My audio and video are seperate files, I perfectly synced them up with a sound test.
When I render and save or preview my movie, the seperate audio file slowly goes out of sync from the soundwaves.
Example:
Black = When it should be said
Red = Said
In a 11 minute video, 20 seconds in the audio already has a full second delay.
What do I do?
In early testing that I did for using a separate recording device I found that using a cell phone for audio was really terrible. The clock rate that the phone used just didn't work with the video I recorded.
What I didn't know at the time was that I could alter the expected audio for the video by re-rendering it with something like Reaper. Check your video (or rendering profile or project preferences) to see what the audio is expected to be in terms of bitrate (16 or 24) and kilohertz (44.1 or 48) then see if you can do something to line up the formats so that you don't get the drift. Good luck - it's a pain.
Quick fix in Vegas is to hold CTRL and drag the end of the audio event to stretch/contract it until the audio is in sync. Zoom your timeline with your mousewheel for more accuracy.
Then right click on the event, choose Properties, make sure you have Elastique set as the time stretch method, and try the different Stretch Attributes to see which sounds best. I've seen it claimed that both Pro and Efficient are better, so use your ears. You can also do very fine control of the new length in that window by typing in numbers.
Of course, this doesn't address the underlying reason for the loss of sync.
As Ralf said, I've had sample rate issues cause this for me, but usually vegas is very good about keeping audio in sync regardless of sample rate. That said, always try to make sure your sample rate matches what the video is being recorded at just to be safe. Nick's method will definitely work, but it isn't ideal as you lose audio quality in the process. Your goal should be to make sure your sample rates match.
Sometimes nothing works, though. I've had external recorders that would drift in sync no matter what bit or sample rate they were set to.
Another thing to keep in mind, if you are using video that came from an SD card that spans into a new file ever 4.4GB, make sure that you are compensating for the offset of that span. Some cameras lose 2-3 frames of sync each time the video spans, which can add up over the course of a project.
It slowly gets out of sync from when I play the preview, if I play the preview right next to the soundwave, it's perfect and then starts to get out of sync from there.
I'd guess it's caused by your soundcard's sampling frequency setting.
I'd guess it's caused by your soundcard's sampling frequency setting.
I'm trying to find out what to do. Not mainly what the problem is.
That's the order usually one goes for solving issues: Before you'd know what to do it should be very helpful to know what the problem is …
That's the order usually one goes for solving issues: Before you'd know what to do it should be very helpful to know what the problem is …
...and in this case, the problem isn't that your project is drifting out of sync, but why. If you aren't interested in the why then use the solution Nick Hope proposed -- that at least will get a passable result.
Also, have you OP, tried to look at the properties of the sound file? Then check that against the properties your project expects? I find that I get audio drift quite often if I use my webcam output. I can't actually use the output directly and use Handbrake to transcode it, but in the process I alter the frames per second (usually from 15 to 30) and then find the audio track is a bit longer than the video and so find the audio to be ever so slightly to be out of sync that it's just enough to make me wonder if I'm seeing it correctly or not.
Anyway, best of luck.
I agree with Marco. Your soundcard and file sample rates probably are different. Possibly a rate your soundcard doesn't support or isn't set up correctly to support.
I found out what it is, I had the pitch shift effect on my voice because it was a bit sore when recording. It didn't just bring the pitch down, it made the audio slower.
That doesn't explain how it could be sync at different points.
I found out what it is, I had the pitch shift effect on my voice because it was a bit sore when recording. It didn't just bring the pitch down, it made the audio slower.
The Vegas pitch shift effect can attempt to preserve duration or not. Did you check the "preserve duration" option?
I believe the waveform is always pre-effects so the sound will not match the waveform when duration in altered by an effect.