Purpose of resize [Archive]

rjc7394

18th April 2005, 23:10

I'm still fairly new to this. Is there a reason why a video with large frame size would benefit by being reduced in size? (i.e. 740x480 to 640x480). Is file size the only reason?

Sirber

19th April 2005, 01:07

more bits per pixel, higher quality.

Neo Neko

19th April 2005, 04:07

NTSC 720x480 are non-square pixels. Meaning that on the PC at least you would have to do resize at playback. If your system had the cycles to do so. So resizing means lower power systems can play it back with less effort. It also can help subjective visial quality a bit. But not especially much.

rjc7394

19th April 2005, 04:21

That's what I figured.

Shinigami-Sama

21st April 2005, 00:03

re-size is good for anamorphic encodes too or upsizing to hd resolutions so the tv doesn't have to do

ukb008

21st April 2005, 02:16

This is a post by jggimi elsewhere that may be relevant:

DVDs -- commercially produced ones, anyway -- have a fixed resolution: 720x480 if NTSC, 720x576 if PAL. These pixels are not square, unlike the pixels of a PC monitor. (And if .avi files are played back on an .avi-capable standalone player, it expects square pixels as well.)

DVDs will be flagged with a Display Aspect Ratio (DAR) of 4:3 or 16:9. GK/AutoGK will recognize this and resize to square pixels for you.

A "widescreen" movie should have a DAR of 16:9, but there is no reason it must. There are plenty of "widescreen" DVDs out there with DARs set to 4:3. It just means there's less pixels for the movie, and more for letterboxing.

See http://www.doom9.org/aspectratios.htm for more info.

EDIT: Yes, you can encode DVDs to .avi with no resizing ... but, you must use a player that resizes on playback.

Regards.