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Does Dolby 5.1 folddown create delay when played back on DVD player as stereo?

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IndianCowboy
Does Dolby 5.1 folddown create delay when played back on DVD player as stereo?
on Mar 1, 2007 at 1:36:43 am

Hi,

I have a 90 minute film (Uncompressed NTSC 10:2:2, 23.98FPS) that plays with the audio in sync in Final Cut Pro - both the stereo LT-RT as well as the Dolby 5.1 tracks (L, C, R, LS, RS, LFE).

But when I encode the video using BitVice to an MPEG-2 and the tracks using Compressor to a 5.1 ac3, and then use DVD Studio Pro to put these together on a DVD and play it on my regular DVD player in stereo, the audio seems delayed by a few frames uniformly across the film.

Does the DVD player introduce delay when it folds down the 5.1 tracks into stereo or is there something else I'm missing here?

Thanks for your help!
Nikhil


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Noah Kadner
Re: Does Dolby 5.1 folddown create delay when played back on DVD player as stereo?
on Mar 1, 2007 at 8:12:09 pm

Nope but it's possible you're audio and video streams don't match. Make sure they come from the same source and have identical timecode.

Noah

Unlock the secrets of the DVX100 and Final Cut Pro!
http://www.callboxlive.com


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IndianCowboy
Re: Does Dolby 5.1 folddown create delay when played back on DVD player as stereo?
on Mar 3, 2007 at 2:28:14 am

Hi Noah,

My sources were -

Video: Digibeta captured into FCP as a 10:2:2 Uncompressed, then reverse telecined using Adobe AE into a 23.976 quicktime file

Audio: DA-88 tracks (from Dolby 5.1 mix) captured into AIFF files

FCP PLAYBACK IN SYNC: I sync both in FCP using a sync point, and then when I play it in FCP, they are in sync and play in sync.

DVD:

MPEG2 - I export the video track (using in-out points) and use BitVice to encode it to mpeg2 using the 23.976 with flags option.

AC3 - I export each individual Audio track (using same in-out points), take them into Compressor as a surround group, and get an AC3.

I marry the two in DVD Studio Pro and when I play it back, that's where the sync issue seems to happen.

Question: I was told there's no question of timecode in a situation like this. Am I missing something?

Thanks!
Nikhil


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Noah Kadner
Re: Does Dolby 5.1 folddown create delay when played back on DVD player as stereo?
on Mar 3, 2007 at 9:37:54 pm

I'd try playing it on a couple of different systems. It could be your playback hardware. And if the delay is consistent do a test with sync beeps and timecode, figure out what the offset is and re-output your footage to compensate.

Noah

Unlock the secrets of the DVX100 and Final Cut Pro!
http://www.callboxlive.com


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