Coding problem? Need some pro help.

minna415 wrote on 2/25/2005, 5:06 AM
Can one of you experts -please, please- give me some kind've explanation as to why I would have a avi. clip that was captured in Vegas, can play interlace free and crystal clean in Windows Media Player, but has a ton of interlace problems and jaggedness in Vegas - in the preview window and on the timeline. I have tried everything on earth and really need some expert help here.
Thank you for any help you can give.

Comments

Jay Gladwell wrote on 2/25/2005, 5:32 AM

Many variables...

What is the resolution of your preview screen? Do you have access to an external monitor?



filmy wrote on 2/25/2005, 8:40 AM
I agree with Jay - could be a few things here. Preview window is one - the size of it and the preview resolution is another. For the heck of it set quality at "Best (Full)" and drag out the window to full screen, make sure "Simulate Device Aspect Ratio" is on. Are you still seeing jaggies?

Interlace - do you have to correct setting for the project *and* the clip itself? I have a project that is progressive but when they shot some pickups they shot interlaced - the interlaced shots sometimes look a bit off (interlace wise) but are fine for the render. Also when I preview on an external monitor things look better as well - unless you have an effect and are previewing at lowest quality.

Beyond those suggestions I think one would need more info to guess any further.
minna415 wrote on 2/25/2005, 7:57 PM
I know enough that you can never trust whats seen in the preview window. The clips were shot 24p and my project settings are accordingly. And even when I burn a test DVD in Vegas Architech the lines in the clip are still there, and heres the thing, they dont even look like an interlace problem, but more like if you had corduroy pants. never seen this before. Something is happening to the clip as it is brought into any editing software, and thats what I'm hoping someone can help me figure out whats the problem.
BillyBoy wrote on 2/25/2005, 8:17 PM
First check if Vegas is "seeing" the project as it really is. Expand the explorer window so you can read what it says once your source file is on the timeline. For example it should say something like
720x480x32 29.970 fps, the length in minutes/seconds.., Alpha = none, field order = lower field first, mpeg2 etc.. IT WILL BE DIFFERENT for a 24p source, I don't have any handy, so I used a typical MPEG data. The point is Vegas should report what your file actually is. Next right click on the source file on the timeline, properties, media tab, do the same kind of check. Lastly confirm your project setting also agree. It sounds like it maybe a field order reversal. Could be something else. Try reversing the field order, see if it helps.
Spot|DSE wrote on 2/25/2005, 8:26 PM
Minna, is pulldown being managed correctly? How did you capture? You're rendering to 24p template or custom settings? Do you have any track motion or pan crop edits happening? Illegal colors potentially blowing out contrast points?
You should be able to trust what you see in the Preview Window if it's set to Best/Full.
If you're seeing it in any editing software and not just Vegas, are you sure that the footage is clean? If it's in every software, it would boil down to either a camera issue or capture issue, as far as I can tell. Any analog in the chain of transfer?
minna415 wrote on 2/25/2005, 8:55 PM
Thanks for the reply Billy, I do notice ( I have been working with Vegas for sometime, so I'm not a noob) down at the bottom in my project #'s it says 720x480x32 but when I right click on the clip it says in Attributes -720x480x24 is that a reason I might be having a problem? How do I fix this - or can I - I've tried changing the project setting numerous times now to no avail.
minna415 wrote on 2/25/2005, 9:06 PM
I've never had a problem capturing footage up until now. Its straight firewire into Vegas, and it did it in Premiere pro too. The scenes in question are all inside nightclub shots with nothing but red lighting. I've done nothing to the clips but just import them into a 24p template, and like I said the strange thing is the clips play fine in windows media player, but seem to be having something happen to them when they are brought into an editing software.
Spot|DSE wrote on 2/25/2005, 9:16 PM
Could you post a small bit of a clip so that we could have a shot at it firsthand?
minna415 wrote on 2/25/2005, 9:25 PM
I dont have a server, any other way to post other than doing what you hate Spotted which is to email you one?
Spot|DSE wrote on 2/25/2005, 9:28 PM
dse at sundancemediagroup dot com

I'm signing off for the night, but will catch it first thing a.m.
John_Cline wrote on 2/25/2005, 9:29 PM
First of all, the color red has always been problematic for video. Secondly, the algorithm used in DV codecs sometimes has a problem with high contrast, single colors (particularly red) in areas where the single color sharply transitions to solid or near solid black. It was this type of scene which caused me to discover the serious flaw in the Pinnacle DV codec a few years ago. Pinnacle finally rewrote the color space conversion routines and minimized the problem, but I don't ever recall seeing the Vegas codec do it. But I have tended to avoid those conditions since I found out DV codecs had a problem with it.

The problem usually manifests itself with faint vertical stripes spaced every 8 pixels across the image. Like I said, it is particularly noticable on sharp diagonal color transitions. This, of course, may not be your problem at all, but it does sound somewhat similar, especially if the "corduroy pants" effect you describe is vertical as opposed to horizontal. I'll get in touch with DSE in the morning and see if he can get shoot me a frame grab via e-mail. I'm going to be on dial-up for the rest of the weekend, otherwise I'd ask you to send me a copy of the clip, too.

John.
minna415 wrote on 2/25/2005, 10:33 PM
I really appreciate everyone's help. Again one more point I dont get, is yes these scene's look a little rough for any digital camera even a canon xl-2 to handle, but why again is it looking completely stable in Windows media player? I find that too odd.
The clip is in the mail Spot.
theforce wrote on 2/26/2005, 7:54 AM
Similar issue reported yesterday (okay in media player, bad in Vegas), turned out to be some bad slow motion keyframes at the end of the clip.