video overlay?

[Gujs]

I would like to know if it is possible to use video overlay on linux just like on windows. Like I can place a picture above the video and special color in the picture would pass through the video.

I am using ubuntu 8.04 and vlc to test this, but can't find the right color. On windows this is really simple, you can just do a screenshot of a video and the the right color is in the screenshot picture. Can somebody please help me get this color in linux?


PS: I mention windows just for better understanding of the problem. Don't want to start a flame war!

[7oby]

It depends whether you can do that.

First of all overlay is deprecated in Windows as well as Linux. Some hardware doesn't even support overlay such as the X4500 engines:

http://www.mail-archive.com/[email protected]/msg04072.html

Playing back video streams is done with the XV extension:

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

Display drivers support old fashioned overlay as well as textured video, which facilitates the 3D engine to perform the job. If your hardware supports both and your application doesn't allow to switch between the two XV backends, then check intel manpage option "XvPreferOverlay". Still - there may be cases where you wont see overlay. Maybe if you use KMS:

http://www.phoronix.com/scan.php?page=news_item&px=NzQ0Nw

Overlay will allow for tear free video playback (vsync) which is work in progress I think for textured video:

http://www.phoronix.com/scan.php?page=news_item&px=NzQ2MQ

If you use a compositing window manager I'm not entirely sure to which extend overlay still can be used. The wikipedia page above gives some information.

I'm aware this isn't the answer you expect yet, but gives you some more details and maybe after reading that you don't need overlay at all anymore.