Welcome to Doom9's Forum, THE in-place to be for everyone interested in DVD conversion.

Before you start posting please read the forum rules. By posting to this forum you agree to abide by the rules.

 

Go Back   Doom9's Forum > Capturing and Editing Video > VirtualDub, VDubMod & AviDemux

Reply
 
Thread Tools Search this Thread Display Modes
Old 17th May 2011, 14:00   #1  |  Link
donfrenchiano
Registered User
 
Join Date: Aug 2010
Posts: 35
Resizing in avidemux

Ive been using gordian knot and autogk to encode dvds to avis for years and recently i began looking at avidemux. I was wondering how AutoGK determines how it resizes a video. autogk picks a resolution for you automatically and its different every time. In avidemux you have to specify it manually as far as i can tell. Is there some way to determine what would be the best resolution to resize a video to based on size, bitrate or something else?
donfrenchiano is offline   Reply With Quote
Old 17th May 2011, 16:21   #2  |  Link
LoRd_MuldeR
Software Developer
 
LoRd_MuldeR's Avatar
 
Join Date: Jun 2005
Location: Last House on Slunk Street
Posts: 13,248
There is no such thing as a "best" resolution, except for the original video's "native" resolution!

Generally it is highly recommended to not resize at all. If you do resize, you should know why you need a resize. And then you also know what your target resolution is.

If you do not have a good reason to resize, then simply do not resize


Be aware: Some applications use "bits per pixel" (aka "bpp") as a metric to predict the quality of the re-encoded video.

So maybe (I don't know, I just speculate) AutoGK will lower the resolution based on the target average bitrate (target file size) until a certain minimum "bits per pixel" value has been reached.

It should be obvious that using "bits per pixel" as a quality indicator is complete nonsense, because it completely leaves out the "complexity" or "compressibility" of the individual video!


Having said that, in extreme cases, such as ultra-low bitrate encodes, it may indeed make sense to downsize the video prior to encoding. Generally that's not the case though.
__________________
Go to https://standforukraine.com/ to find legitimate Ukrainian Charities 🇺🇦✊

Last edited by LoRd_MuldeR; 17th May 2011 at 16:26.
LoRd_MuldeR is offline   Reply With Quote
Old 18th May 2011, 14:49   #3  |  Link
detmek
Registered User
 
Join Date: Aug 2009
Posts: 463
I didn't use AutoGK since 2007. but AFAIK it does compressability test using CQ2 to calculate resolution.
detmek is offline   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT +1. The time now is 13:37.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.