To make a <video> responsive, you only have to set its width to 100%... not a big deal.

But yeah, I love flowplayer, it has a nice js API. Too bad it's not IE6 compatible.

Why on earth do you need IE6 support?

IE6 is not even in the top 12 browsers according to StatCounter.

Globaly, yes. But if you want, per example, to target China, IE6 is mandatory. http://www.ie6countdown.com/

(and even Japan is at 4.7% according to this site. 4.7% is significant enough.)

Mandatory? For everybody?

There's a cost to supporting IE6, and a cost to not supporting it. Depending on what you're doing, it might make much better sense to do something like:

http://code.google.com/p/ie6-upgrade-warning/

IE6 usage is falling fast, even in China.

Not really. You obviously need to take care of the height too and it must depend on video dimensions. Other players out there are designed for fixed widths.

A 100% width <video> keeps its natural aspect ratio. Like an <img>.

Sure, but taking care of other parts of the player needs to be taken care of. Not that it's hard but it's surely not a feature of video players out there.

Well, yes, but it's nice to see how flowplayer resizes its interface with browser width on-the-fly.

Agreed. It's all win; testing it on some pretty old hardware and it's really smooth.