trouble syncing.... why?

gary-beckwith wrote on 4/8/2016, 8:51 PM

I shot two videos of myself playing a song on guitar, hoping to be able to sync them and show two camera angles and mix the audio.

First I shot the first video...and captured the audio with a separate mic (Zoom H1). then I put the audio I recorded (.wav) from the H1 on to an mp3 player, listened with headphones while I played and recorded the 2nd shoot.

It was done with a decent camera... making MTS files that are HD.

When I put the two videos on the Movie Studio timeline, they don't sync up well. I can line everything up at the beginning, but one of them starts to get out of sync. I had to put breaks in every 30 seconds or so and add a tiny bit of time to the 2nd video or it is way off by the end.

both videos were shot with the same camera on the same settings. The 2nd take was recorded while listening to the WAV file that came from the H1, (not the first take of the video) but I don't see why there would be a time issue like this where I have to input extra time every few seconds or it gets out of sync

Any explanation why this might be happening???



Former users wrote on 4/8/2016, 8:58 PM
Were you listening to a WAV file or MP3 file (converted from the WAV)

Did you try syncing up the H1 audio to the first video shot to make sure it stayed in sync?

Are you recording at the same frequency as the project (normally 48k)?
musicvid10 wrote on 4/8/2016, 9:03 PM
Well, each device has its own internal clock. Unless the two devices are synced by a SMPTE timecode,, the clocks will inevitably drift apart over time.

Think of two small boats set adrift on a calm ocean. They will reach opposite shore hundreds of miles apart. Now tie the same two boats together with a ten foot rope. You get the picture.

Now, the Zoom h1 (which I own) has more inherent drift than its successors, the h4n and h5. Are you interested in just getting them better in sync, or getting the best quality music. IOW, a professional recording? I can help you with that, but it's a rather lengthy tutorial process that works best with a $200 plugin in Vegas Pro, not Movie Studio.

To start, just ungroup and time-squeeze the longer of two audio recordings in Vegas to match two visual waveform sync points, and see if that works well enough for you. Down-dithering may introduce a little echo, but it's preferable to the Q-noise and flanging that can occur with time stretching. Unless of course you are playing an electric guitar

Run your tests and post back.

D7K wrote on 4/8/2016, 9:33 PM
Plural Eyes can help you, its about $100. I wonder if he could use Acid Studio and sync each video sound track to the same beat.
musicvid10 wrote on 4/9/2016, 8:44 AM
Pluraleyes isn't made to work on Movie Studio, but with Vegas Pro.
I said that above, so as not to give OP the wrong information.
Nor is it $100. Closer to $300 now, I see.

gary-beckwith wrote on 4/9/2016, 10:21 AM
wow thanks for all the replies folks.

to answer that one question, I recorded the audio in WAV, format..... however there was one more step, i ran it through audacity to trim and boost it, then I exported to WAV.

I guess I have learned that I can't record the same thing with two different devices (and run through a process) and assume they will match up perfectly. I've had pretty good luck before doing this kind of stuff before.... recording the audio on the H1 and the video on something else and I can usually match things up. But this time it didn't work. Luckily the audio had a few pauses in it, which gave me an opportunity to split it and introduce a little extra time.

From now on I'll have to be mindful of this and try to use the same devices and minimize processing.

musicvid10 wrote on 4/9/2016, 4:41 PM
Or test an h5.

UKharrie wrote on 4/9/2016, 6:17 PM
Did you try the suggestion of Ungrouping the Audio and stretching it to fit the Zoom Recorder ( what a daft name!!! )? Surely if they are right at the start ( perhaps using a clapper-board - and again at the End ) you can introduce a small time-error ((perhaps "Correction" is better?)) . . . This effect is linear from start-to-finish.

From what You Said:- Whilst stealing a bit of time using Split ( OR adding at the same point ), is a bit like introducing a fresh Start - and I presume the very last notes, before the Split, will still remain out of sync?

I've read/heard similar tales when using two devices - due to their Xtals drifting - but surely these are the same Xtals that are used in Clocks? - the whole point being they are super-steady . . . . it's true if you move from Hot Desert to Artic the clock will change very slightly - but over the length of a song?

However, one needs to bear in mind the Xtals in our Gear are not used just for timekeeping ( your Camcorder will have a good one for time/date ) - but the actual recording digitals may use an industrial controller - and if they omit the Xtal and use the internal Clock ( which is amazingly good ). . . . it will not be acceptable for Timekeeping.
+Another possibility is that the internal routine is upset by program-changes as the controller is forced to correct things like Gain - in early audio this was Analogue and was done with simple circuits - but if the gain is set digitally then the controller has to go away and fix the overload - and when it returns it's lost some clock-cycles. Of course a good programmer would include dead-clock-beats for normal operation, so these can be bypassed when a routine is imposed . . . thus eliminating the loss-gain of clock-cycles. But that takes Effort and maybe more memory so the cheaper models don't.

Oh my head huts . . . . . Have you tried the time squeeze/expand using CONTROL Button and Push/Pulling the end of the Media? I'd expect that to work OK . . . Then adding some cutaways also helps cover any errors - but I think this time-issue "Fix" needs to be done at the start of the Edit.....and then apply "New Group" FWIW
( Of course you need to "Ungroup" at the start - but you knew that ).

Good Luck.
Former users wrote on 4/10/2016, 12:22 AM
There is an old saying, a man with one clock always knows what time it is, a man with two is never sure.

The same applies to television clocks. No matter how good the equipment, unless they are locked to the same clock, they will not run the same speed. I am lucky that my Tascam recorder only drifts a frame or two over two hours, but even cameras that are free running will drift from each other.
musicvid10 wrote on 4/11/2016, 5:27 AM
Had a guy tell me all my cameras would be in sync because they got a 60hz pulse from the power line. He didn't seem to believe me when I told him camcorders run on DC, and had for thirty years.

I should have known by his bell-bottoms and Abba pendant ....

blakeharris wrote on 4/15/2016, 7:51 PM
What is the proper way to sync two cameras while you are recording video with them ?
mike_in_ky wrote on 4/15/2016, 9:45 PM
This might be old fashioned, but try using a clapboard at the beginning and end of the recording session. Then, just line up the claps.
Former users wrote on 4/15/2016, 11:12 PM
If you are talking about KEEPING them in sync, you need a sync generator that is connected to all cameras. Then they have a common reference for clocking.

Any other way is just random.
musicvid10 wrote on 4/16/2016, 4:38 PM
Look, stretching causes flanging and quantization noise.
Squeezing creates some echo and softens consonants.
So one needs to ask whether the audience is ok with the way speech sounds, or they are critical music listeners.
If your devices are already in sync, lucky you.

For the second group of listeners, the way I've settled on is the following:
1. Cut your second audio track into 9 or 10 minute chunks, cutting in a quiet spot, and exactly at zero-crossings.
2. Lock the camera's audio track from the right-click menu.
3. Run Pluraleyes on the chopped-up track, one event at a time with the cursor approximately in the middle of each new event. Everything should now be in sync, with micro-gaps or micro-crossfades, Try it with the mini-fades at cuts turned off, and listen for clicks.

4. Save a copy of your project. Test-render the audio only and listen to the whole thing without vision.

~ Yes, it's time consuming, but I've gotten some nifty concert mixes from 6 or more unsynced, but professional devices. Yes, it's a lot of work.