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Discussion Starter · #1 ·
Hi All,


I just tweaked the firmware of my DVD player and I can set the NTSC video IRE (Black level) to either 0 or 7.5. It's my understanding that there are two NTSC standards and North America uses 7.5 and Japan uses 0 IRE.


Does this mean if I set my IRE level to 0 even though I'm living in Canada that I'll get darker blacks and my bandwith for the IRE level will be a 0 to 100 rather then the normal 7.5 to 100? Is the X1 calibrated internally for IRE of 7.5?


I'm using the s-video input with an interlaced DVD player.


I guess the only way to know for sure is to play with my Digital video Essentials (whenever it is finally shipped from Amazon.ca) with both settings to see if dropping the IRE level to 0 gives me darker blacks.


If anyone here has some more info on this subject please post.


Thanks for listening.

Nowhereman.
 

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Black is black, whether that level is 0 or 7.5 IRE. The projector has to be calibrated for the source. One advantage for 0 IRE is HDTV uses it as the black base level so there is less adjusting to do between different standards. That may not be an issue if your projector has different settings for different inputs.
 

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Discussion Starter · #3 ·
Thanks for the feedback John,


I figured that the black level would be black but if I lower the IRE to 0 from 7.5 the total dynamic range should be increased even if it's only 7.5% it's still an increase in it's range isn't it? That is probably the reason HDTV is setup at IRE 0.


For example if IRE was set at 50 (just hipothetical) the contrast level would have to be lowered emensely just to get black to show up and the dynamic range would only be half what it should be.


There is a noticeable difference between IRE 0 and IRE 7.5, I haven't done any serious testing with my X1 yet. But I did do some testing with my Sony TV about a year ago. At that time I set the DVD player to IRE 7.5 and setup the TV so that the scene in LOTR "mines of Moria where all the orks come out and surround the Fellowship" looked perfect to my eyes. I still had nice details in the pillars and the ground. Then I set the IRE level to 0 and played the same scene. This time I couldn't make out the details on the pillars without making the picture brighter.


I'll try the same tests tonight and I'll let you know if I notice as much of a difference.


Nowhereman.
 

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I just used DVE to adjust my X1 tonight. I feed a Panasonic XP50 to it through both componenent and composite. The progressive image would display the 0 IRE on the pluge, the interlaced would not. Don't ask me why?
 

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Discussion Starter · #5 ·
Ok I played with the IRE setting on my DVD player last night and this is what I found.


With IRE setup at 7.5 I had to set the brightness level at 56 while wathing LOTR's. At this setting the black bars at the top and bottom of the projected image would disappear into the normal black area of the 16x9 image (since LOTR is 2.21 to 1 widescreen).


With the IRE setup at 0 I had to crank the brightness level upto 68 to get the same level.


The blacks are not more black but the darker colours are definately darker until the brightness is setup to a higher level. So once the brightness level is cranked up the picture did look the same as IRE 7.5.


But I still believe at IRE 0 there is more range of colours so I will be leaving it in this mode.


Nowhereman.
 
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