Camtasia Sync Multiple Audio Tracks

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  • Updated 5 years ago

I use Camtasia Recorder for lecture and desktop video capture in a university classroom.  I wear a mic, and Camtasia captures that audio along with the desktop in real time.  Unfortunately, there is no way to capture multiple audio streams in real time, so I cannot capture both my microphone and a classroom microphone along with the video.  Therefore I use a separate Zoom microphone to capture the classroom audio as an MP3 file which I then bring into Camtasia.

What I'd like to be able to do is import this MP3 file and have it automatically sync up with the audio track that Camtasia has captured.  (My voice is in both streams and so could serve as the basis for this.)  Unfortunately, it seems like this is not something that can be automated.  I've found that if I sync things up to the best of my ability, after a few minutes the audio tracks are significantly out of sync.

Is there any easy way to accomplish what is desired here?  (I'd like to edit the video/after recording and switch among the audio tracks depending on whether I or a student is speaking.  There's just no easy way to do that as it stands now.)

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Posted 5 years ago

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kayakman, Champion

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with both audio sources on timeline, can you line up the waveforms; do they look in sync vs time?

are you hearing out-of-sync during timeline play?

even if you hear the issue, does it persist after producing?

the MP3 may be the problem?

perhaps try loading just the MP3 on the timeline and exporting that as a new, single WAV file; then use that WAV in the project along with other original audio; will those then sync up?
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Rick Stone

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Hi there

I don't suppose it's possible to simply use the zoom to capture your voice along with the classroom? If so, maybe that would assist with solving the issue?

Another option to allow capturing classroom audio at the same time would be to acquire and use a small mixing device that you would connect the microphones to, then have a single line out to the computer microphone input.

Cheers... Rick :)
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Thanks for the replies thus far.  I've found that using just the Zoom gives decent overall audio, but does a poor job capturing my voice when it is the focus.  The mic I wear captures me great, but virtually none of the audience. 

Someone else suggested to me using a small mixing device, but I think it's probably too much equipment for me to have to manage.  I'm also thinking that if it merges the two sources in real time, that removes my ability to pot up or down the audio tracks in post production, which is what I'd ideally like to be able to do.

On the front of using WAV in lieu of MP3, I've wondered if the reason for the 'audio separation' could be resolved by the settings on the Zoom.  As it stands now, I sync up the audio as best I can at the beginning of the sequence.  Things sound good.  If I then go about 20 minutes into the overall sequence, there is an echo that makes it sound like I'm in a cave.  At 90 minutes the audio tracks are many seconds separated.  I've presumed that these differences are because I'm not using high-end professional tools and neither Camtasia nor the Zoom are perfect in their capture.

Would love to hear other ideas or follow up.  Thanks everyone.

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If you had a mic plugged into your computer for the classroom sound; e.g., 4-channel front and back, it would be recorded as system sound on your Camtasia clip. Using your audio recorder (or iOS / Android / device app) and a second mic, e.g., a Lavalier, clipped on your shirt, you could add in the recorded audio in post. Syncing in Camtasia Studio would need to be done visually as others have previously mentioned, and then you'd still probably want to edit the system sound up or down to taste. 
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Rick Stone

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Personally, I don't own a zoom quite yet. But when (or if) finances ever allow it again, I might pick one up!

I'm also interested in filmmaking. As such, I'm part of a facebook group called "The Frugal Filmmaker" and I also watch videos made by "The Frugal Filmmaker" where you make all sorts of things using PVC tubing and whatnot. This morning I watched a video where he demonstrated using a lavalier microphone connected to a zoom to get great audio. What is unclear is if you are able to record both a lav connected to the zoom as well as allowing the zoom's built in microphones to capture audio.

Wondering if that might be a potential solution? As you said the zoom does a pretty good job, maybe it's worth looking into?

Cheers... Rick :)
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John S. Richards

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Two Ideas:

1. During editing, lining up several audio recordings is easy using visual audio markers Kayakman noted above. Think of a film slate clapper.

I use a Dog Clicker to add visual markers on the audio track to line-up & sync recordings
See here:

2. Which Zoom?
The H2n can save recordings as a .WAV files. WAV is a better file type to use.
Think of MP3 & WAV audio files as similar to JPG & PNG image files.
MP3 & JPG both compress data more, where WAV & PNG save more data for your production use.
Hope this helps.
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Mark W4CHL

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I had a similar problem with external voice over to MP3 mixing with an hour long MP4. The audio sync, both for the MP4 video+audio and my external MP3 files would be delayed by about 1/4 sec by end of the single video track. In this case, the audio is not out of synch when played within Camtasia Studio, it is out when replayed as an MP4 file output from Camtasia Studio.  

I fixed this by:
 1) split the MP4 audio and video after importing into Camtasia Studio 8.5.2
 2) transformed the MP3 files into WAV files
 3) import all the MP3 to WAV files, as I import one, split the whole project at the end of every WAV file (there were 5 across a 55min video)
 4) re-render using the Custom output to include ~16 markers

There is no noticeable sync problem now. I don't know which step or steps minimized the audio drift, but there is no perceptible audio delay with video now!

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