add borders due to TV

[poopity poop]

in TSVCD there is a menu creation system that lets you see the actual viewing portion of the stream that the TV sees. I did some tests to see what my TV sees vs what the actual stream is showing( from the computer). I was wondering if anyone had considered actually squishing the picture in slightly to add lots of borders to the SVCD stream.
Unfortunatly I forget my settings exactly but I'll try to remember them.
on a 2.35:1 AR:
On the resize I cropped all but the picture on the 720x480, resized it to 440x250, then added borders to 480x480.

If you don'tfeel liek trying this. It looks like a 480x480 stream streched a little top to bottom due to aspect ratio, but instead of the sides of the picture touching the edges there is about 20 pxels of black.. This black is taken out by the TV. So what you get is more of the pictuer with the same AR. Has anyone tried this, r am I the only one who has thought of doing this? If so, did it work out for you?

[Boulder]

I think you're supposed to add the borders first and then resize.

Check this URL out:

http://www.iki.fi/~znark/video/svcd/faq/

[ulfschack]

Either way destroys interlacing. So for (most) DV encoders this is not the way to got. Use avisynth before putting it into TmpgEnc or CCE or whatever. Suggestion:
------------------------
avisourse("c:\vid.avi")
AssumeFrameBased
SeparateFields #now at 720x288 framebased, 50 fps
#inser temporal and/or spatial noise filters here ...
BicubicResize(416,256).AddBorders(32,16,32,16).weave
-------------------------

This will get you an interlaced video 480x576 with 32 borders on all sides. Note that the left/right borders streches to 720/480*32=48 (altough we really can't say pixels here, you know what I mean) if you set 4:3 a/r in the encoder.

cheers

[poopity poop]

wow, my hope in humanity has risen. Very good site recommendation and very itneresting avisynth script, I know there are some good encoders out there :).

But unfortunatly I may not have explained myself compeltely. What I meant was this:

My source is a DVD 720x480.
What I'm wondering is should I add some black borders left/right so that when the TV crops off some of the image st due to the way TV's work, it iwll not crop off as much seeing as how I moved it in.
I was just wondering if all TV's crop off like 20 pixels or so or jsut the two TV's I have tested this on

[Boulder]

My TV does crop, I'm not sure how much but I guess it's 16 pixels. That's why the 8 pixel borders should be added to the source before resizing so that you won't lose any image data there and the ratio stays where it was. At least I've never seen those borders on the TV screen. I've done my capturing at 704x576 (full PAL resolution) and will try 720x576 (no need for the borders) to see what happens, eg. does it crop the picture etc.

[dZeus]

Adding borders destroys the contents, as in it's made with overscan specifications in mind. If you don't like overscan, why watch it on a tv in the first place? It's inherently in the nature of a TV to use overscan, if you don't like it, you should watch it on a monitor.

Did you ever thought about the fact that everything you watch on aerial also is displayed in overscan? It's completely normal, and adding black borders would change the way it was intended to be watched.

[ulfschack]

@poopity poop

Yes, I understood what res you were using. I just thought that you could do the thinking instead of me :) Just use the same line of thought with 480 instead of 576 vertical res. As a matter of fact I'll do it for you. (For 720x480 video

BicubicResize(480-2*LR,480/2-TB).AddBorders(LR,TB/2,LR,TB/2).weave

Here you'll end up with an 480x480 video, where
LR = left or right border width (assumed symmetrical)
TB = Top or bottom border width (assumed symmetrical)

Keep in mind that LR becomes LR'=LR*3/2 when streching the pixels to 4:3 on the tv.

And to answer your initial question (at last) I have seen over-scan of varying magnitude on just about every TV set I've tried. 32 and 48 might be a little thick but in no way exaggerated. It's also my experince that the tv stretches more in the x-direction, which is logical since the x on a regular TV is 4/3 times as long as the y.

@dZeus

What a crock o'bull.

I suppose we could in the same line of reasoning and conclude that win98 crashes so often cause it's the way it is intended. I know what I intend for my SVCDs, and it's certainly NOT for 18 % (I figured it out by adding multicolored borders around the frame) of my precious bits go to waste. Not to mention hampering the allready narrow angles of most DV camera lenses (well, I did mention it after all, didn't I).

(By the way, how do you know if you "like overscan"? It's not as if you can see it, right?)