to stream data from an isochronous endpoint on Windows, this took me way to long to figure out: https://github.com/gabesk/tv/blob/master/actual_implementati... (see usb_reading_thread routine) as well as this blog post: https://gabesk.blogspot.com/2018/08/streaming-from-isochrono... (that version does real-time black and white, but I never finished real-time color as my laptop at the time couldn't handle it with my poorly optimized decoding routines).

You all have inspired me to finish this properly and publish it. Maybe even as a top level post on HN.