Comments on: Using the AIR 2.0 Native Process API to control MPlayer

By: Michael Christoff

Michael Christoff — Thu, 24 Jun 2010 18:27:34 +0000

No worries, at least I learned something =)

Btw, it looks like Visa and above do things without an overlay according to
the wikipedia article.

By: Shane Doolan

Shane Doolan — Wed, 23 Jun 2010 00:48:30 +0000

No you are not missing anything, I must be wrong in presuming os x would work in a similar way to windows. It would appear that os x does not use a color key and/or also takes into account if the window is clipped when determining which pixels to replace with video when performing the overlay.

http://en.wikipedia.org/wiki/Hardware_overlay

I tried it on my machine running xp and can confirm it works, but I cant supply you a screenshot as the screenshot fails as expected when using video overlays...

Sorry for leading you up the garden path!

By: Michael Christoff

Michael Christoff — Wed, 23 Jun 2010 00:12:51 +0000

Not sure, I'm missing something, but I gave it a try on os x and it didn't
seem to work. Checkout this screenshot:

http://img.skitch.com/20100623-1m6t852ww8r6hjjd...

I didn't size the AIR window to be exactly the size of the mplayer window…
is that a requirement? I figured I would get a cut off picture, but it would
at least prove or disprove the theory. Maybe I'm still misunderstanding how
the overlay works.

By: Shane Doolan

Shane Doolan — Wed, 23 Jun 2010 00:02:01 +0000

thats exactly what I am saying, except that mplayer uses a key color of #020202.

And again thats only tested in xp but I since the overlay is done by the graphics hardware I presume it would work the same in any operating system.

Let me know if you try it.

By: Michael Christoff

Michael Christoff — Tue, 22 Jun 2010 23:55:06 +0000

That is pretty interesting! I was unaware that video overlays worked like this. So what your saying is that if I create an AIR window with the background color #000001, startup a video with mplayer, then position the AIR window in front of the video (keeping the size the same) the video will show in the AIR window?

By: Shane Doolan

Shane Doolan — Tue, 22 Jun 2010 23:23:28 +0000

The color #000001 is the key color VLC selects to be replaced when the graphics card performs a video overlay, MPlayer uses #020202. To see what I mean press print screen on a playing video, you will get an (almost) black box in your screenshot where the video was playing. Take the same screenshot and drag it infront of the playing video and you will see the playing video appear in the screenshot.

In this way you could control the size and location of mplayer or vlc in the background. All clicks, mouse moves, hot keys would be captured and handled by the Air application as the Air app maintains focus.

Like I said its not pretty, and I have not tried this on anything other than windows xp. Just thought it could be an interesting approach to try.

By: Michael Christoff

Michael Christoff — Tue, 22 Jun 2010 21:46:34 +0000

I get what your saying Shane. From what I can see though it doesn't look like mplayer already has an API for controlling the video rectangle so that would be something that definitely could be done but would require moderately extensive mplayer source digging and a pretty good understanding how the GUI layer works on all of the platforms (the part that AIR abstracts!). Also, like you mentioned, it could get messy for certain interaction cases in the window, for example double click for full screen, showing on screen controls when the mouse moves, capture hot keys properly.

Also, what do you mean by #000001? Don't you mean #000000 (black)? What is the purpose of having a slightly non-black target?

By: Shane Doolan

Shane Doolan — Tue, 22 Jun 2010 07:07:40 +0000

I may be off target, but couldnt you position mplayer or vlc behind the Air app matching the size and location of a target rectange filled with the color #000001?

As long as Video output is accelerated (therefore using an Overlay) the video should appear in place of the rectangle.

Its not pretty, but as long as you could keep mplayer/vlc in the backgroud and the rectangles lined up it would appear as if the video was in the Air app.

To try it out simply create an empty app or or open paint and give something a backgroud color of #000001 and drag it over a vlc/mplayer window...

By: Michael Christoff

Michael Christoff — Tue, 01 Jun 2010 06:40:51 +0000

Intersting work Yuri! I'd love to see your code so I encourage you to post.

A few questions I have...

Is the Quicktime Java API self-contained or do you need quicktime installed?
What's the licensing like?
What are you using for the GUI layer? Java swing?

It would be great to even see a little screen cast.

By: Yuri Cauwerts

Yuri Cauwerts — Mon, 31 May 2010 15:43:51 +0000

Hi Michael,

Very interesting article, I am doing the same kind of thing with video.

My solution:
I wrote a Java borderless application that uses Quicktime for Java (which is deprecated since a few months ). this java-app listens to stdin and outputs some useful information to stdout. By sending the right commands you can also make the video always stay on top. Sending setPosition and setSize calls the methods of the java-app, so it can be bound to the AIR-app.

The Quicktime API is *very* powerfull, but it takes time to get the hang of it.
I can switch audiotracks on/off, change audio balance, add timetracks, add text on top of the video, change speed, …
Quicktime gives me the possibility to scrub in realtime without any delays.
I have read that MPlayer is also very good at scrubbing in realtime, it also depends on the IPB-frame structure of the video probably… (anyone?)

Maybe I should try adding MPlayer as a possible choice of videoplayers in my java-app… I suppose it has a better future…

I'll post some more information about my java-app, someplace, somewhere sometime… If anyone is interested offcourse…

Regards,
Yuri Cauwerts