Matching audio

[Lor]

Not sure if I should post this in the NLE forum or here so for the moment I'll post it here. The moderator can move to where it's appropriate.

Will someone tell me if the audio from the Sony PMW-EX1 is 48kHz/16bit, 48kHz/24bit, or 96kHz/24bit? I had the opportunity to shoot an anniversary celebration. I was trying to sync the songs from the video shoot with the exact songs that I ripped from a CD and they don't match at all. If I match the beginning then by the middle of the song, it is already out of sync. I'm using Avid. I have resampled the songs to 48kHz/24bit and still it would not sync.

[matthew77]

Sample rate shouldn't matter - the EX1 material should play back at the exact speed it was recorded. And bit depth certainly will make no difference.

The only issue I can think of is the 29.97-30fps discrepancy, but that seems unlikely to be the culprit here, if you are looking at picture and sound together. You might want to try to "pull up" the sample rate of your ripped material to 48.048 Khz (or 44.144).

How far out of sync are they going? What NLE are you using?

During the shoot, what kind of system was being used for playback of the material? Certain DJ systems allow speed changes, even of iPod material and CD's. If it was vinyl, it is almost definitely going the wrong speed.

[Lor]

The file was originally 128bit MP3 format at 44kHz and so I also resampled it to 48kHz. I'm using Avid.

In about a minute or two into the song it starts to get out of sync. I have not measure the out of sync but my guess is that it's about 1 second to 2 seconds difference and getting worse.

It was a live concert with the singer singing from stage.

[Sumfun]

If you're trying to match a live concert to a recorded song, of course it's not going to be an exact match.

[mrpicklehead]

yeah sumfun is right, thats not going to work very well at all. you'll have to get very creative with your editing.

next time it might be worth your while patching into the PA system with either another camera (if you have one) or get your hands on a portable recorder like the M-Audio Micro track or a Sony PCM50 (which I have and I love it!). Even then you can end up with sync issues but it'll make what you are trying to do easier.

Good luck!

[Sumfun]

Just add some cutaway shots, then you can resync the musicians to the recorded music.

[Lor]

Just add some cutaway shots, then you can resync the musicians to the recorded music.

Many thanks for all your suggestions. Right now, I end up in doing exactly as Sumfun as suggested. I have to resync them whenever the singer is in the frame.

Okay, so the sample rate does not matter. Sample rate only affects the pitch and not the length of the song, correct? Besides maybe the band is playing the song a bit slower/faster than the recorded version, what would have caused the syncing to be so way off? I remembered doing this a couple of years ago with a pretty cheap consumer camcorder and I was able to sync them pretty good (not the same song/singer of course). That is why I was wondering if there is any different with the EX1 camera.

[matthew77]

Sample rate can affect both pitch and duration (they go hand-in-hand - when you change the pitch, you change the duration - except when you use DSP to deliberately affect one without the other).

But in practice, sample rate actually affects neither because rarely would you record at one sample rate and play back in another. It's actually hard to do that in any audio or NLE software without specifically trying to. Even if you take an audio file of one sample rate and put it in a timeline of another sample rate, the NLE will resample the song to the correct rate. Many NLE's can do thin on the fly, without rendering.

And yes, it is EXTREMELY unlikely that a live performance of a song will stay in sync with any other recorded performance, unless there is heavy use of a sequencer or metronome and it is set identically in both performances.

[Lor]

Just a test, I tried re-sync a different song and it was the same thing. It is clear that the live version was performed at a much slower speed making the song a bit a longer than the recorded version.

Thanks for the explanations. At least it's not my editing skills that's in question.:)