Syncing Audio and Video from different sources?

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Hello folks, I'm a total newbie with Camtasia and just purchased it over the weekend and wanted some feedback. Our church has a local radio show here in the Washington DC area and we also do a YouTube live at the same time by recording the broadcast on a Mac. Since the audio is much better with what the radio station provides then what we get with the Mac, I'd prefer to use that audio but it's been very difficult to sync the two.

For most of our broadcasts, we use a CODEX Bric II, which provides outstanding audio but it's not been possible for me to sync that with the MAC video feed. I take the audio and then mix it in Adobe Audition before we post it. It appears I'm a few milliseconds off though when I try to sync the audio with the video (unless I just use the audio recorded on the MAC). I thought I must be missing something but wasn't sure if any of you have any words of wisdom?

Photo of mredinnova


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Posted 3 years ago

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Photo of jksettle12


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One way to tackle this - Suggest you keep the sync process simple and do it in FCPX or Adobe.   Or another application that is built for editing and has a strong audio component to it.    Then get one high res file outputted for your Camtasia use.   
Photo of docsope


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I used to be a Film & TV dubbing mixer.  I am so used to this.  If audio is recorded on a separate machine that has not been 'genlocked' to the video recorder, they will start to drift as the clip goes on.  Each machine is controlled by its own piezo crystal and divided down by a load of flip flops (No, I am not making this up) so what you call 30fps on one machine could be a 'gnats whisker' out (don't know if that's just a UK term) when compared with another.  My advice would be to sync up the unedited video and audio tracks at the start, using both the radio audio, and the camera audio.  Go to the end of the recording and see how much it has drifted, then use the clip speed feature by right mouse clicking on the Radio audio, selecting 'Add clip speed' from the pop-up menu and adjusting the duration in the right hand pane (Cam V9).  when you have matched them, right mouse click on the video track and select 'Separate audio and video' and then either disable the now separated audio track or delete it (please take a back-up version of your project first). 
There is another method ... re-sync every so often - long and tedious and doesn't give the best result.

Good luck
Photo of mredinnova


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Thank you both. I've not heard all of these phrases so you're teaching me and I appreciate that. I'll give that a go, I tried matching the wave forms and then deleting the camera audio but I was still a few frames off it appeared. I'll keep at it, thanks again!
Photo of davemillman


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So I'm going through an exercise right now, syncing audio on twenty clips that each 1-3 minutes long. In Audition or Audacity I can sync with arbitrary precision, while in Camtasia the sync can be off by as much as half a frame, or 1/60th of a second. 

Even if 1/60th of a second is a problem, which it isn't for me, the sync drifts over the course of the recording. In a perfect world, there would be no drift, but this particular Zoom audio recorder drifts with respect to this particular Canon DSLR. So when the edit is done, if the drift is more than a frame (which only happens on clips multiple minutes long), I'll just slide the slower clip forward a frame. 

Oh, and a clapper is your friend. Stock photo below, pros use it with just one hand.

Or you can just clap your hands within view of the camera....