Width 720 x more or less

[}{KeYmAkEr*}{]

Hello

I was wondering if encoding xvid at 720 width is a good idea?

Is it bad to go any bigger like 800 width?

What I can't understand is why popular files are encoded at only 640 width....wouldn't you be losing 80 pixels?:confused:

[Tommy B.]

I was wondering if encoding xvid at 720 width is a good idea?
Go ahead. As long as the bitrate is high enough, there is no problem with this.

Is it bad to go any bigger like 800 width?
Increase the image size and don't forget to increase the bitrate. Basicly the same as the question above.

What I can't understand is why popular files are encoded at only 640 width....wouldn't you be losing 80 pixels?
Yupp, you do. But it is a good trade off between quality and compression. By reducing the resolution from 720x400 (let's asume you have 16:9 movie) to 640x352 you save 62720 pixels (288000 for 720 vs. 225280 for 640). You will lose some details, but this shouldn't be that easy to notice.

[killingspree]

Originally posted by }{KeYmAkEr*}{

Is it bad to go any bigger like 800 width?


imho it doesn't make much sense! if your source is dvd (720) increasing the frame size to 800 will just dramatically increase the required bitrate - but you won't get much better quality as the movie is upsized anyway during playback! so imho the biggest resolution making sense is 720x*** for dvd backup purposes!

but, why don't you conduct a number of tests! take a chapter from one of your dvds, encode it at 800, 720 and 640 horizontal pixels and take a look at the quality/size difference. this way you'll see what works best for you!

kr
steVe
PS: i don't think those stars (*...*) in your thread title are necessary!!

[Trahald]

Just to keep in touch with my xvid side (so i dont get too rusty before mpeg4able hddvd/blu-ray debuts) i play around with encoding dvds to xvid. i go for 1280x720 and use lanczos resize. the results actually look better than the original full screen. basically thats cause my ati's on-the-fly resizer isnt on par with lanczos.
im just saying there can be reasons to upsize if you are going to use a good upsizer filter. if you are planning on using simpleresize or bilinear, dont bother. a sharpening bicubic or lanczos , imho, may be worth it for you. (800xXXX still leaves too much to go for the playback resizer)

[SeeMoreDigital]

The answer to this question is yes and no!

But it is of course very dependant on the source...

With PAL 720x576 and NTSC 720x480 progressive anamorphic DVD sources, generating 'true 16:9 frame' images (ie: 1024x576 for PAL or 848/864x480 for NTSC) can yield very impressive results. However, I think it would be pretty pointless generating encodes, from such sources, using horizontal pixel widths other than these!

But to retain as much definition as possible, it's vital that you keep the vertical pixel count the same as the source.

Check out some of Soulhunters posts for more information together with screen-shots.


Cheers

[}{KeYmAkEr*}{]

I can't seem to find Soulhunters posts and yes i did use the search button.

[SeeMoreDigital]

Originally posted by }{KeYmAkEr*}{
I can't seem to find Soulhunters posts and yes i did use the search button. Have a look here... (http://forum.doom9.org/showthread.php?s=&threadid=74477)


Cheers