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 > Video Encoding > MPEG-4 AVC / H.264

Reply
 
Thread Tools Search this Thread Display Modes
Old 9th November 2005, 06:04   #1  |  Link
Richard Berg
developer wannabe
 
Richard Berg's Avatar
 
Join Date: Nov 2001
Location: Brooklyn, NY
Posts: 1,211
Constant quant or equivalent for compressability test?

With Xvid I'd test compressability using constant quant=3 or similar. What is an equivalent setting I could use with x264? The final encodes will use Sharktooth's HQ-Slower/Slowest presets but I want to see what effect various filtering methods have.
Richard Berg is offline   Reply With Quote
Old 9th November 2005, 07:09   #2  |  Link
Audionut
Registered User
 
Join Date: Nov 2003
Posts: 1,281
From a vague memory, x264 quant 18 = xvid quant 2.
Keeping in mind that x264 default constant quant setting is 26 vs xvid default of 4.

Personally I think quant 26 is to much compression, and would run the compression test at quant 24 first pass, with a 100% quality "so to speak" second bitrate run.
__________________
http://www.7-zip.org/

Last edited by Audionut; 10th November 2005 at 01:13. Reason: Corrected xvid default quant.
Audionut is offline   Reply With Quote
Old 9th November 2005, 08:07   #3  |  Link
buzzqw
HDConvertToX author
 
Join Date: Nov 2003
Location: Cesena,Italy
Posts: 6,552
i prefer quant 19, but as usually quality is a personal thing


BHH
buzzqw is offline   Reply With Quote
Old 10th November 2005, 00:10   #4  |  Link
708145
Professional Lemming
 
708145's Avatar
 
Join Date: Dec 2003
Location: Stuttgart, Germany
Posts: 359
Quote:
Originally Posted by buzzqw
i prefer quant 19, but as usually quality is a personal thing
BHH
I prefer -crf 22 so far

bis besser,
T0B1A5
__________________
projects page: ELDER, SmoothD, etc.
708145 is offline   Reply With Quote
Old 10th November 2005, 01:18   #5  |  Link
Audionut
Registered User
 
Join Date: Nov 2003
Posts: 1,281
Thinking about it, a --crf # run would probably be the best bet as far as a compressability test is concerned.

Say Joe likes the quality of --crf 23. So he runs a small test at that setting.
Finds the resulting bitrate.
Encodes his clip, 2 pass at the resulting bitrate.
__________________
http://www.7-zip.org/
Audionut is offline   Reply With Quote
Old 10th November 2005, 01:30   #6  |  Link
708145
Professional Lemming
 
708145's Avatar
 
Join Date: Dec 2003
Location: Stuttgart, Germany
Posts: 359
Quote:
Originally Posted by Audionut
Thinking about it, a --crf # run would probably be the best bet as far as a compressability test is concerned.

Say Joe likes the quality of --crf 23. So he runs a small test at that setting.
Finds the resulting bitrate.
Encodes his clip, 2 pass at the resulting bitrate.
save some time by doing first pass with --crf X and then directly a second pass with the bitrate of the crf run :P

edit: just specify --pass 1 in the --crf run

bis besser,
T0B1A5
__________________
projects page: ELDER, SmoothD, etc.
708145 is offline   Reply With Quote
Old 10th November 2005, 07:29   #7  |  Link
omion
Registered User
 
omion's Avatar
 
Join Date: Nov 2003
Location: San Diego, CA
Posts: 325
I'd have to add my support to the --crf switch (with --pass 1, as Tobias pointed out). This is why I wanted the --crf switch in the first place .
__________________
"We demand rigidly defined areas of doubt and uncertainty!" - Vroomfondel, H2G2
omion 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 11:30.


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