Vegas-Built Audio Peaks mismatch Video

dcfc87 wrote on 12/8/2005, 6:30 PM
I'm currently working with Vegas 6.0c and I've actually had this problem with 5.0 as well.

I have an MPEG-2 video that is approximately 30 minutes long. The audio is embedded in the file and Vegas creates the two tracks when I insert the file into the blank project. As it usually does for audio it hasn't seen before, Vegas built the peaks for the file. The problem is is that what Vegas says is synced up is not. The really confusing part is that when I play the video while it's in the timeline, the audio starts off synced up with the video, but as it goes on, the sync is lost. And nowhere do the peaks actually match the playing audio. I'm pretty sure it's the file and not Vegas. But has anyone ever had this problem?

Comments

B.Verlik wrote on 12/8/2005, 7:32 PM
Check to see, in Vegas Project Properties, in the audio tab, that your sample rate is set to 48,000 Hz. Sometimes you make a CD and set it to 41.1Hz and forget to switch it back. That's usually the problem. But I'll wait for an answer before I dig for more reasons.
farss wrote on 12/9/2005, 2:02 AM
Is the audio Dolby by any chance?
dcfc87 wrote on 12/9/2005, 9:53 AM
I think my problem is is that the large clip I'm editing is feeding off of an external drive. I think that explains the delay and mismatch problems.
B.Verlik wrote on 12/9/2005, 11:21 AM
OOOOOooooh. And transfered via USB2? aHa!
dcfc87 wrote on 12/9/2005, 12:09 PM
No it's its IEEE 1394, but that still wasn't the problem. I transferred the file over to my system and dropped it into Vegas. The sync problem was still there.

I did however, come up with a fix. I re-rendered the audio track of the file. The original wasn't in sync with its own wave display. I replaced the defunct audio with the new one (which works fine). I just have to go through and match the audio to the video.

You would think that if I matched it in the beginning, the whole thing would be in sync, but it's not. I think this has something to do with something else I noticed: in my video track, some of the preview frames that the event displays in the timeline were completely red. They are scattered throughout the event display. While I'm going through and correcting the audio sync, I notice that the audio before these red frames are in sync. The audio AFTER these frames is not. Once again, these red frames are not in the file itself. Vegas is using them in the timeline display. I'm suspecting these are signaling some sort of corruption in my file.
B.Verlik wrote on 12/9/2005, 1:13 PM
This sounds unique. Almost as if you've dropped some video frames, but not the audio. Might be some Windows or Virus scanner apps kicking in during the transfer. (I'm obviously fishing now)
You can also Stretch or shrink the audio by holding down the Ctrl key and placing cursor at the end of audio and dragging one way or the other (you'll see wavy line when holding Ctrl key down and hovering cursor at end of audio track). You'd probably have to put a 'split' in the audio track at the locations where you get the red frames and do each section that way. You would have to do all that from a rerendered audio file and mute original audio. (just a possible suggestion, you may already be doing)
farss wrote on 12/9/2005, 2:16 PM
Seen this before. Sometimes it seem an mpeg-2 vision stream contains non video data blocks, same can also happen with ac3 audio tracks on DVDs. So far I've only seen this from camcorder DVDs but you never know.
They will through Vegas off the track it seems but players sometimes cope OK.
Bob.
Pullmanite wrote on 12/9/2005, 2:40 PM
Go to Options>Preferences>Audio Device

Try changing "Audio device type" and see if this works.