It's funny about video vs. pc levels. Seems everyone has a different opinion as to which should be used, L1 or L2 and what devices require one or the other. I wish someone had a definative answer but we seem to flip flop back and forth on the subject. I can't recall who it was, but another AVS super veteran dropped in on this thread for one or two posts many many months ago and basically said to use L1 for stand alone DVD player because they are calibrated to video levels (reference black is at 16), not PC levels. He also said that most software DVD players like TheaterTek and MCE are also calibrated to video levels or L1. I do know that when I used any L2 setup including ROne's with my DVB318 player, it looked horrible with a white haze and washed out colors. When I switched to L1, poof, it was great (although a bit too dark). Same with my MCE PC. I'm going on a google mission today and try to really figure out what the deal is. I wish I could find a reliable website that really explains it in full detail.
update - here are some posts on AVS about setting up a HTPC for these levels. Unfortunately nothing about a DVD player, however, after reading it, the more convinced I am that L1 or RGBStudio levels is the proper setting. It seems that even for software dvd that's the case, although the thread is pretty confusing and I only quickly breezed through it.Levels Thread #1Levels Thread #2
I found this in a review for a Denon DVD player. It gives us a bit of info for what to use for DVD players. I think the key is that DVD video is usually tuned to RGBStudio levels thus it seems appropriate to use L1. If your DVD player can be set to PC levels (enhanced black etc...), then L2 would work, however, why would you do this if the people who engineered the DVD used Studio levels for black/white? Here's what the Denon review said:
The video output can be selected in the setup menu for either PC RGB levels or Studio RGB levels. Unless your display is set up for PC RGB levels, we always recommend using the studio RGB output which allows for below-black and above-white information.
OK, found this FAQ info on AVS and I think it basically supports the thought that using L1 is correct, not L2 for both HTPC and DVD. If I've missed something in the mix, let me know but I'm fairly certain L1 is the ticket.
Projectors with digital inputs have to be able to handle both video applications and computer graphics applications. They should be able to calibrate or switch their white and black levels to accommodate both Studio levels and PC levels, but some don't. Because video sources and graphics sources may be used simultaneously in some applications, video source manufacturers tend to include an option to leave the digital outputs at Studio levels, or to re-map them to PC levels.
Mapping Studio levels to PC levels can be done a few ways. Sometimes all the levels are just shifted down 16 steps, thus clipping off BTB data, but not introducing banding/contouring or clipping highlight details. If there are other PC level sources fed to the display, their whites will be substantially brighter. This is undesirable. Usually the levels are expanded: digital 16 (black) is shifted down to 0, and 235 (white) is shifted up to 255 (or sometimes a value slightly lower than 255) thus expanding the numerical range between black and white. In this case, re-mapping Studio levels to PC levels will destroy BTB and peak white image data, and introduce banding/contouring artifacts because of the expandion. This is also undesirable.
Always try to maintain Studio levels whenever possible in your system. You should use Avia PRO or DVE to test whether or not levels are being clipped. Both discs contain patterns with both BTB and peak white data. Note that the current consumer Avia does not, it only contains data in the range or 16-235. Thus if BTB or peak white data is being clipped, you won't see it with Avia! If you are clipping the black or white bars in Avia, then your system is doing even more severe damage to the video by clipping above black shadow details and below-white detail: very bad! Note that Avia PRO also has some very useful ramp patterns with levels encoded at equal width so as to be completely banding-free. These are very useful for observing banding/contouring caused by the playback system.
...In any case, I just reiterate that it is important to design your HTPC and settings purposefully so that you can maintain Studio RGB for video playback, and calibrate your display to this and not to the graphics' PC RGB levels.
For DVD players when using a digital output (DVI, HDMI).
When using digital outputs, your primary concern is to get the DVD's image data output as undisturbed as possible. As simple as this might seem, design/price constraints, sloppy engineering, and features' can get in the way of transferring the digital data from the DVD intact. Always try to avoid using any image-altering features such as picture controls. These adjustments will usually have negative impacts on picture quality.
When using digital outputs, the major adjustment option you have is the one for digital levels. As is common in consumer labeling, the labels for this can be confusing. The most common labeling will at least hopefully show that you are making an adjustment to the DVI/HDMI digital outputs, and usually the options will read Normal/Enhanced' or Normal/Expanded' or Video/PC,' or some such label. The latter is clearer, as this adjustment is choosing whether or not the digital image data is correctly output using Studio (also called Video) levels, or is incorrectly re-mapped to PC levels. You should choose to maintain Studio levels by checking to make sure this option is properly set. Usually the default setting will correctly choose the option for Studio levels. Check to make sure.
Note that the Studio/PC level option will only work for DVI and HDMI RGB. If you are using HDMI YCbCr, Studio levels should be preserved correctly(and as far as I'm aware sources aren't screwing this up, yet) and the option change will either have no effect or be unavailable.
Because you are using digital outputs, adjustments for analog outputs shouldn't be a consideration. Unfortunately again, due to cost-saving designs, sometimes analog output adjustments, such as those for IRE setup, are implemented digitally even though they have nothing to do with digital outputs. Here your concern is still to ensure that the digital image data is being left as undisturbed as possible. In a well-designed player, the IRE option will have no effect whatsoever when using digital outputs. If this setting causes any change in the image when using the digital outputs, you should use test patterns to see which option leaves data un-clipped. In this instance, the degree of clipping or image alterations may be severe, so Avia, DVE, or any good test disc will come in handy. In Avia, look for the moving near-black and near-white white bars; in DVE use the ramps (Title12:Chp14) and check for clipping (if you have access to Avia PRO, the Deep Ramps are excellent tests!). Use the IRE setup setting that maintains as much data as possible through to your display. The default setting may more likely be the preferred setting. Default is usually the 7.5IRE setting. This was reported to be the case on the Denon 3910; users should test this on their players and share model-specific observations to aid others!
With the hope that digital levels and IRE are conceptually disentangled, you should understand that the IRE setup option is really for the analog output, and shouldn't have to be discussed when using digital outputs. Unfortunately, instead of implementing these analog adjustments in the analog domain, cost-conscious designs seem to be altering the digital values, which necessitates double-checking this option to make sure your digital levels are not being tampered with.
If you are using an HTPC, I will dodge the complex arena that is computer video, and merely recommend strongly that you do your best to maintain Studio levels and prevent your computer from expanding the video to PC levels. To check this, examine deep ramps on Avia PRO, or use the ramps and PLUGE patterns on DVE. Note that consumer Avia does not contain data outside the bounds of reference black/white (16-235) so you will not be able to observe the clipping of data outside these bounds using Avia. Moving to PC levels will usually clip data 1-15 and 235-255; this data is present in the ramps and PLUGE patterns on DVE (T12 Chps 13-15) and in many patterns on Avia PRO.
Remember that proper playback of video requires Studio levels to maintain the full range of image data, including that data outside the bounds of reference black/white. Achieving this on a PC can be difficult, and it also means that your desktop and your video cannot both look correct at the same time. Expanding your video to match PC levels (0-255) will make your desktop and your video agree' and eliminate the need to recalibrate, but you've also negatively impacted video playback by clipping useful image data and introducing banding/contouring artifacts. This is undesirable, you should strive to maintain Studio levels if at all possible.