Piano World Home Page Forums Our Most Popular Forums Digital Pianos - Electronic Pianos - Synths & Keyboards Need advice for software to sync video with audio recording

As everyone knows, I'm a total Luddite , but I bought a Zoom H4n recorder some months ago to make some piano recordings to synch with the video from my Panasonic TZ-40 camera (whose stereo mics pick up too much extraneous noise, and smooths out all the dynamics because of its automatic recording level).

Once uploaded into my MacBook Pro, it was easy to bring them both together in iMovie, 'delete' the sound from the video (i.e. turn it down to zero) and substitute the sound from the H4n, aligning the two tracks on the screen to synch them perfectly. Even in a long fifteen-minute piece, the synch from beginning to end remains perfect, with no 'drifting' whatsoever.

So, I don't understand how the sound and video can drift out of synch, once they're perfectly aligned at the start - surely the timing for both is entirely electronically controlled in digital recordings, and therefore cannot slow down/speed up along the way?

Bennevis, we posted about the same minute, your experience you just shared reflects my own, except my videos are not nearly that long.

That's a pretty good video, I think. One thing to clarify, however, if I may do so without heading too far OT. The presenter in that video either misunderstands or over-simplifies the sample rate thing. There's nothing inherently problematic about recording audio at a different sample rate than your video camera uses, *provided* that the editing software correctly conforms the audio during import. You may have to investigate or change some sequence settings to make sure the imported audio is treated correctly, if its sample rate is different from the sequence defaults.

The audio drift thing will rear its head if, for example, the editing software treats a 44.1 kHz audio clip as if it had been recorded at 48 kHz. It is probably simpler just to use the same sample rate everywhere in the workflow if you can, but it isn't a requirement.

Cheers,

B.

Yes, that's exactly what I mean.

When you record sound and picture separately, the clock signals for each recording device will be different. They may be highly accurate, but they are not synchronized with one another. Depending on the application, the difference may or may not cause a perceptible discrepancy in sync when you marry the resulting audio and video clips in an editing program.

Modern digital recorders like DSLR video cameras and Zoom audio recorders have highly accurate clocks. The drift between them may be as little as a couple of frames per hour. In lots of applications, the errors are small enough to disregard. If your entire program is fifteen minutes long, you'll never notice a difference. Over the length of a two-hour concert, it might get to be a problem.

Other kinds of sync problems with double-system sound on digital recorders can be caused, essentially, by software: machine settings being inconsistent (see the stuff about sample rates supra); compression software behaving unexpectedly; editing programs having mysterious default settings; et cetera.

All else equal, modern digital devices like the Zoom recorders should behave well in the applications that PW members are generally using them for, but double-system recording has certain pitfalls, so you want to make sure you are doing it for a good reason.

To answer you (MacMacMac) I don't know if it's possible to merge audio and video into one file, which is needed if you want to avoid having to sync up. If such a solution exists, I would very much like to know about it myself.

I can't understand how it could not be possible. My webcam captures both audio and video, and I can record it. (I don't, but there's software for that.)

So why can't I just tell that software to use another audio device instead of the cheapo webcam mic?

I have a Logitech web camera, and therefore probably the same software. In the settings for Mic, I can choose another microphone as the source for audio, if I have one (which I don't as I have my camera set up on a desktop computer.)

I say, simply try it, your Presonus should identify itself on your computer, and appear as an option which can be selected, in the list of microphones available in the Logitech webcam software (the Controls box.)

my suggestion is Sony Vegas.

and recording at 48 kHz.

recording at 48 kHz, and the fact that Sony Vegas let me slice video frames into small sections (hundredths of a second, methinks), lets me sync external audio (recorded with better equipment), with the video.
you just line up the audio waveforms, and sync them up by eye and ear.

it's been a few years since I bought Sony Vegas.
I think it cost $100. which is to say, that I did not need the features that come with the more expensive editions.
I did have some trouble with some pixelation and artifacts.
but really not too bad. the trouble could have been partly from not strong enough computer. also, things improved when I got a Sony videocamera.
all that said, for the most part, it worked very well.