Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Bouncing DVD Logo

bouncingdvdlogo.com

Post reply on HN
Print view View original

281–290 of 293 posts

Re: Bouncing DVD Logo

#281

Post by aasasd »

blattimwind wrote: post #196
aasasd wrote: post #165

Earlier quoted context omitted.

I still don't know what it is about 60 Hz that made me see the flicker plainly as a strobing light. TVs at 50 Hz—nothing (other than being generally bleh back then). Had to use 800x600 instead of 1024x768 just to have 85 Hz instead. On LCDs, I still can see faint flicker on some static backgrounds, and I think 60 Hz might play a role here too—though it seems to also depend on the brightness and Flux being on or off.…

Three reasons: You sit much closer to a computer screen compared to a TV, so your peripheral vision has a better chance with the computer screen to see flicker. Computer CRTs supported higher refresh rates, so they used phosphors with shorter afterglow (otherwise you'd get ghosting/S&H-like artifacts like TFTs produce). You can notice this one when you photograph a computer CRT vs. photographing a TV with the same sh…

Btw, I count only two reasons there.

Re: Bouncing DVD Logo

#282

Post by segfaultbuserr »

dmos62 wrote: post #279
segfaultbuserr wrote: post #274

Earlier quoted context omitted.

I don't think it was a major concern. First, you can always display a dummy black image without turning off the CRT. Also, VESA defines two "off" modes in DPMS (1993): blank and fully off. "Blank" allows the monitor to partially suspend without shutting down the CRT completely, which allows an instant recovery.

Might as well have an animation, as opposed to "black light"?

> as opposed to "black light"

BTW, the "black" on a CRT is almost a true black. The electron beam is off when the signal voltage is less/equal to the black level, there's no "black light" if the black level is perfectly calibrated. Displaying a black image fullscreen is indistinguishable from an endless vertical/horizontal blanking interval from a practical standpoint. There's a measurable decrease in power consumption, although it's not much (it can be great enough on a large TV, though).

On the other hand, VESA blanking mode turns off additional circuitry, and it can save a lot of power while still keeping the CRT heater on, suspending the screen without the disadvantages of a long wakeup time or stressing the tube.

Re: Bouncing DVD Logo

#283

Post by blattimwind »

aasasd wrote: post #281
blattimwind wrote: post #196

Earlier quoted context omitted.

Three reasons: You sit much closer to a computer screen compared to a TV, so your peripheral vision has a better chance with the computer screen to see flicker. Computer CRTs supported higher refresh rates, so they used phosphors with shorter afterglow (otherwise you'd get ghosting/S&H-like artifacts like TFTs produce). You can notice this one when you photograph a computer CRT vs. photographing a TV with the same sh…

Btw, I count only two reasons there.

(1) You sit much closer ... (2) Computer CRTs supported ... (3) And at the end ...

Re: Bouncing DVD Logo

#285

Post by Lammy »

chrisseaton wrote: post #239
dmos62 wrote: post #234

Earlier quoted context omitted.

You're talking about the most popular movies that were transfered to digital or even restored. Most films weren't. Plus, we lost immense amounts (most) of cinema that was produced before ~1950s when better film started being used.

> You're talking about the most popular movies that were transfered to digital or even restored. Most films weren't. How are you watching a film on DVD if it hasn't been transferred to digital?

DVDs have been around for over twenty years. There are plenty of things that were released on DVD but now hang in license limbo due to a publisher going out of business or whatever. There may have been a transfer done for a DVD release that would need to be re-done for HD, and that all takes time, money, usually personal interest of some sort, and of course the physical items still have to exist (2008 Universal Studios vault fire, anyone?)

Re: Bouncing DVD Logo

#286

Post by hunter2_ »

TylerE wrote: post #175
aasasd wrote: post #165

Earlier quoted context omitted.

I still don't know what it is about 60 Hz that made me see the flicker plainly as a strobing light. TVs at 50 Hz—nothing (other than being generally bleh back then). Had to use 800x600 instead of 1024x768 just to have 85 Hz instead. On LCDs, I still can see faint flicker on some static backgrounds, and I think 60 Hz might play a role here too—though it seems to also depend on the brightness and Flux being on or off.…

AC power is 60hz so room lighting (especially florescent) also flickers at 60hz. It’s a sort of wagon wheel effect.

Fluorescent lighting, assuming it's not starting to fail, flickers at 120 Hz because each half cycle lights it up equally (+ or - doesn't matter). Incandescent also has 120 Hz flicker but the valleys are almost as bright as the peaks (slow response) so it's essentially imperceptible.

Cheap LEDs like some holiday minilights are rectified so they'll flicker at 60 Hz and I can't stand them.

Re: Bouncing DVD Logo

#287

Post by hunter2_ »

TylerE wrote: post #265
aasasd wrote: post #176

Earlier quoted context omitted.

I dropped a hint right there that the AC frequency is definitely not 60 Hz where I am.

Actually you didn't. There were many countries that used PAL for TV broadcasts but have 60hz AC.

They didn't say PAL, they said "50 Hz TV."

PAL and 50 Hz TV are not synonymous. Brazil has 60 Hz AC and uses PAL-M which is 60 Hz TV. AC=TV even in these odd cases.

Old CRTs couldn't possibly clock their flyback to anything but mains.

Re: Bouncing DVD Logo

#290

Post by Fnoord »

hunter2_ wrote: post #159
function_seven wrote: post #151

Earlier quoted context omitted.

It does. I’m sure most people don’t think the quality difference is worth the hassle of storing physical discs and paying for them. Compressed 1080 is good enough.

A decent number of streaming services have very good 4K and all you need is a Chromecast Ultra with a $200 TV to make it all work.

True, except now in EU, the bitrate of 4k streaming is low because the EC asked companies to reduce it. This because of the COVID-19 pandemic leading to everyone [who can] being required to work from home.
Post reply on HN