Interpreting 709 vs 601 Color Bar Test Patterns - AVS Forum
Forum Jump: 
 
Thread Tools
Old 03-02-2012, 07:01 AM - Thread Starter
Member
 
Plasma54321's Avatar
 
Join Date: Sep 2008
Location: Florida
Posts: 164
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
This is a general question regarding the various 709/601 color bar comparison test patterns on many calibration discs.

I know that the color spaces are different for each standard (SD = 601, HS = 709) and the correct one I should be using for HD material and displays, but how do you interpret the pattern with your eyeballs? I'm assuming it is just a quick visual check.

More specifically, if I have a Blu-ray player and HD TV what should I be looking for? What is right? What is wrong? How do you know? In particular if you use the Belle Nuit HD Test Chart Pattern at http://www.belle-nuit.com/testchart.html

How do you use it? Then if you have a DVD (SD) and upscale to HD are the observations the same?
Plasma54321 is offline  
Sponsored Links
Advertisement
 
Old 03-02-2012, 07:29 AM
AVS Special Member
 
airscapes's Avatar
 
Join Date: Dec 2008
Location: Philadelphia
Posts: 4,733
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 91 Post(s)
Liked: 130
Quote:
Originally Posted by Plasma54321 View Post

This is a general question regarding the various 709/601 color bar comparison test patterns on many calibration discs.

I know that the color spaces are different for each standard (SD = 601, HS = 709) and the correct one I should be using for HD material and displays, but how do you interpret the pattern with your eyeballs? I'm assuming it is just a quick visual check.

More specifically, if I have a Blu-ray player and HD TV what should I be looking for? What is right? What is wrong? How do you know? In particular if you use the Belle Nuit HD Test Chart Pattern at http://www.belle-nuit.com/testchart.html

How do you use it? Then if you have a DVD (SD) and upscale to HD are the observations the same?

You need a blue filter that goes with the disk or a blue only mode within the TV. There are blue and white bars and blue and magenta I think.. the AVS disk has them labeled with the words Color and Tint.
When the pattern is up and flashing (avs flashes to make it easier to see) and you look at it through the proper color blue filter, the ides is that the white and blue will be the same color. What you are trying to do is match the luminance of blue with that of white by moving the color control.
Then look at the tint bars and use the tint control to make them the same.

If the set has a blue only mode, or blue filter mode in the menu, or it is a crt and you can turn off the red and green guns, you do not need the plastic filters. You put up the pattern, turn on the internal blue only and look at the pattern with out the aid of a hand held filter. Make you adjustments and you are done.

The thing about this in the digital world using HDMI, those controls should not even be there! They are there to keep joe consumer happy. A programmer had to wire the code to alter the values. I have a DLP projector from 2005, no color or tint for HDMI, those were analog controls. You would be better off just leaving them at the factory default assuming there is a centered default.
Don't get to hung up on color and tint, brightness, contrast, backlight, aspect ration (pixel mapping 1:1) and shaprness are more important to worry about.

I say this because like you, I had the same question not that long ago and have been asking these very same questions of every expert I have encountered..

Hum.. after rereading your post I think you may be asking about picking color space not setting color?
If you are talking about 4:4:2, 4:4:4: RGB etc.. I am at a loss as well at this time.. I ordered the SM bench mark disk and here is a web page that talks about the patterns.
http://www.spearsandmunsil.com/artic...olorspace.html
airscapes is online now  
Old 03-02-2012, 08:17 AM - Thread Starter
Member
 
Plasma54321's Avatar
 
Join Date: Sep 2008
Location: Florida
Posts: 164
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Quote:
Originally Posted by airscapes View Post

Hum.. after rereading your post I think you may be asking about picking color space not setting color?
If you are talking about 4:4:2, 4:4:4: RGB etc.. I am at a loss as well at this time.. I ordered the SM bench mark disk and here is a web page that talks about the patterns.
http://www.spearsandmunsil.com/artic...olorspace.html

Yes, this is not about setting the color level - nor tint. Also, this is not about selecting color decoding (unless this is some method to correct for a wrong color standard - SD 601 vs HD 709).

I am interested in the portion of the Belle Nuit Test Pattern (ABOVE the embedded chart Title) that shows Black/Red/Green/Blue stripes with 601 and 709 labels. The question is with a particular video setup what do the different blocks mean and how should they look? What is correct? How do you tell visually?
Plasma54321 is offline  
Old 03-02-2012, 08:56 AM
AVS Special Member
 
JohnAd's Avatar
 
Join Date: Jun 2000
Location: London
Posts: 1,725
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 16
Quote:
Originally Posted by Plasma54321 View Post

I know that the color spaces are different for each standard (SD = 601, HS = 709) and the correct one I should be using for HD material and displays, but how do you interpret the pattern with your eyeballs? I'm assuming it is just a quick visual check.

More specifically, if I have a Blu-ray player and HD TV what should I be looking for? What is right? What is wrong? How do you know? In particular if you use the Belle Nuit HD Test Chart Pattern at http://www.belle-nuit.com/testchart.html

How do you use it? Then if you have a DVD (SD) and upscale to HD are the observations the same?

I believe that you turn saturation to 0 and the 3 bars with the relevant standard should all be the same brightness.

For DVD it should go from YCrCb on disk to RGB with 601 and then back to 709 if you scale and then use a YCrCb wire format. If this is done correctly with the dvd version the 601 pattern will be equal brightness. On the HD one the 709 should be equal brightness.

John

My Company - Upsilon Software
Free Projects - DScaler & hcfr fork
JohnAd is offline  
Old 03-02-2012, 09:21 AM
AVS Special Member
 
airscapes's Avatar
 
Join Date: Dec 2008
Location: Philadelphia
Posts: 4,733
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 91 Post(s)
Liked: 130
Quote:
Originally Posted by Plasma54321 View Post

Yes, this is not about setting the color level - nor tint. Also, this is not about selecting color decoding (unless this is some method to correct for a wrong color standard - SD 601 vs HD 709).

Sorry, should have realized when I saw the pattern name it was something far more advance..
airscapes is online now  
Old 03-02-2012, 03:03 PM - Thread Starter
Member
 
Plasma54321's Avatar
 
Join Date: Sep 2008
Location: Florida
Posts: 164
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Quote:
Originally Posted by JohnAd View Post

... turn (color) saturation to 0 and the 3 bars with the relevant standard should all be the same brightness.

For DVD it should go from YCrCb on disk to RGB with 601 and then back to 709 if you scale and then use a YCrCb wire format. If this is done correctly with the dvd version the 601 pattern will be equal brightness. On the HD one the 709 should be equal brightness.

I think I get the first part. You do not look at the color in the test pattern. You must set the COLOR Control = 0 to make it Black and White then just make sure the appropriate standard stripes blend together - same luminance.

The second part I'm not quite sure I get it.

"DVD it should go from YCrCb on disk to RGB with 601 and then back to 709 if you scale and then use a YCrCb wire format."

YCrCb wire format <= What is this term mean?

This is the case of a SD DVD being either played with or without upscaling.

1) If not upscaled (480i or 480P output) you should match 601 stripes (as described above).

2) If SD DVD and upscaled to 720P, 1080P or 1080i for display it should be the 709 standard. Right?
Plasma54321 is offline  
Old 03-03-2012, 07:20 AM
AVS Special Member
 
JohnAd's Avatar
 
Join Date: Jun 2000
Location: London
Posts: 1,725
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 16
Quote:
Originally Posted by Plasma54321 View Post

YCrCb wire format <= What is this term mean?

What goes down the cable between the dvd player and the tv. This will be either RGB or YCrCb at a given resolution.

Quote:
Originally Posted by Plasma54321 View Post

This is the case of a SD DVD being either played with or without upscaling.

1) If not upscaled (480i or 480P output) you should match 601 stripes (as described above).

2) If SD DVD and upscaled to 720P, 1080P or 1080i for display it should be the 709 standard. Right?

In both cases the correct decoding will be that the 601 should be the same brighness, what should happen in the second case if you're sending upscaled images from the player at hi-res is that the image gets decoded at 601, scaled, encoded back before sending to the tv at 709 and then decoded at the tv in 709. The 2 stages at 709 should cancel each other out leaving you with a correctly decoded 601 pattern.

My Company - Upsilon Software
Free Projects - DScaler & hcfr fork
JohnAd is offline  
Old 03-03-2012, 10:13 AM
AVS Special Member
 
alluringreality's Avatar
 
Join Date: Jul 2006
Posts: 3,203
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 46 Post(s)
Liked: 40
Quote:
Originally Posted by JohnAd View Post

I believe that you turn saturation to 0 and the 3 bars with the relevant standard should all be the same brightness.

This does not work on my TV.
alluringreality is offline  
Old 03-03-2012, 10:18 AM
AVS Special Member
 
alluringreality's Avatar
 
Join Date: Jul 2006
Posts: 3,203
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 46 Post(s)
Liked: 40
Quote:
Originally Posted by Plasma54321 View Post

how do you interpret the pattern with your eyeballs? I'm assuming it is just a quick visual check.

An incorrect decode mainly looks like a change in brightness of the colors. Page 55 from http://www.videoessentials.com/dvehd...gram_final.pdf is the Digital Video Essentials description. I agree with "When one or the other color bar set is being properly decoded the largest difference between the two will be seen in the green channel, followed by red and finally the blue." Personally I just use measurements, and I find actually trying to describe which is correct without a reference as being a bit difficult.
alluringreality is offline  
Old 03-03-2012, 10:46 AM
AVS Special Member
 
JohnAd's Avatar
 
Join Date: Jun 2000
Location: London
Posts: 1,725
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 16
Quote:
Originally Posted by alluringreality View Post

This does not work on my TV.

Yep, I think my memory was off, I just tried out the patterns and for me the squinting trick works for comparing brightness.

Just played around a bit oin MPC-HC with the GetGray NTSC disc and if you go from right to wrong decoder matrix the green basically drops out from the 601 pattern only the 709 one doesn't really change that much.

John

My Company - Upsilon Software
Free Projects - DScaler & hcfr fork
JohnAd is offline  
 
Thread Tools


Forum Jump: 

Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off