DVE HD or Avia, which one is right?

Well, if you calibrate HD input using HD DVD player, there is ONLY DVE HD... If you are comparing SD side of DVE with Avia, there are documented discrepancies between them (I am assuming that SD side, which I didn't check, is pretty much equivalent of "old" SD version), specifically when calibrating gamma (there are treads here about the problem), with consensus being that Avia patterns are either mislabeled or labeled in very confusing way, requiring extra calculations to render proper results.


Kris

Yes, Avia's "IRE" labels are mislabeled and confusing. Furthermore Avia has a chroma error that results in a magenta push. This magenta bias is unnoticeable at higher IREs but becomes quite significant at very low IREs. For SD grayscale calibration, the GetGray disk is much better.

DVE HD is a completely different format, so it's not really comparable since it's a different playback chain. The regular SD DVD of DVE and AVIA are both authored correctly as far as the levels go, although the greyscale patterns on Avia are not completely accurate.

I believe Avia's grayscale is intentionally incorrect and meant to be used without tools. Setting your grayscale by eye always leads to high temp results, and Avia's "imperfection" helps nullify this.


But, yes, definitely not for use with tools.



Quote:
Originally Posted by fugiot /forum/post/0


I believe Avia's grayscale is intentionally incorrect and meant to be used without tools. Setting your grayscale by eye always leads to high temp results, and Avia's "imperfection" helps nullify this.


But, yes, definitely not for use with tools.

Click to expand...

Huh? Where did you get that idea from? This is a new urban legend.

Purely from my own experience. I compared my results between Avia and some neutral grey patterns displayed via HD-JPEG. Avia's patterns gave me a much lower temp. I don't have a colorimeter, but it's obviously much closer to D65 than trying to use a true neutral pattern. I also tried Avia's patterns with the color turned down to zero, also resulting in a very blue grayscale.

Well you can think whatever you want, but saying that Avia: "is intentionally incorrect and meant to be used without tools" attributes intent to Guy Kuo's work that is not based on any evidence, and is simply wrong. Guy explicitly describes the grey patterns in consumer Avia as having color "contaminant" and being a "problem" attributable to the MPEG2 encoder used at that time. The Avia discs that follow avoid this problem(including the S&V disc).


Further, the fact that the error is ridiculously minor, and is difficult to measure with colorimetry equipment let alone the naked eye, seems to indicate that there are other much more significant issues going on with your methodology or system if you are actually seeing visible changes.

Hm, don't know what to tell you, but I definitely get better results from it.



Quote:
Originally Posted by fugiot /forum/post/0


Hm, don't know what to tell you, but I definitely get better results from it.

Click to expand...

Well, you're free to think that, but re-reading your post you say that you don't have any colorimetry equipment, so quite frankly, you don't have any way of establishing that there is any difference or that you are getting more accurate results. And unless the other patterns you are using are grossly wrong, they should look exactly the same to you as the Avia patterns.


In this image:
http://archive.avsforum.com/avs-vb/a...211&fullpage=1


One half is the Avia greyscale pattern, in the other half is a completely accurate pattern. Can you tell which is which by eye?

Well, I don't know how accurate my PC monitor's grayscale is, but the bottom half looks most similar to Avia on my TV. Either way, I can say that I definitely get different results with Avia, but I also have a very discerning eye.

That's possible, but it certainly doesn't lead to what you are seeing. If indeed you were capable of seeing the slight difference in the Avia patterns (we're talking on the order of one or two levels here), it would shift your grayscale towards blue(higher temp) compared with a neutral pattern, which is the exact opposite of what you report. So either way, it neither makes sense, nor is it at all attributable to Avia.