I did some testing yesterday with the Citra core after the buildbot recompiled it. The ntsc-vcr shader was still broken under normal circumstances, but setting the first pass to 1x rather than 4x fixed things. 4 times 1600 is 6400, which may cause issues, but playing back a wider (~1800px) video with the shader worked, albeit slowly; the shader never worked at 4x first-pass even at native res. (I’ll double check the exact changes later, just in case.) It seems like there are still some kinks to work out.
It took a bit to get the shader, Citra, and OBS running at speed together (I used Threaded Video, turned off V-sync, maybe made another change I can’t remember), but I posted a video of the results. So it seems like it all works pretty well, even if there are still bugs.
(On an unrelated note, is Super Game Boy support or FFmpeg ever going to not be broken? I’d be willing to chip in $20 or so to a bounty on one of the issues, but I’m not sure how I’d get the bounty up in the first place.)