aspect ratios...

temaranight · Post by **temaranight** » Tue Jan 27, 2004 11:50 pm

Crossing this over from my vid annoucement thread this just got me to wondering. Now..going by the A&E guide, when I set up my premire project..the pixel aspect ratio should be set to square pixels and is the same in the export settings..okay..fine..but that's all I ever saw mentioned on aspect ratio the rest of the way through the steps unless I missed something. The only other thing I did was resize the vid and I did that using this.. <i>BicubicResize(480,352,0,0.5)</i>. Now..was there something I should have done to make the final encode 16:9 as Tash said ..or is that just a matter of preference? I'm asking this because I'd really like to know..I am trying to learn more about encoding since it isn't my strong suite just yet..

Scintilla · Post by **Scintilla** » Wed Jan 28, 2004 12:10 am

480x352 is 4:3, not 16:9... so you'd want to resize it to something different... Ermac and AD suggest 512x272, 512x288, or 480x256.

temaranight · Post by **temaranight** » Wed Jan 28, 2004 12:35 am

Thank you..that's what I was needing to know..like I said..I'm trying to learn and become a little better at this as I go along...*now that you say that..and I go back and look..I see now where it said that ><* Thanks agian

Kaji01 · Post by **Kaji01** » Wed Jan 28, 2004 12:51 am

So where's 720x480 figure in then? That's what my DVD rips seem to be, anyway...

BigDude · Post by **BigDude** » Wed Jan 28, 2004 1:34 am

When you rip a DVD, the fotage on them is always 720x480. (?)
Its up to you to resize the fotage to the right resolution from there. The DVD usually says on it 'Widescreen', 'Letterbox', or 'Full Frame' on it.
Full Frame would be your basic 720x480 res., Letterbox would also be that. Widecreen could be 720x360, but it still comes off the DVD as 720x480.

Thats how I figure it.

Zarxrax · Post by **Zarxrax** » Wed Jan 28, 2004 2:17 am

TV's don't have square pixels, rather they have a .9 ratio. So When its displayed on tv, 720x0.9 = 648 which rounds to 640. So therefore, 720x480 is 4:3 on a tv set, while it must be resized to 640x480 for display on a PC.

Jnzk · Post by **Jnzk** » Wed Jan 28, 2004 2:42 am

http://www.rose-hulman.edu/~yipdw/amvre ... pplet.html

Handiness. 8)

Tab. · Post by **Tab.** » Wed Jan 28, 2004 7:17 am

Ah I dunno if trythil ever got that thing save to use

TV's don't have square pixels, rather they have a .9 ratio. So When its displayed on tv, 720x0.9 = 648 which rounds to 640. So therefore, 720x480 is 4:3 on a tv set, while it must be resized to 640x480 for display on a PC.

Kind of. The real image inside the 720x480 frame is 711x486, 711 * 72/79 = 648x486, which crops down to 640x480. The easiest thing to do for digital applications is just assume 704x480 as the active frame and 10/11 as the PAR (704*10/11=640x480), which gives you about the right AR (an error of only 0.25% between 10/11 and 72/79).

WilLoW :--) · Post by **WilLoW :--)** » Wed Jan 28, 2004 8:22 am

BigDude wrote:When you rip a DVD, the fotage on them is always 720x480. (?)

720*576 for PAL

trythil · Post by **trythil** » Wed Jan 28, 2004 9:00 am

Tab. wrote:Ah I dunno if trythil ever got that thing save to use

It's safe to use, I think. I used it a couple days ago to get 4:3 material to look correct when used together with 16:9 stuff. Here's the result. Vaughn and Hitomi are from the anamorphic Escaflowne movie; the background is composited in from the Escaflowne TV series, which is 4:3.

The image looks correct to me, anyway. Sometime later this week I'll have to go back and compare the background against what it actually looks like in the TV series.

I should put the source code for the calculator up so that others can play with it if they want...ok, done.

http://www.rose-hulman.edu/~yipdw/amvre ... zeCalc.rar

Source code is viewable at

http://www.rose-hulman.edu/~yipdw/amvresizecalc/src/

The project file included is for use with JCreator, and the program has been tested using the Sun JDK; however, the Java files themselves do not make use of any extremely esoteric extensions and should compile with any reasonably complete Java development environment.

Yes, I'm well-aware of the futility of GPLing a program that has been tested and developed under such conditions, but the code should still remain free for experimentation and redistribution, even though it sucks.