Audio shifts randomly even when it's locked(?!)

DDUBS wrote on 8/7/2018, 10:22 PM

I have a really, REALLY weird problem in Vegas Pro 15, although I've had this problem before in Sony Vegas Pro 13.

I'm making a music video, and I have a single sound effect synced up perfectly with the video at multiple points. The timing is so precise, that the events start between frames. The video is locked on the timeline, and every time I sync a copy of that sound, I lock that as well.

But randomly, while I'm editing other sounds, I'll see the sound I previously locked having shifted slightly. That doesn't make any sense. So I'll go back and readjust it, but when relaunching Vegas Pro, it will shift again. What's more is that when opening a new window of another program, and opening Vegas Pro again, it'll be back to normal. This doesn't happen with any other audio in the timeline, and it's driving me nuts. Even if it sounds good in preview, when I render, it sounds out of sync. I'll then go back to the editor, and it's out of sync. And again, it's locked. The video is locked, the clips are locked, it should NOT be moving. I've tried everything and I don't know what's going on here.

I'm using Windows 10, an Intel Core i7-3770K CPU @ 3.50GHz, an Nvidia Geforce GTX 780, and I have 16 gigs of RAM, and the project settings are 720p @ 59.826fps, "Best" stretch quality on both video and audio, and I've disabled resampling.

Comments

rraud wrote on 8/8/2018, 10:12 AM

Try disabling "Quantize to Frames" (Alt+F8) in the 'Options' menu.
At the same time, a 'Snap to' setting may be causing this.. which is also under the 'Options' menu. You want to temporarily engage "Ignore Event Grouping" as well.

Otherwise, move or re-post this on the Vegas Pro main forum page, where the really smart folks hang out.

DDUBS wrote on 9/18/2018, 8:37 PM

Try disabling "Quantize to Frames" (Alt+F8) in the 'Options' menu.
At the same time, a 'Snap to' setting may be causing this.. which is also under the 'Options' menu. You want to temporarily engage "Ignore Event Grouping" as well.

Otherwise, move or re-post this on the Vegas Pro main forum page, where the really smart folks hang out.

I tried those things, they didn't help. I should stress that the audio itself is not being shifted on the timeline. It's just that it sounds grossly out of sync in the preview, and will randomly sound in-sync either after a render, reopening the window, or even just clicking it.

Also....I thought this was the Vegas Pro forum page? I'm confused...

Former user wrote on 9/18/2018, 9:36 PM

Just some wild ideas, none of them may be valid but...

Is the sound effect on an internal drive?

Is it the same sample rate as the project and the other audio?

Are you using a soundcard that is built into the motherboard or an add on such as an M-audio external sound device?

Are you using an ASIO driver?

Are you using any audio effx?

DDUBS wrote on 9/19/2018, 1:07 AM

Yes, yes, no, no and no.

rraud wrote on 9/19/2018, 10:42 AM

Try the 'Windows Classic Wave Driver' or the 'MS Sound Mapper' in audio device settings.
"Options> Preferences> Audio Device"

DDUBS wrote on 9/20/2018, 12:50 AM

Didn't help. This is happening at pure random.

Rendering the video without the clip and adding it back in by itself seems to fix it. But that still doesn't explain why it won't play well with the project before then.

rraud wrote on 9/20/2018, 8:58 AM

What format are the audio (and video) files? Are there any audio plug-ins being used?

Former user wrote on 9/20/2018, 10:00 AM

If you have a time, I would try another sound bite and see if the same thing happens or if it is unique to this one. Also, did you say that it doesn't actually move on the timeline, but just plays back at a random time?

DDUBS wrote on 9/20/2018, 7:11 PM

What format are the audio (and video) files? Are there any audio plug-ins being used?

Video is avi (rendered as mp4). Audio is mp3, and I've tried it with ogg as well.

If you have a time, I would try another sound bite and see if the same thing happens or if it is unique to this one. Also, did you say that it doesn't actually move on the timeline, but just plays back at a random time?

Already tried that. It is absolutely unique to this sound bite. Originally, it did move in a completely different location from before. But now it doesn't, it just plays back and sounds different from before, and will switch back and forth between being correct and wrong.

Former user wrote on 9/20/2018, 8:04 PM

Wow, that is strange. If you are into experimenting, what would happen if you create a new file with that sound bite only and then replace? (render to another format or something) Just curious, but I understand if you are tired of messing with it.

rraud wrote on 9/22/2018, 12:04 PM

MP3 sucks in the editing stage and should only be used for end user format. I would try rendering the MP3 to a PCM <.wav> file "Tools> Render to new track" and re-check alignment. PCM files are not an lossy type so they do not need to be decoded, with could cause latency.

Most (if not all) MP3 encoders inherently add 30ms or so silence at the head and tail of a file., of course this should be visible in the waveform, so I'm not sure that's the issue.