Are you seeing a colour shift in 720p and 1080p h.264 slideshow exports?

Question

When I export video from Lightroom 3 (or 3.2), I see that 720p and 1080p output can be very different in colour from other resolutions. It's as if my display profile were being ignored when playing back those particular resolutions.
Playback client: Apple's QuickTime Player X on Mac OS X 10.6.4. If I use VLC or QuickTime Player 7, colour is consistent across all export resolutions but is consistently wrong compared with the original photographs. (Again, it's as if the ICC display profile is being ignored.)
Display profile: my display is profiled and the profile is an ICC v4 file but I can reproduce the issue with some v2 profiles, as well.
AVC vs h.264
One oddity (that might be a peculiarity of QuickTime Player) is that when I view the 720p and 1080p movies, and ask for information about codecs (command-i), QuickTime Player X tells me that these two movies use AVC encoding. For all the other sizes, it says claims h.264. My understanding is that these two are effectively the same thing; on the other hand, it's curious that the two sizes showing different colour from the rest are identified differently. And QuickTime Player 7 claims AVC for all resolutions and always gets the colour wrong.
Is this just a QuickTime Player X bug? It gets colour right for all resolutions except 720p and 1080p, and provides a clue by saying the movie uses the AVC codec? Or is this an encoding issue?
Other sizes are fine
Exporting and playing back any other h.264 movie size, from 320 pixels right up to 960 pixels, provides perfectly acceptable colour in QuickTime Player X .There's a slight shift compared with the originals but nothing dramatic, and it's consistent across different sizes.
Any thoughts? Can you reproduce the problem?
I've tested this on a bunch of different Macs but they're all running 10.6.4.  Can anyone see this problem? Would anyone like to test on Windows and report back? The results seem to vary wildly depending on your display profile and how far it is from a canned profile so if you really want to be sure of seeing the differences, switch your display to "Wide Gamut RGB" for the playback test, then compare the 720p/1080p files with the rest, including the sRGB reference.
Would anyone like to tell me I'm being a complete idiot and overlooking something blindingly obvious? I won't be upset.
I was just about to post a note on the blog but thought I'd better post something here first. I'll probably ask readers to provide feedback here rather than on the site. I get the feeling that this issue won't be a big deal for most people.
Some examples for download
I have a zipped collection of single-image slideshows generated by Lightroom at each available resolution, together with a 960-pixel JPEG (sRGB) of that same image to act as a reference. You can download it here (5.9MB). For the moment, you'll probably have to ignore the URL that you see in the slideshows and in the Read Me file—it points to the blog post that I was preparing but which I haven't yet published. I'll do that next so anyone reading the blog will come here and post.
Thanks in advance, and apologies if I'm being dumb about something.
Update
I've added a 720x480 file that shows the same problem and updated the URLs shown in the movies and the Read Me file.
Message was edited by: Bahi Para

Answer 1

Bahi,
just to illustrate what mess this is, I tested for you on Leopard (10.5) and Snow Leopard (10.6) using the same wide gamut monitor. Here are two screenshots from that experiment. I converted the screenshots from my display profile to sRGB to show you what I see and scaled down 50% (this is a 30" behemoth). First Leopard.
You see they are all the same, but different from the sRGB export you provided. The GB sticker is too blue and the tint on the car is wrong. I doubt anybody but a photographer would notice though.
Next is Snow Leopard:
Here the 320 pixel, the 480 pixel and the 960 pixel image are different from the 720 pixel, the 720p and the 1080p ones. Neither is strictly correct as they are all different from the sRGB display. This is consistent with their being no real color management, just gamma corrections and color space transforms (video is usually not stored as RGB but as YUV, necessitating a transform for display). Annoying, but not much you can do about it.
Just doing some quick googling I came across many mentions of issues such as this. It clearly is just a big mess.