How can I embed video from Arca in another site?

Quick/automatic approach:

Enable the module "Islandora Video Embed", and in the Blocks menu (Structure -> Blocks), add the Video Embed Code block to a page region such as Sidebar Second.

Now, when you view a Video object, a block appears containing embed code you can copy and use on any website.

Manual approach:

Get the full download link from your object's Manage page, and include the video's complete filename.

For example: to embed https://arcabc.ca/islandora/object/kora%3A296

• Manage the object, click Datastreams, and pick the datastream you want to use for the embed code. Choose OBJ or MP4.
• Right click the Download link, copy the link
  • For the OBJ: https://arcabc.ca/islandora/object/kora%3A296/datastream/OBJ/download
  • For MP4: https://arcabc.ca/islandora/object/kora%3A296/datastream/MP4/download
• Find the filename for the datastream and add it to the URL you pasted, after a slash (/). 
  • For OBJ, the filename is the datastream label:
    • https://arcabc.ca/islandora/object/kora%3A296/datastream/OBJ/download/ZoomTestJuly2012.avi 
  • For the MP4, the file name is file.mp4:
    • https://arcabc.ca/islandora/object/kora%3A296/datastream/MP4/download/fi...
• Use this URL in your standard HTML video embed code.

Example embed code:

<video width="320" height="240" controls>
  <source src="https://arcabc.ca/islandora/object/kora%3A296/datastream/MP4/download/fi..." type="video/mp4">
Your browser does not support the video tag.
</video>

Result: