4 ms·

"Viewing angle and speed of refresh are rather critical for arcade machines, and both are largely solved problems for LCDs at this point" This is true, but not

by mrob 10y ago

"Viewing angle and speed of refresh are rather critical for arcade machines, and both are largely solved problems for LCDs at this point" This is true, but not for the cheap IPS LCDs he advocates. The important point is image persistence. Each frame is a sample of a single point in time. To accurately represent motion it needs to be shown for as close to a single point in time as possible. Most LCDs sample-and-hold, i.e. they set the pixel and keep it there until the next frame. This results in blurring when your eye tries to follow motion. See: http://www.blurbusters.com/faq/references/ http://www.blurbusters.com/faq/references/ Modern gaming LCDs can strobe the image like a CRT, eliminating this blur. It causes noticeable flicker at 60Hz, but it's the only way to get sharp looking motion from these fixed framerate games (motion interpolation adds latency which is no good for games).

speeder 10y ago
I wish someone would ressurect crt or come up with similarly cheap tech. I own lots of monitors, but after I tried my CRTs again recently, I fell in love with them again, the image itself, and the motion is much better than any flat panel that is affordable. (Also my CRTs aren't high end even! they were medium range, or outright cheap when I bought them new, one is even 1024x768, that now feels too small, but the image quality overall is soooo awesome...)
- spikej 10y ago
  ... and Duck Hunt! :P
- overcast 10y ago
  SED(Surface Conduction Electron Emitter Display) was what I was most excited for, and it died before it got started. It's basically a matrix of tiny CRT monitors. https://en.wikipedia.org/wiki/Surface-conduction_electron-emitter_display https://en.wikipedia.org/wiki/Surface-conduction_electron-em...
  - mrob 10y ago
    SED doesn't have the high quality motion of a CRT or a strobed LCD because it's PWMed. You will either see ghost images trailing motion, or sample-and-hold blur, depending on the PWM frequency.
codinghorror 10y ago
I don't know that arcade monitors from the 80s had zero ghosting or phosphor persistence. And a TN display is going to sacrifice so much on angle of visibility that I don't know if 120hz updates are worth it. That said it is an interesting aside and there are a few more details here http://www.mameworld.info/ubbthreads/showflat.php?Number=305674 http://www.mameworld.info/ubbthreads/showflat.php?Number=305...
amelius 10y ago
In real life there is also blurring, because of the finite speed of the human retina. So perhaps CRTs are actually too sharp because they miss the blurring of the intermediate pixels (unless you can correct this in software).
- mrob 10y ago
  No display device can bypass blurring caused by finite speed of the human retina because it is viewed by the human retina. The blurring we are talking about takes place during "smooth pursuit" eye movement, where the eye tracks the moving object. During smooth pursuit a real moving object makes a static image on the retina. A strobed display makes a series of static images on the retina, and the human brain is very good at interpreting intermittent short images as motion (consider hunting a small animal through thick vegetation) so this also looks good. The sample-and-hold display presents a series of moving images on the retina when you are expecting a static image, and this is seen as blur. CRTs are actually less sharp than real life because of non-zero phosphor decay time. A modern gaming LCD can be sharper than a CRT because LEDs can turn off faster than phosphors.
  - amelius 10y ago
    What I meant is the following. Consider two frames of a video. In the first frame, a colored dot is at position (0,0). In the second frame, a colored dot (same color) is at position (10,0). The eye/brain interprets this as a dot traveling from the far left of the screen to the right by 10 pixels distance. Now, to the eye, there are 9 pixels missing between the two dots. In reality, if a dot was moving, those 9 pixels would have been briefly lit up on the retina. Hence, you need some blurring to make a sequence of frames appear to be realistic.
    - mrob 10y ago
      Although higher framerate is preferable, the brain can easily interpret the motion despite the missing information. There is no blurring in reality, so adding blur only makes things worse.
bitwize 10y ago
Oh great, that's just what we need, the return of flicker. Now my sister can get sick when attempting to play games again, just like the old days. Besides which, I thought the particular way CRTs blur and ghost was part of the appeal?

by mrob 10y ago

speeder 10y ago

I wish someone would ressurect crt or come up with similarly cheap tech. I own lots of monitors, but after I tried my CRTs again recently, I fell in love with them again, the image itself, and the motion is much better than any flat panel that is affordable. (Also my CRTs aren't high end even! they were medium range, or outright cheap when I bought them new, one is even 1024x768, that now feels too small, but the image quality overall is soooo awesome...)

spikej 10y ago
... and Duck Hunt! :P
overcast 10y ago
SED(Surface Conduction Electron Emitter Display) was what I was most excited for, and it died before it got started. It's basically a matrix of tiny CRT monitors. https://en.wikipedia.org/wiki/Surface-conduction_electron-emitter_display https://en.wikipedia.org/wiki/Surface-conduction_electron-em...
- mrob 10y ago
  SED doesn't have the high quality motion of a CRT or a strobed LCD because it's PWMed. You will either see ghost images trailing motion, or sample-and-hold blur, depending on the PWM frequency.

codinghorror 10y ago

I don't know that arcade monitors from the 80s had zero ghosting or phosphor persistence. And a TN display is going to sacrifice so much on angle of visibility that I don't know if 120hz updates are worth it. That said it is an interesting aside and there are a few more details here http://www.mameworld.info/ubbthreads/showflat.php?Number=305674 http://www.mameworld.info/ubbthreads/showflat.php?Number=305...

amelius 10y ago

In real life there is also blurring, because of the finite speed of the human retina. So perhaps CRTs are actually too sharp because they miss the blurring of the intermediate pixels (unless you can correct this in software).

mrob 10y ago
No display device can bypass blurring caused by finite speed of the human retina because it is viewed by the human retina. The blurring we are talking about takes place during "smooth pursuit" eye movement, where the eye tracks the moving object. During smooth pursuit a real moving object makes a static image on the retina. A strobed display makes a series of static images on the retina, and the human brain is very good at interpreting intermittent short images as motion (consider hunting a small animal through thick vegetation) so this also looks good. The sample-and-hold display presents a series of moving images on the retina when you are expecting a static image, and this is seen as blur. CRTs are actually less sharp than real life because of non-zero phosphor decay time. A modern gaming LCD can be sharper than a CRT because LEDs can turn off faster than phosphors.
- amelius 10y ago
  What I meant is the following. Consider two frames of a video. In the first frame, a colored dot is at position (0,0). In the second frame, a colored dot (same color) is at position (10,0). The eye/brain interprets this as a dot traveling from the far left of the screen to the right by 10 pixels distance. Now, to the eye, there are 9 pixels missing between the two dots. In reality, if a dot was moving, those 9 pixels would have been briefly lit up on the retina. Hence, you need some blurring to make a sequence of frames appear to be realistic.
  - mrob 10y ago
    Although higher framerate is preferable, the brain can easily interpret the motion despite the missing information. There is no blurring in reality, so adding blur only makes things worse.

bitwize 10y ago

Oh great, that's just what we need, the return of flicker. Now my sister can get sick when attempting to play games again, just like the old days. Besides which, I thought the particular way CRTs blur and ghost was part of the appeal?