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 9th December 2007, 16:13   #1  |  Link
turbines
Registered User
 
Join Date: Dec 2003
Location: North Carolina
Posts: 16
Xvid Brightness & Contrast Control

I have some good copies of some old B&W movies that have been compressed using Xvid and DivX. The problem is that all frames are rendered too dark and important details are missing. I would like to edit these using Virtualdub or some other application that allows the use of brightness and contrast adjustments and then save the file with approximately the same size and quality as the original. I know that I can use the B&C filters in VD but I also see that the Xvid encoder has a brightness slider in it's configuration properties that can be used with fast recompress as opposed to full processing. Is there any advantages to using fast recompress? Can someone explain the best way to do this?
turbines is offline   Reply With Quote
Old 9th December 2007, 16:29   #2  |  Link
LoRd_MuldeR
Software Developer
 
LoRd_MuldeR's Avatar
 
Join Date: Jun 2005
Location: Last House on Slunk Street
Posts: 12,756
"Fast recompress" will connect the Decoder directly to the Encoder with no video filters in-between.
This avoids unnecessary color-space conversions and thus should speed-up the re-encoding.
But in your case "Fast recompress" won't be suitable, because you obviously need to use a filter

Nevertheless in your case I would re-encode the videos in Avidemux.
It has all the filters you will need and you can set the Xvid encoder to "Same Qz as input" mode.
The latter should give you approximately the same output quality as the input was.
AFAIK the VfW interface of Xvid does not offer "Same Qz as input", so you can't use that option in VDub!
Of course re-encoding always kills some quality, but that can't be avoided

Only way to avoid re-encoding and keep 100% quality is:
Keep your video as-is (no re-encode) and correct the brightness/contrast at playback time!
__________________
There was of course no way of knowing whether you were being watched at any given moment.
How often, or on what system, the Thought Police plugged in on any individual wire was guesswork.



Last edited by LoRd_MuldeR; 9th December 2007 at 18:03.
LoRd_MuldeR is offline   Reply With Quote
Old 10th December 2007, 15:23   #3  |  Link
turbines
Registered User
 
Join Date: Dec 2003
Location: North Carolina
Posts: 16
This was helpful. Thanks
turbines is offline   Reply With Quote
Old 10th December 2007, 15:26   #4  |  Link
turbines
Registered User
 
Join Date: Dec 2003
Location: North Carolina
Posts: 16
Another question. What is I wanted to maintain approximately the same size file whilst sacrificing quality a bit? The original is about 714 MB and I would like to the filtered re-encoded version to also fit on a CD-R
turbines is offline   Reply With Quote
Old 10th December 2007, 18:45   #5  |  Link
LoRd_MuldeR
Software Developer
 
LoRd_MuldeR's Avatar
 
Join Date: Jun 2005
Location: Last House on Slunk Street
Posts: 12,756
Quote:
Originally Posted by turbines View Post
Another question. What is I wanted to maintain approximately the same size file whilst sacrificing quality a bit? The original is about 714 MB and I would like to the filtered re-encoded version to also fit on a CD-R
Use Xvid in "2-Pass" mode and set the target files size to 700 MB.
This will give you the maximum quality for the given size

If you use Avidemux, see my comment "How can I set the target filesize (e.g. 700 MB) in Avidemux?" in the FAQ:
http://forum.doom9.org/showpost.php?...59&postcount=1
__________________
There was of course no way of knowing whether you were being watched at any given moment.
How often, or on what system, the Thought Police plugged in on any individual wire was guesswork.


LoRd_MuldeR 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 06:05.


Powered by vBulletin® Version 3.8.9
Copyright ©2000 - 2017, vBulletin Solutions, Inc.