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2nd November 2007, 14:58 | #41 | Link |
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Jdobbs, this thread is also releant for DVD-RB as you use dgdecode.
but let's have this summary (which is OK, according to Kumi and myself tests, and with Wilbert, Jdobbs, Oppo guys and other posts) and works with 709 DVD and 601 DVD: First CCE does NOT do colorimetry conversion and is expecting nothing as input. If your original DVD is 709, dgdecode will decode it as 709, and you have to input directly into CCE, and CCE will output 709. The only warning is to be sure that your original DVD is 709 (and dgdecode seems not sufficient) and check that your DVD player or DVD software player is 709 compliant. Your display must also expect 709. If your original DVD is 601, dgdecode will decode it as 601, and you have to input DIRECTLY into CCE (without any colormatrix filter) and CCE will output 601. The only warning is to be sure that your DVD player or DVD software player is 601 compliant (it is true for Oppo and PowerDVD ("original" settings) and that your display is expecting 601. DVD 601 seems easier to handle because when dgdecode identifies them as 601, you are sure they are 601. PS: all that was said, is for SD output. For HD ouput the scaler or DVD player scaler has to handle properly the 709 and do the conversion for 601 DVD. my two cents. Maybe if you all agree, Jdobbs could do a sticky post from this one? Last edited by fjhdavid; 2nd November 2007 at 18:07. |
2nd November 2007, 18:28 | #42 | Link | |
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Sorry, but I can't resist:
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2nd November 2007, 18:45 | #43 | Link |
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maybe my english is not as good as yours, I am sorry about that (but I am sure my french is better....smile)
but remember that the aim of DVD-RB is to do the best DVD possible, and if you are wrong in matrix color, it is a pitty, but one more time if someone can demonstrate something different, I would like to hear (I don't care about document from 1995 or 2007 (becaude jdobbs showed us maybe two contradictory one (post 32)), I don't have any 709 video so I trust Kuni (post 38), I just said be careful with dgdecode as it seems it say 709 even when there is no header extension written But about 601 DVD, I am sure that you don't need colormatrix() and I have evidences about that (post 37), I have also evidence that PowerDVD and Oppodigital players are 601 compliant (post 29 part2) But please be free to sending me a 601 video footage I can check with my PC which show me I am wrong with 601 DVD Last edited by fjhdavid; 2nd November 2007 at 19:27. |
2nd November 2007, 19:52 | #44 | Link | |
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It's obvious that CinemaCraft engineers are comfortable with encoding Rec.709 WITHOUT the sequence_display_extension(). Thanks to that, you can easily argue that DGDecode's assumption of Rec.709 coefficients on input streams without explicit flagging is reasonable and correct. |
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2nd November 2007, 20:00 | #45 | Link |
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maybe you are right Kuni,
but, to convince me, can you just do a simple test for me: take a 601 pure red showing RGB = (X,0,0) (or a part of a picture) convert it with DVD-RB and CCE WITHOUT any colormatrix filter then read the output and tell us the re-encoded output RGB value now do the conversion with DVD-RB and CCE and a colormatrix (bt601->bt.709) before encoding as it "should be" if I understood your purpose then read the output and tell us the re-encoded output RGB value thanks for your help Last edited by fjhdavid; 2nd November 2007 at 20:05. |
2nd November 2007, 20:06 | #46 | Link | |||
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Let me respond on two points:
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But assuming that you are correct by your statement that PowerDVD uses Rec.601 upon display, then your encoding will look the same as your original. About (*), which brings me to the following point: Quote:
About your last post: Quote:
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2nd November 2007, 20:17 | #47 | Link | |
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Look, it's already proven that CCE does not flag it's output stream, even when it's fed Rec.601 input. This fact alone demolishes your entire argument about how "601" is the "SD standard". I now retire myself from further participation in this thread (it's not going anywhere.) Last edited by kumi; 2nd November 2007 at 20:19. Reason: I'm done here... |
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2nd November 2007, 21:08 | #48 | Link | |||||
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2nd November 2007, 23:56 | #49 | Link |
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Wilbert and Jdobbs thanks for your point about my post. I will go further in testing if I can.
Kumi and Dragongodz, I am sorry you lost your time with me. My purpose was just to try to understand why: people from PowerDVD and WinDVD assume 601 for DVD SD (powerDVD and winDVD are nb 1 and 2 of PC DVD player) people like Joe Kane from DVE and guys from getgray are doing wrong DVD calibration tools for SD DVD why MTK and Cirruslogic, wellknown chip maker are using wrong colormatrix why, we don't have any info from CCE guys to tell us their specs I am also wondering how you are playing your DVD with all this people doing wrong bt.601 compliant stuff? but as you said it is maybe not important... |
3rd November 2007, 00:03 | #50 | Link |
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I'm reading "ITU-T Rec.H262 (2000 E)". All the ITU-T docs are available for free since a short while:
http://www.itu.int/rec/T-REC-H.262/en The relevant quote (page 44) says something different (than the 1995 version): In the case that sequence_display_extension() is not present in the bitstream or colour_description is zero the matrix coefficients are assumed to be implicitly defined by the application. What's that supposed to mean? Last edited by Wilbert; 4th November 2007 at 13:50. |
3rd November 2007, 00:23 | #51 | Link | |
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It means "if the sequence_display_extension() isn't there -- your guess is as good as mine." they were just afraid to write that into the spec.
It also says this: Quote:
Last edited by jdobbs; 3rd November 2007 at 00:28. |
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3rd November 2007, 01:26 | #52 | Link |
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look at this address even if they are talking about SDTV:
(sigmadesigns is also a wellknown decoder chip maker used in a lot of DVD player) http://www.sigmadesigns.com/public/S...omaticity.html But for Wilbert an Jdobbs, I read also ITU-T Rec.H262 (2000 E)". The application should be for example SD (or HD), or SD TV, or HD TV, as the player would recognize by the height and width which application the mpeg2 stream are talking about? It could be the same with PAL and NTSC as the player would recognize the application with the refresh rate (25hz and 30hz)? PS: I tested DGindex and it is a 709 compliant DVD player... Last edited by fjhdavid; 3rd November 2007 at 11:30. |
3rd November 2007, 16:36 | #53 | Link | ||
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BTW, thanks for the ITU link. Quote:
I just added this header to HCenc to see what happens for different input/output combinations, the next table shows the RGB values for the red, green and blue colorbars using PowerDVD. Code:
input output red green blue 601 601 RGB=187, 0, 0 RGB= 2,187, 2 RGB= 1, 0,187 601 709 RGB=187, 0, 0 RGB= 2,187, 2 RGB= 1, 0,187 709 601 RGB=171, 0, 2 RGB= 17,220, 8 RGB= 1, 0,179 709 709 RGB=171, 0, 2 RGB= 17,220, 8 RGB= 1, 0,179 Now lets see how DGIndex handles it: Code:
input output red green blue 601 601 RGB=188, 1, 1 RGB= 3,188, 3 RGB= 1, 1,188 601 709 RGB=204, 19, 0 RGB= 0,160, 0 RGB= 0, 12,195 709 601 RGB=172, 0, 2 RGB= 18,221, 9 RGB= 1, 0,179 709 709 RGB=188, 1, 1 RGB= 4,189, 3 RGB= 0, 1,187 What does this mean for DVD-RB using CCE? IMHO nothing, DVD content already has 601 characteristics, CCE encodes the YUY planes to YV12 planes and doesn't write the sequence display header so DGIndex correctly sees it as 709 but DVD players will ignore it and use 601 for the conversion. However if you use Colormatrix to convert the DVD from 709 to 601 you will end up with the wrong colorimetry, and DGIndex will still report it as 709... For those who are interested the testfiles used can be downloaded here
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3rd November 2007, 16:50 | #54 | Link |
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So here are the questions, since the standard can't apparently be trusted:
1. Can we assume DVDs with no sequence_display_extension() are Rec.709 or Rec.601? 2. What conversion is DGDECODE doing when it frame serves it to HC or CCE? 3. Why is it that when I do see sequence_display_extension() used on a DVD it is always used to specify Rec.601? It would at least give you the impression that the default is other than Rec.601, wouldn't it? Since DVD-RB scans the file and creates the D2V file itself, I could very easily make the D2V default to Rec.601 -- but is that right? Sigh... Last edited by jdobbs; 3rd November 2007 at 16:53. |
3rd November 2007, 17:32 | #55 | Link | |||
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As long as nobody here has the DVD specification it's all speculation...
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The testfiles also show wrong colorimetry using 709 as input. Quote:
The sequence display info is only parsed, not processed. Quote:
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4th November 2007, 00:27 | #56 | Link | |||
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I agree
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use 601, ignore headers. Quote:
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btw, restream can add matrix coeffs to a stream, it sets to I470. Don't know if there's a tool to set the header coeffs to 709. I like that Hank added the feature to add the header in a test version of HC, I'm sure it will make it through to the next HC. anyway, i think it's good to know what behaviour to expect with conversions to rgb so basically i gave this answer to the op: consider 4 sources: A Code:
colorbars(720,480) killaudio() converttoyv12() trim(0,120) No sequence_display_extension present. B Take stream A and use restream to add sequence_display_extension with colour, restream sets matrix coeffs to 'I470'. C Code:
colorbars(720,480) killaudio() converttoyv12(matrix="rec709") trim(0,120) No sequence_display_extension present. D the same as C but set matrix coefficients in header to 709. Like I said I don't know of a tool to do it, but Hank's colorbar input709to709output stream linked to above fits the bill. slap the 4 sources on a disk or use them for input to your apps. Scenario 1: Mpeg2 is converted to rgb using 601 always. Source A = Normal (N) ; B = N ; C = Red Push (RP) ; D = RP Scenario 2: Mpeg2 is converted to rgb respecting the header, in the absence of the header 709 is assumed. A= Green Push (GP) ; B = N ; C = N ; D = N Scenario 3: Mpeg2 is converted to rgb respecting the header, in the absence of the header 601 is assumed. A = N ; B = N ; C = RP ; D = N Scenario 4: Mpeg2 is converted to rgb using 709 always. (nicely hypothetical) A = GP ; B = GP ; C = N ; D = N That way you know what's happening on the end part. and effectively what to do before you get there. If Scenario 2 is actually the standard, and is abided to, then what CCE (and other encoders) does is wrong by not setting color matrix coeffs in the header, and I would run them through restream to add a header. As for knowing what you are working with... I'd treat dvds with no header as though they are 601. Of course you can just wing it visually, deciding if you're ok, or if you've been pushed either red or green, and revert with colormatrix. anyway, that's what I think. gl |
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4th November 2007, 01:43 | #57 | Link |
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I am happy that Hawk315 found same results as my post 37 with the RGB values, even if Hawk has been able to do more things than me thanks to its knowledge, and as I said in my post 41: "CCE does NOT do colorimetry conversion and is expecting nothing as input"
As I said many many times in this thread, we don't care about the norm (and maybe we never know if there is a followed norm) but we must be pragmatic: Even if assuming that 709 DVD were true, NO DVD players on the market (as long as I know) would play the 709 DVD without chromacity error (as DVD players use only two or three different chip decoder that are 601 - see my posts)), and ONLY Dgindex for PC (as I know (see my post 52)) would be able to read the re-encoded 709 DVD!!! IT IS NOT an EVIDENCE of something, it is a FACT. Now, everyone can do what he wants but it is a non sense to use a colormatrix (bt 601->bt709) with 601 DVD. I know my english is bad (someone else, like Manono can write it), but I think we need a sticky post about this subject. But even if there is nothing more on the subject, lets me thank, one more time, Jdobbs for its work, as I used it everyday. Last edited by fjhdavid; 4th November 2007 at 01:57. |
4th November 2007, 01:51 | #58 | Link | ||
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Since the standards are murky, what if we blind test the users on Doom9? Carefully author a DVD with a few test patterns, have users view them, and then answer some questions about their visual impressions. The questions would be designed to determine which of Immersion's four 'Scenarios' is in effect for a particular SAP (see post #56). If enough users participate, we might be able to arrive at some real-world conclusions regarding the desirability of different colorimetry/header combinations. But... is this type of blind study possible? Or rather, given a test DVD with a few sample clips: does there exist a series of simple-to-answer questions that will tell us which of Immersion's "Scenarios" a given SAP is using? Last edited by kumi; 4th November 2007 at 01:53. |
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4th November 2007, 01:59 | #59 | Link | ||
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Last edited by jdobbs; 4th November 2007 at 11:00. |
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4th November 2007, 02:05 | #60 | Link |
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All the DVD players on the market are using a DVD decoder chip, and major chip manufacturer (MTK, cirruslogic, sigmadesign) are 601 compliant (see my previous posts).
then if 709 DVD was the norm, all this DVD player would play 709 DVD with a chromacity error (independantly from DVD-RB or HC/CCE)....do you think that all these engineers are wrong? I don't know but I doubt... this is why Hawk and myself said that DVD must be 601 compliant as there is so much info on the net according to this fact. |
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