Resize capture question

[91638]

I capture with a WinTV Card from an analogue source (TV) and i just want to ask if i have understand the resizing correct for conversion to DVD 720x576.

1st Szenario
------------

Capture Resolution : 768 x 576
Coded Pixel : 760 x 560


Target resolution (motion area) : 672 x 544

consider PAR : 672 * 59 / 54 = 672 * 1.0926 = 734

DAR for target resolution : 734 / 544 = 1.34926

So i have to cut the horizontal resolution to : 560 * 1.34926 = 756

Conclusion:
-----------
From 768x576 cut to 756x560 and resize to 672x544 (letterbox to 720x576)



2nd Szenario
------------

Capture Resolution : 720 x 576
Coded Pixel : 712 x 560


Target resolution (motion area) : 688 x 544

So i have to cut the horizontal resolution to : 688 * 560 / 544 = 708

Conclusion:
-----------
From 720x576 cut to 708x560 and resize to 688x544 (letterbox to 720x576)



Is this right or am i doing something wrong ? Hope someone can help. Thanks a lot.

[Wilbert]

1st Szenario
------------

Capture Resolution : 768 x 576
Coded Pixel : 760 x 560
What do you mean with Coded Pixel? The image inside the clip?

Ideally your capture (at this res.) shouldn't contain any black bars and you should resize to a 4:3 format (like 640x480). As can be seen in the capture guide: [url=http://www.doom9.org/capture/preface.html], the par is here 1:1.


2nd Szenario
------------

Capture Resolution : 720 x 576
Coded Pixel : 712 x 560
Ideally (if your capture card doesn't perform any internal scaling) the image should be 702x576. You should crop to 702x576 (or 704x576 is also fine) and resize to a 4:3 format. PAR is here 128/117 (or 59/54 as a slightly worse approx.).

How, apperently your capture card did some internal scaling (stretched the image including from 702x576 to 720x576). So, you can just resize to a 4:3 format without any cropping. You can use a generic PAR of 48/45 here.

remark) I find it a bit strange that you have in both cases 8 pixels overscan (768-760=8 and 720-712=8)?

[91638]

What do you mean with Coded Pixel? The image inside the clip?

I mean the resolution after cropping. I crop some pixel, because the border is not clean.

Ideally your capture (at this res.) shouldn't contain any black bars and you should resize to a 4:3 format (like 640x480). As can be seen in the capture guide: [url=http://www.doom9.org/capture/preface.html], the par is here 1:1.

I don't want to have a PAR 1:1 because i want to burn it on a DVD and watch it on TV with a Standalone. I think that i need the PAR 59:54 (or 128:117 as you wrote)

How, apperently your capture card did some internal scaling (stretched the image including from 702x576 to 720x576). So, you can just resize to a 4:3 format without any cropping. You can use a generic PAR of 48/45 here.

I hope i have understood it now:

If i capture at a resolution of 720x576 i have a PAR 48/45
So i have to adjust the PAR 48/45 to PAR 59/54. I resize the image to 720*(59/54)/(48/45) x 576 = 738 x 576
Target motion area is 672 x (576*672/738) = 672 x 524
Letterbox to 720x576. Now the PAR should be 59/54, so the movie should be displayed correct in a standalone DVD Player.

Hope this is correct.

remark) I find it a bit strange that you have in both cases 8 pixels overscan (768-760=8 and 720-712=8)?

This is just an example. I've noticed that sometimes i have to cut less or more than 8 pixels.

Thanks for your help, Wilbert.