What is I.R.E...and how should I set it...?

F

Family Guy

Guest
New DVD player in the house...Pioneer 737. It has unlimited tweaks for the picture. Maybe to many IMO.
However, there is one that is called I.R.E. You can set it to 0 or 7.5. According to the manual, it's to adjust floating black, whatever that is:confused:
If I set it to 0, the picture is to dark to watch, if I set it to 7.5 the picture is brighter, but on my lowly projector (a Sony HS1), the blacks then become dark grey again. I managed to get the blacks black with months of tweaking and a hoya filter...looks like there's more tweaking ahead...:(
 

vonhosen

Novice Member
In simple terms the black levels between PAL & NTSC (& NTSC from Japan or USA) are different.


PAL & NTSC from Japan should be set to 0 IRE
USA NTSC at 7.5 IRE
 

LV426

Administrator
Staff member
I have found that you can use the other picture tweaks on the 737 to counterbalance whatever your IRE value is. After some experimentation, I have ended up with two 'memory' settings - one for PAL, one for NTSC, with both IREs set to 0 but values for black and white levels different for each. And the same brightness and contrast settings used for both signal types on my projector.
 

buns

Banned
anyhow, i believe someone knowledgeable stated ntsc dvd (US) should be with 0 IRE setup, though it seems others will disagree on this point.

I'd go with Nigels idea, i think most will adhere to this. For the most part, the only difference will be NTSC peak white will be lower than that of PAL, but only marginally so.
(it will be 92.5 IRE not 100 as for PAL)

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F

Family Guy

Guest
Originally posted by vonhosen
In simple terms the black levels between PAL & NTSC (& NTSC from Japan or USA) are different.
PAL & NTSC from Japan should be set to 0 IRE
USA NTSC at 7.5 IRE
I noticed the difference when watching Dances With Wolves (Korean region 0 version...which is NTSC) when ste to 0 IRE, the picture was just to datk to watch. When set to 7.5, the picture was watchable, but as I said, blacks were grey. Now I'm not sure whether this disc is US or Jap NTSC, but I'm guessing that if I were to play with the white and black levels and make 2 seperate settings as suggested by nigel.

Thanks for your help guys...cracking player IMO. Only picked it up on Friday and for what it is and does, I got it for an absolute steal. Even non progressive pal pictures look superb...
 

buns

Banned
If you have a calibration disc originating in the region your discs come from, then it will take into account any strangenesses like this.....

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gmt steve

Novice Member
Peak white is no different for NTSC or PAL, they are both 100IRE (Institute of Radio Engineers). As stated, Japanese NTSC and all PAL have black at 0IRE, wereas USA NTSC has black at 7.5IRE. To complicate matters, all component outputs should place black at 0IRE, although in practice this is not always done. You should set the 737 to OIRE which will give a little more video dynamic range.
The thing that confuses me is that if I feed my DVD directly into my monitor, then PAL and NTSC discs have the same black level. However when a iScan Ultra is placed in the path I have different black levels for PAL and NTSC which is very inconvenient, but does mean I can make effective use of the Pioneer's memory settings.
By the way, do bear in mind that the centre of the scale is 0 when adjusting the white/black levels and also the High and Mid sharpness parameters. If you put the scale all the way to the left, then that is a minus setting.
 
F

Family Guy

Guest
So looking at it another way, 0I.R e is black and 100 I.R E is white, yes? Which would explain that when set to 7.5, blacks look slightly grey.
However, the contrast ratio of my PJ is such that when set to 0, the picture is to dark...
I've never had this setting before. I can see avia coming out tonight. However, it's NTSC only, but I do have a pal disc with THX optimode on it, but have heard that the black level on these is set to 0, whether pal or ntsc...:confused:
 

Gordon @ Convergent AV

Distinguished Member
AVForums Sponsor
0ire and 100ire are voltage levels.

It is perfectly possible to have a 7.5ire signal that corresponds to BLACK and a 0ire signal that corresponds to BLACK. Ideally set your DVD player to output BLACK at 0ire for NTSC. Then adjust your display or processor brightness control to get its black point correct.

If you see differences in black level when feeding a video processor NTSC and PAL signals (even although NTSC is set to 0ire black on the DVD player), it is likely due to the way the TV decoder chip in the processor is set up. With Lumagen products you have the ability to adjust these settings on PAL and NTSC basis and also per input......oh.....and some DVD players change the voltage they set black to if the disc they are playing has copy protection flagged on it....but that's just going to make this really really confusing....

Gordon
edit: Just also agreeing with previous posts that there should be no set up on Component signal anyway...ie black should always be at 0ire....but this is not always the case. In fact there are HD STB's in US that seem to add set up to their HD component outputs.......Nothings simple eh!
 

buns

Banned
Zero setup is a feature of the EBU N10 component video, all variants of 576i video and HDTV

Poynton, Digital Video and HDTV
suggesting setup should now be zero in modern video systems. This quote i can verify elsewhere so in which case why do we have the need to specify a setup? ..... then again i now find some stuff conflicting with this.....even more confusing i read that many computer monitor interfaces (whatever that means) utilise a 7.5% setup..... :(

In any case, considering a system with setup, there are only 92.5% IRE units above black. So, if as gordon says, you set 7.5 IRE as black, there will only be 92.5 IRE units higher than it, hence white will be equivalently 92.5 IRE as compared to 100 with zero setup....

someone may correct me if you tell me that dvd doesnt count as component video, but as far as i know it is

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F

Family Guy

Guest
Thanks for your help guys...I'm changing my cinema room around to allow for a bigger picture so I'll employ all the new learned tactics when the PJ goes back up on Thursday.
 

gmt steve

Novice Member
It doesn't actually matter whether you set it to 7.5 or 0 IRE. You can then use white and black level controls on your montor to then set levels properly with (for instance) a PLUGE pattern. I think the idea is to have all your sources the same, since most monitors don't have separate memorys for each input. So since all of your sources in the UK should use 0IRE then set the player to the same. As I said 0IRE will actually give a little more headroom but you probably won't notice.
 

buns

Banned
surely if you set to 7.5, you will be limited to 92.5 IRE units above this (irrelevant of how you set your brightness) so you are limiting your dynamic range by having information meant to be for 100 units crammed into 92.5

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gmt steve

Novice Member
As I said 0IRE will actually give a little more headroom but you probably won't notice.

You should set the 737 to OIRE which will give a little more video dynamic range.
I thought that's what I said.:confused:
 
F

Family Guy

Guest
It's become apparent that my previous DVD player (a Yamaha 540) had it's IRE set to 7.5. When I run avia, all the settings are basically right when I put the IRE to 7.5, but to dark when set to 0.
I'm going to set it 0 and re calibrate my PJ and TV using avia...seems to me to be the best bet.
 

MJeeves

Well-known Member
I'm really confused by this...

I have a Pioneer 868 DVD player feeding a Sim2 projector via HDMI. Most of my software is U.S. NTSC. Should I set the black level to 0 IRE or 7.5 IRE?

Pioneer say one thing and Sim2 another. Also the Pure Cinema modes on HDMI video adjust offer several choices. Sim2 prefer Auto 1, Pioneer say Auto 2 (as do some forum members), and my dealer recommends Pure Cinema ON.

Any 868 owners out there to help with this minefield?
 

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