Video / Audio Sync issues

J

jdd

Member
About a month ago I started having issues with the timing of the audio and video that I was capturing on the tapes (I have always used Panasonic HDVM63AMQ tapes). At first I thought it might be an issue with the audio track recording at a different speed, and switched to a separate audio recording device, but even still there is an issue. Has anyone ever had a problem with the video dropping frames while the audio records at 100 percent through the entire tape? It isn't so noticeable often, just a frame here and there, but after a 5 or 6 minute clip with someone talking you can notice that by the end the clip is off maybe 4 to 7 frames.When I record straight into Adobe OnLocation as expected there are no issues but I cannot always be recording straight onto my computer.

any help would be greatly appreciated.
 
I saw this issue once, long time ago. It happens when I was capturing 10 minutes plus clips. It was annoying. Are your recording on your computer what you got on tape on one clip?
 
I capture the clips as they are, I am currently shooting a number of long interviews outside, so some of the clips end up 20-35 minutes. I have tried to break up even long interviews into different clips, but the problem seems to still be there. Were you able to find a way to work around this issue?
 
Have you made any changes to your computer recently? Added hardware or software? Changed NLE's? Or changed settings in your NLE? Does the sync issue present itself even when playing the tape directly from your DVX to a TV? Or is it just in the captured video?
 
I haven't made any changes to my OS, or made any changes to any programs associated with my editing workflow, the only change I have made is adding another external hard drive to the other two I am currently using as the others have been filled. But I am using exactly the same make and model as the other two I have, I always capture the raw files to my internal drive, then after I am done capturing the files transfer them over to the external drives. I have not checked it out on a television, as I do not have one down here with me, is that something I should check it out on?
 
Never capture to the same hard drive your capture program resides on, which is typically the C: drive. Always capture to a completely separate physical drive, not just a separate partition of the same physical hard drive.

Adding an additional USB drive could be over-taxing your power supply, which could cause problems.

If you play the tape on your DVX, viewing it on the LCD screen, does the sound stay in synch with the image? I'm betting it does. Which means the problem is most likely not the camera, but rather a problem with your capture.

Most likely you're dropping frames because you're capturing to the C: drive. You've probably always captured to the C: drive before, and never had a problem. But as the C: drive fills up or becomes more fragmented, you can experience dropped frames in capturing. Try changing your capture settings so it captures to one of your external drives, and see if the problem goes away. Also, try disconnecting all but one of the external drives, and capture to that.
 
Thanks for the advice, I have been importing video onto my main hard drives and transferring the footage to other drives for so long, and no one has told me any different. So I ran over to someone's house with a television and reviewed the footage from several tapes, and it seems to be as you suspected. I should have checking this out first, now looking back it seems so obvious.

So my next question is do you have any advice on what can I do to make the import process smoother for myself going forward? I am currently shooting a lot of footage, but not editing most of it yet. Should I not fill the hard drives all the way up if the fragmentation is an issue? I am currently using 2 TB Mybook Studios which are plugged into an outlet, and using the Firewire 800 connection to my computer. Generally I have no need for more than one to be daisy chained together, so I have one hooked into my computer at a time.

thanks for taking the time to spell this out for me.
 
I haven't used firewire external hard drives, only USB drives. So I'm not sure if there's an issue with using firewire to capture both from the cam and to a drive. That might be a bottleneck.

Filling up your external data drives shouldn't cause a problem. But when your internal C: program drive begins to get full, it can affect performance rather drastically -- and any performance hit is likely to cause dropped frames on capture.

Fragmentation can occur on any drive, but is more often seen on the C: drive. Fragmentation usually occurs if you do a lot of creating and then deleting of files. Most of the time we capture to an external drive and keep the captured video files -- we don't delete them. But stuff gets deleted all the time on the C: drive. This is why the C: drive can fragment much sooner than a data-only drive.

If your external drives have their own power supply, and aren't drawing power through the computer's power supply, then you're probably not having a power supply problem. I think if you capture straight to the external drive, rather than the internal C: drive, then your problem will most likely go away.

Do consider defragmenting your C: drive soon, though. If you've been in the habit of moving video files off of it to another drive, then there's a good chance it's fragmented.

Good luck!
 
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