odd contrast/levels problem

R0cky wrote on 4/21/2006, 2:46 PM
Have a piece of media (DV AVI) that looks fine when you view the raw clip in some other application, but when you put it on the timeline and preview it, either on the computer or my preview monitor that i've calibrated with the AVIA DVD, it looks washed out.

There are zero effects being applied. If you burn it to DVD it looks washed out.

Adjusting the contrast or levels fixes it. I It looks fine if I play it in a software DVD player.

I think this is a clue: If I do contrast or levels correction on the event it looks good. If I do it on the media clip it looks good. If instead I apply the same effect to the video track or video bus track it looks worse, i.e. levels are more messed up. How can this happen?

Shouldn't it all be the same if this is the only media on the time line and there are no other FX anywhere?

thanks all,
rocky

Comments

DGrob wrote on 4/22/2006, 6:33 AM
Just a guess, are your project properties set correctly? Darryl
R0cky wrote on 4/22/2006, 9:01 AM
yes, project properties are right. This is a plain vanilla DV AVI clip. Of the four places your can apply an FX effect to it, event, track, video bus, and media, 2 places the effect works properly and 2 places it acts the opposite of what's intended.

Example: Apply the contrast FX to increase the contrast. It increases if done at media or event level, and reduces contrast if done at video bus or track level.

Plus of course, that the levels/contrast are wrong to begin with with no FX anywhere. They look fine in other apps or if I burn the clip to a dvd and watch on my calibrated monitor.
GlennChan wrote on 4/22/2006, 10:10 AM
1- What DV codec are you using?

The default Vegas DV codec will decode to studioRGB (blacks at 16, whites at 235 RGB). Most other DV codecs (i.e. in windows media player) will decode to computerRGB (blacks at 0, whites at 255 RGB).

2- Similarly for MPEG2, some codecs will decode to 16-235 and others 0-255.

3- For MPEG2 encoding, I believe the default for Vegas' encoder is studioRGB. It wants to see studioRGB levels.

4- The AVIA DVD can be wrong if you are using different decoders/codecs or digital-->analog converters.
i.e. you have both a DVD player and your DV camera (doing passthrough from Vegas) hooked up to your monitor.
The DVD player may put blacks at 7.5IRE (IRE is an analog unit, not digital) whereas the DV camera may put blacks at 0IRE.
R0cky wrote on 4/25/2006, 10:58 AM
Captured using Canopus advc-300 so I assume it's the Canopus DV codec. Playback and rendering using Vegas' native DV codec which I thought was Main Concept's.

I think the problem with the levels is that the advc-300 settings used during capture. It has an agc function which messed them up I think.

Looked at the histogram and saw that it was biased high. Using the levels tool brought it back to 16-235 and things look good.

I think the problem with getting different behavior if i put FX on the media, video bus, track, or event was that I accidently had 3 instances of mike crash's auto levels in every event. I think they got there by copying event attributes to the whole project a few times. Apparently copying event attributes with no FX does not erase previously applied FX.

I know there's a command somewhere to remove all event FX, just gotta find it now.
craftech wrote on 4/25/2006, 11:30 AM
My guess is that you are rendering with the wrong template.

What is the exact name of the template you are using for the video and the audio?

John
R0cky wrote on 4/26/2006, 3:35 PM
Rendering template doesn't matter when I'm talking about the source media (AVI) on the timeline. The levels are messed up there.

To answer your question, when I render I use the DVD Architect NTSC Video stream template.
GlennChan wrote on 4/29/2006, 3:52 PM
On the timeline in the event, right click --> delete FX will get rid of all filters on a clip.

I don't know if that helps.