Youtube's different players

Most videos I find on YouTube are played in their good old fashioned standard dark grey player. The one that looks like this:


Now there is an option to try the new "beta" player, too. It's very similar except less curvy and more minimalist. That looks like this:

Every time I personally try to upload a video to YouTube, it appears as the first type, or the second type if you've selected that you want to try the beta version. However, I've noticed that the odd video seems to use a third type of player that looks a bit like a hybrid between both styles:

If a video has this player, there doesn't appear to be an option to choose the new beta player either, nor is there an option to choose the quality. I'm not sure if it respects the quality setting in your profile or not.

After a quick check of the source, I found that the first two types of players are /player2.swf and /swf/watch.swf. That's fine, and it's a choice so you know you're getting a different player. The latter type of player is /player_dcad.swf.

What does "dcad" mean and why is there a third type of player that appears to be used by very few videos in YouTube? It seems that every video in a given person's account is played by the dcad player, or every video is played by the normal player -- no account seems to mix between player types.

Are these users doing something inparticular to select a special type of player or is it just happening by chance? There doesn't seem to be a time correlation, as some new videos use the traditional/beta players, whereas others use the dcad player.

You can view the swf files at the following URLs:

• Normal player: http://youtube.com/player2.swf
• Beta player: http://youtube.com/swf/watch.swf
• "dcad" player: http://youtube.com/player_dcad.swf

Curiously, there is also another player at http://youtube.com/player.swf which I assume is some very old version of the YouTube player.