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Discussion Starter · #1 ·
Hi folks,


I recently started recalibrating my system using DVE and there are a few things I'm baffled about - which someone here might be able to explain to me:


1. From the pluge patterns, it looks like DVE focuses on contrast settings only for CRTs. The thin side lines are obviously intended to check for high voltage stability.


What about fixed resolution displays? I can't understand what their idea for adjusting contrast is for those types of devices...


Shouldn't there be an upper limit to those types of devices based on the same principle that DVE uses for the pluge patter (i.e., 98IRE and 96 IRE windows)?


2. While the Chroma/Luma "clock" screen is an interesting one, there is no Y/C delay adjustment or testing pattern. This is strange, as it is one of the screens I think are very important (I use it often!) on AVIA.


I'm baffled as to why this specific screen was left out...


BTW, the 2-3 S&W moving zone plate is AMAZING for testing 3:2 pulldown. Any ideas why there is no equivalent 2-2 sequence on the PAL disk?
 

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Hi Ofer,

Quote:
Originally posted by oferlaor
Hi folks,


I recently started recalibrating my system using DVE and there are a few things I'm baffled about - which someone here might be able to explain to me:


1. From the pluge patterns, it looks like DVE focuses on contrast settings only for CRTs. The thin side lines are obviously intended to check for high voltage stability.


What about fixed resolution displays? I can't understand what their idea for adjusting contrast is for those types of devices...


Shouldn't there be an upper limit to those types of devices based on the same principle that DVE uses for the pluge patter (i.e., 98IRE and 96 IRE windows)?

There is.


I don't have the disc to hand, so all this is from recent memory.


For contrast, there are patterns which have very small IRE steps, up to and over 100. And bigger areas on some of the patterns with the usual 10 IRE steps. Finally there is the general screen test pattern which contains a 100 IRE block with a 98 IRE inner block. All of these can be used to set contrast... you just increase until you start losing the steps, and then back off.


Some digital devices do not go above 100 IRE so you will not see this info anyway.

Quote:


2. While the Chroma/Luma "clock" screen is an interesting one, there is no Y/C delay adjustment or testing pattern. This is strange, as it is one of the screens I think are very important (I use it often!) on AVIA.


I'm baffled as to why this specific screen was left out...
Again, there is a pattern which can be used, although DVE doesn't explicitly state this, Joe Kane has talked about it. It's a pattern which rows of vertical colours. You can use this to check Y/C chroma delay.


One of the biggest criticisms of DVE is the lack of documentation.


Mark
 

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The Snell and Wilcox MPEG decoder TEST pattern has the pluge 98 within a 100 block within top left corner I think. The spinning Snell and Wilcox pattern in top right corner is designed to break video processors. It spins at just the right speed to trip things up, causing lots of nice pretty artifacts at the same moment in it's cycle every time, to spare embaressment I won;t mention the devices that can't cope with this.............


G
 

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Hi Ofer,

Quote:
Originally posted by oferlaor
Hi folks,


I recently started recalibrating my system using DVE and there are a few things I'm baffled about - which someone here might be able to explain to me:


1. From the pluge patterns, it looks like DVE focuses on contrast settings only for CRTs. The thin side lines are obviously intended to check for high voltage stability.


What about fixed resolution displays? I can't understand what their idea for adjusting contrast is for those types of devices...


Shouldn't there be an upper limit to those types of devices based on the same principle that DVE uses for the pluge patter (i.e., 98IRE and 96 IRE windows)?

There is.


I don't have the disc to hand, so all this is from recent memory.


For contrast, there are patterns which have very small IRE steps, up to and over 100. And bigger areas on some of the patterns with the usual 10 IRE steps. Finally there is the general screen test pattern which contains a 100 IRE block with a 98 IRE inner block. All of these can be used to set contrast... you just increase until you start losing the steps, and then back off.


Some digital devices do not go above 100 IRE so you will not see this info anyway.

Quote:


2. While the Chroma/Luma "clock" screen is an interesting one, there is no Y/C delay adjustment or testing pattern. This is strange, as it is one of the screens I think are very important (I use it often!) on AVIA.


I'm baffled as to why this specific screen was left out...
Again, there is a pattern which can be used, although DVE doesn't explicitly state this, Joe Kane has talked about it. It's a pattern which rows of vertical colours. You can use this to check Y/C chroma delay.


One of the biggest criticisms of DVE is the lack of documentation.


This *might* help:

http://www.videoessentials.com/test_patt.htm


Mark
 

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Discussion Starter · #5 ·
Also,


Didn't you find the fliters that came with the unit to be VERY VERY dark? Why did they use twice as much film for that?


Mark,


The Y/C delay lines you mentioned are a joke because you need to actually find out how much the Y/C delay is (in ns). The procedure in AVIA is much smarter and gives you a numerical result regarding each of the color component offsets.
 

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Ofer,


I don't like the current DVE much at all. It's a big disappointment as far as I'm concerned. Joe is doing a lot to push image quality, and for that we should be genuinely thankful, but the current DVE just isn't that useful compared to what we already have. Also, the DVHS tape has so many more test patterns, compared to the current DVE. There is a Pro DVD version on the way which should contain all the missing patterns.


I also find the filters too dark, however I assume they are correct, but, for CRT calibration, I always cap the tubes rather than use a filter.


AVIA is still my current favourite calibration disc and AVIA Pro should be shipping any day now. I cannot wait :)


Mark
 

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I had an opportunity to see the Beta version of AVIA PRO at the Home Expo Show @ Long Beach last Nov. Joel Silver was using it to set up the Runco/ Krell system. There is just about anything you could ever dream up. But it is ONLY for DVD Not HiDef. So there are very few options for HiFef setup.
 

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Quote:
Originally posted by Gordon Fraser
The spinning Snell and Wilcox pattern in top right corner is designed to break video processors. It spins at just the right speed to trip things up, causing lots of nice pretty artifacts at the same moment in it's cycle every time, to spare embaressment I won;t mention the devices that can't cope with this.............


G
You big tease - the only reason you're not posting is that it's a very long list:D
 

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Hi Guys,


There isn't a PAL 3:2 movement pattern because you don't get 3:2 in PAL ! There is of course the Field motion version for Video originated sources and the Frame motion for 2:2 Film based sources (I guess this is what you were after, Ofer?)


The characters on the spinning cube are from our (old) logo - they are the ancient symbols for base metal and Gold - If you look at our logo the symbol on the left is the base metal (i.e. Lead), the S&W name is then within an arrow pointing to the Gold symbol. This represents the art of Alchemy (turning lead into gold).


The Y/C delay patterns are there on DVE, but as Ofer mentions, they aren't a lot of use for visual timing - they are the green/magenta bars in various patterns - they are designed for use with a waveform monitor and are the classic 'Bowtie' pattern. Personally I use the colored cross hairs in the M-PEG test pattern to do Y/C delay adjustment visually.


Hope this is of interest !
 

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Discussion Starter · #12 ·
Dear Richard,


First, thanks for popping up here, you guys are legends on our forum.


I meant a 2:2 pulldown pattern of course (3:2 pulldown is not of much use), which I understand is called "frame motion" on DVE.


So, from what I understand from this, the field motion basically force the scalers to go video mode, while the frame motion is essentially 2:2 pulldown (on both PAL and NTSC) and the 3-2 sequence is a conventional film sequence.


What we should be seeing on those patterns should be the perfect circle (With no moire aritfacts inside it) at all times, right? I do see the artifacts when the circle suddenly stops moving, though.


Regarding the spinning patterns, I didn't realize how cool the story behind this was. Very nice!


About Y/C. I'll check the colored cross hairs, but one of the things I most eagerly waited for was a proper Y/C delay pattern that could let me do Y/C delay adjustment on my scaler for PAL (I could already do this for NTSC through AVIA). A proper pattern is preferable to doing it without one (based on my eyes).


Anyway, I'll give it a shot.


Thanks!
 

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Discussion Starter · #13 ·
OK,


I sat down with the DVE S&W patterns again just now.


First, I have to say that the S&W logo is really a cool design (Even more so, now that I understand the idea behind it...).


The 3-2 pattern works fine while the circle is moving, but once it hits the edges and stops, the Vision Pro + SDI goes back to video for a minute. I haven't had time to check how the Faroudja chip handles things for a good comparison.


The field and frame ones (at least for NTSC) yield the exact same results - both are fully locked on video (I use the Sil504's register to review how it sees the image - and it matches exactly what I'm seeing on screen).


Is anyone seeing different results using DVE?
 

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Ofer,


In an ideal world the moving zone plate should be consistent throughout the sequence, even when it bounces off the edges - but most de-interlacers fall over at this point and the recovery time back to film mode is important.


As you mention, correct de-interlacing should give a set of concentric circles with no moire inside and consistent at all times.


If you put the chapter into loop, the point at which the loop occurs could cause any scaler to drop out of the correct mode depending on what the player does during the 'rewind' so be careful not to get mislead by that!



The spinning cube element was actually taken from our Test Card M sequence for testing M-PEG broadcast systems (there is an .avi and .mov version on our website for anyone really interetsed!)


all the best,
 

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Quote:
Originally posted by RichardA
In an ideal world the moving zone plate should be consistent throughout the sequence, even when it bounces off the edges - but most de-interlacers fall over at this point and the recovery time back to film mode is important.,
Joe Kane told me that he intentionally broke the 3:2 PD sequence on the moving zone plate on the first Video Essentials DVD. I.e., there are intentional 'bad edits' when the moving circular zone plate stops. I don't know if DVE is like this or not.


- Dale Adams
 

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Quote:
Originally posted by oferlaor
The field and frame ones (at least for NTSC) yield the exact same results - both are fully locked on video (I use the Sil504's register to review how it sees the image - and it matches exactly what I'm seeing on screen).
Ofer,


There isn't a register in the SiI504 that accurately reflects what the 504 is doing with respect to source-type detection. This is performed almost completely in software in the companion microcontroller (uC) to the 504. While the uC does provide an indication as to what mode it is in, the indicator is highly filtered to remove momentary mode changes. There is also a pure hardware-based detection mechanism in the 504, and there are registers which indicate what mode it is in, but that mechanism is turned off when the uC is used (which I'm sure it is in the Vision). In most cases the uC's indicators give you a general idea of what's happening, but not an exact one.


- Dale Adams
 

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Quote:
Originally posted by oferlaor
Is anyone seeing different results using DVE?
I see different results almost every time I run it :)


I think this pattern (to paraphrase Richard A speaking at the Event in the UK) is deliberately hard and should not really be used as a guide to "real world" performance, more like what mistakes it makes should give clues as to the design of the deinterlacer.


In your case would say that the alogorithm for spotting "weaves" in the final image doesn't take into account motion. As the zone plate contains high vertical frequencies this can confuse many alogorithms (including DScaler) into thinking the picture has weave artefacts even though it is still. I'm surprised this same algorithm isn't used to detect weaves in the moving image as with this method the best compromise thing to do is to stay in video mode throughout.


John
 

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Discussion Starter · #18 ·
Hi Dale,


I know that this is correct, but the indicator does give a really good overview of what's going on.


It does look like DVE intentionally breaks the 3:2 sequence at the edges. IMO, a broken 3:2 pulldown sequence should have its own menu and an unbroken one can be used for comparison.


Richard,


I still have to check that sequence with the FLI2200 to see what the difference in recovery there would be, however, the Sil504 certainly switches back to video mode on each occasion where the circle stops. It's amazingly easy to see when you're in video mode vs. film mode when this happens.
 
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