Student video file submissions file size discrepancy

Student video file submissions are downloading as much smaller file sizes than shows up in Speedgrader. I attached a screenshot of a video file in Speedgrader that shows as 90.3 MB, but it downloads as only 3 MB. Does anyone know why? Is there a compression going on in the background to limit file sizes stored in Canvas Assignments? Also, they don't show up in Files, where do we find them?

student video file size issue.jpg

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Accepted answers

Greg

Thank you for including the screenshot, @kbarclay. I did some testing and verified what you reported. I had students submit a video file in two different ways. One was submitting a media recording, which compressed a video by 90%. That's quite a compression ratio, and comparing the one the student uploaded and what the instructor downloaded shows the difference: The student uploaded with a 1920x1080 aspect ratio, but the file the instructor downloaded was 640x360. I then checked the student's Files area, where their uploaded media is stored, and I see the smaller file. So it looks like Canvas does the compression at the moment of upload.

The other option was to have the student submit the video as a file. In that case, the same thing happened. It went from a 33MB file on upload to a 3MB file on download. What's interesting, however, is that Canvas's pages indicate it's a 33MB file but its preview is the smaller aspect ratio.

My guess is that the file compression is there to help Instructure save on storage.

ColtonShanahan

Munson IT Tech here. I may have found a solution to this issue.

Our instructors were reporting the same thing when it came to downloading this Semesters Student Finals. We found that anything over the 500mb limit was getting crunched down to a lower resolution, from 4k down to near 480p video.

After some digging I found within Course > Settings > Quotas, that our user quota was only set at 500megabytes, and our Course Quota at 2500 megabytes. We brought our user quota's up to 2500megabytes and Course quota to 25000megabytes to ensure enough headroom for the course storage, and click Update.

We tested uploading a 1.5 gig file, and downloaded it as intended and we were able to pull a 4k file this time. Possibly a new feature or update to Canvas could have reset these values to a default setting. This seems to have resolved our issue without having to Zip(compress) files. Students did have to resubmit their work however.

All comments

Greg

My guess is that the file compression is there to help Instructure save on storage.

PaulMcCormick

This seems to be a new issue that started around the time of your post. I have had students uploading videos all semester and only files that have been uploaded since Weds/Thursday have been over compressed.

Darmilatron

This has just caused a major issue on our course, is there somewhere to disable this undesirable functionality.

jhenline

We're also experiencing this issue. I've done some testing with various video and the results are not consistent. In some cases, the videos are being compressed and in others, they are not. It would be great if there was documentation explaining which videos, based on criteria such as file size, resolution, bit-rate, etc. would be compressed or re-sized after uploading.

PaulMcCormick

In my tests yesterday I found that if you place the video in a zip file it wasn't compressed during the upload.

Darmilatron

We had to get all of our students to re-submit their work as zip files, this works for now without the files being transcoded.

ColtonShanahan

Munson IT Tech here. I may have found a solution to this issue.

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