[Webwalker]

I am considering buying AVIA Guide to HT.

I already have the AVIA tune-up DVD, which allows me to adjust brightness, contrast, colour, hue, red push, sharpness etc.

I hardly needed to move the out of the box settings, except that I tuned in a little more contrast, and dropped the sharpness.


Will the AVIA Guide to HT make much of a difference to this PJ? Seems by most reports that it sings really well straight out of the box.


Thanks.

 

[Chris Sander]

You're not going to gain much more from the full AVIA unless you have calibration equipment, or a well trained eye and some calibration skills. I guess you do get a few more useful test patterns for the end user, like overscan checking, but the normal user will not gain much over the tune up DVD.


Chris

 

[lovingdvd]

AVIA can be helpful but this and other calibration discs like VE are not the perfect solution.


Case in point - I finished what I thought was a perfect tuning/calibration using AVIA. I had everything tweaked great according to the patterns. The I put on a movie - Knockaround Guys - and it looked a bit on the dark side.


I froze one of the darker frames and with a few clicks on bringing the brightness higher I realized that it was set to low as I started to see more detail in the blacks as I moved up a few notches. So although it may have gotten me in the ballpark it wasn't perfect.


The other thing to consider is the source material - it could also have been that AVIA did a great job but this particular material wasn't to spec. Unrelated to any particular pj, its a bit frustrating to have each cable channel seemingly require its own calibration levels...

 

[Tony-V]

I read a few comments about setting brightness correctly with a digital projector. The pattern with the black and blacker bar WON'T work correctly.

Use the color bar test screen, set your 16:9 projector to 4:3 (side bars), the black bars where no image is projected will show you the blackest black your projector can display. Now use the bar on the low right side and change brightness until it matches your side bar (no image). Any other approach will give you wrong brightness settings since the (I think it's called pludge) pattern was made for CRT's and not digital displays.


Anybody correct me if I'm wrong.


Regards,


Anthony

 

[glenned]

One of the famous ISF guys posted about this issue. The VE pattern for seeting black levels works OK. The Avia doesn't. Below is my understanding of how to properly set black levels with Avia.


When setting black level with Avia, you want to be able to still see both grey bars. If you lower Brightness until the left bar dissappears, then you will lower it too much. Bring Brightness back up until you can just see the lighter of the two bars. The black bars on totally black screen is easier to use when doing this.


Putting the PJ into 4:3 mode as Tony-V suggests allows you to do an additional comparison. The black bars on the sides are created by turning off the mirrors. This is the deepest black your PJ can make. Lower the black in the 4:3 picture until it just matches. If you go any lower, you will crush blacks.

 

[lovingdvd]

Tony-V and glenned - Great posts. I remember Mark Haflich talking about this approach and was following the thread on AVS about it.


Does anyone have a link to that thread? Apparently there was a detailed discussion about it.


Your description of setting brightness is easy enough. BUT - how do you set contrast? Is it ok to set brightness with the approach you mention above, and then use the AVIA test patterns to set contrast?


The problem I had with this approach (as compared to the AVIA approach) is that it is very subjective. If I recall correctly, you have to set brightness by sort of eyeballing a greyscale ramp, and when trying it a few months ago it left me guess as to whether I was doing this correctly. Any tips on this?

 

[Tony-V]

well once brightness is set I actually do use AVIA or the THX option on Episode 1 or 2 for contrast.

 

[mooneycj]

Setting Contrast with Digital Projectors


I've had the same difficulty setting contrast and brightness with my Sharp DLP projector. This is the procedure I use. I think it's accurate and works well.


I use the Video Essentials disc. To set black level, I adjust the pluge test so the left darker than black bar just disappears into the background, and the lighter bar is just visible. Also, if you stand right up next to the screen. There is a point where the digital noise or dithering in the background just goes away, and 1 click up it comes back. I adjust the brightness so this artifact is just 1 click from being visible, and the left vertical stripe has disappeared into the background.


For the initial setting of contrast I use the AVIA disc and put up the crossed gray scale pattern. I adjust the contrast to the highest setting before the last 2 brightest whites don't bloom and merge together. I make my final adjustment by putting the Video Essentials disc back in and running "video montage of images." About 1/2 way thru the montage, there is a scene where a train comes across the screen from left to right in the lower 1/2 of the image. In the background, the sky is cloudy. In the right upper corner of the image, there is a small white oblong cloud that is just visible. I put that image on pause and tweak the contrast again until the cloud is visible (white cloud on grayish background) and not blooming. Usually there is just 1 click on the Sharp contrast setting that is perfect. Another scene that is good for this is the fish jumping up the small waterfall. There are some very bright reflections off the water that will bloom if the contrast is set too high. Hope these suggestions help, try 'em, you'll like 'em!


Corey J

 

[lovingdvd]

Quote:

Originally posted by glenned The VE pattern for seeting black levels works OK. The Avia doesn't.

Strange. Any idea how the patterns for setting black level differ between AVIA Vs. VE and what accounts for VE working and AVIA not working?


Similarly the VE pattern for setting contrast cannot be used since it depends on a CRT to bend a line, whereas it is said that the pattern type used by AVIA does work for setting contrast.

 

[lovingdvd]

Regarding the posts here about putting up a 0 IRE pattern and adjusting brightness until the video noise goes away... Do I want to leave the setting at the point where the video noise disappears completely from the 0 IRE image when standing at the screen, or do I want to leave it at the point where it is one click about that and the noise just becomes visible?


Does that work the same as putting up a pluge in 4:3 and comparing the side bar blacks to the blacker than black line on the pluge?

 

[mooneycj]

lovingdvd:


From the viewing position I adjust the brightness on VE so the left bar fades into the "darkness" and the lighter bar is just visible. There is usually 1 or 2 clicks up or down that give that picture. Then, I go up next to the screen and fine tune the last click up or down so the "dithering" just becomes invisible (the left bar is still faded into the background, and the light bar is still just visible).


Corey J

 

[Guy Kuo]

If your are using a DLP and AVIA, go right up to the screen and look for the DLP dithering. When set correctly the left moving "black bar" in AVIA will be visible as well as the right one. There should be no visible dither noise in the black background. The left black bar in AVIA is 1% above digital black. The right one is 2% above digital black. Depending on your DVD player's settings, digital black can be at either 7.5 or 0 IRE. The black bars simply sit very slightly above whatever IRE level which the player outputs as black. The darkest bar is such a small amount above black (1%) that from normal sitting position it is often too dim to be visible. Hence the instructions on the disc. If you go right up to the screen (or better yet focus the projector on a very near screen), you can look for the DLP dither. Black should have no visible dither going on but the two moving bars should be visible. If either bar is missing, then your setup is clipping off intended shadow details.

 

[NKUEHN]

As an aside, when you look at the gray bar on the Sharp Z10K, notice the "noise" with all your non DVI output and then look at it thru DVI, big difference! Just a comment from Kevin Miller who recently calibrated mine. He used VE for all these tweaks.


He used AVIA for the focus and to evaluate overscan which mine has and couldn't get it all resolved with the AVIA 100 IRE Cross Hatch Pattern. Anyone else have this trouble with the 10K?


Nic

 

[lovingdvd]

Quote:

Originally posted by Guy Kuo If your are using a DLP and AVIA, go right up to the screen and look for the DLP dithering. When set correctly the left moving "black bar" in AVIA will be visible as well as the right one. There should be no visible dither noise in the black background. The left black bar in AVIA is 1% above digital black. The right one is 2% above digital black. Depending on your DVD player's settings, digital black can be at either 7.5 or 0 IRE. The black bars simply sit very slightly above whatever IRE level which the player outputs as black. The darkest bar is such a small amount above black (1%) that from normal sitting position it is often too dim to be visible. Hence the instructions on the disc. If you go right up to the screen (or better yet focus the projector on a very near screen), you can look for the DLP dither. Black should have no visible dither going on but the two moving bars should be visible. If either bar is missing, then your setup is clipping off intended shadow details.

Guy - this differs slightly from the instructions posted here earlier and I think adds an interesting element regarding the darker of the two bars. Previous posts said to bring black level down so the darker bar disappears and shows no dithering, whereas your reporting that the darker bar should still be visible.


Last night I performed some tweaks using this "disappearing dithering" technique. I must say that it is an excellent technique. Not only because it is easy to find the point where the dithering disappears, but also because it is easy to perform this test with regular material where no test patterns are available. For example I don't have any way to generate test patterns for HDTV. But if watching the right show its easy to find an occassional area of the screen that is supposed to be showing all black. Therefore you have a great reference for setting black level with regular material!


Now Guy - getting back to your approach - here's what I'm planning to do next. I'm going to put VE into 4:3 mode with black bars. Then I will tweak it so that there is no dithering in the 4:3 black side bars, and just a bit of dithering in the darker black bar.


Actually I'm wondering if this will be possible. From what I recall last night when standing at the screen there was no darker bar at the point where the dithering disappeared from the 4:3 bars with one of the bars still visible. Are you certain the darker bar is 1% above black? If so are you sure that one click of brightness can adjust with enough granularity to account for just a 1% difference in black?

 

[Guy Kuo]

"Are you certain the darker bar is 1% above black? If so are you sure that one click of brightness can adjust with enough granularity to account for just a 1% difference in black?"


If we are still talking about AVIA then yes. The darker one of the moving bars is 1% above digital black. As for granularity of the controls on the projector, I can't speak for the projector manufacturer. If the darkest bar can't be seen when you achieve zero dither in the black background, then the overall system is losing the very dimmest black details somewhere along the processing chain.


If you are talking about VE's PLUGE blacker than black bar, then remember that it is considerably below digital black so there shouldn't be any dither see in it. Just be sure that you don't turn down brightness too far using VE, just go dim enough such that the background is just dither free and no further down. The PLUGE patttern's brighter bar is several times higher above digital black than either of the bars in AVIA. So, if you see that bar go black, you are really way way too far down in brightness.

 

[glenned]

In Avia, the standard needle pulse and steps pattern to set Contrast (Max White Level) works for digital PJs just the way that Avia's instructions explain. Increase Contrast until one of the two moving white bars fades into the white background and dissappears. An easy test afterward is to put a 100 IRE pattern on screen and increase the Contrast until the screen does not get any brighter. Set Contrast at the lowest setting which gives you the brightest white. Both of these techniques give the same result.


Guy is right about how to set Black levels, and about the diferences between Avia and VE. In Avia, I use the the moving black bars on an all black field, or the moving black bars on a half grey field to set Brightness. It is easier to see the lighter bar and the change in dithering in the black background using those test patterns rather than the standard pattern where half the screen is white and the other half is black with moving black bars. That pattern is intended for certain CRTs that vary black levels based on the average brightness of the display.