Closing the loop on this one - Michael has uploaded an MP3 file in downloads and was trying to use that as a remote link in a forum post. The link to the listing, in Downloads, is what was being used in a forum post - its structure is as follows:
https://site.com/files/file/1-name/
That definitely won't work, as it isn't a link to the file but a link to a page from which the file can then be downloaded. So, check the 'Download this file' button and the URL is...
https://site.com/files/file/1-name/?do=download&csrfKey=stuff
Now that...that can be used as the URL in an audio/video tag (tested, works) but the problems are as follows:
The csrfKey is unique to the person downloading the file - one person's csrfKey in a URL will not work for someone else. RESULT: no download
There is no way, from the URL alone, to tell if the file is an audio file or a video file, so no idea which player to show
No way to determine, from the URL alone, which category the file is in within Downloads (in case you wanted to only make files in a specific category 'embeddable'
Number 2 & 3 are potentially items I can figure out but I don't use Downloads, nor do I have a need for it, so I can't develop for it as I can't see its code - and at $75 to add it, with a $10 renewal, it is not something I am going to spend money on. Maybe at a later point, yes...but at this time, no.