Just the result of some tinkering.
First off, it's now possible to embed all kinds of media attachments easily. You no longer need to add any file extensions onto your attachment URLs, rmrk handles it all for you. For example, you can stream this MP3 attached to this post. The Generic tag is [ audio ], though if you have troubles you can use filetype specific ones: [ mp3 ], [ aac ] or [ m4a ]. Previous embed codes containing edited URLs will still work fine.
The player has now been widened, the entire song duration is displayed also, and the pointless fullscreen button when playing only audio is gone.
The same goes for video, and the [ video ] tag.
Finally, there is also a new simplified youtube tag. The old [ youtube ] tag required you to cut out the video ID and provide a size, which was cumbersome for some users. Most times that I see a big white square in posts, is because they've not done this with the youtube tag. For that reason, there is a new [ yt ] tag. Just paste a youtube video URL into [ yt ] tags and the rest is handled, even if there is extra junk such &feature=related and so on
Again, the old [ youtube ] tag will be preserved and old posts using it will still show fine. Soon the bbcode button you see when posting will change to the [ yt ] tag.