separate audio tracks from Zoom not syncing

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cabennet
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Joined: Thu Apr 01, 2021 2:02 pm
Operating System: Windows 10

separate audio tracks from Zoom not syncing

Post by cabennet » Thu Apr 01, 2021 2:14 pm

Hi, I'm using Zoom to record a podcast. I import into Audacity the separate audio tracks after I convert to MP3. When a participant goes silent, the recorded track seems to drop out and cause syncing issues. I just realized as I type this, that likely the conversion to MP3 is what is causing the silent part to be dropped out.

any thoughts?

kozikowski
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Joined: Thu Aug 02, 2007 5:57 pm
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Re: separate audio tracks from Zoom not syncing

Post by kozikowski » Thu Apr 01, 2021 2:59 pm

Never use MP3 in the middle of production. It has too many instabilities, sound damage, and unpredictable behaviors. Save MP3 for your music player running on the beach.

It's possible to set Audacity to stop recording during silences. Transport > Transport Options > Sound Activated Recording.

Screen Shot 2021-04-01 at 07.55.35.png
Screen Shot 2021-04-01 at 07.55.35.png (73.84 KiB) Viewed 480 times

How did you get your sound tracks? Nobody wrote that all sound recorders had to be running at exactly the same speed. Sample rates can vary slightly and cause the ends of takes to miss even though the beginnings are spot on.

Koz

kozikowski
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Joined: Thu Aug 02, 2007 5:57 pm
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Re: separate audio tracks from Zoom not syncing

Post by kozikowski » Thu Apr 01, 2021 3:02 pm

Stick with WAV (Microsoft) 16-bit at either 44100 or 48000 sample rate (be consistent) instead of MP3.

44100 is very common.

Koa

cabennet
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Joined: Thu Apr 01, 2021 2:02 pm
Operating System: Windows 10

Re: separate audio tracks from Zoom not syncing

Post by cabennet » Thu Apr 01, 2021 6:28 pm

thanks, I use Zoom to record and get the separate tracks and then edit in Audacity. I think it's the conversion to MP3 causing the issue. Zoom records to M4A

DVDdoug
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Re: separate audio tracks from Zoom not syncing

Post by DVDdoug » Thu Apr 01, 2021 7:01 pm

I think it's the conversion to MP3 causing the issue. Zoom records to M4A
Maybe... MP3 adds a few milliseconds of silence to the beginning but it's a constant delay that doesn't get worse over time.
When a participant goes silent, the recorded track seems to drop out and cause syncing issues.
If you record using WASAPI-loopback that can sometimes happen because WASAPI can't record when there's no digital audio stream. ...But that's different from a silent stream.

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