https://www.speedrun.com/smw/thread/f7cr2

A video and/or splits are not required, but are very heavily suggested. Runs without any sort of proof are up to the moderators’ discretion on whether they are verified or rejected. However, if a video is provided, it must be concise. That is, the video should only contain the run being submitted, and not an entire night’s broadcast for example. The run should start within 30 seconds of the beginning of the video, and the video should end after the credits or after resetting and file checking for the number of exits completed. The video should also contain the game audio. If the video supplied doesn’t meet this criteria your run may be rejected. If you do not have the capability to record video of your speedrun, consider recording your splits and submitting those.

It's up to the mod whether they verify or reject a no vid run. Usually things like that would be discussed before deciding to get a more general opinion than just one of the mods. A run not having audio isn't an insta-reject reason, but may be rejected if the mod thinks it's sketchy. Again, this would probably be brought up between mods because it's a lot easier to splice without audio.

Essentially, if the run looks sketchy the mod may reject it and video/sound are a couple ways to reduce the likelihood of this. (And no, there's no set time for which you HAVE to provide video for. That said, somebody coming out of the blue with a WR no video doesn't have great chances)

no access to a capture card, timing a run and not submitting for a while; losing the recording over that time etc. Usually it's not a problem to provide video proof, which is why most runs on the leaderboard do have video, but there's also no point in rejecting a 45 minute 11 Exit time for example.

Just my 2 cents, but you can record a run with a webcam, use a camera, or use a phone. Pretty sure a person would likely have access to one of those forms.

This was the first game I decided to speedrun, I ordered a capture card, but it took a couple weeks to ship from japan. While I waited I did speedruns and used livesplit to keep track of my times. I submitted my first times with only a splits.io. I can only state my opinion on the matter which is: I think it's a positive to the community to allow new runners to post early runs to the boards as long as they aren't top level times.