I wonder if this is so 'generic' that e.g. AppleTV could add support for this? Take a photo of your TV with an iPhone when AppleTV is showing test image. And then the AppleTV output is calibrated appropriately to compensate for uneven backlight.
TV backlight compensation (2020)
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Re: TV backlight compensation (2020)
#12Clever solution! It kind of reminds me of when I sometimes run sound through customized EQ and compression to compensate for crappy speakers. My approach is not quite as scientific as this though, just "tweak until it sounds good." I didn't know there was a version of MPC with a live shader editor, that is also very cool. This is actually a pretty good use case for such a feature.
My home receiver came with a microphone. You plug it in and the receiver blasts noise through the speakers, and comes up with EQ to compensate automatically. This wasn’t an expensive receiver, either.
If you want a more scientific approach, you can use a tool like Room EQ Wizard, which is free—although it works best if you have some kind of flat response microphone, or calibrated microphone with a known response curve.
(I’ll also add that you’re compensating for crappy acoustics in your room as much as you are compensating for crappy speakers.)
Re: TV backlight compensation (2020)
#13Earlier quoted context omitted.
I think the reasonable solution is: Buy a new TV. We're not talking about a jumbotron display here. A cheap new TV with proper color is likely very inexpensive.
Why create waste when it's not necessary?
If you're not doing it as a hobby, the one-off effort put into repairing an item (or in this case, engineering the correction) is also "waste".
If you want to dedicate that time to improving the planet, avoiding the waste of one TV is likely not a better use of your time than e.g. fixing some bug in some popular open source software that causes it to be less efficient.
Let's say you make a change to Firefox that makes it use 0.1 Watt less on average, and let's be conservative and assume the ~350 million Firefox users use it for one hour a day on average. That's 35 MWh per day saved. Assuming 0.1 kg CO2e/kWh, that's a saving of 3.5 tons of CO2e saved each day.
Re: TV backlight compensation (2020)
#14I wonder if this is so 'generic' that e.g. AppleTV could add support for this? Take a photo of your TV with an iPhone when AppleTV is showing test image. And then the AppleTV output is calibrated appropriately to compensate for uneven backlight.
There are already some companies that let you calibrate your TV's colors with your phone camera. Apple TVs do it and adjust the output signal while some new Samsung TVs can do it and actually apply hardware calibration. Adjusting for unevenness in the same way seems potentially harder but doable.
Re: TV backlight compensation (2020)
#15Earlier quoted context omitted.
Why create waste when it's not necessary?
If you're not doing it as a hobby, the one-off effort put into repairing an item (or in this case, engineering the correction) is also "waste". If you want to dedicate that time to improving the planet, avoiding the waste of one TV is likely not a better use of your time than e.g. fixing some bug in some popular open source software that causes it to be less efficient. Let's say you make a change to Firefox that make…
Fair point, but I bet that making Firefox take 0.1W less on average is vastly more work that fixing a TV image. And if you write blog post about it, maybe other people can fix their TV with less work.
Re: TV backlight compensation (2020)
#16I wonder if this is so 'generic' that e.g. AppleTV could add support for this? Take a photo of your TV with an iPhone when AppleTV is showing test image. And then the AppleTV output is calibrated appropriately to compensate for uneven backlight.
There are already some companies that let you calibrate your TV's colors with your phone camera. Apple TVs do it and adjust the output signal while some new Samsung TVs can do it and actually apply hardware calibration. Adjusting for unevenness in the same way seems potentially harder but doable.
Isn't this done with a ICC profile and a lookup table, in which case varying or across the screen does not sound feasible?
Re: TV backlight compensation (2020)
#17I wonder if this is so 'generic' that e.g. AppleTV could add support for this? Take a photo of your TV with an iPhone when AppleTV is showing test image. And then the AppleTV output is calibrated appropriately to compensate for uneven backlight.
Calibrating color with an iPhone is already a feature in tvOS, so correcting for local errors looks like a nice improvement in that direction.
Re: TV backlight compensation (2020)
#18This is such a cool idea and execution. I also like the DIY approach to patching MPC BE yourself, which shows how far OSS can take you. I wonder, when applying a linear transformation like in the shader described, will the total available color space decrease? Simply put, if a one-dimensional color value on the arbitrary scale between 1 and 100 needs to be decreased by 20 for correction, the resulting maximum will be…
Mostly yes but it also depends. What happens is exactly that, there will be a clipping in the color band(s) you are correcting for.
This can easily be verified with a simple thought experiment: imagine an area is almost completely red. This area will have to be complemented with full blast of green and blue to even achieve white, or partial blast of green and blue to achieve gray.
It can not achieve any color without a red component, hence reducing the area of the color triangle for that part of the screen.
Re: TV backlight compensation (2020)
#19Clever solution! It kind of reminds me of when I sometimes run sound through customized EQ and compression to compensate for crappy speakers. My approach is not quite as scientific as this though, just "tweak until it sounds good." I didn't know there was a version of MPC with a live shader editor, that is also very cool. This is actually a pretty good use case for such a feature.
I use AutoEQ (https://github.com/jaakkopasanen/AutoEq) for my headphones. It works by "parsing frequency response measurements and producing equalization settings which correct the headphone to a neutral sound". They also have a huge database of already measured and equalized data, which is what I use.
Re: TV backlight compensation (2020)
#20Earlier quoted context omitted.
OLED TVs already compensate for burn in. A lot of your pixels are probably already somewhat "burnt" but you can't perceive it due to the corrective measures your TV takes. You'll only really notice it when it's irredeemably bad.
OLED TV's try to prevent burn in, I am not sure it can compensate burn in
I don't see how the TV can compensate for the burnin without having an external picture of the screen.
I have a couple of years old OLED TV, and it has burn in... The Netflix logo, the netflix animation, and subtitles are quite visible all the time now. This is despite running periodically the TV pixel refresh or however it is called...