rezize divx.avid to dvd standard

[bex]

if you resize a ntsc divx wide screen that has no borders like most of them are you can work out what what borders to add by dividing the width by 1.777

for example a divx is 640 x 336

if you divide 640 by 1.77777777777 you get 360 subtract the height of 336 and you get 24 half this and you get 12 (each for top and bottom)

so the script
aviSource("about.avi")
addborders(0,12,0,12)
BicubicResize(720,480)
ResampleAudio(44100)

my question is this, what is the divisble for pal divx/xvid

[Bidoche]

You are assuming here that the aspect ratio for 16:9 is 16/9 which in fact is not the case....

640x336 is good enough 16:9, no need for borders.

Edit: there is a nice guide about aspect ratio somewhere here, it should have your answers.

[Wilbert]

Your DivX is that 640x336 (1.905:1) without black borders.

The main question is whether you want to make an anamorphic [1] or a letterbox [2] dvd.

[1]: your dvd must be 720x480. Resizing to 16/9*480x480 = 853x480 gives the correct aspect ratio. Scaled: 640x360.

In this case you have to add borders from 640x336 to 640x360 and resize to 720x480.

[2]: your dvd must be 720x480. Resizing to 4/3*480x480 = 640x480 gives the correct aspect ratio. Scaled: 640x480 :)

In this case you have to add borders from 640x336 to 640x480 and resize to 720x480.

PAL:

[1]: your dvd must be 720x576. Resizing to 16/9*576x576 = 1024x576 gives the correct aspect ratio. Scaled: 640x360.

In this case you have to add borders from 640x336 to 640x360 and resize to 720x576.

[2]: your dvd must be 720x576. Resizing to 4/3*576x576 = 768x576 gives the correct aspect ratio. Scaled: 640x480.

In this case you have to add borders from 640x336 to 640x480 and resize to 720x576.

I hope this is clear (and I didn't mess up). Of course you can check this with FitCD.

edit: corrected it.

[bex]

the divx in this case was 1.85:1

[Wilbert]

What is the resolution with and without any black bars?

[onesoul]

To help you understand what happens between conversions of different formats and different pixel ratios try using Video Size Calculator which is more simple to understand then Fitcd (after understanding, Fitcd will get more easier to handle) because it doesn't handle other matters than the conversion itself. The proggie can be found at this page (http://home.bip.net/gunnart/video/), just scroll down, the author is Gunnar Thalin.

edit: don't forget that pixel ratio is different on pal, ntsc, monitor and anamorphic video. This link (http://www.mir.com/DMG/aspect.html) which can be found in the doom9 forum (don't remember where) explains it beautifully.

Cheers

[scmccarthy]

If you hunt long enough, you will find a site about aspect ratios that expains that the correct pixel aspect ratio for non-anamorphic NTSC is 72:79 rather than 10:11. Below I give you the original explaination followed by what the explanation would look like with the corrected aspect ratio, bearing in mind that both are close enough:The pixel aspect ratio for 525-line video (NTSC) is 10:11....

An image with a standard display aspect ratio of 4:3 (i.e. TV) with 480 lines (i.e. NTSC) would thus have:

640 square pixels per line, or
704 non-square 10:11 pixels per line

Note that a 720 pixel scanline has thus captured an extra 8 pixels on either side! A 720x480 frame is not actually a 4:3 image. :The pixel aspect ratio for 525-line video (NTSC) is 72:79....

An image with a standard display aspect ratio of 4:3 (i.e. TV) with 480 lines (i.e. NTSC) would thus have:

648 square pixels per line, or
711 non-square 10:11 pixels per line

Note that a 720 pixel scanline has thus captured an extra 4½ pixels on either side! A 720x480 frame is not actually a 4:3 image. 648x486 is the 4:3 image, with the extra 6 lines tossed out.

There is a site which discusses all this, including the 486 instead of 480 lines for NTSC.

10:11 and 40:33 are the pixel aspect ratios I used to used for NTSC, but now I have accepted that 72:79 and 96:79 respectively are more accurate still.

Stephen

[scmccarthy]

Adapting Wilbert's instructions for NTSC non-anamorphic (letterbox [2]) while using a 72:79 SAR:

Try resizing 640x336 to 702x336 or 711x340 and add borders to all four sides to 720x480. If you watch the DVD on a TV, the side borders will probably be hidden due to overscan; in which case, you will see more of the original picture.

Stephen