I have a large number of podcasts I wanted to make available on Canvas, which were originally mounted on a previous VLE. These have the audio synchronised with powerpoint slides using ProfCast and there has never been a problem when I had saved them in .m4b format previously. Canvas only recognises the .m4b as an audio file and does not display the video component. I then started to convert them to either .m4v or .mov format, and whilst these play back in fine Quicktime, or Windows media player, but after being imported into Canvas there is a loss of synchronisation between the audio and video so that the slides are no longer synchronised with the audio. This makes them pretty useless for teaching purposes. I think Canvas converts the files into its own (or someone else's) format as there is a delay between uploading and being able to access the files. Is there anyway to stop Canvas auto-recognising the filetypes so that students could play the files using the player of their choice, rather than the Canvas player. Or any other ideas about this loss of synchronisation?