Quantcast KDVD: AC3 Has Audio Delay? - digitalFAQ.com Forums [Archives]
  #1  
10-24-2003, 01:30 AM
J-Wo J-Wo is offline
Free Member
 
Join Date: Nov 2002
Location: Toronto, Canada
Posts: 454
Thanks: 0
Thanked 0 Times in 0 Posts
When I extract the AC3 audio from the VOB files using DVD2AVI, most of them have a delay of -66ms. If I were to just stick these ac3 files into DVDlab and author, will I hear this delay? Is there a way to compensate for it without having to reencode my audio?
Reply With Quote
Someday, 12:01 PM
admin's Avatar
Site Staff / Ad Manager
 
Join Date: Dec 2002
Posts: 42
Thanks: ∞
Thanked 42 Times in 42 Posts
  #2  
10-24-2003, 09:27 AM
kwag kwag is offline
Free Member
 
Join Date: Apr 2002
Location: Puerto Rico, USA
Posts: 13,537
Thanks: 0
Thanked 0 Times in 0 Posts
66ms is .066 seconds.
So even though it's less that 1/10th second, some people (me!) can see lip sync differences. Although it's almost negligible. You have to really be looking for it.
If there are no adjustments on your authoring program, you could try extracting the AC3 to WAV with MPEG Mediator, and re-encode the audio. There shouoldn't be any delays there.
Or, this is just an idea, you could add 66ms of "black" MPEG encode to the start of your material by joining it.
This will in effect delay the actual video start time by 66ms, so your audio will start in sync with your movie.

-kwag
Reply With Quote
  #3  
10-24-2003, 02:59 PM
J-Wo J-Wo is offline
Free Member
 
Join Date: Nov 2002
Location: Toronto, Canada
Posts: 454
Thanks: 0
Thanked 0 Times in 0 Posts
any idea of a simple avisynth line I could add to my script to add 66ms of blank video? I guess it might depend on what framerate I'm encoding in huh...
Reply With Quote
  #4  
10-24-2003, 05:44 PM
incredible incredible is offline
Free Member
 
Join Date: May 2003
Location: Germany
Posts: 3,189
Thanks: 0
Thanked 0 Times in 0 Posts
Send a message via ICQ to incredible
Take it easy man ...

As we're pushing the limits you should also reencode your Ac3, cause this will also safe space.
So use besweet for Ac3 reencoding as you can set there the delay compensation too. Cause an orig 2.0 Ac3 / 192kbit or 224kbit?? Too much for our compression sensibilities
Also 448 5.1 AC3 ... give 384 a chance or even (just to try) 224kbit at 5.1 ... I tried it and it sounded ok on my surround system.

Reply With Quote
  #5  
10-24-2003, 06:02 PM
jorel jorel is offline
Invalid Email / Banned / Spammer
 
Join Date: Aug 2002
Location: Brasil - MG - third stone from the sun
Posts: 5,570
Thanks: 0
Thanked 0 Times in 0 Posts
try AC3Machine:

http://www.doom9.org/index.html?/ac3machine.htm

Reply With Quote
Reply




Similar Threads
Thread Thread Starter Forum Replies Last Post
KDVD: Muxing Audio Delay Shibblet Video Encoding and Conversion 10 01-30-2005 11:22 PM
Audio Codecs: AC3 Delay Corrector jorel Audio Conversion 0 03-17-2004 06:26 PM
BBMpeg: Setting the audio delay canon Video Encoding and Conversion 3 12-07-2003 02:42 PM
KDVD: How to add ac3 audio delay? dooger2 Video Encoding and Conversion 2 12-05-2003 05:09 AM
KDVD: Audio Delay? nicksteel Video Encoding and Conversion 2 06-20-2003 09:58 AM

Thread Tools



 
All times are GMT -5. The time now is 04:21 PM  —  vBulletin © Jelsoft Enterprises Ltd