In assesmentQ there are certain restrictions regarding the audio and video fragments that can be uploaded, see Which audio and video formats are supported?
When a video fragment is too large, you can solve this in two ways:
Cropping your video so that you get two separate files, for example. This can be done on Microsoft computers via the Photos application.
Compress your video. This means that you are going to optimise the file size. An ideal tool for this is HandBrake (free and downloadable at: https://handbrake.fr/).
You will first upload your video in the tool and then change the 'presets' to 480 pixels. This is sufficient quality for a digital environment. Then you indicate a location where the video can be saved (at: 'browse') and finally click on 'Start Encode'.
More info on the Handbrake tool: https://support.vidello.com/article/311-compress-video-using-handbrake