Author Topic: Wrong Colour Space Conversion (WD Confirm FIXED and in next firmware, no ETA)  (Read 21937 times)

November 24, 2009, 09:10:42 AM
Read 21937 times

coastline

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PLEASE SEE PAGE 3 for Sigma Designs confirmation of issue and Western Digital's responses!!

Issue:  WDTV along with some other devices using Sigma chipsets (eg popcorn hour) incorrectly use BT.601 (not BT.709) as the default Colour space Matrix to decode unflagged HD material.  Most Bluray content is unflagged.  (Hokeysmoke (thanks) gives a better description on page 3, along with more detailed posts on his own threads which you will find links to through this thread)

Sigma have acknowledged the issue - and informed their customers (the manufacturers) of methods to resolve the issue.
Syabas already have Firmware in beta testing for the c-200 and I believe are also working on firmware upgrades for the A-100, and A-110.
Western Digital support today (2/2/10) informed me that it has now been recognised as a bug and is now entered on list of problems to fix.  NO ETA on firmware update for this but according to them it is a "TRIVIAL" change so shouldn't take too long.

 :) :) :) 19/2 WD confirm that this BUG has been fixed and will be available in the next firmware update, no ETA on when that will be released though ;D ;D ;D

(I added this section so you can get an idea of the issue from the start of the thread - I am not a video decoding expert and any information I have put forward apart from my own observations has been gleaned from others.  I apologise if the accuracy of any of that information suffers in my paraphrasing but I have attempted where possible to include links to the various threads this information was obtained from)
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Hi all,

Had my WDTV Live for a couple of weeks.  Generally very happy with it apart from the issues others have reported that will no doubt get fixed in time.

However I have not heard much about colour issues and I seem to have quite a major one.

Bluray MKV's (ripped with Makemkv) seem to have really overblown reds.  Skin tones make everyone look like they've been at the gin.

I've tried three separate displays.  My main is an infocus X9 PJ, but have also tried on a friends 50" G10 Panasonic and my old Sagem Rear Pro.  Whilst there were differences in the colour callibration of all three displays, they all show overblown reds coming from the WDTV Live.

Now non of my displays have had any professional calibration but I have used DVE to the best of my ability on the two that I own and have never had this problem with other sources.

I have noticed it mostly on the Highlander Bluray and also Angels and Demons (have not ripped a huge number of Discs yet so am limited to what I have to play with).  Highlander is really bad though.  I don't seem to have the same issue with any DVD rips so far though.

I have a panasonic BD35 player which was used to calibrate my X9 (with DVE HD Basics) and the colours on Highlander are fine.  Switch to the WDTV Live and everyone's hit the gin again.

I came across a thread somewhere about the WDTV 1 having issues with colour decoding and someone posting that it hadn't been fixed- something about the boxes not using BT709 to decode HD material.  All DD to me and not sure what issues it would cause but thought someone on here might know more.

I know sometimes different sources can need separate calibration settings but the difference between the two sources is huge!

I have HDMI res on the WDTV Live set to auto and Colour also set to auto (anyone tell me what the colour settings should be set to).  I have tried altering colour setting to see if there is any difference but nothing of note.  Also tried 8 bit and 12 bit deep colour mode.

I'm hoping I have a duff box because otherwise this is the perfect device for me.

Any advice would be greatly appreciated, Thanks in advance.

Tony




« Last Edit: February 19, 2010, 02:21:21 AM by coastline »

November 26, 2009, 09:55:38 AM
Reply #1

coastline

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November 26, 2009, 01:19:58 PM
Reply #2

jayallan

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Coastline,

I am not experiencing this, and I have a fully calibrated system.  However, mine is not a fair test as my video is going through my DVDO which is processing it, and could be correcting what you see.  Lets see what other have to say.
WDTV LIVE with current official FW > HDMI > DVDO > Sony CRT Projector 150" 16/9 screen.  Toslink audio to Yamaha DTS receiver. No Network set up yet.

November 26, 2009, 01:48:16 PM
Reply #3

coastline

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Thanks Jayallan,

Apologies for Bumping my own thread.  I know it's not great forum etiquette but this issue is spoiling a great device for me.

I have looked further into the other post about colour on the WDTV1 and downloaded a test pattern which does show that the WDTV does not decode colour correctly if HD files are not tagged as BT709.  The difference does look like the colour issues I am having but I could just be reaching.

I really want this device to work for me - been waiting a long while for an affordable media player like this.

I am hoping I just have a dud box and can replace it but don't want to send it back and look like a muppet if it's a general issue.

Once again thanks for the reply.

November 26, 2009, 01:50:37 PM
Reply #4

coastline

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November 27, 2009, 02:15:58 PM
Reply #5

jayallan

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I would be interested to see who else is experiencing this problem.  Try another box if you are able!

WDTV LIVE with current official FW > HDMI > DVDO > Sony CRT Projector 150" 16/9 screen.  Toslink audio to Yamaha DTS receiver. No Network set up yet.

December 01, 2009, 05:48:18 AM
Reply #6

coastline

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Hi All,

From the sounds of the two threads listed below (If I am reading and understanding them correctly! ???) I think my problem might be incorrect colour space conversion where HD video is decoded using BT.601 (standard definition) not BT.709 (HD)

http://www.networkedmediatank.com/showthread.php?tid=20381&page=1&highlight=601+701
http://wdtvforum.com/main/index.php?topic=683.0

Quote
Bug Description: ITU-R BT.601 color space conversion matrix is being used for high definition content, whereas the correct conversion should be using the matrix defined in ITU-R BT.709. This leads to colors that have too bright greens and too dim reds and skin tones shift hue toward magenta. ITU-R BT.601 is correct only for standard definition content such as DVD sourced material. Blu-ray, HD-DVD, and off-air HDTV should all use BT.709.
  This from HOKEYSMOKE on an NMT forum.

I guess my Reds aren't overblown just not the right hue.

Hokeysmoke if your listening I'd be interested in hearing if you have had any official confirmation of this bug and is anyone anywhere doing anything about it.

Supposedly if HD files are flagged with the correct colour space then the WDTV will decode correctly but it's default behaviour if no colour flagging is present is to use Standard definition BT.601. decoding.

I would have thought that the simplest solution to this was some kind of file editor that could add the required flagging where necessary - but that is probably too simplistic.
 

December 01, 2009, 08:41:41 AM
Reply #7

Hokeysmoke

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The only information I have is from the NMT forums and the new C200 which uses the same chip as the WDTV Live.  The C200 as well as the WDTV both exhibit the same problem.  Therefore it's likely that the WDTV LIve also has the problem because it is associated with the Sigma Designs SDK and not specific hardware implementations.

Regarding calibration, this issue cannot be calibrated out because picture information is lost in the brightest portion of the image.  This loss occurs when the Sigma Designs chip converts HDTV content to RGB using the BT.601 color space conversion matrix, rather than the correct BT.709 matrix.  The green channel actually ends up about 40% too bright, although it's hard to see in content due to the fact that white is the correct brightness.  You need fully saturated green to see the full impact.

If the following test clip changes color during the clip, then the player has the problem.  Note that the opposite is not necessarily true.  If it does not change color it still might have the problem as well.
http://www.cypheros.de/files/Testbild_colour_description_alternating_120sec.ts

Regarding adding flags to content, I've found no one who can do it.  Apparently the flags are embedded continuously throughout the file (so that if the color space changes the player can switch on the fly).

As I've stated elsewhere, the fact that files are not flagged as BT.709 does not make the files wrong or improper.  At least 2/3rds of the HD files that have been analyzed have no flag whatsoever.  These include off-air, HD-DVD, and Blu-ray files.  Nearly all Disney titles, for instance, have no flags.

« Last Edit: December 01, 2009, 08:51:23 AM by Hokeysmoke »

December 01, 2009, 01:00:40 PM
Reply #8

coastline

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Many Thanks Hokeysmoke,

I'm going to lodge a support ticket with WD and see what they have to say about it.

I had already tried the clip from your other threads on the issue and it does indeed change colour.  The colour differences also approximate the issues I am having.  I noticed it originally in Skin tones but going back to Highlander which is the Movie I had most issue with the Grass in one of the clips is a little radioactive too.

This issue was really noticeable to me so I'm surprised that it hasn't made more of an impact on the forums.  I guess at the price point of these devices you don't expect perfect results - but if it wasn't for this bug it would be pretty perfect for me.

I'll keep you posted how I get on.


December 03, 2009, 05:06:11 AM
Reply #9

rtga

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I can verify that my WDTV Live exhibits this issue too.  I checked it with the test clip - I honestly didn't notice any major issues on actual HD-DVD sourced material, but I haven't taken the time to calibrate my set and for the most part I'm still in the experimental stage with my encoding/remuxing process, so I haven't even watched more than a few minutes of any given movie. 

Does anybody know if the regular WDTV shares this colorspace problem?

December 03, 2009, 05:33:02 AM
Reply #10

coastline

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Yup, along with the c200 according to Hokeysmoke as they all use the same chip.

December 03, 2009, 06:53:45 AM
Reply #11

coastline

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Support ticket logged - fingers crossed!

December 03, 2009, 11:04:25 AM
Reply #12

rtga

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Support ticket logged - fingers crossed!

I suppose I should log one as well and maybe get some eyes on this glitch.  I saw in the NMT thread that apparently there's a really easy fix for it too?

December 04, 2009, 04:16:51 AM
Reply #13

coastline

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I'm still puzzled why more people aren't noticing it!   It might be that my particular setup (BD35 Bluray Player, Infocus X9) exaggerates the differences.  What's your display RTGA?

December 04, 2009, 06:16:51 AM
Reply #14

rtga

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I'm still puzzled why more people aren't noticing it!   It might be that my particular setup (BD35 Bluray Player, Infocus X9) exaggerates the differences.  What's your display RTGA?

I have a 46" samsung LCD - it's an LT-4669 which is basically the top of the line 120Hz panel from 2 years ago.