Canvas Studio: Commenting
Comments may be added directly to a video or audio file to create commentary or ask questions. When Canvas Studio media is shared at the account level, users with editing rights can delete any comment at any time. If you are the owner of a video or audio file, you can delete comments in any media that you own. Comments cannot be edited except by the user who created the comment.
You can also reply to a comment that has been posted in the timeline. Currently, replies only support one reply level. You cannot reply to another user's reply. Deleting your comment retains your name and shows that the comment has been deleted. Professors can delete any comment at any time, except in Groups. Deleted comments cannot be recovered.