[nightstalker]

Hi Guys,


Just got my Hitachi the other day. Looks fantastic!!. No VB and I don't notice any screendoor on my 100' 1.0 gaiin matte white screen from 10 feet.


I did a quick calibration with the THX optimiser on one of my Star Wars DVD's and in the contrast section I ended up with my setting at -18, having looked at other users settings mine should be roughly +3 / +4 has anyone else got their contrast set so low and if not should I use a proper calibration disk?


Thanks





Sorry this should have gone in the Hitachi thread.. Can't seem to delete it

Moderators please delte I will post in the correct forum

 

[Gary Lightfoot]

The THX disks are fine, but only really set the levels up for that particular disk. Ideally, you should use Avia which should set up your DVD player for all disks.


You may then find you have similar settings to other people.


HTH


Gary.

 

[nightstalker]

Thanks for the feedback Gary,


I will pick myself up a proper calibration disk

 

[Gary Lightfoot]

Let us know how you get on.


The black and white levels are refered to as the 'needle pulse tests' in Avia, and can make a huge difference on mpg artefact visibility if the black level isn't set correctly, so I always suggest that they should be done as a minimum alibration.


Just noticed - you also live in PAL land, so Video Essentials may be a better disk. Do you watch mostly R2 or other region disks? Avia is more suited to NTSC than PAL (for black level), so you may not get get the black level quite right unless your DVD player has a 0ire or 'below black' setting for NTSC.


What DVD player are you using? If it's an HTPC, it doesn't matter - Avia will be just fine.


Gary.

 

[ChrisWiggles]

Quote:

a 0ire or 'below black' setting for NTSC

A pet peeve of mine when this gets confused. IRE setting is not necessarily related to whether or not BTB data and peak whites are preserved.

 

[nightstalker]

Iv'e ordered a copy of Video essentials, should get it next week.


I'm using a Momitsu V880 upscaling to 720

 

[TheFerret]

Quote:

Originally posted by nightstalker Hi Guys, Just got my Hitachi the other day. Looks fantastic!!. No VB and I don't notice any screendoor on my 100' 1.0 gaiin matte white screen from 10 feet.

That's got to be an AVS record for screen size. I don't know too many people sitting 0.10 screen widths away.
Quote:

I did a quick calibration with the THX optimiser on one of my Star Wars DVD's and in the contrast section I ended up with my setting at -18, having looked at other users settings mine should be roughly +3 / +4 has anyone else got their contrast set so low and if not should I use a proper calibration disk?

Also, note that this Lumen output will probably change after a couple of hundred hours get on the lamp.

 

[Gary Lightfoot]

Quote:

Originally posted by ChrisWiggles A pet peeve of mine when this gets confused. IRE setting is not necessarily related to whether or not BTB data and peak whites are preserved.

Hi Chris,


Could you elaborate more please?


In some Pioneer players, they have a 0ire setting for NTSC, whilst others have a different name for it such as 'below black' which I've always assumed does a similar thing. Are you saying that it may reduce peak white by 7.5 ire when reducing the black level to match PAL or is it something else?


Thanks.


gary.

 

[ChrisWiggles]

The IRE output level is only an analog output option to either conform to US NTSC standards which assumes that black (unambiguously black) is output at a voltage of about 53mV, or 7.5IRE. IRE is a purely analog representation of voltage. Other standards use 0mV, or 0IRE for the output of black (it is the same black).


Blacker than black is separate from the IRE setup option. Black is encoded in digital values (analog is obviously not on the disc, thus IRE does NOT come into play. The disc has no control of absolute IRE output by a source device.). Reference black is digital 16, and value below this are blacker than black data. This data can be maintained through the output whether the source outputs black at 0IRE, 7.5IRE, or some other voltage. Whether or not it is maintained, or clipped, is dependant on the design. You can only say that "setting x maintains of clips BTB data" for one particular player. It has no extension to other players, or perhaps even that same player with software or upgrades that behave differently.


IRE output, and BTB are not de-facto related at all.

 

[TheFerret]

Unfortunately, I am not familiar with a resource that will tell the user whether or not the source is using one interpretation or another, which only serves to further confuse the masses, and me being one of them.


For the layman (me), how do I know whether or not my DVD player, STB, and HD STB are outputting 0-IRE for analog and or Digital 16 to represent black when provided with the appropriately matched content?

 

[Gary Lightfoot]

Hi Chris,


I think you jumped the gun a tad.


The 'below black' I mentioned isn't 'blacker than black', but a manufacturers 'other name' for setting NTSC black level to PAL levels of 0mv or 0ire (thanks for the NTSC value of 0.53mv, I thought it was 0.49mv). Like I said, Pioneer call it 0ire in some of their players (those that have it) so there's no mistake there, what others call it is another issue, but equates to the same thing.


I'm not saying that the 'below black' level is 'blacker than black', so I think you're pulling me up for an error I haven't made. I'm merely pointing out a setting in a DVD player that should set the black level for NTSC the same as PAL, so whatever calibration disk you use, the black level should be set the same - 0ire.


I think the 'below black' decription is just that - below NTSC black, not 'blacker than black'.


Gary.

 

[ChrisWiggles]

I'm very confused by your terminology of below black. Below black signals and data are usually synonomous with blacker than black.


As I explained, the absolute IRE is not the issue. Black is output at a specific voltage. Data that is output at voltages below this is blacker than black, or below black.


This is irrelevant to whether or not there is NTSC setup present. All that the presence of setup determines is the voltage at which black is output. Values below this black output(regardless of whether it conforms to US NTSC standards, or another standard), if the chain is calibrated properly, should be the result of signals or data that represent footroom that contains blacker than black, or below black video information.

 

[Gary Lightfoot]

I think you're trying to over complicate things Chris - it's a menu option within a DVD player under video settings, same as the 0ire/7.5ire option you get with Pioneer DVD players.


Here's a pic from the Pioneer 868 player menu:

 

[ChrisWiggles]

Yes, well as I think i mentioned, this setup option provides user control over the voltage output for black. It allows you to set black to be output at 53mV (7.5IRE) or at 0mv (0IRE).


In each case, blacker than black values may or may not be maintained, depending on the design of this particular player.


And in each case, if BTB values are maintained, they will be lower than 7.5IRE, or 0IRE, respectively.

 

[TheFerret]

This still does make it simple & clear as to how a layman can insure they are generating a black test pattern in order to make adjustments, if needed, to their display.

 

[Gary Lightfoot]

Quote:

Originally posted by ChrisWiggles Yes, well as I think i mentioned, this setup option provides user control over the voltage output for black. It allows you to set black to be output at 53mV (7.5IRE) or at 0mv (0IRE).

My point exactly - so when setting NTSC black output to 0ire, it will be the same for both PAL and NTSC and a single calibration for black is all that's needed for both systems, hence only Avia is needed, and not VE as well. This is useful for a multi-region DVD players (many of which are available in PAL countries such as the UK and Australia), which will use the same single input into a projector and may have only one memory option for storing that particular inputs' brightness and contrast settings (some can distinguish between them both and will store both).


Some players don't show the menu option as 0ire/7.5ire - they call it something else (varies from manufacturer to manufacturer), and is not related to BTB which is a different issue altogether.


Ferret,


US sourced players will give a default 7.5ire output for black, and is all that is needed to calibrate your display using Avia. Each source should be set up in the same way, but that isn't always possible as you will need a tv test card transmitted for off air sources for instance. Hopefully, using a DVD player to set black should get you in the ballpark for other sources if they use the same input.


Perhaps using the DVD players other outputs into the projectors other inputs would be a way of setting up those inputs - what do you think Chris? Would that work or do you think there would be too much variation between sources?. Most pjs have different memories for each input and type, so it will remember the settings.


If you're in PAL land and want to use Avia, you'll be setting the black level incorrectly for PAL, as it will now show black at 7.5ire, losing all the ire graduations below it (down to 0ire - the correct black level for PAL). So shadow detail will be lost, as PAL would be outputting 7.5 ire and lower for dark greys, and these will be incorrectly displayed as black. Idealy you'll need a PAL test disk such as Video Essentials.


Hence the usefulness of using 0ire as a common black output for both PAL and NTSC - the black level will be the same for both systems, and will be displayed correctly if using a multi-region DVD player calibrated using Avia alone (and will be using the same inputs into the pj).


If you don't have a multi-region DVD player, then the usefulness of 0ire for NTSC may be negligable.


Gary.

 

[TheFerret]

For DVD, I am using a pair of Sony DVP-CX985 megachangers. For now, the transport if interlaced Component, through a Pioneer Elite VSX-45TX and then into the interlaced Component input of an DVDO iScan Pro, which transcodes and deinterlaced to 480P RGBHV, and then switches through a Kramer 2x1 RGBHV switcher. I may have forgotten the hamster and wheel somewhere along the line.


The other input on that DVDO iScan Pro is an S-Video for DirecTiVo. The other input on that Kramer is a Samsung SIR-TS160 HD-STB. Everything is then finally fed into the 7" CRT projector with calibrated inputs for 480P/4:3 (SDTV), cropped 480P/4:3 & 480P/16:9 for DVD, 768P/4:3, and 720P/HDTV & 1080i/HDTV.


I did not perform the calibrations, but was hired out to a professional. I know the HDTV is calibrated to 0-IRE, the 480P/4:3 (SDTV) is 7.5-IRE, but I cannot remember how the DVD inputs and 768P were configured.

 

[HoustonHoyaFan]

Quote:

Originally posted by TheFerret For DVD, I am using a pair of Sony DVP-CX985 megachangers. For now, the transport if interlaced Component, through a Pioneer Elite VSX-45TX and then into the interlaced Component input of an DVDO iScan Pro, which transcodes and deinterlaced to 480P RGBHV, and then switches through a Kramer 2x1 RGBHV switcher. I may have forgotten the hamster and wheel somewhere along the line. The other input on that DVDO iScan Pro is an S-Video for DirecTiVo. The other input on that Kramer is a Samsung SIR-TS160 HD-STB. Everything is then finally fed into the 7" CRT projector with calibrated inputs for 480P/4:3 (SDTV), cropped 480P/4:3 & 480P/16:9 for DVD, 768P/4:3, and 720P/HDTV & 1080i/HDTV. I did not perform the calibrations, but was hired out to a professional. I know the HDTV is calibrated to 0-IRE, the 480P/4:3 (SDTV) is 7.5-IRE, but I cannot remember how the DVD inputs and 768P were configured.

The Sony 725 dvd players did something interesting with setup, and unfortunately did not have a user menu setup choice.

SVideo (480i) it used the NTSC setup of 7.5 IRE for black

Component ( 480i ) it also used NTSC of 7.5 IRE

Component (480p) it used the HDTV setup of 0 IRE


what a pain!

 

[ChrisWiggles]

Gary: you're still confused a little bit:

Quote:

If you're in PAL land and want to use Avia, you'll be setting the black level incorrectly for PAL, as it will now show black at 7.5ire, losing all the ire graduations below it (down to 0ire - the correct black level for PAL). So shadow detail will be lost, as PAL would be outputting 7.5 ire and lower for dark greys, and these will be incorrectly displayed as black. Idealy you'll need a PAL test disk such as Video Essentials.

I really don't want to be critical or anything, but you're confusing the basics of what IRE is and means, and thus making statements that seem logical to you, because of the way you've picked up the issue of IRE on the forum(not your fault, it's a VERY common mess), but that are completely illogical.


IRE is an ANALOG voltage value. There is NOTHING related to absolute IRE values or voltages on the DVD. Your statement assumes something along the lines that Avia contains material to 7.5IRE, while VE/DVE goes down to 0IRE. This is absolutely absurd. There is *no* IRE anywhere on the disc. There just isn't. IRE corresponds to voltage, there's no voltage on the disc. The disc is PURELY defined in DIGITAL steps.


That data is translated into an analog waveform for output via analog outs, and ONLY THEN does IRE enter the picture. Stating that *any* DVD is "encoded with blacks to X IRE" is not correct. Absolute IRE is not defined or controlled by the disc at all.

 

[ChrisWiggles]

See Guy Kuo's long post here explaining the issue in more detail:

http://www.avsforum.com/avs-vb/showt...67#post3306967