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  #1  
Old 03-11-2007, 01:55 PM
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minister minister is offline
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Default AC3, is it Sample Accurate?

when converting to an AC3, does it maintain the Sample sync? meaning, we have 2 Reels of a film that will go into DVD Studio Pro as 2 separate Mpegs and AC3 files. the editor will butt-splice them. there is no issue with the butt spliced PCM files, but will the AC3 files also transition without a hitch?

mr. neyrinck?
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Old 03-11-2007, 01:59 PM
The Chinese The Chinese is offline
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Default Re: AC3, is it Sample Accurate?

Minister-

That's a big maybe. The Concatination pointcan be problematic, because the AC3 File isn't perfectly frame accurate... I would provide handles. When I was at TCS, we had problems like this frequently, and solved them by provided a few seconds of handles, so the DVD guys could find the point where the AC3 frames can fall in sync.

Think of it as 24Fr across 30Fr Video.

-Todd
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Old 03-11-2007, 02:04 PM
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Default Re: AC3, is it Sample Accurate?

the Chinese,

JEEEZ! i posted that 30 seconds ago. CHOP CHOP! he he...

got it!

i was afraid of that....

i will concoct a concatenation plan,
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Old 03-11-2007, 02:11 PM
The Chinese The Chinese is offline
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Default Re: AC3, is it Sample Accurate?

Quote:
the Chinese,

JEEEZ! i posted that 30 seconds ago. CHOP CHOP! he he...

got it!

i was afraid of that....

i will concoct a concatenation plan,
He he he Sittin in front of the computer beats weeding the front lawn and picking up cat poop....

Chino
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Old 03-11-2007, 02:14 PM
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Default Re: AC3, is it Sample Accurate?

chino

i'll concoct a concatenation course and you clean up the cat caca.

rocka!
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Old 03-11-2007, 03:47 PM
airon airon is offline
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Default Re: AC3, is it Sample Accurate?

All the dolby recording sessions I've been at, the consultant tested the AC3 crossover between reels, so provided that guy has done his job, the DVD guys should be happy.
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Old 03-11-2007, 03:58 PM
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Default Re: AC3, is it Sample Accurate?

hi airon,

this is not from a Dolby Printmaster via a DMU...

this is a software encode for a DVD of the 'sales version' of the film.
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Old 03-12-2007, 05:35 PM
sleadley sleadley is offline
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Default Re: AC3, is it Sample Accurate?

I have encoded quite a few DVD's for commercial release. I use and recommend the AC3 encoder that is available for Pro Tools made by neyrinck It is timestamped and is sample accurate. I have checked it with long program materials and it always correct.
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Old 03-12-2007, 07:37 PM
Sonsey Sonsey is offline
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Default Re: AC3, is it Sample Accurate?

Hey Tom, I tried this myself on a DVDSP project a while ago and it DIDN'T work - definite sync problems. However I was using Compressor not the Nerynck plugs, so YMMV. However my solution was to do the two pieces as separate TRACKS inside DVDSP and simply have one jump to the other. Of course depending on the DVD player this could cause a slight pause as the track jumps, so it might not work for your application.
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Old 03-12-2007, 10:11 PM
Tstein Tstein is offline
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Default Re: AC3, is it Sample Accurate?

AC3 is not frame accurate. Dolby admits that sometimes you will get lucky and an edit (or edits) will work. But sooner or later you will have get a glitch. This is one of the reasons they invented Dolby E.

Good Luck,
Ted
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