Mpeg renders NO Good on reds

videoman69 wrote on 4/28/2003, 4:05 PM

OK here is the 3rd time.
Either reds or oranges are rendering bad on
MPEG 2 renders. I have tried the NTSC filters
but that gives wierd edges to these colors
of objects. It looks like VV4 is adding some
undesired filtration. If I just PTT the
un-rendered video looks like the original video.
Add a dissolve and the renders are clamping down.
Render to an mpeg and it clamps down.
This is for DVD so hot NTSC should not be
a problem. What has anybody else seen
regarding this?
Adding a filter would not be a problem
but it just makes anything that has
orange or red in it not look to good.

Comments

BillyBoy wrote on 4/28/2003, 4:13 PM

Can you put up a sceen shot or a short bit of the vid? Ones of those things where it would be better to "see" what you're talking about.

videoman69 wrote on 4/28/2003, 4:14 PM

I will try that tomorrow. Have to run now.
I will also try to play with the color corrector.

videoman69 wrote on 4/29/2003, 11:38 AM

I saved some .jpgs but on those I could not tell a diff.
Saved on with no processing, then one using Broadcast color
clamp and then one using CC.
So - I digitize a clip. Put in time-line
then PTT it looks like original.
But you do a dissolve and the rendered section
gets clamped down then the original clip colors
pop back up.
Or if I render an .m2v file the colors
are clamped and on oranges & reds I get
bad banding.
However - I run the same clip through
a DigiSuite it looks OK if I just
play it back.??

Former user wrote on 4/29/2003, 11:46 AM

I ran into this with VV3. I am not using VV4, but one fix is to force the surrounding shot to render also so that all of the reds get clamped the same. Add an effect that doesn't change anything and this will force a render (such as 99% transparency or something)

Dave T2

videoman69 wrote on 4/29/2003, 12:19 PM

Thanks,
I did that but the clamped video looks awful.
Is there a way so the renders do not get clamped?
Or is there a better way to deal with hot colors
in DV?

Former user wrote on 4/29/2003, 12:26 PM

This might be too obvious and I don't know that it will help, but have you tried using the Saturation filter and bring the color saturation down?

Dave T2

videoman69 wrote on 4/29/2003, 12:30 PM

Have not tried that filter, I will try later.
Thanks

videoman69 wrote on 4/30/2003, 9:12 AM

If anybody has the time.
Download this clip.

www.izonemedia.tv/OV.avi

It is a boy with an orange
shirt. The orange is way
over legal.
This is a 24PA clip from a DVX-100
So use 23.967 Timeline
Try this - put the clip in
a timeline with no effects.
Then put another instance in
and add the broadcast filter.
Then add another and dissolve
to a diff. clip.
Then PTT using 23.976 2-3-3-2
And then look at that.

I am using the SoFo codec and even
rendering to MPEG 2 I get wierd
aliasing.

Now here is the kicker.
I took this clip into my
DigiSuite LX running SR 2000X
It looks good and does not
exhibit any of the color fringing
that I get from Vegas.

videoman69 wrote on 4/30/2003, 9:16 AM

e-mail me for a link

dvd.pro@verizon.net

I don't think you can save it since this
forum will not live post a URL

Thanks

SonyDennis wrote on 4/30/2003, 10:57 AM

Sure it does:

http://www.izonemedia.tv/OV.avi

I'll check it out.

///d@

pelladon wrote on 4/30/2003, 11:11 AM

Fixing the orange shirt was easy, Saturation Adjust->Reduce Oversaturated Colors.

As for the wierd aliasing, if you run the clip in WMP, it does show up. However, when I pipe it out thru my RealMagic DVD card, it seems to play okay on the TV. Of course, it's converting from progressive to interlace to a interlace TV. Don't have a progressive DVD or progressive monitor to check it.

SonyDennis wrote on 4/30/2003, 2:41 PM

videoman69:

Here's what's going on: Your source clip has YCrCb pixel values that cannot be represented in RGB color space (which is what Vegas uses for video calculations). If the compressed image is allowed to pass through without being recompressed, your monitor is showing these colors. If the clip gets recompressed because it has any FX, crossfades, transitions, compositing, etc., it gets decompressed, goes through the video engine, and then get recompressed to DV. This is why applying any filter (including "no change" filters like Brightness & Contrast with the default "no change" settings) causes the hot oranges to become less saturated.

There's a pretty fair chance that these same colors are outside the "legal" broadcast color range, so you'd want to clamp them anyway.

My recommendation for this clip would be to apply either Broadcast Colors or a no-change filter at the media level, so no matter where it's used it will be processed. If you're using the clip extensively and want fast pass-through performance, re-render the clip (with the filter) to a new file, and use that instead.

Regarding color fringing, I'm not seeing any more than I'd expect from 4:1:1 DV or 4:2:0 MPEG. Could you be more specific about where and what you're seeing.

///d@

videoman69 wrote on 4/30/2003, 3:28 PM

Thanks SonicDennis, I always forget that http.
Anyway, I realize that Oranges & reds are hard to
handle in video but what I see on my MPEG renders
in VV4 is causing the edges of these colors to
create undesirable aliasing, But the same video
rendered as MPEG from my DigiSuite LX does not
exhibit the same behavior. I tried all the filters
you are talking about in VV4 but they all created
the aliasing. SO now I have to re-think my project
and will probably stick with my DS LX because the
MPEG renders there look like the footage with no
aliasing.

dmcmeans wrote on 4/30/2003, 4:06 PM

Have you upgraded to 4.0b?

I had a "blockiness" problem with bright reds rendered as MPEG2 using 4.0. The problem is corrected in 4.0b.

David

videoman69 wrote on 4/30/2003, 5:59 PM

Thanks,
I am using 4.0b
I really wanted to shoot my docs
in True 24P but if I cannot rely
on decent MPEG renders then it all
becomes a moot point.
It does do true 24P .mpgs.
I might try doing an uncompressed render
and then a TMPEG render.