I’ve dealt with similar issues before, and adjusting CSS media queries or using flexible layouts usually helps. Sometimes forcing an overflow setting or adjusting the scaling in CSS can do the trick as well. If you're also working with different video formats, converting files can sometimes be necessary for compatibility. I’ve had to convert 3G2 files before, and I found this https://www.movavi.com/video-converter/3g2-converter.html converter quite handy for getting them into a more widely supported format.