Velocity envelope ouput is choppy

mrp wrote on 5/15/2002, 11:01 AM
I captured some VHS clips, slowed down the action with a velocity envelope of 50%, and outputted to DV. The recording did not look as smooth as it did in preview. It was a little jumpy/choppy. Is this to be expected or is there a way to improve the result.

Canon Elura DV camcorder
Western Digital, 7200 rpm, ext. firewire HD
Windows 98se

Comments

Lauri37 wrote on 5/15/2002, 1:30 PM
There are threads on slomo you could check out. I have the same problem. When I look at the manual it says to resample the event but I have not had any good results whenI do the resample under properties of the clip. Others have tried deflicker and using render for the whole project( wow!). Until I get more answers from Sonic I am using an outside slomo program with my REX Edit machine. Means I have to transfer via firewire to the other computer and back again but the results are what I need.
murk wrote on 5/15/2002, 3:08 PM
I haven't much hands on with other NLE systems, but from all that I have read, speed changes in video usually looks poor unless you spend a lot of cash for a turnkey system or use software specially designed for doing this.
Control_Z wrote on 5/15/2002, 5:38 PM
Make sure you had Quantize to Frames on when you lined up the events; resample all video; best quality.

I too have had inconsistent results with a small percentage of slo-mo clips in VV3 and now use P6 for it. Looks good when it works though.
morslem wrote on 5/15/2002, 7:06 PM
Where do you find Quantize to Frames?
FadeToBlack wrote on 5/15/2002, 8:03 PM
HPV wrote on 5/15/2002, 10:14 PM
I found Vegas speed changes to look very good. Blend fields in project properties can help with some footage, but requires you to render the clip to a new track or file. Vegas 3 also has an "reduce interlace flicker" setting at clip level.
There is a trick that people use with other NLEs that might help you out.
Set a copy of the speed adjusted media on a track above the original, offset it about one frame ahead, and then adjust the opacity to 50%. I've also heard that the speed adjustment should be an even divisible number from the source frame rate.

Craig H.
morslem wrote on 5/16/2002, 2:03 AM
I`m really new to this system so I just have to ask some questions. where do you see if Quantize to Frames is on? Under options I really can`t see this.
How do I reduce interlace flicker?

M
Chienworks wrote on 5/16/2002, 5:08 AM
Quantize to Frames is only in Vegas 3. If you're using version 2, it won't be there.
Control_Z wrote on 5/16/2002, 7:02 PM
Well, even in VV3 I can't really tell if mine's on either. So if that's the problem you'll have to do like I did - customize the toolbar and put a button there for it. Easy to see then if it's pushed in or not.

Since this option is dangerous for video editing it really should be locked by default. I accept that some musicians may be so precise that 1/30 sec accuracy isn't enough for them, but I can't help but to believe they're rare, so let em hold down some arcane key combo to do it - ctrl-alt-shift-Q-drag or something.
FadeToBlack wrote on 5/16/2002, 9:08 PM
Caruso wrote on 5/18/2002, 4:19 AM
I just completed editing two 2-hour pieces (different talent versions of the same production). In the first, there was one instance of unexplained jerkiness in the video that lasted about 15-seconds.

The second project has a half dozen 15 to 30 second spots that have this unexplained jerkiness. Dreadful as the prospect is to me, that's enough of a defect to make me want to do the project over again if I can isolate where this jerkiness is coming from.

Could quantize to frames (being disabled) during editing cause this? We aren't talking about velocity envelopes here. My use of FX is basically limited to dissolves, and a few pan/crops, two spots where I used compositing (and they look fine).

Will turning quantize on and re-rendering help?

I used resample during my original render.

If I go back to the source avi files, they play fine on my computer, no jerkiness.

If I play those same files from within my project, they look jerky (even in sections where there are no FX for my computer to contend with.

The rendered file plays jerky in those spots, and, of course, output to tape is also jerky.

I'll continue to search the forum for answers - posted here to see if quantize had any effect on this. I'm not certain that it should, I've never turned it on or off, so I don't know if it defaults to on or off (I to am left wondering whether its on or off - other items in that menu use a check - I could do without the little icon in the check box).

Thanks in advance for any suggestions. Please hurry, I need to get this one out.

Caruso