Overscan a Movie that is 352x480 ?

The Untouchable · #1 01-21-2004, 08:32 AM

Is it even worth it to overscan a movie thats 352x480 ?
I use Avisynth 2.5.4 & when I set overscan to "Resize 2"
The movies I encode with "Tok" (Fullscreen) look much blockier & worse,
Rather than without "Resize 2"
Am I doing the wrong setings ? or am I supposed to select "Overlap 2" ?
If so ... I can't get "Overlap" figured out for "Avisynth 2.5.4"
(I used it back in the dayz of wayback with "Avisynth 2.08")
But that won't work with "Avisynth 2.5.4"
Can someone tell me In detail what the difference between
"Overscan Overlap 2" & "Overscan Resize 2" ... & also
can someone give me a sample of what kwags latest script with
"Overscan Overlap 2" would look like
Please

Thanks In Advance
I've waisted many hours & many days on test encodes with no answer

Dialhot · #2 01-21-2004, 09:06 AM

That is not possible to have a worst image with overscan than without !

The more the overscan is, the bigger are the black borders arround the picture. And the bigger they are, the less you have data to encode. And the less data you have, the higter is the CQ.

when overscan is raised, quality is raised !

Nevertheless, the diff between overlap and resize isn't in the result (they both give an image of 352*480 with a black border of 16 pixels on each side).

The difference is : with overlap, you put the black border ON the image. That means that you can cut the top of the head of the caracter ifor instance.
With resize, the picture is REDUCED to enter between the borders. For instance, 352x480 with overscan 2 (so a border of 16 pixels on each side) means that you the picture is reduced to (352-2*16) x (480 - 2*16). This way you do not cut anything.[/quote]

For the script is simple :

resize

Code:

MPEG2Source(...)
...
GripCrop(352,480,overscan=2)
Gripsize(...)
...
GripBorders()

overlap

Code:

MPEG2Source(...)
...
GripCrop(352,480,overscan=0)
Gripsize(...)
...
GripBorders()
Letterbox(16,16,16,16)

(as you can see, the overlap is obtained with the letterbox function, and the resize is handle inside the gripcrop command)

Note : All this is given automatically by moviestacker. You don't use it ?

The Untouchable · #3 01-21-2004, 09:18 AM

Thanks for replying dialhot ... that clears up alot for me !!
I wanna use "Overlap" not resize (cuz with resize I lose pixels)
Thats why my pic quality sux @ 352x480,
I wanna use Overlap but cant figure out how to set it on kwags script with avisynth 2.5.4 (did with 2.0

but now I need help with 2.5x series
Can u post what Kwags script with overlap 2 would look like >? Please

N/M THANK U !!!

Dialhot · #4 01-21-2004, 09:20 AM

Quote:

Originally Posted by The Untouchable

I wanna use "Overlap" not resize (cuz with resize I lose pixels)

You missed something : as I wrote you do not loose anything with resize but you cut the image with overlap !

See me words :

Quote:

with overlap, you put the black border ON the image. That means that you can cut the top of the head of the caracter ifor instance.
With resize, the picture is REDUCED to enter between the borders. This way you do not cut anything

And I repeat : YOU CAN'T HAVE A WORST PICTURE.
If the picture is good in 352*480, it is BETTER when you use overscan WHATEVER this overscan is (overlap or resize).

If the picture suck in 352*480 with overscan then that means that this resolution is too big for that movie.

Quote:

Can u post what Kwags script with overlap 2 would look like >? Please

Just did that while you were typing your post

The Untouchable · #5 01-21-2004, 09:26 AM

I meant ta say that I'd rather use overlap & add black borders overtop of a movie rather than resize & squish the picture together even more than it already is with 352 x 480
Thanks Bro !!

Dialhot · #6 01-21-2004, 09:29 AM

Quote:

Originally Posted by The Untouchable

I meant ta say that I'd rather use overlap & add black borders overtop of a movie rather than resize & squish the picture together even more than it already is with 352 x 480

Okay. I see your point.

Thanks Bro !!

[/quote]
You're welcome.

The Untouchable · #7 01-21-2004, 10:06 AM

Dunno But Its not doing anything

kwag · #8 01-21-2004, 12:22 PM

As a rule of thumb:
Use "Resize" for Full Screen movies.
Use "Overlap" for Wide Screen" movies.

-kwag

Dialhot · #9 01-21-2004, 12:47 PM

Quote:

Originally Posted by The Untouchable

Dunno But Its not doing anything

The answer is in the other post you opened on that today.

incredible · #10 01-21-2004, 01:34 PM

Friends please keep in mind that 352 as width value will be stretched two times!
That would mean if overscanning (wrong word but you know what I mean) a 352x480 and choosing the value of 2 in Gripfit which causes 16px on each side: Finally on tv you get a overscan area of 32 which you could see on most Tv sets! as the whole width will be stretched more than for example 704x480, 720x480 or even 480x480.

So I recommend to use on 352x480(576) Gripfit's overscan of 1 including adding an overlap on top and the bottom of 16px using letterbox() at the end of the script

That ends up in:

------16-----
8-----------8
------16-----

= perfect in case of 352x480(576)

Edit: even if finally the image will be stretched to 640x480 (NTSC square pixels) this would be the better way, well as by this I afterwards do not say its perfevt anymore as I do not own a NTSC tvset neither I do get NTSC signal

just try as you live in NTSC Tvset land

The Untouchable · #11 01-21-2004, 09:10 PM

Thanks u guys all 3 of u

J-Wo · #12 03-07-2004, 11:23 AM

Quote:

Originally Posted by kwag

As a rule of thumb:
Use "Resize" for Full Screen movies.
Use "Overlap" for Wide Screen" movies.

-kwag

hey Kwag, I know you posted these rules a long time ago but...could I ask if these rules apply if you have a 16:9 tv? I find that when I use Overlap for widescreen movies, I am missing info on the top and bottom portion of my screen. So as a rule I ALWAYS use Resize. And I find I can use a resize of 2 on resolutions <= 480x480, and a resize of 3 above that.

incredible · #13 03-07-2004, 01:17 PM

The problem in "resized" overscan areas on Widescreen movies is that a 2.35:1 proportion fitted in 4:3 already gots very large borders and therefore a too small movie treatment area. You also can do a PANSCAN to 1.85:1 and THEN resized Overscan but that would mean even more loss of movieinformation at the sides but on the other hand a larger Picture on TV....
... but as we do KVCDs in here its anyway not the way as this would cause significant loss of CQ