Doubled audio tracks in capture?
 

I'm trying to convert several VHS tapes to DVD, and I'm having issues with sound quality. I'm using an iMac with a BlackMagic Ultrastudio HD Mini capture device, a Panasonic AG-1350 VCR, and BlackMagic Media Express. I've been using iMovie and Final Cut Pro to edit the videos once they've been captured.

At first, I thought it was just a crackling/garbled noise in the background of sections of each film. After toying with the volume, I noticed that it is actually an echo of the audio track- same words/music replayed and slightly delayed. The same thing occurred when I tried using a different VCR. I'm learning as I go with all of this, so I have no experience with correcting this sort of problem.

What could be causing it, and how can I fix it?

The first thing you do is try to listen to the VCR out via an external amplifier, Headphone or TV speakers.

Sound quality was fine when tested on a tv.

In that case possible audio driver issue, maybe the OS audio driver is back feeding the capture card's audio feed into recording and slightly leaking to the playback stage, Try to disable all OS audio features, like microphone, input ..etc, just leave the capture's card audio input.

After disabling the iOS audio, I'm still having the same issue. Could it be the capture device? I feel like that's the only variable here that I haven't tested against something else.

Can you post a short sample of the sound, something with some sharp, short sounds?

Are you capturing via thunderbolt, HDMI, or SDI?

Can you tell us the exact connections?

Probably not your issue, but some folks have complained of audio issues when they were hearing a mix of the direct analog sound and sound out put in a digital or HDMI stream, which is delayed by the latency of the system.

Sorry for the delay!

I was going to go a new route with a new piece of equipment, but my supervisor would like me to exhaust all other avenues first...

I've attached an MP4 clip with the sound in it. The sound is not constant. The video usually starts out fine, and then the sound develops and either comes and goes or persists. I've also attached pictures of my connections. The only thing going from the Black Magic device to the iMac is a thunderbolt cable. I've tried using HDMI as well, but had the same issues.

Any ideas?

Your video file is corrupted and too small (4KB).

Anyway one more test to isolate the problem for good, Connect a HDMI cable from the capture device to the TV and listen to the sound, If the sound is clear it's your computer, if not it's the capture device.

I'll try that. Thanks!