Vegas 11 Quantize to Frames or not
 

Hi All

I have a technical question about Vegas 11 and quantize to frame boundaries on the time line.

I do mostly multi-cam shooting of live musicians and use video from varying video sources, that are not synced together in any way. Up to now I've been snapping to frame boundaries, which is the default Vegas mode of editing.

However, if i turn off quantize to frames, I can exactly match the audio tracks (and Video tracks) together, and produce a much better in sync product.

I read somewhere in the documentation this can lead to problems with rendering and transition effects, which is why the quantize to frame boundaries is the recommended setting.

Has anyone had issues in Vegas 11 when quantize to frame boundaries is off? Is there a better way to match and edit multiple video sources that are not time coded together?

Thanks

Re: Vegas 11 Quantize to Frames or not
 

When dealing with video, ALWAYS leave Quantize to Frames turned on!

If you want to adjust the audio individually, that's fine You're not going to see a sync issue of a half a frame anyway. By default, Vegas pro 11 will adjust audio only without quantizing anyway but you would need to unlock it from the associated video.

Re: Vegas 11 Quantize to Frames or not
 

Thanks for your answer thats good to know.

Is it possible to shift the audio track from it associated video track and re lock it to its new position?

I ask this as in the past I've had issues where the audio track for some reason becomes offset from the video (without me realizing it) and it cost me lots of editing time sorting it all out.

Re: Vegas 11 Quantize to Frames or not
 

Click the audio event to select it and press u to ungroup it from the associated video event.
Once it's in position, click it again, shift+click the associated video event and press g to group them back together again.

Re: Vegas 11 Quantize to Frames or not
 

I'm curious to know a) what the issues are with turning quantizing off and b) if there are issues, what is the benefit of being able to turn it off in the first place? Why would one want to do it if it is only going to cause problems?

Re: Vegas 11 Quantize to Frames or not
 

a. you might not cut on a frame edge.

b. you can shift audio sub frame increments

Re: Vegas 11 Quantize to Frames or not
 

I've always edited my videos with Quantize to Frames turned off to sync them precisely & I've edited hundreds of videos without any issue. Never actually gave it any thought until now.

Re: Vegas 11 Quantize to Frames or not
 

Similarly, I've always edited with Quantize to Frames turned ON, synced audio with it on, and never noticed an issue. Who's going to hear a half frame audio difference? Now, a frame or two - you can definitely here - but a half frame (at worse case and should have 1/4 frame or less)? If it averaged 1/4 frame, that's 1/120th of a second!

I have heard many instances where people had video doing strange things. Many times it turned out they were editing with Quantize to Frames turned off and were NOT cutting the video on frame boundaries which is something you definitely do not want to do.

Re: Vegas 11 Quantize to Frames or not
 

Leslie/Edward - thanks for the explanations. Makes sense. I'm like Nicholas - I've always edited with quantize off and never had a problem, or even thought about it. I completely see the potential risk though so I'll see how I get on with quantize on, just switching back on the odd occasions I might want perfect sync with audio.

Re: Vegas 11 Quantize to Frames or not
 

Mind you my Vegas crashed quite randomly while I edit, wonder if Quantize to Frames could be a reason.

Re: Vegas 11 Quantize to Frames or not
 

Another thing to note: if audio is not grouped with video, it will automatically adjust without "quantize to frames" in recent versions of Vegas. So audio by itself already allows sub-frame adjustments. So if you simply turn on "Ignore Event Grouping", you can move the audio sub-frame without touching the video. Just remember to turn off "Ignore Event Grouping" when you're done.

Re: Vegas 11 Quantize to Frames or not
 

Musicians do! I edit live performances and mix from multiple audio feeds. Having the audio perfectly matched is important when filming fast moving fingers....So this discussion has been a great help to me.

As a followup, I made this 3 take music video here.

George-Painted Corners Video.mp4 - YouTube

I turned off Quantize to frames. and having the switch off, made a difference in matching the parts together. However, there are no transitions or cuts involved. The Veg would render out on my main desktop workstation fine, but would not render out on a laptop, until i turned off GPU rendering. (I lost a lot of time figuring that one out). That experience prompted me to ask this question as most of my projects are more complex than that Video.

Re: Vegas 11 Quantize to Frames or not
 

Editing with Quantize to Frames off can lead to horrible, horrible resampling of the video.

Re: Vegas 11 Quantize to Frames or not
 

Thanks David, thats the kind of feedback I was looking for..

Could you expand on your statement?

While I know re-sampling can be turned "smart","forced" and "disabled", I have no clue as to what those switches do or problems they cause.

Re: Vegas 11 Quantize to Frames or not
 

If you don't quantize to frames, your video frames may not match up with the frame stops on the timeline. In order to line things back up for the render, Vegas may have to resample your footage to match. This can mean that instead of rendering whole frames from your video, it may blend or interpolate frames, leading to ghosting or possibly interlace artifacts (all depending on your footage and what you're rendering as).

You can see all this on your timeline; frame edges are marked by triangles in your footage; if they don't line up with the frame markers on the timeline, you may be in the danger zone; it'll be worse the farther off they are.

Keep in mind that all of this can be a particular nightmare if you're throwing ripple edits and mixed frame rates into the mix. Oh, I made a horrible, horrible mess of a project once.

Re: Vegas 11 Quantize to Frames or not
 

Q to F always, ALWAYS on. If people haven't experienced an issue, that's luck. When I see the PINK out of whack syncs, I know just where and how I should slip the V or A, and it snaps back.

It's a powerful tool to have available, but only to be used under extreme conditions of Audio matching.

Grazie

Re: Vegas 11 Quantize to Frames or not
 

I agree with Ray that I can definitely hear the difference if tracks are slightly out of sync. I use Edius for video editing and Vegas for audio exactly because I can edit with quantize to frames off. I export audio from Edius after sync in multicam, edit audio tracks to mix in Vegas and then import back into Edius for final export.

Ron Evans

Re: Vegas 11 Quantize to Frames or not
 

Well... there's a difference between "slightly out of sync" and "less than 1/60 of a second out of sync". But, yes, audio can definitely by adjusted at subframe levels. I would NOT adjust the video at sub-frame levels, though.

Re: Vegas 11 Quantize to Frames or not
 

Less so now most cameras are HD AVCHD etc but with DV the spec allowed the audio to be 1/3 a frame off. Mixing several DV camera audio one can see that when the pictures are in sync the audio can be off by this 1/3 frame, different for each camera . For three cameras the audio could be more than a frame off between them. Just adding these audio tracks with this less than a frame out of sync audio problem is very audible for lip sync dialog and definitely music. Certainly not acceptable to my ears.

I also see this shift if I record one track from my shotgun mic and the other from the facility mixing board. So use the audio shift in lots of situations. My main reason for Vegas since it was an audio editing program.

There is still a noticeable difference though between my NX5U audio and the XR500 or CX700 AVCHD so I still use the work flow. Edius cannot shift audio in these fine increments as easily as Vegas hence my work flow. Video of course is always frame sync. Comments are only for audio.

Ron Evans

Re: Vegas 11 Quantize to Frames or not
 

Have you considered using plural eyes, it should sinc all your media with a click of the mouse....

Re: Vegas 11 Quantize to Frames or not
 

Plural Eyes sync audio so that if the audio is off by a frame then Plural Eyes will sync to the audio and the video will be off by that frame. You will still have to fine tune the video and then the audio to get fine sync of both. If you have lots of clips it is definitely a time saver. If however you have started the cameras in a multicam show and left running to the end then I find it just as quick to line up manually. If they are consumer cameras without genloc then the audio will still have to be corrected. At least that is the case with my NX5U, XR500, SR11 and CX700 over an hour clip. When I shot with FX1, HC96 and TRV50 in DV there were very big differences.

Ron Evans

Re: Vegas 11 Quantize to Frames or not
 

Strange, I have never had a problem syncing my NX5U, AX2000, Canon HG21 and HG10 on shows that last well over 2 Hours, generally the cams are never shut off till the end of the show...plural eyes just syncs the video as well as the audio perfectly when I pull them into vegas for a multicam edit, I have yet to make any fine tuning.......

Re: Vegas 11 Quantize to Frames or not
 

Do a little test and you may see what I am talking about. On a resent show 55min Act 1 45 mins Act 2. Cameras were my NX5U, Sony SR11 and Sony XR500 all shooting 1920x1080 60i. All cameras always left running for the show. In video sync at the beginning, if I expand the timeline to a frame then the NX5U and the SR11 audio are in sync the XR500 audio is delayed by 1/2 a frame. With frame sync ON it is not possible to get this any closer, either a 1/2 frame ahead or behind. So in this case it is important to choose which is correct by looking at the video frame. For dance this is important. Hence my comment about fine tuning.

After 55 mins the SR11 audio has drifted to a delay of just under 1/2 frame and the XR500 just a little more than at the beginning. These in reference to the NX5U audio which of course could also be drifting !!!! . Similar time differences for Act 2. I don't view this is a problem for consumer cameras that are not genlocked. This is exactly why pro cameras are genlocked to hold video and audio sync to a reference clock. Vegas and other NLE's will frame sync the multi track video but the audio may thus be out of sync. In my mind this is the real value of Vegas over Edius. The audio on the non reference tracks can be stretched or squeezed ( with audio clock increments) to bring them into sync, effectively correcting for the clock drift in the camera. With AVCHD the drift is small when I used to shoot Hi8 and even DV the drift was significant between cameras. Spec for DV allows audio to be within 1/3 a frame of video so for 3 DV cameras at limits of spec the audio could be over a frame out and drift as well. So I have done this fine tuning for a long time. I don't always mix all the tracks anyway, usually taking a mic at stage level and/or a shot gun as main with a stereo mix to give some body to the overall mix.

Ron Evans

Re: Vegas 11 Quantize to Frames or not
 

I find the trouble with PluralEyes is that it won't allow me to export the audio to SoundForge, it comes up with an 'error' message. I've just tried the demo and it does what it says, great sync. I would have bought it if it allowed me to export. I suppose I could export the audio before running PluralEyes.....

Re: Vegas 11 Quantize to Frames or not
 

Great discussion from everyone. Thanks

For the record I mostly shoot and edit live multicam music events. I've edited a few more projects since and I can turn off QTF and sync muticams exactly provided GPU rendering is Turned Off. The results are great. If GPU rendering is turned On Vegas will crash (VP V511; nvidia V295.73)

As to pluraeyes, I'd understood that it is for syncing video tracks (with audio) together on the time line. After that you can edit the audio tracks anyway you wish.

Ray

Re: Vegas 11 Quantize to Frames or not
 

Hi; I know this thread is old, but I thought I would answer your rhetorical question: Classical Musicians. These people have an extraordinary internal clock - they have to otherwise they could not perform.

For example, if the sound is off by +/- 1/2 frame , the strike of the mallet on a kettle drum will be noticeably out of sync with the audio. Kettle drum mallets, particularly during a drum roll, move very fast. The mallet, bouncing off the drum head while the performer keeps downward tension on it for the next strike, can easily hit the drum 5 times in a second. The distance traveled from the apex can be as much as 2 feet. That works out to 20 feet per second. A half-frame time at 30 fps is 1/60th of a second. 1/60th of 20 feet is 4" - in other words, the sound of the drum strike could occur with the mallet 4" above the drum head, easily noticeable.

I do multi-cam recordings of orchestra dress rehearsals, and have had these small sync problems brought to my attention. After I fixed them with quantize off, the musicians were pleased.

Steve

Re: Vegas 11 Quantize to Frames or not
 

Here is the key sentence:

Re: Vegas 11 Quantize to Frames or not
 

A follow up


I've completely changed my approach to question I that posed in this thread. Edward Troxel (and others) are correct ; Always edit and render video on frame boundaries. Vegas is much more stable and error free that way.

The editing process I've adopted since, is:

Import A/V sources and place them on the timeline

Verify quantizie to frames is on.

Choose a particular video frame and match up all the video tracks to the chosen frame. I often use the drummer as a reference as a drum hit or cymbal smash will be pronounced in all tracks, both visually and sonically. Ignore the out of sync audio for the time being. The most the video tracks can be visually out of step is 1/2 of a frame, which is not a problem. Once all the video tracks are matched up, sync lock the video tracks together as a group, or temporarily lock them so the tracks don't accidentally move.

Choose one video sound track as the master sound track. Turn off quantize to frames and then slip the secondary audio tracks until they match the master track. Ignore and mute any audio tracks that are of no use. Once all the good audio tracks are in sync, lock them down, by whatever method you prefer. Then turn quantize to frames back on. (very important)

Continue on editing as normal.

I had asked about quantize to frames as I couldn't fathom what the switch was for. Once I realized the switch is for unlocking audio tracks from the video tracks it became clear to me how to use it. Audio requires a much finer adjustment as compared to video, and so setting quantize to frames off, allows this to happen. In multi cam music shoots, which is the type of shooting I mostly do, it is an important step in the editing process. Now if my cameras all had time code sync, then then everything would match right from the cameras, making most of the above unnecessary.


Happy editing...

Re: Vegas 11 Quantize to Frames or not
 

Ray thanks for coming back and updating this thread with your invaluable experience of the power of QtF.

Grazie