doesn't make any sense from the usability stand point unless the media player stays in background, but even them, what hapens if you scroll a bar and don't want to change the song?
From another PoV, if you do not have buttons, what do you put on screen?, the video shows the instructions populating the entire screen wich makes a really bad looking player. This is not inventive, mouse gestures are here for good.
I think this can be really useful on a small touchscreen. A way to prevent gestures to interfere with the normal gui elements would be to only register gestures while pressing some region of the screen or a button.
I am not sold on gestures either. give me a player where half of the 'now playing' screen is the album art, with decent sized volume slider to the side of it and the whole bottom has a position indicator with time remaining on the far right and time played on the far left and the rest can be the biggest buttons in the world and still look good.
But on the other hand, if this could be made so that it was a 'global' gesture and one just had to say, for example, hold a hardware key and make a gesture, while using a different program, THAT would be useful. being able to skip, rewind, pause, play, from the web browser with almost no interruption and no teeny-tiny play ff rw icons cluttering up my browser that i could never hope to hit with my sausage fingers anyway, would be a big deal. Can someone get on this now?