Q: Menu gamma shift after burning and only after building DVD

Jeremy,

Welcome to the wonderful world of Gamma in Final Cut Studio.

I posted some information on this that is likely relevant to your situation, even though you're working in DVD Studio Pro. Much of the content of this posting still applies:

http://discussions.apple.com/thread.jspa?threadID=1550459&tstart=15

Scroll down in that link to my posting.

The short version of the story is that if you're not using a display gamma of 1.8 (i.e. if you've calibrated your computer monitor, or are using a non-default display color profile), you're going to get unpredictable results frequently while using Final Cut Studio applications. What you see will not be anything resembling what you get.

The end lesson is "always use an external, calibrated, broadcast monitor." But for those who can't or won't, there are some proposed workarounds in that link above.

-Matt

Jeremy,

Firstly, you'll want to read this link:

http://creativemac.digitalmedianet.com/articles/viewarticle.jsp?id=23956

It's important for me to say that I haven't verified this is still the case in DVDSP version 4, but at the very least it used to be a problem, and is directly related to your issue.

Outside of that, even if that mostly resolves your issue, there's still the monitor profile to take into account during authoring time if you want to be -really- accurate.

Although your source image is in sRGB color space (Gamma 2.2) it is unlikely that your monitor is displaying this color space perfectly, meaning that you're designing in photoshop with your eye judging color that is does not accurately reflect the color that actually exists in the file (nor does it represent your output color space, for that matter). On top of that, sRGB to YUV/YCC color space conversion for Rec. 601 can cause some noticeable shifts in color, especially in linear color ramps.

Unless your monitors are running custom calibrated profiles (i.e. generated by a hardware calibration device such as a Spyder3 targetting Gamma 2.2), this is what's going on. 99 times out of 100, this is the case.

To prove the point, I brought your sample PSD file into After Effects and output it unmodified via an AJA Kona 3 to an external, calibrated monitor doing a hardware RGB to YUV conversion to Rec 601 at Gamma 2.2. The file displays relatively light-colored blues on the external monitor. I then opened the file on a random Windows Vista machine that is used for day-to-day work, and the blues looked darker and the ramp was more well-defined, which is probably what you wanted.

The point is: the external, calibrated monitor is showing the "real" color, where "real" in this case means "the color you'll get on a standard NTSC television at standard video gamma". All of the other devices are quite simply lying, and showing other colors.

Your existing DVDs that show the "gamma shift" verify this. But if you need further proof, simply output your PSD file directly to a calibrated monitor via the proper hardware to verify, and you'll see the problem firsthand. Then, adjust your file using the calibrated external monitor for critical color evaluation, and you'll find that your problem goes away and that your DVDs look normal.

Now let's say that you output the file to your calibrated monitor and everything looks right, and then DVDSP still eats your image anyway. In that case, the issue may very well be directly related to the article linked earlier in this message, which describes some real oddities in how DVDSP makes color space conversion decisions for still images.

Let us know if the issue is resolved by following the instructions as described at the link above.

Thanks,

-Matt

Jeremy,

I totally hear you and understand. In your case, it sounds like the issue is happening at build time when the PSD file is being converted from one color space to another in the background - and if what you say is accurate, the conversion is different from one OS to the next.

One way this could be explained if the color profile the PSD is being interpreted with during conversion is different between operating systems. For example, if DVDSP requests the color space conversion, and during this process the embedded profile from the PSD is disregarded, and an alternate RGB profile is used as the source color space for the conversion. If the profiles used during this process are more than slightly different between Tiger and Leopard, this would likely cause a gamma shift.

This is essentially what they're talking about in the link I posted above, at least in part. Again, we haven't run into this issue recently, so it's possible that this is no longer an issue in DVDSP4. However, that doesn't mean that the conversion -process- is different on an internal level between Tiger and Leopard, and could be generating different results.

If that's the case, you'd just need to find out what color space DVDSP expects to be converting from, and pre-convert your PSD into that color space (before DVDSP import), make adjustments so that it looks right, save it, then import it into DVDSP. Or, if that "bug" described at the link still exists, just change your display profile to sRGB and restart DVDSP4, and rebuild your menu. I rather hope that this isn't the case, because that's a pretty lame "bug" and they should really just let you choose your color profile conversion settings in DVDSP.

Interestingly, in the DVD Studio Pro 4 User Manual, on page 97, it specifically says that it supports PSDs created in 8 bit RGB mode in Photoshop, which should mean sRGB source color space is the accepted color space for incoming PSD images. If DVDSP4 is expecting that color space, and there's a gamma shift being introduced during build ONLY on some platforms, it definitely supports the idea that a color space other than sRGB is being used for the conversion, and perhaps the issue described in the above link still exists.

Again I'm just thinking out loud, completely speculating. I can't verify at the moment that this is accurate, but it might be a place to start looking.

Hi Jeremy,

I am working through some color shift problems myself.

I am curious, does your menu need to be a PSD, have you tried exporting a TIFF or a TGA of it.

do you get the same results?

I am currently trying to troubleshoot a problem I am having with a video timing out to a still menu that is identical to the last frame of the video. Everything works fine in DVDSP pre and post mux, but the problem is my authoring needs to be done on a PC. On the PC the still image is darker than the video.

In doing some tests I found that if I exported the still image from After Effects, there was no color shift on the PC but in DVDSP the still image was brighter than the video.

Makes me think gamma/ YUV to RGB translation is being handled differently in Adobe Apps.

I was thinking if you could export tiffs out of a FCS application there might be some worthwhile observations to be had.

Hey, Jeremy
I am having the exact same issues. Here is my thread. You wrote that you only solved it by going back to tiger. I am in Tiger and it still doesn't work.

http://forums.creativecow.net/thread/155/870990#870990