You can add library streaming clips, embedded code, or direct links to Canvas. Below is an example for adding a film into an Assignment using the Canvas rich text editor. Use either the "Insert/edit media" or "link" icons.
Streaming through Zoom has had very mixed results, due to varying bandwidths and other issues. You can try checking the "Optimize screenshare for videoclip" box. If students are experiencing less than optimal viewing conditions, you can direct students to view materials on their own, in a separate window and with their audio muted, and then return to the main meeting for discussion.