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CUE! Why, oh why?

post #1 of 103
12/11/06 at 1:29pm
Thread Starter 
There has been much discussion of CUE since the A2 was released and confirmed to have CUE during 1920x1080i/60 output/processing. Since it has become distracting to the A2 initial impression thread, I felt it appropriate to start a new thread on CUE to discuss this old issue with DVD playback. I'll introduce CUE and its history for the (many) people that will no doubt stumble on this thread and read thinking its a major issue.

CUE was discovered in 2001. Cue results from an improper processing of video chroma (color) information in the player's processing. It used to only apply to MPEG sources (DVD) but now it is affecting AVC, VC-1 and MPEG sources. Chroma resolution over 9mhz is effectively killed resulting in missing information and jaggie color (similar to bobbed resolution for color). Most people don't notice CUE or realize what they are seeing is infact an error. Ignorance is bliss in this regard but since 2001 videophiles have been seeking to curb this unncessary video malady.

Modern CUE issues in HD DVD

It basically an error that affects HD DVD playback only and is common on the BD side as well. The HD-A2 does not have CUE with its 720p output. The A1 has issues with both 720p and 1080i. The issue stems from the video processing and it appears that Broadcom chips are at fault. All Broadcom products on both BD players and HD DVD players exhibit CUE. The new A2 apparently does not use Broadcom and has CUE free 720p, but for some reason still fails at 1080i.

All this being said, many, even videophiles, won't care that much about CUE given its obscure nature and the fact it is often overshadowed by bigger issues such as audio dropouts or not displaying a true 1920x1080 (Samsung BD). Stacey Spears has done some evalutions on each BD and HD DVD player and their faults and strengths can be seen here.
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post #2 of 103
12/11/06 at 1:41pm
I used to have a DVD player with horrible CUE and it made watching any DVD scene with solid colors unwatchable. I've never seen anything like that on either HD DVD or Blu-ray to date. I have no doubt that the players may fail the CUE test patterns, but in practical application I have yet to experience any side effects of this on real movie content. And believe me, I'm as nit-picky a viewer as you'll ever meet.

If someone has a specific scene they feel demonstrates the CUE artifact, I'll certainly give it a closer look.
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post #3 of 103
12/11/06 at 1:43pm
Thread Starter 
Quote:
Originally Posted by Josh Z View Post

If someone has a specific scene they feel demonstrates the CUE artifact, I'll certainly give it a closer look.

I totally agree, I don't notice CUE one bit. Cars seems to be a title that draws some attention as it has solid colors and those colors are bright. Disney, namely Pixar titles, will undoubtedly get noticed more often. All in all I created this thread to educate people who don't know about CUE and take the discussion away from the A2 initial impressions thread.
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post #4 of 103
12/11/06 at 1:51pm
Yeah, considering the A1 supposedly had it as well and in this regard the A2 is supposed to look similar to the A1, I don't consider it a major issue cuz the A1 looked fine.

The big almost deal-killer issue for some at the moment with the A2 so far seems to be the inability of the player to consistently play some SD DVDs at all.
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post #5 of 103
12/11/06 at 2:10pm
No issue here either. I noticed this on SD DVD with ease, but have yet to notice this on any HD DVD. I wish it wasnt on test patters either, but im glad I do not see it in real world use.
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post #6 of 103
12/11/06 at 2:19pm
i don't even want to know what it looks like for fear of it bothering my future movie watching!
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post #7 of 103
12/11/06 at 2:39pm
I noticed something like this when I was at my local BB today. However it was with some of the BD players not an HD-DVD. They had a demo disc that including a scene from The Incredibles. The first thing I noticed about the picture was how jagged the characters costumes looked. Didn't look good.

No problems with my add-on yet tho.
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post #8 of 103
12/11/06 at 2:52pm
Quote:
Originally Posted by svsneo View Post

I noticed something like this when I was at my local BB today. However it was with some of the BD players not an HD-DVD. They had a demo disc that including a scene from The Incredibles. The first thing I noticed about the picture was how jagged the characters costumes looked. Didn't look good.

No problems with my add-on yet tho.

What do you mean by jagged? Are you sure you were seeing CUE? (Just wanna be sure, because not all jaggies are due to CUE of course.)

If indeed it is CUE, which model of player?
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post #9 of 103
12/11/06 at 3:10pm
Keep in mind they don't calibrate the TV's at BB at all. Those things make just about every source look bad.
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post #10 of 103
12/11/06 at 3:11pm
Allow me to copy&paste my posts regarding CUE from the A2 thread:

Now that it has been confirmed that the A2 still suffers from CUE with its HD 1080i/60 output it is per definitionem true that you NEVER EVER can restore the original frames encoded on the disc by going through a fancy (and totally unnecessary to begin with) IVTC process. PQ always suffers with 1080i/60 decoding and output. CUE is not just a slight announce - it is VERY serious. We are talking here about an enthusiast format that's most important selling point is its vast improvement in PQ/AQ. CUE is a antediluvian issue that slashes real world chroma resolution/definition. HD-DVD sure doesn't deserve this.

Question is: A1/XA1 has the same issue. And still Toshiba didn't change it for G2. I sincerely hope that they don't use "CUE free" as one upgrade argument for the upcoming XA2... And be aware: This is a defect present in the decoder - if XA2 still uses the same 1080i decoding process and "deinterlaces"/IVTC the 1080i/60 stream for 1080p/60 output (which is confirmed information) it will also suffer from CUE! So only REAL 1080P decoding will make this problem go away (or they get their 1080i chroma upsampling to work properly).

NATIVE 1080P/24 DECODING AND OUTPUT IS THE HOLY GRAIL. Listen to Joe Kane for once...
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post #11 of 103
12/11/06 at 3:12pm
btw... people keep wondering how exactly the CUE influences PQ.

Stacy Spears commented on that in the PS3 thread (the PS3 doesn't suffer from CUE):

Quote:
Originally Posted by sspears View Post

The chroma bug pretty much kills chroma resolution over 9 Mhz, or Nquist / 2. This translates into fine chroma detail. If you compare Corpse Bride on the PS3 to the Samsung or Toshiba, you will see a perceived increase in saturation on the PS3.

Let me explain it in laymen terms... just imagine resolution gets cut by half and is interpolated ("bobbed") back then - that's what some VERY bad HDTV devices do instead of proper IVTC. They take the 1080i/60 stream, throw away half the resolution (every other field) and just interpolate the resulting 1920*540p stream up to 1920*1080p. BUT half the REAL resolution/detail is gone forever.

Now imagine a simular thing happens with just the chroma channel of the video stream - welcome to the wonderful world of CUE.
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post #12 of 103
12/11/06 at 3:13pm
Quote:
Originally Posted by lymzy View Post

So in what format should we output the 1080i60 video source? Nothing fancy about the IVTC, it is a simple lossless process if done right. In fact many master might be in the 1080i60 form and needs to be IVTC before encoding. Don't quote Joe again and again. Report back if you see the difference with your own eye.

I can assure you that I spot the defects caused by CUE very easily - and I can hardly stand them. I continue to quote "famous" persons like Joe and Stacy and Kris because my user ID is "TheLion" - which is a "name" not known, respected, trusted and believed by many So MY words obviously don't hold much weight around here (and at my own house for that matter , greetings to my little darling).

But looking at my post history you will see me pushing for NATIVE 1080p/24 decoding and output well before the quoted interview with Joe Kane was published (actually he was answering a question which I submitted for this interview...).
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post #13 of 103
12/11/06 at 3:14pm
Quote:
Originally Posted by amirm View Post

Not saying CUE is good or anything. But that using an example of downsampling overall video resolution to show that less than ideal chorma interpolation is the same thing, really, really exaggerates the severity of the situation here.

Depends on the content. With some colorful animation titles and stuff like Moulin Rouge EVERYBODY can clearly spot the difference between a player with CUE and one without (especially in red).
Amir, there are even cases where CUE has a more significant and severe impact on perceived PQ than (luma channel) interpolation - eg. look at a CU Siemensstern test pattern.

But I certainly agree with you that generally we perceive resolution and a sense of detail primarily through luma information.
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post #14 of 103
12/11/06 at 3:15pm
Quote:
Originally Posted by lymzy View Post

My post said if done right. I called it BS that you could tell the difference between so called native 24p output from a correctly IVTCed 24p output.

If the decoder introduces CUE no IVTC process in the world will help you. And even if it doesn't IVTC isn't half as straight forward as logic suggests - just about any IVTC/deinterlacing chip (even state of the art ones like Gennum VXP and SO Realta) " falls out of film mode" (read "correct" IVTC "weave") and just bobs/=interpolates the image in some instances during very though scenes.

Even $4000.- dedicated video processors "don't do it right" all the time. Don't expect anything else to accomplish this task "faultlessly".
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post #15 of 103
12/11/06 at 3:16pm
Quote:
Originally Posted by DTV TiVo Dealer View Post

I am sorry to disagree. I have a very good video eye and can rarely see CUE and very slightly when I do. CUE varies in degradation and the A2 has very little CUE and I can only see it when the resolution is set to 720p.

I agree when viewing video on a 1080p 24 Hz display with source material and a device that supports native 1080p and all devices in the circuit also support 1080p 24 fps you will get the very best video, but less than 1% of all HD displays can support 1080p 24. So by making these posts we are doing nothing but confusing the members and guests who read this forum. I understand this is an advanced forum, but I would bet that if we took a pole of the displays used we would still come up with less than 5% of the users with true native 1080p 24 displays.

Please also consider that all HDTV have scalers built-in to convert any signal to the displays best resolution and when you combine a HD DVD player with a external scaler you get as good an image as possible, just as good as any player that can output 1080p 24.

Most importantly remember every HD DVD player interlaces the HD DVD disc's native 1080p 24 to 1080i 60 and ALL of the (data) information is included with the output, it's just interlaced to match the majority of HDTV capabilities best and most HDTV handle this signal excellently, especially those very few 1080p 24 displays that easily reassemble all of the interlaced data back to 1080p progressive lines.

-Robert

Robert,

I'm sorry but I disagree. Read my posts above.

PLEASE, let's not downplay a issue like CUE. This is serious. And it has been for years now. It is not something just the golden eyes like Kris and Stacey in their fancy labs are able to spot. Depending on the content CUE artifacts are jumping right at you watching a movie on a large and decent FP setup. HD resolution sure lessens the obvious defects compared to DVD. But as always : the better and more revealing ones setup the more severe a issue like CUE gets. And as always: ignorance is a bliss.

And Robert,

the point is that if you introduce CUE during decoding chroma detail/resolution/information is lost forever (and with our 4:2:0 sources we don't have much of this to begin with) and the result is that the IVTC process can per definitionem not restore the original frame stored on the disc. AND CUE is a by-product of 1080i based decoding - decode in 1080p/24 and there cannot be CUE. Sometimes the easiest and most straight forward things are the best. And if you have your native 1080p/24 stream after the decoding stage you can still convert it (-> infamous 3:2 pulldown) to 1080i/60 for mainstream output. THAT'S the way it SHOULD be done.
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post #16 of 103
12/11/06 at 3:20pm
What I saw look liked the toy in the top right except it was on the red colors of the characters costumes in The Incredibles.



I know that not all jaggies are from CUE but what's shown here looks nearly indenticle to what I saw. It was the Samsung player playing on a Sony XBR2. I watched a couple more clips and it looked pretty good except for this one scene. I know that not many of the players on the floor are set up anywhere near to what they should be.

Just trying to explain what I saw.
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post #17 of 103
12/11/06 at 3:34pm
Quote:
Originally Posted by TheLion View Post

Robert,

I'm sorry but I disagree. Read my posts above.

PLEASE, let's not downplay a issue like CUE. This is serious. And it has been for years now. It is not something just the golden eyes like Kris and Stacey in their fancy labs are able to spot. Depending on the content CUE artifacts are jumping right at you watching a movie on a large and decent FP setup. HD resolution sure lessens the obvious defects compared to DVD. But as always : the better and more revealing ones setup the more severe a issue like CUE gets. And as always: ignorance is a bliss.

And Robert,

the point is that if you introduce CUE during decoding chroma detail/resolution/information is lost forever (and with our 4:2:0 sources we don't have much of this to begin with) and the result is that the IVTC process can per definitionem not restore the original frame stored on the disc. AND CUE is a by-product of 1080i based decoding - decode in 1080p/24 and there cannot be CUE. Sometimes the easiest and most straight forward things are the best. And if you have your native 1080p/24 stream after the decoding stage you can still convert it (-> infamous 3:2 pulldown) to 1080i/60 for mainstream output. THAT'S the way it SHOULD be done.


I have a question here then. I have the HP md6580n 1080p HDTV which accepts native 1080p/24. I know now that 2:3 pulldown is applied to this to output 1080p/60. Would I get any cue given this process with a player like the Sony blu ray or possibly (and purportedly) the XA2 when it comes out given it (they?) output at 1080p/24.
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post #18 of 103
12/11/06 at 3:43pm
Quote:
Originally Posted by HPforMe View Post

I have a question here then. I have the HP md6580n 1080p HDTV which accepts native 1080p/24. I know now that 2:3 pulldown is applied to this to output 1080p/60. Would I get any cue given this process with a player like the Sony blu ray or possibly (and purportedly) the XA2 when it comes out given it (they?) output at 1080p/24.

No, there wouldn't be any CUE as long as the player natively decodes in/to 1080p/24 (like the Sony/Pioneer/PS3/any HTPC does).

This is because you never enter the "interlaced domain" in your picture chain. 1080p/24 content -> decoding -> output -> HP's internal progressiv (!!!) frame rate conversion to 1080p/60 -> display

Hope that helps.
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post #19 of 103
12/11/06 at 3:47pm
I've seen input on the 1st gen and 2nd gen HD-DVD players as well as BD players describing this effect, but how do the XBOX 360 add-on players stack up? Curious if they have CUE as well.
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post #20 of 103
12/11/06 at 3:47pm
And let me cut and paste what I put into that thread:

"Robert told me over PM that the CUE issue IS fixable with a firmware update and WILL be fixed in a future firmware update."

Robert, could you confirm this publicly? If that's the case, this thread is a non-starter.

Thanks,
Chris
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post #21 of 103
12/11/06 at 3:47pm
Quote:
Originally Posted by TheLion View Post

No, there wouldn't be any CUE as long as the player natively decodes in/to 1080p/24 (like the Sony/Pioneer/PS3/any HTPC does).

This is because you never enter the "interlaced domain" in your picture chain. 1080p/24 content -> decoding -> output -> HP's internal progressiv (!!!) frame rate conversion to 1080p/60 -> display

Hope that helps.

The PS3 outputs 1080p/24fps? I wasn't aware of that. Is that why it does not have the CUE bug?

Also, is the A-2 CUE bug for both 720p and 1080i or only 1080i?

Thanks
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post #22 of 103
12/11/06 at 3:57pm
Quote:
Originally Posted by plazman View Post

The PS3 outputs 1080p/24fps? I wasn't aware of that. Is that why it does not have the CUE bug?

Also, is the A-2 CUE bug for both 720p and 1080i or only 1080i?

Thanks

The PS3 does output 1080p/60 by decoding in/to 1080p/24 and then does a progressive frame rate conversion to 1080p/60. Stacey confirmed that. There cannot be CUE in an all progressive process chain. (btw PS3 native 1080p/24 output is confirmed to be part of an upcoming firmware update)

CUE is for A2 1080i output as well as for A1 and AX1. Samsung, Philips and Panasonic on the blue side of things.
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post #23 of 103
12/11/06 at 4:45pm
Does this only happen with content that is stored interlaced on the disk?

If it happens to content that is stored progressively, what is happening?

Sorry, Im just confused as to how the bug described at http://www.hometheaterhifi.com/volum...ug-4-2001.html applies to content that is stored progressively to begin with.
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post #24 of 103
12/11/06 at 5:18pm
Quote:
Originally Posted by abr27440 View Post

Does this only happen with content that is stored interlaced on the disk?

If it happens to content that is stored progressively, what is happening?

Sorry, Im just confused as to how the bug described at http://www.hometheaterhifi.com/volum...ug-4-2001.html applies to content that is stored progressively to begin with.

It happens when content is decoded as/into an 1080i/60 stream. Basically HD-DVD players treat the 1080p/24 content on disc as it was an interlaced stream.
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post #25 of 103
12/11/06 at 5:28pm
Quote:
Originally Posted by TheLion View Post

No, there wouldn't be any CUE as long as the player natively decodes in/to 1080p/24 (like the Sony/Pioneer/PS3/any HTPC does).

This is because you never enter the "interlaced domain" in your picture chain. 1080p/24 content -> decoding -> output -> HP's internal progressiv (!!!) frame rate conversion to 1080p/60 -> display

Hope that helps.

Hey thanks. That sounds great. Definitely looking into the Sony/Pioneer/XA2 then. I must say though, that the A1 PQ has been fantastic on my set. So any further improvement is not something I'll hold back on.
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post #26 of 103
12/11/06 at 7:10pm
Quote:
Originally Posted by TheLion View Post

PLEASE, let's not downplay a issue like CUE. This is serious. And it has been for years now. It is not something just the golden eyes like Kris and Stacey in their fancy labs are able to spot.

You should be commended for bringing the significance of this problem to the attention of people no matter what player of what format that it exists in.

Good job.

B.T.W.
It is not necessary for you to quote Joe K. for the credibility of your views on this forum.
I thinks you have paid your dues(independently!) by now on that account.
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post #27 of 103
12/11/06 at 8:53pm
Quote:
Originally Posted by Penton-Man View Post

You should be commended for bringing the significance of this problem to the attention of people no matter what player of what format that it exists in.

Good job.

B.T.W.
It is not necessary for you to quote Joe K. for the credibility of your views on this forum.
I thinks you have paid your dues(independently!) by now on that account.

Thank you for your kind words, Penton-Man! I appreciate it.
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post #28 of 103
12/11/06 at 9:29pm
Quote:


PLEASE, let's not downplay a issue like CUE. This is serious. And it has been for years now. It is not something just the golden eyes like Kris and Stacey in their fancy labs are able to spot.

I will downplay it. I honestly don't think it's that serious in the greater scheme of things. I admittedly haven't seen the A2 in action, but it's anything like the A1 like people say, then in reality very, very few will care. I certainly don't care (much).

I agree it is an issue, but as far as I'm concerned, it's like 5th on the list that needs to be addressed. There are MUCH more pressing issues that need to be addressed first.
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post #29 of 103
12/11/06 at 10:09pm
Quote:
Originally Posted by BuGsArEtAsTy View Post

as far as I'm concerned, it's like 5th on the list that needs to be addressed. There are MUCH more pressing issues that need to be addressed first.


May I ask what the other 4 issues are ?
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post #30 of 103
12/11/06 at 10:36pm
Quote:
Originally Posted by Forceflow View Post

I totally agree, I don't notice CUE one bit. Cars seems to be a title that draws some attention as it has solid colors and those colors are bright. Disney, namely Pixar titles, will undoubtedly get noticed more often. All in all I created this thread to educate people who don't know about CUE and take the discussion away from the A2 initial impressions thread.


omfg wait a freaking second

wich blu ray player do they sell at walmart?

i renember seing one playing cars. and i was telling my girl about the picture problem and come to think about it, it was cue. but it was VERY noticible. on a 42" screen

on my 60" screen i notice it to on some shots with my a1 but when im seating like 2 feet from teh screen


oh yah and i was about 2 feet from the 42" blu ray setup but it had about twice the cue. very noticble without looking for it. and wiht hd-a1 its hardly noticible
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