Is there a way to get clips from your library to autoplay?

I'm currently putting together an experimental survey questionnaire where participants watch a clip and then answer a series of questions that occur after the clip.
I need the clip to autoplay because the participant cannot take breaks etc. between clips as they are all excerpts from a short story and it will disrupt the flow/make the results unreliable if participants are clicking at different time points whereas if the clip is on autoplay participants will be more similar in time stamp (the participants are students within a tutorial class, so they will be using the same computers etc. so the timing should be similar). Participants will be informed beforehand that the clips will autoplay as well so they will be able to expect it/be prepared and not be taken by surprise/miss parts of the video if it autoplays.
I have tried to set autoplay up by adding ?autoplay=1 and autoplay="true" in the following HTML;
type="video/mp4"> ?autoplay=1
However, when I try it in Safari and Chrome the clip does not autoplay. Any help would be greatly appreciated! I'm very new to HTML coding, as I usually use other programs/don't usually do survey experiments.