Quantcast KDVD: AC3 Has Audio Delay? - digitalFAQ.com Forums [Archives]
  #1  
10-24-2003, 01:30 AM
J-Wo J-Wo is offline
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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?
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10-24-2003, 09:27 AM
kwag kwag is offline
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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
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10-24-2003, 02:59 PM
J-Wo J-Wo is offline
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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...
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10-24-2003, 05:44 PM
incredible incredible is offline
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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.

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10-24-2003, 06:02 PM
jorel jorel is offline
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try AC3Machine:

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

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