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Old September 19th, 2016, 02:39 AM   #1
Inner Circle
Join Date: Nov 2005
Location: LOWESTOFT - UK
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Multitrack audio and 7 cam live nightmare

Not really a question, but a rant! I'm in a tribute band, and it was suggested we record the next show at a large 1400 seater theatre. Great idea but while I have a business that does lighting sound and video, my people are already busy on the normal show. I said we could easily hang a laptop on the digital desk and record all the show sources, 23 of them. However, we needed to get someone in for the video. I could edit their footage later. One day before, the video people let me down, so I have just one spare body and he gets the central pit camera, the rest are unmanned and locked off. I grab the four go pros and go pro Chinese things we have laying around and this brings the number up to 7. Not all can be mains powered so we adjust the set list to put the vital songs into the first half of each 60 minute set, and we rebattery in the interval. In total we had a real mix of formats but bar one camera that was soft throughout, decent images. The sheer number of clips though is daunting and as the cameras drop out at different points when batteries fail, cards fill up and one tape ended, getting these into a synced timeline is going badly. On top of this the audio has to be done too, and as this also involves three separate sections this won't align with any of the video because they're different lengths. The small cameras on stage have dreadful audio being so close to the sources so that it may as well be a different song sync wise. It has taken me over a day so far just to get all the sources into the edit machine and I've not looked at sound yet! I'm also certain quite a few of the wanted songs came just after the majority of batteries died looking at clip lengths. One of the real gopros seems to somehow have got out of sync with its picture and sound, and one locked off wide shot got kicked and isn't wide now after a crop to fx it.

Just shows that proper planning is vital. I have a Pentax DSLR I have never use for video as I hate them, but I discovered on its first video outing that it has a time limit. Never gave it a thought. It shut down thirty seconds into the show. Annoyingly, that 30 secs looked good, after the wasted images of people coming in as. Had to start it early. The cheap Chinese 4K on its first outing looks damn good reduced down to 1080, but only got 35 mins on its new battery. What a weekend!
Paul R Johnson is offline   Reply With Quote
Old September 19th, 2016, 07:21 AM   #2
Major Player
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Location: Raleigh, NC, USA
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Re: Multitrack audio and 7 cam live nightmare

The cure for sync issues (syncing multiple cameras, syncing cameras with sound, etc.) is SMPTE time code. Solves all your problems, except one -- it doesn't come on cheap POV cameras like the GoPros. You either pay for cameras with time code capabilities, or you pay with your time in post trying to sync things manually.

Lacking SMPTE time code, you can sync the old fashioned way. You've got a drummer yes? Start your sets with something that lets the drummer visibly strike something -- makes it easy to see (sync cameras) and hear (sync sound to that visible snare drum strike the cameras see). If all your cameras can't see the drummer, a unison chord will work -- the drummer sets a count and the whole band strikes a chord (and the singers clap, etc.). That will at least put your sync in the ball park very quickly in post.
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Old September 20th, 2016, 12:20 AM   #3
Inner Circle
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Location: Tucson AZ
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Re: Multitrack audio and 7 cam live nightmare

Been there, done that. I wanted to rant too. Didn't come up with any clever solutions except to just put my head down and slog for a week or so.

Good luck!
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Old September 20th, 2016, 03:21 AM   #4
Join Date: Feb 2013
Location: Cambridge, UK
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Re: Multitrack audio and 7 cam live nightmare

Hi Paul,

As a fellow musician and videographer I feel your pain!

Most of my video work is weddings and schools, but one of the schools that I just finished editing, was with five cameras, 3 of which split the 75 minute show into 3 files. I also had 3 sound recorders for picking up stage voices, so not a dissimilar problem to yours.

As this is something I have to do quite often, it's not neccesarily as difficult as you think. The good thing is that you are recording music, so it should be very easy to pick out the same songs from each camera. I would start with the first file from each camera, picking out the first song and very roughly lining it up with the other cameras using the first song starting point as a manual audio line up within a couple of seconds of each other.I use Magix ProX7 for editing, which enables me to instantly audio sync the tracks automatically and some other NLEs will allow the same. If you can't do that with your own, just show the wave form for each track while linked to the video and it is quite straightforward to find obvious peaks that you can line up to your previously rough synced tracks.The GoPros and Clones will probably have much lower sound levels, so you will need to heavily boost the track volume to see the wave form.

Once the first clips are aligned, its then a matter of dropping in following clips and adjusting for the gap between files. The last thing to drop in can be your master audio track, or you could drop that in first and align the camera audio to it.


Last edited by Roger Gunkel; September 20th, 2016 at 03:22 AM. Reason: spilling mistook
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Old September 20th, 2016, 04:13 AM   #5
Inner Circle
Join Date: Feb 2009
Location: Brisbane, Australia
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Re: Multitrack audio and 7 cam live nightmare

Maybe someone could invent a product such as a "mosquito beep" thinggy.

How would it work? You press a button and it generates a loud beep tone at 19kHz. Nobody but teenagers will hear it, but the camera mics will. You can then use the beep (visible in the spectral view of the camera audio) to sync your clips. This could even be a software function for a plugin to perform.

Just an idea ...

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