"Conforming" video with Vegas?

TeetimeNC wrote on 10/22/2008, 5:26 PM
I see posts in other forums dealing with conforming video in FCP and Premier. Basically what they are doing is dropping 60p footage on a 30p timeline. The "conformed" video then plays at half speed (i.e., slow motion).

When I drop 60p footage into a 30p project, it does not play at half speed unless i change the playback rate or use a velocity envelop. Is this equivalent to what FCP and Premier folks are doing when they conform their video?

I just want to get the best possible slomo out of my new HMC150 and Vegas 8c.

Jerry

Comments

Chienworks wrote on 10/22/2008, 5:46 PM
Vegas auto-conforms for you.
TeetimeNC wrote on 10/23/2008, 5:45 AM
Vegas auto-conforms for you.

Kelley, can you elaborate? Specifically, when I drop a 60p into a 30p project, it seems to me I would end up with 30 fps at full speed. If I then slow the footage to 50%, won't Vegas interpolate or blend new intermediate frames, rather than using the discarded alternate frames from the orginal 60p? What I want to do is use all 60 frames in the source but render them at 30p, therefore yielding highest quality slomo.

Jerry

farss wrote on 10/23/2008, 6:02 AM
I'm not Kelly but I think this is the wrong way around. Vegas does the opposite of conforming. It looks at the recorded frame rate and interpolates that into the frame rate defined in the project. If it conformed it then your footage would do exactly what you want and your clip would playout at 30 frames per second of what you recorded i.e. half speed.
To fix this you probably just need to Disable Resample in the clips properties and extend the clip length.

Bob.
TeetimeNC wrote on 10/23/2008, 7:23 AM
Thanks Bob,

I think what you are saying and my observation is that Vegas does NOT auto-conform. If I drop my 60p clip into either a 60p, 30p or 24p project it is still exactly the same length and it plays at full speed. If, on the other hand, if I drop my 60p clip into a 24p project, set the playback rate at 0.4, disable resample, and extend the clip length I get the desired conforming.

Jerry
rmack350 wrote on 10/23/2008, 7:43 AM
That makes sense. Vegas doesn't automatically conform, it automatically resamples. Disabling resampling for a clip ought to force it to conform. Not sure I like the word "conform" for this if that's the term being used ...

Rob
johnmeyer wrote on 10/23/2008, 9:03 AM
Vegas, like Einstein, says that time is invariant. If you have 25 seconds of video, and you put it on the Vegas timeline, it will play for 25 seconds, regardless of whether your project settings are for 24p, PAL, NTSC, HDV, etc. The beauty of this approach is that you can just dump all sorts of footage on the timeline and start editing, without worrying about all the things that must be done "under the covers" when you put a 24p video into a 29.97 project.

If you want to slow down footage, then use one of the several Vegas techniques for slow motion. And, if you don't want intermediate frames, then turn off re-sample, and Vegas will simply duplicate frames to make the video fit the longer duration.

I have never been exactly sure whether Vegas gives you field-doubled 30p from 60i, so I do it outside of Vegas whenever I want to use this "trick" for slow motion.
TeetimeNC wrote on 10/23/2008, 11:11 AM
John, so I guess my question still stands - if I put 60p on a 30p timeline, how do I get Vegas to use all 60 frames in slomo? In other words, if I had one minute of 60p, I would like to get two minutes of 30p with no generated frames. Doable in Vegas?

> I have never been exactly sure whether Vegas gives you field-doubled 30p from 60i, so I do it outside of Vegas whenever I want to use this "trick" for slow motion.
johnmeyer wrote on 10/23/2008, 12:26 PM
Playback rate=0.5. Disable Resample.
TeetimeNC wrote on 11/9/2008, 6:22 AM
John, your suggestion worked beautifully. I was able to "overcrank" my 60p footage to smooth 24p slow motion by using a 40% velocity envelope and rendering to 24p. When I play it frame by frame, every frame is an original out-of-the-camera frame - no generated frames. I did set resampling off but that may not be necessary.

I have another question. Suppose I have some 60p source and I want to render some 24p that has a mix of slomo and regular speed. I have done this already by just leaving the velocity at 100% for the regular speed clip. When I play the rendered clip both the slomo and full speed parts look good to my eye. I'd like to understand what Vegas does here when rendering a 60p 100% velocity clip to 24p. Is it just throwing away frames - sort of a reverse of 3:2 pulldown concept? Or is it doing some blending? Is there a better approach for mixing overcranked slomo and regular speed 60p clips?

Jerry