If you argue that you shouldn't record videos of an emulator because you're playing on your phone then I don't even know what to say. iPhones, pads, android devices, whatever, have probably the least accurate emulators, contains the most programming shortcuts, hacks to make games work "anyway" and blablabla. If anything they are the ones that should definitely require video.
I don't like how you think you could just pick up your old tamagochi and play an emulator on that and be like "this thing doesn't have local recording so I guess I'm off the hook!" when that's completely beside the point of everything that has been argued so far.
I think that a minimum of 24 fps, 96p, full (256) colour video files of standard formats such as avi and mp4 should be the definition of video proof. If it's any less than that it's gonna be impossible to tell anything anyways.
I think official PC Sonic emulator games just are variations of the Gens emulator, or that's what I've heard anyway. I don't really like them though since they're relatively featureless and inaccurate compared to other unofficial emulators. If you're talking about PC games like Heroes or Generations I think it should be considered a valid platform, at the very least for the games that feature a stat-saving feature.