Menu stills: 720x540 or 720x480

[tomeczek]

The still images of the menu (the background), according to DVD specs, should be the size of 720x480. On the other hand, the 4:3 ratio NTSC TV uses the size 720x540.
That means that the original still image will be stretched when viewing on TV: original circles will become ellipses, squares will be rectangles, and the people will be much slimmer.
My first idea of fixing the problem was: create 720x540 image, squeeze it vertically to 720x480 (using Photoshop) and use this image as the menu's still. TV would stretch it to 720x540, which is my original size.
That works, when it comes to the image itself. But the subpictures, which make "buttons”, are not in the right position anymore! :mad:
Has anybody ever worked on this problem? How to fix it?

[Lord of the Discs]

use the force, tomeczek, with the search button (try "720x540")
and get surprised ...

LotD

[Kika]

On the other hand, the 4:3 ratio NTSC TV uses the size 720x540.

To be absolutly correct, NTSC TV 4:3 is 711x486 according to Singnal timing and Sampling Frequenzies. ;)
But that's not good too handle. So NTSC was set to 720x480 (considering on the Mod16-Rules in MPEG).

Tomaczek, you have to read a lot about Display Aspect Ratios (DAR) and Pixel Aspect Ratios (PAR).
Pixels in MPEG-Videos are not square, they are non-square.

[dan]

I made a little guide about making menus in photoshop for NTSC, it has how to make the subpictures line-up (as well as a lot of other stuff)...

http://forum.doom9.org/showthread.php?s=&threadid=45870

For full-screen menus, make your menus AND your subpictures for those menus at 720 x 540(ish). Make sure they line-up (in photoshop or however you're making the menus) at that resolution, then resize both to 720 x 480 and import into Scenarist. They should still line-up.

Hope this helps..
Dan

[Richard Iredale]

I have found that if I create my menus at 720x540, I can import them directly into Maestro and Maestro will automatically re-sample them down to 720x480 (for NTSC).

[hendrix]

Originally posted by tomeczek
the 4:3 ratio NTSC TV uses the size 720x540.

hmm?..where did you get that info - NTSC is 720X480 not 720X540
broadcast D1 is 720X486

[SupaCoopa]

Computers use DAR of 1:1. Photoshop (for instance) dictates that NTSC resolution is 720x540. You make a circle and it shows up a circle. You then import this 720x540 in Maestro and it automatically resizes it to 720x480, but you can also stretch it (after finishing your design) using Photoshop to 720x480 -as it does a better job than Maestro in resizing- and give the "distorted" image to Maestro. You see the preview in Maestro and the circle is no longer a circle. Now NTSC DVD has a DAR of ...I can't remember, but it doesn't matter because your player knows it, and when you playback the thing a circle appears as circle on your TV. The same thing happens with DVD playback on PC, where the software rescales/stretches the image to appear OK.

To recap in brief, from my personal experience in DVD menu design with Photoshop and Maestro.

For NTSC: Design in 720x540 for 4:3 and 864x486 for 16:9. Resize both to 720x480 after completing the design, import to Maestro and set the correct aspect ratio flag (4:3 or 16:9).

For PAL: Design in 768x576 for 4:3 and 1024x576 for 16:9. Resize both to 720x576 after completing the design, import to Maestro and set the correct aspect ratio flag (4:3 or 16:9).

These apply to both still and motion menus.

[Kika]

The DARs of PAL and NTSC are equal, so there's no need to use other Resolutions to create your Picture with square Pixels.

Oh, and by the way: 720x576 is not 4:3. 704x576 is 4:3! Same on NTSC. The 720-Format is using an Overscan of 16 Pixels. So if you want to create a Picture (square Pixel) for a PAL-Menu in 720x576, you have to create on with the Resolution of 786(!)x576, not 768x576.

http://toolbox.sgi.com/TasteOfDT/documents/video/lurker/pixelaspect.html

[tomeczek]

Thank you All!!!
A lot of material to study and think about.
BTW, I am creating my movies in Scenarist 2.6.

@Lord of the Discs
Can you explain what you mean by:
"use the force, tomeczek, with the search button (try "720x540")
and get surprised ..."

[Lord of the Discs]

I have seen several posts about the subject so I had the idea that
you forgot to search for it, my post was supposed to be funny, not
insulting or so ...

LotD

[SupaCoopa]

Kika, useful link that one, but what you say contradicts with the info found on that page.

It says
Pixels in the graphics world are square. A 100 pixel vertical line is the same length as a 100 pixel horizontal line on a graphics monitor.
Pixels in an ITU-R BT.601-4 digital video signal (also known as Rec. 601 and formerly CCIR 601) are non-square. A 100 pixel vertical line may be longer or shorter than a 100 pixel horizontal line on a video monitor, depending on the video standard.
Also further down it says
What Is the Pixel Aspect Ratio of Non-Square Pixels?
For 525-line Rec.601 video, the pixel aspect ratio is exactly 11/10.
For 625-line Rec.601 video, the pixel aspect ratio is exactly 54/59

That lot doesn't seem to be the same as The DARs of PAL and NTSC are equal, so there's no need to use other resolutions to create your Picture with square Pixels

Also both 720x576 and 704x576 -and their NTSC equivalents- can either be 4:3 or 16:9. The resolution doesn't change in different frame aspect ratios, it's just a matter of how the material is encoded withing the standard resolution. As for overscan, that's is why all DVD authoring programs have those lines round-around, so that you will constantly be reminded that some part (way more than just 16 pixels in wide) is cut off on TV screens. One takes that into account when designing for TV screens and makes sure no important elements will be lost.

I believe that the page you linked to gives some figures useful for specific use with a specific system. For home-made DVD with our humble PCs, if you create graphics in 786x576 or 820x576 or whatever you will only get distorted images on TV playback. Adobe Photoshop 7 and Adobe Premiere 6+ (to name just two) specifically define the resolutions I noted above as the correct ones for making DVD content on computer.

All of the above in a very friendly tone :)

[Kika]

@SupaCoopa

I talked about the DAR, not the PAR, that's a completly different story.

The DAR (Display Aspect Ratio) is 4:3 or 16:9. So all you have to do is to draw your Menu-Pic in a Square-Pixel-Format. The resize it to you Video-Format:

PAL:
786x576 -> 720x576
768x576 -> 704x576 <- That's (if not 16:9 anamorph) is DAR 4:3, PAR 1.092:1 (or 1:0.9152)
But you can use ANY 4:3 or 16:9-Square-Pixel-Format.

Adobe Premiere is not exactly right. It talks about a PAR of 1.0667 for DV/DVD (PAL-World), but that's definatly wrong.