I'm trying out Vegas 7.0b.

I put some hi-res still photos and keyframe some motion to them.

Then i render as Sony MXF 35Mbps / 25p.

I drag the resulting MXF into timeline, and notice the color is different than the original!! Oranges becomes more red, greens become more bluishgreen...

I tried exporting to Quicktime Avid DV100, the colors are same as orig, no problem.

It seems Vegas's MXF export alter the LUT or something?
Anyone seen this?

Hornady, this may be similar behavior to FCP. It alters the gamma differently depending on what it thinks you're working with. Try using a video clip and doing the same thing to see if it gets altered.

-gb-

Here's a snippet from Apple's website, take note of the last sentence.

What causes this?
Final Cut Pro assumes that QuickTime movies for codecs that support the YUV color space (including DV, DVCPRO 50, and the 8- and 10-bit Uncompressed 4:2:2 codecs) are created with a gamma of 2.2. This is generally true of movies captured from both NTSC and PAL sources. When you eventually output the sequence to video, or render it as a QuickTime movie, the gamma of the output is identical to that of the original, unless you've added color correction filters of your own.

However, during playback on your computer's monitor, Final Cut Pro automatically lowers the gamma of a sequence playing in the Canvas to 1.8 for display purposes. This is to approximate the way it will look when displayed on a broadcast monitor. This onscreen compensation does not change the actual gamma of the clips in your sequence.

RGB Image Files and Sequences Issue
When importing a still image file or sequence from Shake into Final Cut Pro, the gamma may be incorrectly boosted when the sequence is output to video or rendered as a QuickTime movie.

Hornady, I have just run a test and you are indeed correct. I'll investigate right away.

Greg - thanks for your info. What i see is not really altered gamma. Gamma is almost the same, only colors change a bit.
It seems most likely that Vegas is handling color LUT wrongly? Like a wrong handling of BT.709 to BT.601 conversion?

Simon - if you grab an mxf clip from your camera into vegas, then re-render it into a new mxf file, then put the new mxf back into XDcam disc, then playback both file (original and re-rendered), do you see difference in camera or in broadcast monitor? If yes, then this is a major color issue for vegas workflow...

thanks,
hornady.

Greg - thanks for your info. What i see is not really altered gamma. Gamma is almost the same, only colors change a bit.
It seems most likely that Vegas is handling color LUT wrongly? Like a wrong handling of BT.709 to BT.601 conversion?

Ok, thanks for the clarification on that. Not being a Vegas user, I'll defer to Simon and see what he comes up with.

Hope you get it figured out very soon.


-gb-

Hmm, this is a difficult one.

OK, don't say anything, just nod your head...
OK i got it...! Vegas 7.0c will be coming out sooner! Yeah! :)

I´ve seen color shifts with DV Avi files before as well (in Vegas):

I filmed a concert sequence where we used a very cool flood light (VERY blueish). I captured with scenalyer.

Playback in Vegas was fine UNTIL ANY rendering or filter (even 0% filter effect) came into play. Color Space looked somehow cut.

I compared playback of these Avi files with EDIUS thru a STORM2 Card - fine, even with filters.

Comparing vectorscopes I found that my (PANA DVC200 DV) files exceded heavily the BLUE Signal, no problem in Edius, but a big problem in Vegas.

Vegas did cut all colours (B) to a certain maximum - resulting in a less rich / colourful picture.

As a workaround I desaturated all clips in Edius to ~ 60%, editied in Vegas and pushed colours back later in a mastering step in Edius again.

Finally, Vegas RGB colourspace seems to be smaller than my DV recordings...

Probably you deal with the same problem?

ULI

Uli - thanks, altho i havent tried/seen in SD formats, yours maybe same case. BTW, what's your Vegas version?

Well, I encountered this in Vegas 6.

I just checked with Vegas 7 (b) - yep , it DOES change the saturation (but I think it cuts BLUE only in my case)

I uploaded a small piece (26mb) - its just a small clip with fade. Just look the BLUE colour changing with the first frame of the dissolve. Blue Sat totally dies, overall impression changes (since the strong blue dominates the background).

http://www.media-in-work.de/fuer_vvforum/blau_hartmann.zip

You can use ANY procession (filter to Zero etc.) - the colour space is reduced instantly.

I wonder, because I thought miniDV (this was a DV clip from Panasonic DVC200) is the same colorspace like Vegas.

?

ULI

I've experienced this issue before in Vegas 6 and 7, with highly saturated (possibly over saturated) footage.

Part of the reason this happens is because the Vegas rendering pipeline and filters only work with RGB, so any YUV footage has to be converted to the RGB color space. However, the colorspaces are quite different, and I know for a fact that there are certain color values in YUV which cannot be converted to RGB.

Usually the conversion is unnoticeable, however certain highly saturated clips can be substantially affected by this colorspace conversion.

Most other editing programs (including Edius, Liquid, Premiere Pro, Final Cut) can work natively in the YUV color space, therefore eliminating some color space conversion issues.

When dealing with HD there's also the whole BT.709 to BT.601 issue, however this was supposed to be fixed in Vegas 7.

When dealing with HD there's also the whole BT.709 to BT.601 issue, however this was supposed to be fixed in Vegas 7.

Hi ,

I am not too much expert with this...

Would that mean : If I use XDCAM HD and get into "corners" of YUV recording (e.g. fat saturated colours) I will probably encounter the same problem?

And : Even if I use a YUV NLE - how does mpg (DVD) behaves?

Thanks

ULI

i thought there are loss of color range / gamut when RGB convert to YUV ... but not the other way around? Isn't RGB has the widest possible colors in digital conversion? (since RGB is the real primary colors)

what i did test was using hiquality jpegs from digital camera, render them into XDCAM mpeg2 .mxf

i'll post my footage later on when i'm free...

notice the green t-shirt at upper left
notice the reds at lower right

you'll have to download the full sized image. Color difference in small-scaled image here are not very evident.

these are hi-q jpegs.

Vegas 7c free update has now been released which fixes this colour shift problem.