CRT simulation (2014) • Hacker News Board

Re: CRT simulation (2014)

#31

Post by mrob » Mon, Apr 13, 2015, 9:57 AM UTC

pdkl95 wrote: post #30

wtallis wrote: post #16

Earlier quoted context omitted.

In what respect do you think CRTs had universally inferior image quality: viewing angles, contrast, brightness, gamut, color accuracy, spatial resolution, or something else?

CRTs have significantly better motion and latency. The LCD ghosting problem is well-known, and while some more modern screen have minimized the problem, there can still be some ghosting errors depending on the input. Gamut doesn't matter when you have previous frames ghosting over thing More importantly, LCDs buffer a least one frame. Many buffer 3-5 frames (!). This can be a serious problem playing for video games o…

It's very common for LCDs to buffer, and if you're strobing then buffering at least one frame is required to prevent artifacts (although one frame at 144Hz is much less serious than one frame at 60Hz). However, there's nothing inherent in the technology that requires frame buffering and I've seen many benchmarks of LCDs with less than one frame of latency. If you look at high speed camera footage of LCDs you usually see them update with a CRT style raster scan:

https://www.youtube.com/watch?v=nCHgmCxGEzY

Re: CRT simulation (2014)

#32

Post by DiThi » Mon, Apr 13, 2015, 11:02 AM UTC

Aqwis wrote: post #2

Why the motion trails? The Mario example doesn't have them and I can't recall any extreme motion trails from my days of playing console games on CRT TVs.

> One unfortunate downside to this implementation of trails is that it depends on having a consistent frame rate; it has been tuned for 60fps and will not behave exactly as expected at other rates or if vsync is disabled.

It's a very subtle effect, and probably absent in more recent CRTs.

Re: CRT simulation (2014)

#33

Post by pdkl95 » Mon, Apr 13, 2015, 12:23 PM UTC

mrob wrote: post #31

pdkl95 wrote: post #30

Earlier quoted context omitted.

CRTs have significantly better motion and latency. The LCD ghosting problem is well-known, and while some more modern screen have minimized the problem, there can still be some ghosting errors depending on the input. Gamut doesn't matter when you have previous frames ghosting over thing More importantly, LCDs buffer a least one frame. Many buffer 3-5 frames (!). This can be a serious problem playing for video games o…

It's very common for LCDs to buffer, and if you're strobing then buffering at least one frame is required to prevent artifacts (although one frame at 144Hz is much less serious than one frame at 60Hz). However, there's nothing inherent in the technology that requires frame buffering and I've seen many benchmarks of LCDs with less than one frame of latency. If you look at high speed camera footage of LCDs you usually…

I should clarify - I am speaking about the 60Hz LCDs found ~everywhere. Unfortunately, I cannot afford one of the newer fancier >60Hz models, and so I have little experience with them.

Once of the sources of multiple-frames of latency was the scaling/resampling stage that was needed to be compatible with non-native resolutions. Some of those algorithms are very slow. A friend of mine that makes FPGAs used in some LCDs has suggested that this slowness may be because the company making the monitor is too cheap to buy parts that were fast enough. That was a few years ago, though, so maybe these newer 144Hz monitors improved the situation.

Re: CRT simulation (2014)

#34

Post by _tzxu » Mon, Apr 13, 2015, 1:12 PM UTC

tdicola wrote: post #3

I love these CRT shaders but have always wondered, has anyone thought about or worked on a physically accurate simulation of a CRT television? Something that takes a framebuffer as input and simulates the electric signals that control the magnets around the tube, how those magnets affect the electron beam, how the beam interacts with the shadowmask, etc. elements in the front of the tube, and finally how each individ…

This ..... redefines the concept of "ray tracing" as I know it. An interesting proposition. Wonder if you could write a pov-ray module for this.

Re: CRT simulation (2014)

#35

Post by justifier » Mon, Apr 13, 2015, 4:02 PM UTC

rasz_pl wrote: post #14

tadfisher wrote: post #6

This technique is very important for emulation and simulating the look of early games. For example, the Genesis/Mega Drive did not support hardware alpha transparency. Many games (including the Sonic series) simulate the effect by alternating vertical lines, and relying on the "visual munging" of CRTs to produce a convincing effect. Here is a video that demonstrates the effect in Shinobi 3: https://youtu.be/YFOkbfpIl…

>This technique is very important for emulation and simulating the look of early games Why? I dont see people emulating the look and feel of 1920 black and white film projection, or Edison sound cylinders. Its because quality was SHIT, just like CRT.

i am less convinced

i read a long time ago someone's interpretation of the history of film as being invented in reverse: starting with impressionism and developing hyper realism;

it's an overly simplistic break down with all the standard caveats but it has a certain amiable pithiness to it

look at some of these movies that are attempting higher frame rates and you'll see the audience is suddenly unimpressed by the same set tricks and computer effects that were stunning them days before in another film at lower frame rates

i remember the first time i saw an HD tv that i was truly impressed by they were playing a battle scene from film i had seen many times before, i walked by and stopped in my tracks because the wall mount appeared to be a window, the title characters were riding horses on an expanse of pasture before the battle, it was stunningly beautiful, but after some dialogue they took off running down a hill to meet another army and the camera panned back and i could very easily pick out which ten of the hundreds of charging horses were real and which were drawn in triangles, i could nearly count the triangles

very similar to the effect while watching an animated film with lush painted backdrops: you see a forest scene and you just know that one tree branch is going to break off because it was painted by the animators and the hue and stroke is just slightly off

i think efforts like the one in the article, and the one in the comment above linking the shinobi 3 video, may come prebaked into visual media

i buy a copy of iron man 3 in the year 2071 and it will display on my super pixel screen in such a way to make it appear like it is being watched on the tech it was built for, smudging those lines between organics and triangles

with the option to turn it off, then right back on again