Ensure that a speedrun (or video recording) was done in one continuous hop (and not spliced together from many parts)

In speedrunning video games, one records a game being played and beaten in one continuous attempt. However, what can be done to cheat is to do multiple attempts, and splice together clips of the best segments to make one fast speedrun that wasn't done in a single continuous hop. This splicing isn't hard, as e.g. loading screens always look the same, so you can swap the video at those points without being noticed.

My question is: is there some way people can verify that their video was recorded in a single hop?

The reason I believe there's hope in solving the problem is: one mario 64 speedrun was caught splicing because the ambient background noise in the audio had a discontinuity at the loading screens (indicating the video was swapped there). So I imagine that some method of artificially injecting noise might be the key. The answer might also involve using live generated random values, to ensure the overall timing throughout the speedrun is consistent, as opposed to different parts being recorded at separate times.

I understand that there's lots of ways to cheat a speedrun, but I'd like some way to address this particular problem of splicing a video that should be done in 1 continuous shot.

Note that because it's a speedrun, you can't ask the player to perform a random action to verify something is done live, as performing that action would waste time, which one doesn't want to do during a speedrun.

A cryptographic solution would, by definition, have a public design, with only a key possibly secret. If it was an add-on to an external game console or PC program, e.g. timestamping and signing frames made externally and fed to an input, it would be vulnerable to splicing at it's input.

The only thing I can think of that would work robustly is a trusted box, setup by a trusted authority, that both runs the game and signs the outcome, e.g. timestamps and signs all frames in the capture. The capture would then become publicly verifiable by anyone trusting the authority, it's ability to set up secure devices, and the integrity of it's public key.

This compares to the practice of having a referee setting up the game and attesting a record; only automated and working even when the referee is absent.