KVCD: Why 704x480 and Not 720x480?

audi2honda · #1 08-26-2003, 09:18 PM

Why do the KVCD templates not include a 720x480? Will 720x? only burn under the KDVD methods and not as non standard VCDs? It seems to me the extra resolution wouldn't take up to much bitrate and it would be compatible if you ever wanted to put your KVCDs on a DVD-R in the future right?

704x480 won't play on a DVD-R but 720 will or am I way off?

Basically does 720x? work with KVCD and if so will this give me better compatiblity if I ever want to move my KVCDs to DVD-R one day?

kwag · #2 08-26-2003, 10:10 PM

Quote:

Originally Posted by audi2honda

Why do the KVCD templates not include a 720x480? Will 720x? only burn under the KDVD methods and not as non standard VCDs? It seems to me the extra resolution wouldn't take up to much bitrate and it would be compatible if you ever wanted to put your KVCDs on a DVD-R in the future right?

The reason was that 704x needs less bitrate than 720x. And visually, there's really no difference between both.

Quote:

704x480 won't play on a DVD-R but 720 will or am I way off?

You're off

704x480(576) and 720x480(576) are both DVD compliant resolutions. As a matter of fact, I make my KDVDs at 704x480, and not at 720x480

I just finished today putting K-Pax, K19 and General's Daughter on one DVD-R at 704x480, audio 128Kbps with DS2, and looks A.W.E.S.O.M.E

Quote:

Basically does 720x? work with KVCD and if so will this give me better compatiblity if I ever want to move my KVCDs to DVD-R one day?

Sure, but only if you encode MPEG-2. Not MPEG-1.

-kwag

vmesquita · #3 08-27-2003, 08:45 AM

How is aspect ratio for 704x480? Is it the same 4:3 or there is some cropped area?

[]'s
Vmesquita

kwag · #4 08-27-2003, 12:12 PM

Hi vmesquita,

The aspect can be 16:9 or 4:3.

Code:

For anamorphic video, the pixels are fatter. Different pixel aspect ratios (none of them square) are used for each aspect ratio and resolution. 720-pixel and 704-pixel sizes have the same aspect ratio because the first includes overscan. Note that conventional values of 1.0950 and 0.9157 are for height/width (and are tweaked to match scanning rates). The table below uses less-confusing width/height values (y/x * h/w).

      720x480   720x576
      704x480   704x576   352x480   352x576
4:3     0.909     1.091     1.818     2.182
16:9    1.212     1.455     2.424     2.909

Another note. Here are all the valid DVD resolutions:

Code:

Allowable picture resolutions are:
MPEG-2, 525/60 (NTSC): 720x480, 704x480, 352x480, 352x240
MPEG-2, 625/50 (PAL): 720x576, 704x576, 352x576, 352x288
MPEG-1, 525/60 (NTSC): 352x240
MPEG-1, 625/50 (PAL): 352x288

This information (and the best information!) related to DVD taken from here: http://www.dvddemystified.com/dvdfaq.html

-kwag

vmesquita · #5 08-27-2003, 04:46 PM

Kwag,

It looks like 704x480 is like 720x480 without 1 block of overscan. Am I right? SansGrip GripCrop/Borders can deal with it, right? So maybe I should start using 704x480 myself and update my KDVD templates for CCE and the guide... But why Tmpgenc KDVD Template is set to 720x480? Is there any compatibility reason? I know 704x480 is part of the standard, but maybe it is "less compatible"...

PS:Great Link!

[]'s
Vmesquita

kwag · #6 08-27-2003, 05:14 PM

Quote:

Originally Posted by vmesquita

Is there any compatibility reason?

No

Quote:

I know 704x480 is part of the standard, but maybe it is "less compatible"...

It's just as standard as 720x480

Quote:

PS:Great Link!

[]'s
Vmesquita

Thanks!,
-kwag

vmesquita · #7 08-27-2003, 05:34 PM

Kwag,

This link I found in the page you recommended is also very good:

http://www.uwasa.fi/~f76998/video/conversion/

You forgot to answer me why Tmpgenc KDVD templates use 720x480, not 704x480... Any special reason?
Correct me if I am wrong, but if I am already using the max overscan possible with 720x480, then the only gain I'll get using 704x480 is that the encoder will have to store less informatio about black bars (that take little space, but still take some space). Am I right?

[]'s
Vmesquita

kwag · #8 08-27-2003, 07:25 PM

Quote:

Originally Posted by vmesquita

You forgot to answer me why Tmpgenc KDVD templates use 720x480, not 704x480... Any special reason?

I don't know

Quote:

Correct me if I am wrong, but if I am already using the max overscan possible with 720x480, then the only gain I'll get using 704x480 is that the encoder will have to store less informatio about black bars (that take little space, but still take some space). Am I right?

Right. You're encoding less total "Film pixels", so you have more bits per (active picture) pixel, which translates to a higher CQ

-kwag