If you are still uncertain about the steps, scroll down to the author description below to see the link of the video tutorial on how to embed the music/video player on your profile.

Video embedding.

TL;DR: Instructions simplified

Edit: You no longer have to be a Beta Tester in order to use the above code, nor a premium member. Anyone can embed a video onto their profile.

Copy Youtube code.

Use this code for custom boxes. You can change the width and height yourself: (You need to be a premium member to use custom boxes.)

<div class="video"><da:embed profile="youtube" id="YOUR VID-ID GOES HERE" width="500" height="284"></div>

Use this code for journals:

<div class="video"><da:embed profile="youtube" id="yzC4hFK5P3g"></div>

You can substitute "youtube" with "film" or "vimeo" in order to embed dA films or vimeo videos. Simply find the video ID for the video you want that corresponds.

Paste code into Custom Box.

Find video on Youtube.

Look at video's URL in the URL bar above or click on Share.

Find video's ID exactly where it says it should be in instructions.

If link looks like this:

URL ~ youtube.com/watch?feature=player_embedded&v=yzC4hFK5P3g
URL ~ youtube.com/watch?v=yzC4hFK5P3g
Share ~ youtu.be/yzC4hFK5P3g

In which case this video's ID is yzC4hFK5P3g.

Copy ID.

Paste ID in between quotation marks in the code as shown above.

Not the entire link. Just the ID.

It should look like the following (no, the ID does not require being bold and don't forget to paste in BETWEEN the quotation marks):

<div class="video"><da:embed profile="youtube" id="yzC4hFK5P3g" width="500" height="284"></div>

Do not delete the quotation marks. You put the ID in between the quotation marks.

Click on Save. Enjoy video.

If you want to put a Youtube video as your journal's header, use the Youtube Journal CSS journal skin.

Install the skin and when you edit or create a new journal entry, click on Edit Skin and you will find the same code in the header section of the journal's CSS. Follow instructions as above to continue.

Before you ask, I repeat the quotation mark thing because people keep forgetting that the quotation marks are important and the code won't work without them.

Mini music player embedding

If you are seeing "Please enable Flash Player"

Only premium users can use the compact code as far as I am currently aware. It will not work for none premium users and will usually either only show you the original size video or give you an error message "Please enable Flash".

It has come to my attention that embedding a mini music player is also possible, though the player will only play one song at a time and will not autoplay. The code works exactly like the above code as in that you copy and paste it where you want to feature a song (custom box, journal header/body/footer). You find the song on Youtube and grab the vid ID just like the instructions above and paste it where it tells you to add the vid ID in the code.

Transparent:

<div class="ppp"><div class="pagination f sitback-container talk-post cc-userdetails popup2-clear" id="headMast"><img width="300" height="24" src="http://fc06.deviantart.net/fs71/f/2012/153/f/0/enable_flash_plz_by_fli_c-d51zq3w.png"><div class="sitback-slide flex-bottom popup2-clear"><da:embed width="544" height="340" profile="youtube" id="YOUR VID ID GOES HERE"></div>

This will give you the mini player without any background color or boarder.

Color:

However, if you want to add color around your player, you can do this too.

<div class="thumb-holder"><div class="smbutton smbutton-COLOR smbutton-small smbutton-curvy"><div class="pp"><div class="pagination f sitback-container talk-post cc-userdetails popup2-clear" id="headMast"><img width="300" height="24" src="http://fc06.deviantart.net/fs71/f/2012/153/f/0/enable_flash_plz_by_fli_c-d51zq3w.png">

<da:embed width="544" height="340" profile="youtube" id="YOUR VID ID GOES HERE">

</div>

In the "COLOR" spot, you may add one of the following: normal, blue, deepgreen, white, red, purple, green.

I am certain there are other color/customization possibilities, so for those who are familiar with code, feel free to experiment. If you discover anything worthwhile and would like to share, send me a PM with the code so I can post it here.

Note: Just like the video embed, you can embed more than one music player at a time as well. You can stack them.