Questions & Answers

48kHz capture session will not line up with 48kHz camera audio!!!!!!

0 votes
asked Mar 22, 2019 in StudioLive Series III by bendavis6 (210 points)

I was recording a live show on my SL16 series 3 to an sd card on the mixer (capture session) I have done this many times over the last year and a half. However, there was a power surge and the mixer rebooted itself. I started a new session and began recording again. When I got home and offloaded the data from the sd card, I noticed a very concerning issue., the audio from the first band (pre-reboot) was higher pitched and shorter than the cam audio. The singer's voice sounded like a child and the length, even though the session and cameras were started at the exact same time, was over 5 minutes shorter. The second band's set, half was gone (expected with a reboot without properly saving and closing the session) but the audio that was recorded post-reboot, is short by around 20 seconds. The third band's set, is 5 seconds short, and the 4th band's set is about the same.
To be clear, I'm not saying it cut out audio, but when I try to line it up with the camera audio, it lines up for a few seconds, but then gets further and further ahead of the camera audio the longer it plays. The capture audio and camera audio are all 48kHz and all of the camera audio (was shot with multiple cams) lines up just fine. The mixer captured audio is all off. This have never happened before and I'm about to lose $400 if I can't figure this out and get it resolved. PLEASE HELP ASAP!!!!!!!

2 Answers

0 votes
answered May 24, 2019 by bendavis6 (210 points)
Best answer
Actually, that is all wrong. What ended up being the issue was this:

the brown out completely fried my sd card. when I tested a brand new card, everything worked fine.
0 votes
answered May 24, 2019 by Michael Martin (88,980 points)
#1, you didn't have the camera system and the mixer clock sync'd. Just because they are the same sample rate, doesn't mean they are in sync.

#2, You stated that you had a power surge. Clearly something went wrong after that and unfortunately there isn't much to explain what happened.

That being said, it sounds like, to me, that your first audio wasn't actually in 48 kHz, but recorded to 44.1 kHz, which will sound 'sped up' when played back at 48 kHz.

There is software out there that can repair audio header files, when the audio was encoded in one rate, but tagged for another, causing software to playback to sound weird. WaveAgent is one such program, I believe.

That's your best bet, is to see if you can recover the files by altering the header data for correct sample rate playback.

If I were you, I would start recording via USB to computer as well as SD. Use either as a back up / redundant recording system.