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Shannon Brame
Resolution confusion
on May 10, 2005 at 3:19:17 pm

Recently I replaced a guy who make all of his projects 720x540 and I have had to go into his peices, alter them and then export them. However I have always used 720x480 or 486 depending on the export format. Someone please explain the difference. I know it has something to do with square and non square but as I come from a purely broadcast world I have never used the 540, have I been doing something wrong? All my stuff looked fine when I saw it on tv at home. I feel like an idiot for not knowing this answer but all that I have read makes no real sense to me. please help


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Pixel Monkey
Re: Resolution confusion
on May 13, 2005 at 1:30:43 pm

[Shannon Brame] "I feel like an idiot for not knowing this answer "

Please don't. This is one of the foggy topics on a lot of chat lines.

((Incidently, for one of the best explanations of this subject, check out "Photoshop for Nonlinear Editors", by Richard Harrington http://www.amazon.com/exec/obidos/tg/detail/-/1578202094/103-5853685-234382...))

720x486 is broadcast NTSC. No argument there. All the other resolutions are simply the way individual editing or graphics systems prefer to interface with you. For example, my Avid Media Composer knows fully well to output all its signal as 720x486 non-square pixel NTSC. However, it likes to receive stuff at 720x540. It displays its title tool and other features in this square pixel environment better. When it outputs, it squishes it all through its digital funnel back down to NTSC.

Why all the trouble? It's because of the print world's incarnation of programs like Photoshop, which deal with inches and cm and how true-to-life they look on a computer monitor. Unlike chairon systems which output directly to an NTSC source (and thus are 720x486 thru-and-thru), Photoshop-type programs need to be converted to NTSC, which uses different pixel sizes (nonsquare).

Some systems will automatically convert these for you. Most however, require images to be created at 720x540. When the image is done, manually change the verticle image size, thus squishing the image. When it's broadcast, the nonsquare environment unsquishes it for you.

Clear as mud? Trust me, it works.

______
/-o-o-
`(=)`/...Pixel Monkey
`(___)



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Shannon Brame
Re: Resolution confusion
on May 13, 2005 at 3:02:27 pm

But what I don't understand is if you can create something in photoshop at 720X486 why would you need the 540? A program like after effects is a great buffer, and I have never actually used the 540...have I been doing it wrong all these years?


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Pixel Monkey
Re: Resolution confusion
on May 13, 2005 at 4:01:14 pm

[Shannon Brame] "have I been doing it wrong all these years? "

Yep. See, you wouldn't really notice the difference too much, until you get into situations in your which After Effects and Photoshop stuff needs to match up perfectly with taped footage. Example - we edited a doc in which we wanted to have a blueprint drawing of a building's exterrior dissolve to the completed structure on footage. What we did was export a single frame of the footage from our Avid (540), create the blueprint look in Photoshop (540), and reimport it into the Avid (540). If at any point we changed that to 486, the image distorted vertically.

Seriously, the best way I grasped the concept was by doing the following test:
1.) Find a coffee can, a spindle of CDs, anything that's perfectly circular and shoot it with a video camera, straight-on.
2.) Create a perfect circle in Photoshop at 540 (red over a white bkgd). Name the file "Test A"
3.) Create a perfect circle in Photoshop at 486 (green over a white bkgd). Name the file "Test B"
4.) Open your "Test A" file again in Photoshop and squish the image size to be 486 (it'll look oval). Change the color to blue over white. Name it "Test C"
5.) See which one superimposes over the coffee can best in your edit system.

Cheers!

______
/-o-o-
`(=)`/...Pixel Monkey
`(___)



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Shannon Brame
One more reason
on May 13, 2005 at 7:45:15 pm

I think my avid is clunky. I work in both FCP and Avid....and these issues are not a problem in FCP.


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Pixel Monkey
Re: One more reason
on May 13, 2005 at 9:11:27 pm

[Shannon Brame] "these issues are not a problem in FCP"

Sure they are. Only now you might be getting into DV at 720x480, depending on the system. Try the test. Buy the book. You'll be amazed.

Or don't.

______
/-o-o-
`(=)`/...Pixel Monkey
`(___)



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Shannon Brame
Re: One more reason
on May 16, 2005 at 2:59:44 pm

I bought the book, thats sadly out of print...but I am a resourseful monkey and found it. (ok so it was easy to find)

I am going to try the test when I have some down time. I generally work in 720X486 for broadcast and rarely do I take elements from photoshop to air. It just goes against everything I learned...which is why I am so confused.

I am going to figure this shit out damnit. If it kills all those around me.

Cheers and thanks for you astute help!!! I owe ya a virtual beer or beverage of choice.


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kenh
Re: One more reason
by
on May 17, 2005 at 9:42:14 pm

Shannon,

Here is a relatively simple explanation. Standard Definition TV is 4:3 which works out to an aspect ratio of 1.333. If you look at computer video it is generally listed as being 640x480 (which divides out to 1.333) or the 720x540 (which also divides out to 1.333 or 4:3). This is because most computer applications use square pixels, especially true for photoshop etc. Used to be that way for AVI files etc. till they wised up and started using D1 720x486. Where does that number come from as it divides out the 1.148148? Well, D1 or TV pixels are not square. If you either divide 540 by .9 (aspect of D1 pixles) or multiply 486 by 1.1111 (the reciprical of 0.9) or multipy 1.148148 by .9 (you get 1.3333 magically) you will see how these translate. So in order to get the right aspect ratio from something created in a square pixel program you need to make it 720x540, this is especially true when doing menus for DVDs also. Then it won't get squished when brought onto a D1 timeline.

Aloha,

Ken


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Shannon Brame
Re: One more reason
on May 19, 2005 at 2:44:39 pm

Magically clear as mud. So basically when creating items in photoshop or illustrator make them 720X540 that makes sense, but what about after effects which doesn't use square pixles unless you tell it to? When working in something that is going to D1 do I have to create everything in 540? And why in all the reading, reasearch, and work that I have done have I never had this pop up before?

Thanks for your post it really did bring me one step closer to understanding this. I think I am just over thinking it and eventually I will figure it out.


shan


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kenh
Re: One more reason
by
on May 19, 2005 at 8:42:52 pm

Shannon,

If you choose D1 720x486 in after effects you will be fine, it knows how to handle video so no worry.


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kenh
Re: One more reason
by
on May 19, 2005 at 8:47:56 pm

Also Shannon I just noticed I wrote a number down wrong in the first post.

1.148148 should have been 1.48148. Don't know if that makes the mud any clearer.

Aloha,

Ken


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