interlaced video question for you XV experts

[Michel Dänzer]

On Thu, 2005-03-17 at 16:41 -0500, Jon Smirl wrote:
> A standard TV signal requires interlaced video. How does XV maintain
> sync when playing a video file? 

XVideo doesn't handle interlacing AFAIK.

> For example say I am playing an interlaced file to TV out. How is the 
> framebuffer set up, is there one full screen progressive buffer that is 
> updated at 30Hz and then scanned out interlaced at 60Hz, or is it a half 
> size buffer that is updated at 60Hz? 

As I said, it's implementation dependent, but in my experience,
interlaced modes usually work by scanning out every second line for each
field.

> If there is an half sized buffer what happens when playing interlaced 
> video to a non-interlaced display?

Without very sophisticated de-interlacing it looks like crap and/or
visual information is lost.


PS: In the example you posted to the dri-egl list, it's probably the
player application that does the de-interlacing. If you really want to
learn how all this works, you should probably ask on a video related
list...

-- 
Earthling Michel Dänzer      |     Debian (powerpc), X and DRI developer
Libre software enthusiast    |   http://svcs.affero.net/rm.php?r=daenzer