How To Make Very Fine Audio Adjustments To Sync With Video?

jmorrell wrote on 12/6/2012, 12:14 AM

I am working on a film which recorded the audio separately. 

We used a clap in the video to help match it with the audio.

I am editing on Magic Movie Edit Pro 14.

I am able to match the audio to the video as best as I can using the program, but it still appears to be off just a little bit when I play the clip.

When I zoom in as close as I can to compare the wave of the good audio with the audio on the video, to sync, I see that they are slightly off.

It won't let me move the audio slightly. When I am zoomed in and I try to move it, I jumps to far. I can't slightly adjust it to make it perfect.

Any help? 

Comments

jmorrell wrote on 12/6/2012, 1:51 AM

Ok. I figured out that the problem was that the frames were too big. I couldn't perfeclty match up the audio we recorded on a separate devise from the audio that the video camera picked up, because it would go too far in either direction when zoomed in very closely because of the frames.

So I reset the frame rate from 29.97 to 99.27. That helped in getting the audio closer to sync, but is still off just a little bit. It won't let me set the frame rate to anything higher than that, so I am out of idea's.

I really know very little about editing. Will changing the frame rate like that effect much in the film? Is this a bad solution?  

jmorrell wrote on 12/6/2012, 1:55 AM

I meant that I changed the "frames" in the "movie settings" from 29.97 to 99.27. That gave me more frames in the timeline. 

cpc000cpc wrote on 12/6/2012, 5:07 AM

I'd say the problem is simply that MEP snaps objects to what it thinks is the smallest possible division -- a single video frame. That make sense for video but not for fine placement of audio. If going for more virtual frames isn't enough, what about coming from another direction? It seems that an audio editor (you should find a Magix music editor in your MEP 14 folder) might let you remove a fraction of a frame interval from the start of your separate audio file  -- just enough so that the new beginning syncs when snapped to a video frame boundary.

A frame interval of 1/30 of a second would show about 15 cycles of a concert pitch A. Is that enough resolution?

gandjcarr wrote on 12/6/2012, 6:02 AM

Hi,

If you need something finer than 1 frame you may want to try using timestretch/resample and make the changes in terms of beat per minute.  It is fussy frustrating work and it will change the pitch of the audio but if your adjustments are relatively small, it should not be too noticeable.  If you need anything finer you are going to need to alter the file in something like audacity which can get down to the milli second level, maybe even smaller (I have never needed to go below 1ms so I have not tried it yet.

Good luck,

George

cpc000cpc wrote on 12/6/2012, 6:19 AM

I don't know about timeshift/resample. Isn't the problem that timeshift would help the situation when the tracks are getting more and more out of sync as time goes on? I'd assumed from the start that jmorrell's audio sample was not matching up at the start (or obvious point like a clap stick) and that everything else was an equal amount out of sync.  Also I think timeshift can vary pitch or temp (or both).You can change the play length without changing the pitch.

gandjcarr wrote on 12/6/2012, 10:37 AM

@cpc000cpc,

I think you have it backwards.  Time shifting is used to synchronize audio that is out of synch for the entire duration of the clip.  Audio or video time stretching is used to synchronize when the audio goes more out of synch over time.

Think about it this way.

George

cpc000cpc wrote on 12/6/2012, 6:09 PM

George,

Thanks for clarification, I guess I'm mixing shifting with stretching.

From the MPE 14 Help file:

Timestretch/Resample

This effect device changes the object's speed and/or pitch.

Pitch: This control changes the pitch independent of the object's speed ("pitch-shifting").

Tempo: This control changes the tempo independent of the pitch ("time-stretching"). The object acts as if it were compressed or stretched on the track.

gandjcarr wrote on 12/7/2012, 11:06 AM

Hi,

If you would like, post two clips of the video that goes out of sync one using the camera audio and one using the external audio and if possible include the clap board or hand clap in both.  The video can be as long as you want (up to the YT max) if it better demonstrates the sync problem.  I will have a look at the audio tracks and do my best to show you in a mini youtube tutorial how to solve the problem.

Post both videos as "unlisted" on youtube, not "private" and send me the links via private message on this forum.

For me it is much easier to actually look at the wave forms and determine the best tool to solve the problem than it is to try to interpret text descriptions and make viable reccomendations.

I am assuming that the camera audio is properly in sync, if that is not the case let me know as it will not affect the outcome, but it will make it easier and faster for me to find the solution.

By the way, I record video on my DSLR and use a stand alone audio recorder almost every day, so getting the the quality audio (from my stand alone audio recorder)  to sync with the video for my clients is something that I do all the time.

I am not suggesting that you become a client, simply pointing out that I do this for a living, and any and all advice I provide on this forum has nothing to do with my business.  I provide answers and video tutorials for people on this forum because I admire and respect people who want to learn how to do this themselves.  My clients are people who held up a camera, created images and have no interest or desire to turn them into something creative, they want someone else to do that so that they can show family and friends and say "look what I've done".

George