Can you speed Video and Audio at the same time?

[Jerry1964]

Hello,

I have a project that has one video track and 3 audio tracks, they all need to be speed up 3.45% at the same time. I know about the video velocity envelope for video. This option does not let you use anything other than a full %. meaning if you input 3.45% it sets itself to 3%, so no go there. plus I need to apply to the audio as well.

Is there a way to take 3 or more tracks of video and audio and speed them up ALL at once in exact percent?

I am using Sony Vegas pro 8

Thanks

[guns1inger]

You can adjust the audio using timestretch (I believe it is still called that) under Audio FX in Vegas. Don't know if you can multi-select the tracks and apply it in one go, or if you have to do it one at a time, but the results will be he same either way.

Why specifically 3.45% ?

You may find you are restricted in levels of accuracy simply because it has to conform to framerates to avoid too much damage to the image quality.

[Jerry1964]

I have some old music film that was transfered too slow. I found the audio in better quality on a CD. The CD runs at the proper Speed. After some palying with the 2 sources, I found the film and it's audio run this slow. I know about the audio time stretch, but

Right Clicking the video track properties lets you change the video playback rate with 1.000 being normal

using sony's time-stretch on the audio allows you to change the speed with 100.00 being default This may sound stupid but how do I speed up both tracks to 3.45% with these options. I wish you could change the speed on both with a simple percent +- change

I can find no way of speeding both tracks at the same time

[guns1inger]

There may be an alternative. Work out what the actual difference in running time is, then hold down the crtl key while dragging the end of the clip to the left that amount. This should speed up the video and audio. Dragging to the right will slow it down. You can do this in real time, so you can put the good audio on a second track, then ctrl - drag to match it.

[Jerry1964]

Hi

I've been working for days on this video/audio speed thing. With Sony Vegas pro

I first tried speeding up both the audio and video by holding down control and dragging the tracks. This does not let you put in a %, you can only see how many seconds you have changed it. I tried a sample render, and the video/audio were out of sync. Terrible results

Next, I speed up the Video to 1.035 with the RT click properties tab and changed the playback rate. Once I rendered this, I got a new running time. I then took the original audio and used the RT click properties tab for the audio and time-stretched to the new running time. Now this worked great. So I now have the original video and audio running at the correct speed. Problem is, I drop in the new CD audio on to a separate new track, and it does not match. It's off about 6-7 frames. I tried adjusting the time for this track, and got it close within a frame or two. but when you listen to the audio tracks at the same time, you can tell they are off, you can also see on the waveform they are off.

I have other plug-ins for time stretching, but for some reason none of them let you see the results on the waveform until you render. No good, I would have to render about 100 times before I got it right. I need to see the changes I am making live on the waveform. Worst case, I cut the waveform apart and leave little space gaps? Can you do this and not hear the spaces?

Any other suggestions on a better way to go about this? Could dropped frames be an issue?

[guns1inger]

The Time Stretch plugin will let you put in an exact length to match, so if the audio tracks are identical in content, you should be able to match them precisely.

I don't know why you were getting sync problems with the crtl drag option. My tests didn't show any similar issues.

Frames are only dropped during capturing. Yes, if you dropped frames at that stage, syncing will be an issue. But you won't drop frames during encoding.

[stantheman1976]

[quote="guns1inger"]
I don't know why you were getting sync problems with the crtl drag option. My tests didn't show any similar issues.
quote]

He said it's an old music film, meaning chances are 99.9% it's from an analog source. This would easily explain why the sync is off. Analog recorders don't run at a constant speed so they will drift to varying degrees throughout the recording. Digital sources run at a constant speed so even if there is a difference between sources it can be easily corrected by the "CTRL" drag method gunsl1nger mentioned. I do this myself all the time. Getting multiple analog sources synced together is painstaking. I've only tried it once myself and did not have the patience to do it successfully. You will likely have to chop your source into very small segments and sync those small pieces.