Format questions for video conversion

[b4u]

Hi,

Can anyone please clear up my mind on a basic question?

What is PAL? It's a standard european format (like NTSC is an American/Japan standard).

So is it 16:9 aspect ratio?

I'm reading some info about video capturing, and I know that PAL has a sample rate of 14.769, with active picture width of 52 microseconds, so I'll need 52*14.769 = 768 pixels wide to fully capture the video (side-to-side).

Am I correct? Or not that correct at all?

 

[psiu]

er....dunno bout all that technical stuff, but just like NTSC, it's 4:3 format.

:beer:

 

[Viper GTS]

There's far more to PAL than that.

Start Here

Viper GTS

 

[woowoo]

Pal Is a standard
It's croma subcarrier freq. is twice that of NTSC.
AKA... "Flickervision"

 

[b4u]

Take this example:


Let's imagine I want to make a DivX/XviD (PAL).

Full PAL TV on a PC gives 52 µs * 14.7692 MHz = 768 pixels, ending with 768x576.

My "SAA7108, Nvidia with a WDM driver" has a capture window of 53.33 µs.

How many PC sized pixels fit in the capture window? 53.33 µs * 14.7692 MHz = 788 pixels. So I will get a 788x576 resolution.

The way I see it, I will get 788-768=20 black pixel border on playback. Am I right so far?


Ok, let's complicate then ...


Resizing:

If I want that, cap high, say 720x576.
However, the card caps only 53.33 µs (fixed), so I need less pixels to make up the difference with the 52 µs a PC needs for correct Aspect Ratio. How many?
(52 / 53.333) * 720 = 702 in total.

So, remove 18 black pixels of my 720x576 cap. I now have 52 µs of info in 702 pixels. Resize the resulting 702x576 to 768x576 or a scaling of it.


That resizing part I don't quite get ... why would I want to do that? And why choose 720x576 to cap?

 

[dman]

FYI, you can visit dvdrhelp.com for forums that cover this and all sorts of video related topics. Not that it can't be talked about here.... there's just a wealth of information already there.