Aspectratio, Resizing, Cropping Whats right?

[syzygytec]

I have been reading and reading for days about this and still don't know what is the right thing to do.
In this example I'm using DVD2SVCD latest version. The job is DVD to SVCD, The Bourne Identity, anamorphic 2.35:1. The specific movie is not important to my questions however.
DVD2SVCD in all its wisdom chose a resize of 480,360 and borders of 60,60.
This makes a stretched movie, it's not proper aspect ratio. In Gordian Knot I opened the dv2 file and resized the movie to 480 which makes the height 256 with a -2.8% aspect error and then added borders of 112,112 and it looks right, then auto cropped, smart cropped all, giving me 480,192 with no aspect error and added borders of 144,144 same result really looks right, and the apect ratio is right as far as I'm concerned at least it all seems logical.
So here are the questions. Why did DVD2SVCD choose 480,360? with borders of 60,60? is this just a standard downsizing for it's 16:9(borders added, encoded as 4:3 setting? it just plain wrong and is stretched in height on the fullscreen TV, I get more height but it just seems plain wrong, the aspect ration is obviously wrong.
Now with my resize and crop and larger borders it looks right on the TV, not strectched in any way, but too damn much border.
I mean when you resize a 720x480 movie down to 480 in width your going to loose alot of the 480 height to maintain aspect ratio and my resizing in GKnot seems logically correct to me. Everything Ive done seems logical and correct to me in resizing. Im not happy with such large borders and I know that won't always be the case on this movie it is.
So is there just not so talked about sacrifice being made buy DVD2SVCD not resizing it in correct ratio? to give more picture on the screen?
I am so confused.

[Vejita-sama]

Ok, sorry this is a long post. Mostly background so my final answer makes sense.

Your post/question is a little confusing, so first I recommend you take a look at:

http://www.doom9.org/aspectratios.htm

There are several points to keep in mind. The first is DAR (display aspect ratio). There are 3 DARs that we normally deal with:

1:1 PC
4:3 standard TV
16:9 movies (and HDTV)

The next is resolution. This is a common point of confusion. But resolution and DAR are NOT the same thing. You can have a DAR at any resolution, in theory. I as in theory because in practice there are a lot of limitations in the system.

Standard TVs ONLY display a 4:3 (interlaced) video. Further although any resolution that's divisable by 16 should work the only ones that actually do (on most TVs) are 720x480, 480x480, 352x480 and/or 352x240.

Remember I said that you can have any DAR at any resolution. Well that's true. But because the acceptable TV resolutions are locked that limits how you handle DAR when you convert from one source to another.

Let's say that you have a 16:9 DVD rip that you want to encode to DivX. Since you watch DivX files on your PC you need to convert that to a DAR of 1:1. If you want to make an x(S)VCD then you need to convert to a DAR of 4:3 (if you burn a DVD-R you don't need to do anything).

The only way to maintain a DAR of 16:9 on a 4:3 TV at a NTSC standard resolution is to letter box the source. Now movies are shot at two DAR 1.85:1 and 2.35:1, both are considered 16:9.

Ok, so how do you encode a letterboxed MPEG file? You have to hard encode the black bars at the top/bottom of the MPEG (ampmorphic x(S)VCDs don't exist).

So that means you resize and add borders. Resizing to 480,360 w/ addborders(0,60,0,60) generates a 480x480 MPEG that should look like a 16:9 DAR. However, that's for 1.85:1 movies!

Since DVD2SVCD can't tell if you're 16:9 movie is 1.85:1 or 2.35:1 that's were the error came up. So what you need is a different resize/borders setting:

480/1.85 = 360
480/2.35 = 204

So for a 2.35:1 movie edit the AVS script to read:

Bicubicresize(480,204)
Addborders(0,138,0,138)

And everything should be ok. Again sorry for the long post, but I hope this helps some.

[syzygytec]

Im starting to understand, and sorry if my post was confusing but I think you understood.
After playing the svcd and the DVD on the same TV they do actually look very close.
If this movie played on the TV as a 480x480 square in the middle of the screen as it does in Windows Media player it would look stretched bad heightwise. In my years of making DivX my resizing methods are for 1:1 playback and look right on PC's.
But also according to what you said 360 is not quite right for 2.35:1 and my 360 in the script should have been 204 with borders of 138.
Now is that standard? 16:9 NTSC for SVCD should resize to 480x360 and 2.35:1 should resize to 480x204?

Sorry I'm trying hard to understand and want to, not in a highly techical way mind you, just in a how things work and why way as to be able to do things right.
Yes I have read quite a bit on Doom 9 all day yesterday actually, would have also asked there but 5 days wait before posting. I did not however come acroos the page link you gave and am off to read it now.
There is just so much information on these forums, and I have read quite a bit, it's overwelming in a way, Im trying to make a quick study of it.

[syzygytec]

Just read this.
What is important to notice here is that your playback device does letterboxing for a 16:9 disc when watching it on a 4:3 TV. Now when we're encoding such a stream for VCD and SVCD this process has to be done as well. Unfortunately the only encoder which supports to select a DAR of the input stream is TMPG (set source aspect ratio in the advanced settings, plus video arrange mode to full screen while preserving the aspect ratio). When you don't go thru TMPG you'll have to come up with another way of properly letterboxing.
So going through DVD2SVCD there is no access to this, in its place I suppose are the resizings in the avs script right? so I need to get it right there. Number one is knowing your movie transfer type and then know how to calculate it....Still not fully gripping it..trying