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Zoom Q3 to DVD conversion: audio sync problem

Good morning,


So my client's Zoom Q3 records at 30 fps. I'm trying to edit these files in FCP timeline and compress to DVD preset. Does MPEG-2 have to be 29.97? If so, how do I keep the audio in sync throughout my workflow? If not, what is the correct workflow for 30 fps to DVD?


I have tried:


-- FCP sequence with 30 timebase

-- FCP sequence with 29.97 timebase

-- creating a compressor preset with 30 @ 29.97 selected

-- creating a compressor preset with "so source frames play at 29.97 fps" checked


With any method, the audio drifts out of sync by the end of the song. Suggestions?


Thank you.

Mac Pro FCS3, Mac OS X (10.6), Musician/Videographer

Posted on Sep 5, 2011 9:02 AM

Reply
13 replies

Sep 5, 2011 10:13 AM in response to audioamigo

I know nothing of this Zoom Q3, but here goes...


No, you don't need to do 29.97, but I'm not sure how large the alternative window is beyond 23.98 and PAL.


You should be able to simply drop a representative clip into a fresh timeline and let FCS auto-conform the sequence, cut it, and export it as a QT movie at "current settings." Then all that remains is to toss it into compressor and transcode to MPEG-2. Whatever machinations are required will be handled by Compressor.


This may seem simplistic, but worse case you'll come back to the forum with better information to work with...

Sep 5, 2011 10:38 AM in response to audioamigo

You almost definitely have to convert the material from the zoom before working in fcp. Try converting to prores with the pixel dimensions and frame rate of the original materia using compressor (which comes with fcp)l. After converting, open the prores file in cinematools (which comes with fcp) and conform to 29.97fps. Everything should be ok after that.

Sep 5, 2011 11:41 AM in response to Michael Grenadier

Michael,

I did all that. Although video quality is also and issue, this is primarily an audio sync problem. Cinema Tools does nothing with the audio (except delete it). Conforming to 29.97 creates a video that is seconds longer than the audio.


RatVega,

The Zoom Q3 is a consumer device that has professional audio capabilities but with horrible video. It's specifications are:


Video CompressionMPEG4-SP
Video Resolution640 x 480 pixels (VGA)
Video FormatMOV
Frame Rate30 frames/sec


My client set his Zoom to record audio at MP3. My timeline renders that to 48k for editing.


So, I'm thinking, can I resolve the issue by staying at 30fps all the way to DVD? Should I try Time Stretching the audio to the length of the video?


Thanks for your thoughts, guys!


Eddie

Sep 5, 2011 11:46 AM in response to audioamigo

If you've already converted the file to prores and the audio is still there and in synch, cinematools WILL NOT delete audio and the audio should stay in synch. At least that's the way it works on my system. I've worked with material shot at 30 fps a number of times and this is my successful workflow.


Converting to prores will maintain whatever video quality there was to begin with.


You should never edit with mp3 audio. You need to convert before editing.

Sep 6, 2011 10:42 AM in response to audioamigo

How far out of sync are you at the end of the song? How long is the song? If you're only off a small amount, like 2-3%, you can change the speed of the audio clip without affecting pitch audibly. Maybe. You cna also change the speed of the video clip to match the audio length.

Unlink the audio from the video.

Select the video track and note its precise time from start to finish.

Select the audio track and trim it to the last audio bits. Not its precise time.

Select the audio track and use speed adjust to get the exact same length as the video track. Render. Select audio and video and relink.


You can also trascode the MP3 to 48k using Compressor. This will create a new media track that might evn end up being the correct length.


Or just keep talking to Grenadier.

Sep 6, 2011 3:13 PM in response to David Bogie Chq-1

David, it's a pleasure to speak with you. And, Michael, thanks for your sage advice regarding workflow.


Okay, I see where the problem is... Soundtrack pro is giving me a shorter file by 12 frames.


The video and audio are both 7:18:13 as they sit in my 30 fps ProRes 422 timeline.

STP is returning 7:18:01 of audio


Here's where it happens: I Export Audio to AIFF from the timeline and import resulting file into Soundtrack Pro ... I make EQ and Level adjustments... then SAVE AS and RENAME the file ... then drop the new file onto the timeline...


12 frames shorter.


Color me puzzled.


Eddie

Sep 7, 2011 9:26 AM in response to audioamigo

So this begs the question, how is it that exporting audio from the timeline shortens the file? My workaround would force me to perform audio editing in FCP, but here's another question:


Why Compressor, in the Frame Rate drop-down inside the Video Format tab of the Encoder pane, does NOT offer 30 fps? Instead 29.97 is automatically selected. My video has clearly been kept at 30 throughout Grenadier's thoughtful workflow. That's why I asked this question in my original post and thought it might be related to the audio sync issue. It's surprising because Compressor usually picks up on the file's frame rate automatically. Thoughts?


Thanks again, gentlemen.


Eddie

Sep 8, 2011 2:01 PM in response to audioamigo

Michael, David, and RatVega, thanks for your help diagnosing this.


So, for this camera's files anyway, I am abandoning my old workflow which always included "Export audio to AIFFs"... Open in Soundtrack Pro... Edit... Save as AIFF. Return AIFF file to the timeline.


A successful workaround begins by using MPEGStreamclip to convert the camera's file to ProRes 422 and drop the resulting file onto a 30 fps timebase ProRes422 timeline.... apply audio tools and effects available from the timeline, FCP, Apple, etc... Export to Quicktime... Compressor to DVD (ignore reference in the inspector to "29.97 Selected") Everything stays at 30 frames throughout the workflow, and the audio stays the same length, perfectly in sync with the video.


Thanks again!


Eddie

Zoom Q3 to DVD conversion: audio sync problem

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