[infinitesymphony]

I have a question about calibrating picture quality. Both TVs and DVD players have internal picture quality adjustments, so...

How is it possible to calibrate a TV and a DVD player independently of each other?

 

[JadeEast]

What picture quality setting does the dvd player have?

 

[infinitesymphony]

Most mid-fi and better DVD players have brightness, contrast, color/saturation, tint/hue, sharpness, etc.

Almost everything you'd see on a TV.

 

[JadeEast]

I've never even looked for the picture controls on a dvd player.That could screw a whole bunch of stuff up having two separate devices with different calibration. Doesn't make much sense to me unless you encountered a monitor without adjustments or the player had gone bad. I don't think you can monitor the adjustments at home with the two devices.

One could run color bars out of a dvd player into a waveform/vectorscope and adjust the output of the player until it's output was calibrated. You would still would have to adjust the monitor to the signal from the dvd player.

I can see some usefulness to the ability to do so now that I think about it.

If one were to have their monitor calibrated to a know good signal and then adjusted all sources to "spec" you would then have multiple sources calibrated and the monitor would stay as is. At work I'm a video editor and the monitor stay as is across multiple sources and the signal is adjusted in the the video hardware along the way. Material is provided with color bars for the most part and each is adjusted on input to a calibrated standard. Adjusting the monitor for each source would leave you with no standard to judge from as the goal post would keep moving.

If one were to set up their monitor with a known good source and then switch to the dvd player running the same calibration material and then adjust the new source to match. You would have two calibrated devices the outputs of both the monitor and the dvd player.

Much easier to just calibrate the monitor to a single source and leave it as the standard.

 

[infinitesymphony]

Thanks, JadeEast. You make some great points. It seems that the only way to calibrate both would be to have a third pre-calibrated device.

One potential problem with TV calibration via a DVD test disc is that the TV is then calibrated to the potential flaws of the DVD player. Watching TV with other devices (cable boxes, video games) might suffer, especially if the DVD player has poor color and brightness responses.

I wonder what Secrets of Home Theater and High Fidelity use for their shoot-out to measure video frequency response...

 

[Davesrose]

Just wondering.....but wouldn't a DVD player not even have color controls if you're outputting via HDMI? I do know older component models do have menus where you can adjust brightness, contrast, tint.....but I would think that one of the other benefits of digital HDMI is not having the DVD player having to decode a picture.

Actually, this digital connection is the main thing that's noticable for me with an upconverting DVD player: seems much crisper then my DVD's component.....but it's probably more to do with my TV's video decoder over my DVD's.

 

[infinitesymphony]

Quote:

Originally Posted by Davesrose /img/forum/go_quote.gif Just wondering.....but wouldn't a DVD player not even have color controls if you're outputting via HDMI? Actually, this digital connection is the main thing that's noticable for me with an upconverting DVD player: seems much crisper then my DVD's component.....but it's probably more to do with my TV's video decoder over my DVD's.

Good question. Some people prefer the scaler in an upconverting DVD player, while others find that the one in their TV does a better job.

Still... Why would the color controls be disabled? The DVD player is still responsible for the quality of video reproduction, even if it's not the device performing the upconversion. HDMI doesn't necessarily mean that the receiving device is performing the upconversion. If the DVD player is set to output at 480p to a TV with a native resolution of 1080p, the TV will act as the scaler, whereas if an upconverting player is set to output at 1080p, the TV will just accept the pre-scaled signal. At least, that's my understanding of it.

 

[Davesrose]

Quote:

Originally Posted by infinitesymphony /img/forum/go_quote.gif Still... Why would the color controls be disabled? The DVD player is still responsible for the quality of video reproduction, even if it's not the device performing the upconversion. HDMI doesn't necessarily mean that the receiving device is performing the upconversion. If the DVD player is set to output at 480p to a TV with a native resolution of 1080p, the TV will act as the scaler, whereas if an upconverting player is set to output at 1080p, the TV will just accept the pre-scaled signal. At least, that's my understanding of it.

But since HDMI is digital.....the TV wouldn't be getting a traditional "color" picture. The DVD player might still be processing the digital data (to upconvert resolution)....but if it's digital, it shouldn't be outputting the final color values....as the TV would have to do that when it decodes digital to analog. It should be getting seperate color channels that the TV would have to blend to actual color pixels. I don't know enough about video....but wiki says HDMI can either be RGB 4:4:4, YCbCr 4:4:4 (8–16 bits per component); YCbCr 4:2:2 (12 bits per component). Not sure what the contrast range is now for large screen TVs.....but it would be awesome when they get to 16bpc HDR colors. Anyways, it's more efficient for the TV to do that kind of decoding.

http://en.wikipedia.org/wiki/HDMI

 

[infinitesymphony]

Hmm... I don't own any equipment with HDMI at the moment. Is it possible for you to try changing some of the color/brightness/sharpness settings on your DVD player, then verifying if they appear over HDMI?

If digital video signals operate like digital audio, it would be a matter of reading the information from the disc and passing it to a decoder at some point. If this were true, wouldn't all DVD players appear to have the same picture over HDMI (assuming that the same TV is used)?

 

[Davesrose]

Quote:

Originally Posted by infinitesymphony /img/forum/go_quote.gif Hmm... I don't own any equipment with HDMI at the moment. Is it possible for you to try changing some of the color/brightness/sharpness settings on your DVD player, then verifying if they appear over HDMI?

My component DVD player does have brightness and contrast settings.....but my HDMI upconverting player does not have any color/ brightness settings on it. Also, my TV doesn't scale any HD resolutions....so it would not change aspect ratio or the amount of vertical lines. Hince my theory that digital doesn't really convey color the same way analog would.

The difference in digital video is just like there is with digital audio.....with digital audio, you can hear subtle differences in source....even if you keep the same DAC. The disc reader is doing its own job of reading the data stream and doing any error correcting of it (and in the case of upconverting....actually applying algorithms to scale it).

 

[Artemio]

The general procedure is to leave teh dvd player all set to default, calibrate the TV with either Avia, DVE or the new HD DVE and then trying other sources that can play dvds (game consoles, etc) to find if it is alright. You can then do some minor adjustments, fine tuning from teh dvd player, but in general it is not a good practice. I've found setups in which this has helped though.

Regarding scalers, usually the DVDs make a better job... but Sony and LG usually don't in either end anyway. For that I'd recommend getting the SD version HQV disc to test the scaler if you are so inclined. My findings have been that Tvs usually have really bad upscalers.