I ran into a problem with trying to upload Camtasia lecture files into Canvas. I discovered that because my captioned files in my zipped Camtasia files was in xml format this wouldn't work in Canvas. So what you need to do is to covert the xml file into a srt file which will work in Canvas. To do this go to the following link: https://gotranscript.com/subtitle-converter
Once converted you can upload it to work with your mp4 file into Canvas.
Once converted you can upload it to work with your mp4 file into Canvas.