Sync AC3 Audio to Video function problem

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Sync AC3 Audio to Video function problem

Hi there,

I have an AC3 audio track with embedded time code and a video mpeg-2 segment with embedded timecode that I want to sync together. I use DVD Studio Pro 4.0.3.

In the help file it tells me to drag the audio from the Asset tab to the track editor while holding down the OPTION key.

But, when I do this, the track doesn't synch automatically and I have to do it manually anyway. Any thought on why it won't work ? It works on the Scenarist stations we have here and the tracks are made on profesionnal-grade encoders.

Audio track (AC3)
start time: 09:59:55:00
end time: 10:59:36:12

Video track (Mpeg-2)
Start Time Code:09:59:59:00
End Time Code: 10:02:41:07

I have searched the forums and support pages without finding any hints. Your help would be very appreciated. Thanks !

Arnaud

4 x 2.5 Ghz PowerPC G5 Mac OS X (10.4.8)

Posted on Feb 14, 2007 10:00 AM

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Answer 1

Feb 14, 2007 2:46 PM in response to Arnaud D

The manual spells out what the issue is, and that is that the AC3's timecode is not within the video's timecode range. The exact quote is:

"When you add an AC-3 asset to an audio stream while holding down the Option key, DVD Studio Pro checks to see if its timecode is coincident with the V1 stream’s timecode. In other words, it checks to see if the AC-3 asset has timecode that falls within the timecode range of the video asset. • If it is coincident, it is placed in the stream so that it is in sync with the video. • If it is not coincident, the AC-3 stream is placed at the beginning of the stream."

Your audio's timecode starts earlier than your video's timecode, and ends later. It's a shame that option-dragging the video onto the track that already contains the AC3 doesn't work.

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Answer 2

Arnaud D Author

Level 1

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Feb 15, 2007 11:24 AM in response to Colin Holgate

Thank you Colin. Yes indeed, I have read that part in the help file, but it just didn't make any sense to me at the time.

After running some test to figure it out, I found out that DVD Studio Pro will only sync my audio when the audio starting Time Code is later than the Video starting Time Code.

So in other words, DVDSP only adjust audio start time automatically but does trim the audio automatically, which is just a partial sync function according to me.

I sincerely hope that the development team will add this functionnality in a near future. As it is right now, the DVDSP auto-sync function is almost useless for us here. Moreover, the ability to sync AC3 audio to multiple video segment in the same track would be a great plus. I don't think it would be that hard to implement, but who knows ?

Well at least we can do it manually ! Thanks again Colin !

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