Square Pixels to NTSC? HELP!!!

Square Pixels to NTSC? HELP!!!

Post by Will » Sun, 15 Nov 1998 04:00:00



One thing that I have quickly noticed with transferring images from square
pixels to an NTSC monitor is the inherrant SQUASHING of the image that
occurs.  For instance a circle, when transferred looks like an oval on it's
side. I realize that it must have something to do with going from 640x480
to 752x480, but even when I copy the image and paste it onto a blank IFF
for instance and then transfer, It still looks squashed on NTSC.

Is their a simple way to rectify this problem?  I am bringing images
typically from photoshop to the video toaster.  losing a lot of hair over
this.  ANY and ALL insight is greatly appreciated, Ciao.

 
 
 

Square Pixels to NTSC? HELP!!!

Post by Ernie Wrigh » Sun, 15 Nov 1998 04:00:00



> One thing that I have quickly noticed with transferring images from
> square pixels to an NTSC monitor is the inherrant SQUASHING of the
> image that occurs. [...]

> Is their a simple way to rectify this problem?  I am bringing images
> typically from photoshop to the video toaster.

You need to either increase the width of your square-pixel image by
1.164 or decrease its height by 0.8592.

If possible, start with an image that's 752 x 559 and resample this in
Photoshop to 752 x 480 when you're ready to transfer to the Toaster.

Folks on rec.video.desktop.toaster might be able to tell you more.

- Ernie                              http://www.access.digex.net/~erniew
.     .    .   .  . . ............................ . .  .   .    .     .
QV 3.0   $34.95              http://www.access.digex.net/~erniew/qv.html

 
 
 

Square Pixels to NTSC? HELP!!!

Post by Kevin Thoma » Sun, 15 Nov 1998 04:00:00




>> One thing that I have quickly noticed with transferring images from
>> square pixels to an NTSC monitor is the inherrant SQUASHING of the
>> image that occurs. [...]

>> Is their a simple way to rectify this problem?  I am bringing images
>> typically from photoshop to the video toaster.

>You need to either increase the width of your square-pixel image by
>1.164 or decrease its height by 0.8592.

>If possible, start with an image that's 752 x 559 and resample this in
>Photoshop to 752 x 480 when you're ready to transfer to the Toaster.

>Folks on rec.video.desktop.toaster might be able to tell you more.

>- Ernie                              http://www.access.digex.net/~erniew
>.     .    .   .  . . ............................ . .  .   .    .     .
>QV 3.0   $34.95              http://www.access.digex.net/~erniew/qv.html

Also if your working in the ntsc d1 realm (720x486). Create your images at
720x540 then scale verticaly to 720x486 for transfer. Circles come out
circles.

Kevin Thomas
Senior Editor/Henry Artist
Brick House Editorial

 
 
 

Square Pixels to NTSC? HELP!!!

Post by David McCal » Sun, 15 Nov 1998 04:00:00


Just convert it to 752x480 in Photoshop before you take it to the Toaster.

>One thing that I have quickly noticed with transferring images from square
>pixels to an NTSC monitor is the inherrant SQUASHING of the image that
>occurs.  For instance a circle, when transferred looks like an oval on it's
>side. I realize that it must have something to do with going from 640x480
>to 752x480, but even when I copy the image and paste it onto a blank IFF
>for instance and then transfer, It still looks squashed on NTSC.

>Is their a simple way to rectify this problem?  I am bringing images
>typically from photoshop to the video toaster.  losing a lot of hair over
>this.  ANY and ALL insight is greatly appreciated, Ciao.

 
 
 

Square Pixels to NTSC? HELP!!!

Post by Stevewi » Mon, 16 Nov 1998 04:00:00


Will,

I entered the same problem before.  Render the images with as D1 instead of
square pixels.  This will take care of your problem.


 
 
 

Square Pixels to NTSC? HELP!!!

Post by Richar » Tue, 17 Nov 1998 04:00:00


Your computer monitor is made up of square pixels, but your NTSC TV set is
made up of rectangular pixels.  If you are making animations that will only
be seen on a computer monitor, then you should render your scenes using
"square pixels" in the camera panel.  However, if your end media will be an
NTSC TV, then you must choose D1 or D2.  They won't look right on your
computer, but they will on your TV.

Richard

 
 
 

1. Rendering using non-square pixels

I'm experiencing some bizarre problems rendering frames with non-square pixels using MtoR 2.1 (RAT 4.1) with prman-3.9.1 on IRIX.

Our final frame output is anamorphic 2k (1.316 Aspect Ratio: 2048x1556). The film back we're using is 1.87 AR. This means our images should render looking a bit stretched vertically (or squished horizontally, whatever your point-of-view).

My final output (Maya & MtoR globals) is set to 2048x1556, Pixel Aspect Ratio of 1.42.

The Maya-rendered frame lines up perfectly as an imagePlane behind my Maya camera.

Rendering through MtoR however, provides me with what appears to be a different camera lens length. For example, rendering using a 24mm lens in Maya appears to line up if I change my camera's lens to (approx.?) 17mm.

None of these issues arise with square pixels.

My contingency plan is to render my frames out at 1.87 AR (2048x1095) and stretch them in post. Am I experiencing a bug? Or have I missed something really, really simple that will force me to hang my head in shame every time I read this newsgroup?

If anyone's interested, I can email you two examples and/or .rib files.

Thanks in advance,
AG

----------------------------------------------------

commandpostTOYBOX

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