Can't find info, please help

[Chris Byrne <chris.byrne (at) monstavision.com>]

Hans-Peter Guggenbichler wrote:
> The big question to me is: WHO DOES ALL THIS PROCESSING? 
>
> what confuses me most:
> When I change resolution: Does the driver just tell the tv card controller to provide the
> data stream in the new resolution. Is the data stream from the tv card always the
> same and the the driver does the new resolution? Or is it the application? 

Short version: Yes

Long Version: Depends on your video capture application

Most (if not all) capture cards have the ability to perform some sort of 
hardware scaling. This is work that is purely done in capture hardware 
but the stretching algorithms are usually quite naive.

So instead an application may retrieve an entire field/frame at full 
resolution and perform the stretching itself. Or it may even use some 
sort of video overlay which gets the graphics card to perform the 
stretching.

All of these approaches are very application specific and there are pros 
and cons to all of them.

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

Hope that helps,
 Chris

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