hown to take a letterbox 4:3 pic and make an anamorphic style svcd

[jaay]

i have read various posts and threads and they all seem to be more about changing a widescreen movie to fit on a 4:3 screen by cropping left and right on the picture. what i want to do i to take my letterbox dvd picture and remove the right amount of the top and bottom black borders to give an anamorphic picture that when played on a widescreen tv will not require a zoom function. i appreciate that some movies when anamorphic have small black borders at the top and bottom to allow for different aspect widescreen film ratios. what i would like is an avi script for pal and anotehr for ntsc movies that will crop the right amount of top and bottom borders every time so that when played back on a widescreen tv the ratio is automatically correct.
therefore i dont want to cut any of the actual picture of the film and the script would leave small black borders for a film like T2 (if it was a 4:3 letterbox vers) but wouldn't have any for a movie such a jurassic park (again if it were 4:3 letterbox)
thanx.

ps. perhaps this would be a nice feature for a future dvd2svcd?

[delly01]

You can edit the avisynth-script to do this. Detailed instructions for avisynth-scripts are on www.videotools.net . You will need bilinearresize() or bicubicresize().

For pal and the elimination of 60 lines upper and lower border it would like something like this:
bilinearresize(480,576,0,60,720,456)

If you want to eliminate a different number of lines, you have to change the fourth parameter (60 = lines) and the last one (sourcesize of 576 - 2xlines).

However, I see no point in this. Enlarging the picture will not offer you a more detailed picture, and the stretching can be done by the tv-set itself just fine.

Bye,

Detlev

[Nick]

I haven't got any PAL letterbox dvd's to test this with so these scripts are only what sounds right of the top of my head. The NTSC one seems to work...

I am a bit of a novice at this DVD2SVCD lark so I don't really understand the resize methods. If you are more clued up about this, then I'll leave that aspect to you. I just used simple resize.

So here goes...
Select "Edit when DVD2AVI processing is done" in the frameserver tab.

When invited to edit the PAL movie scripts will contain the line "simpleresize(480,576)" whereas NTSC films will have "simpleresize(480,480)".

The Crop command should be inserted directly before this.
PAL:

Crop(0,72,720,432)

NTSC:

Crop(0,60,720,360)

And that should do it. However, having seen the results I would be inclined to agree with the posting above and just leave it to the TV.

Also, especially with the PAL one which is completely untested, I would STRONGLY recommend a test run just ripping the shortest chapter only and writing to a CD Rewritable to if this works first.

If it doesn't then sorry, at least I tried...:confused:

[delly01]

Originally posted by Nick
So here goes...
Select "Edit when DVD2AVI processing is done" in the frameserver tab.

When invited to edit the PAL movie scripts will contain the line "simpleresize(480,576)" whereas NTSC films will have "simpleresize(480,480)".

The Crop command should be inserted directly before this.
PAL:

Crop(0,72,720,432)


That's an alternative that I would not recommend, enlarging should be combined with some filtering, at least bilinear, better bicubic filtering. The bilinearresize- and bicubicfilterfunctions have an integrated cropfunction, therefore

crop(0,72,720,432)
bilinearresize(480,576)

and

bilinearresize(480,576,0,72,720,432)

do the same, but the latter is faster.

Again, one should read the avisynth doc on www.videotools.net, it's a good reference.

Bye,

Detlev

[Nick]

Thanx for that.

The link was very useful too.

Anyway, trial and error came up with a crop of 60 lines top and bottom for NTSC and simple multiplication gets that to 72 lines top and bottom for PAL, so a by my maths and Delly's knowhow, selecting bilinear resize, you should edit the command line in the Avisynth script to

bilinearresize(480,576,0,72,720,432)
for PAL

or
bilinearresize(480,480,0,60,720,360)
for NTSC

Just re-encoded the first chapter of "The Others" from 4:3 letterbox DVD and Delly's right - this way does work much better!

So, I hope this has got you sorted, Jaay!!

[jaay]

thanx for your input guys, if you're wondering why i did this its because some tvs old Ws tvs dont have a zoom funcation, and i thought since we're taking a bigger picture and making it smaller (res wise) that this would help to reduce the scan lines that are apparent on the tv when you zoom in. i have also been trying the bicubic resize methods with the following properties:
BicubicResize(480,480)
crop(0,60,720,360)
and respectively
BicubicResize(480,576)
crop(0,72,720,432)
i will post some test results later (maybe some screen shots)

ps. i also use this to make 4:3 dvds into anamorphic dvds :)

[delly01]

Originally posted by jaay
BicubicResize(480,480)
crop(0,60,720,360)
and respectively
BicubicResize(480,576)
crop(0,72,720,432)


I hope that it's only a typo - this way around, you will get a too small picture, because you will not stretch vertically (the source is 480/576 high, and it gets resized to 480/576 meaning no change in height) and afterwards crop the lines at the top and bottom. You must crop at first and then resize to 480/576, and as the docs for avisynth state, the bicubic filter itself can crop so you will also waste speed this way.

Bye,

Detlev

[jaay]

yeah whoops, the crop does come before.
the results were very good, the resulting svcd played superbly on my WS screen tv with no need for zooming, reducing any scan lines in the picture. i definitely recommend this method for those few 4:3 letterboxed dvds.

[SupaCoopa]

Although I'm trying to do something a little bit different than jaay (crop a 2,35 to 1,85) I'm not too far from subject here asking:
Why can't I use "Crop" command in my AviSynth script?

As gerti67 suggested (when I asked in an other thread), I edit script to read:
...
Crop(90,72,540,432)
BicubicResize(480,576,0.00,0.75)
...

Well, the result is an MPG of black background with red letters saying something insulting about line 3 of the AviSynth script, which is the one containing the Crop command. Sound plays fine.

What's wrong here, mates?

By the way if anyone feels like helping me here's my thread:
http://forum.doom9.org/showthread.php?s=&threadid=22251