The benefits of (non-perceived) flicker

Article: Lessons in Technology and Innovation from the iPad 3 Graphics and Display
By: dmsc (no.delete@this.more.spam), January 7, 2013 7:36 pm
Room: Moderated Discussions
Ungo (a.delete@this.b.c.d.e) on January 7, 2013 3:57 pm wrote:
> Max (max.delete@this.a.com) on January 7, 2013 1:43 pm wrote:
> > Oddly enough the flickering nature of CRTs (whether perceived or not) makes them inherently superior
> > in displaying motion than modern panel displays. A moving image (updated at the display refresh
> > rate) appears sharp, whereas on a non-flickering display it appears fuzzy. This would be true
> > even if the panel can update instantly, so it's not a problem that will ever go away.
>
> The bolded statement is not true. The reason why moving objects on LCDs often look fuzzy is because
> LCD pixels have poor response times. Take that away, and the fuzziness should go too.
>

No, not at all!!!

This is a really common confusion about LCD.

A simple graph of position/time to try to explain:

Real Motion:

/
/
/
/

Motion on a strobed display:

.
.
.
.

Motion on an LCD:

---
---
---
---

See? The LCD shows a jagged motion, and this is clearly perceptible.

Current LCDs have transition times in the order of a couple of ms, so
all that you describe is non-existent.

What modern 120/240 Hz LCDs do is interpolate the frames using the
detected movement of the scene (for example, using motion-vectors
from the coded stream), and generate intermediate frames, showing
a more fluid motion.

Remember that also all current LCDs do frame interpolation in the
de-interlacer, needed to display the obsolete interlace material
being broadcast.

>
> > On a non-flickering display, the only way to get CRT-equivalent moving images
> > is to use a very high refresh rate, hundreds of frames per second.
>
> The problem isn't refresh rate, it's physical constraints on how fast LC material can respond to refresh.

Not true. Current LCDs are much faster than old CRTs.

>
> > Alternatively, you can force a panel to flicker by strobing the backlight or inserting black frames.
> >
> > The more expensive LCD TVs use both techniques. They motion interpolate to 120Hz
> > or 240Hz, and flicker the backlight at 120/240Hz. The shorter the backlight
> > pulses, the better the motion (and the dimmer the screen, of course).
>
> Do you have a citation for this? I've never heard of anyone doing that. It would be fairly
> impractical with a fluorescent or white-LED backlight (both depend on phosphor to convert narrow
> band light sources to full spectrum, and most phosphor materials can't switch that fast).

Most good LCDs use LED lighting, already PWM controlled for brightness, to
allow the big marketed contrast ratios. The TV simply synchronizes the PWM with
the display frame rate (at 120 or 240 Hz).

Daniel.
< Previous Post in ThreadNext Post in Thread >
TopicPosted ByDate
Lessons in Technology and Innovation from the iPad 3 Graphics and DisplayDavid Kanter2013/01/01 04:14 AM
  Games at 2048 x 1536? Can you tell?Mark Roulo2013/01/01 02:22 PM
    Games at 2048 x 1536? Can you tell?David Kanter2013/01/01 07:58 PM
      Games at 2048 x 1536? Can you tell?Anon2013/01/03 12:04 AM
        Games at 2048 x 1536? Can you tell?Andy2013/01/03 04:05 AM
          Games at 2048 x 1536? Can you tell?Anon2013/01/06 02:10 AM
            Games at 2048 x 1536? Can you tell?EBFE2013/01/06 11:07 PM
    Games at 2048 x 1536? Can you tell?Seni2013/01/01 09:17 PM
    Games at 2048 x 1536? Can you tell?anon2013/01/02 04:00 AM
      Games at 2048 x 1536? Can you tell?EduardoS2013/01/02 09:07 AM
        Games at 2048 x 1536? Can you tell?anon2013/01/03 12:21 AM
          Games at 2048 x 1536? Can you tell?EduardoS2013/01/03 01:03 AM
      Games at 2048 x 1536? Can you tell?Ricardo B2013/01/02 11:01 AM
        Games at 2048 x 1536? Can you tell?Michael S2013/01/03 01:35 AM
          Games at 2048 x 1536? Can you tell?Andy2013/01/03 04:10 AM
            Games at 2048 x 1536? Can you tell?Michael S2013/01/03 06:33 AM
              Games at 2048 x 1536? Can you tell?rwessel2013/01/03 11:56 AM
                Games at 2048 x 1536? Can you tell?rwessel2013/01/03 11:56 AM
                  Oh, for crying out load, would you fix this stupid thing to make it a tiny bit harder to double post (NT)rwessel2013/01/03 12:01 PM
                    /load/loud/ grrr... (NT)rwessel2013/01/03 12:02 PM
                    Oh, for crying out load, would you fix this stupid thing to make it a tiny bit harder to double postDavid Kanter2013/01/10 10:07 AM
                      Oh, for crying out load, would you fix this stupid thing to make it a tiny bit harder to double postrwessel2013/01/10 09:33 PM
                        Oh, for crying out load, would you fix this stupid thing to make it a tiny bit harder to double postrwessel2013/01/10 09:35 PM
                          Oh, for crying out load, would you fix this stupid thing to make it a tiny bit harder to double postrwessel2013/01/10 09:40 PM
                          Me, too! :-)Mark Roulo2013/01/11 08:57 AM
              85 Hz CRT monitorsDoug S2013/01/04 02:12 PM
                85 Hz CRT monitorsAnon2013/01/06 02:16 AM
                  85 Hz CRT monitorsDoug S2013/01/06 12:40 PM
                    The benefits of (non-perceived) flickerMax2013/01/07 01:43 PM
                      The benefits of (non-perceived) flickerAnon2013/01/07 02:59 PM
                        The benefits of (non-perceived) flickerPaul2013/01/07 05:40 PM
                      The benefits of (non-perceived) flickerUngo2013/01/07 03:57 PM
                        The benefits of (non-perceived) flickerDoug S2013/01/07 04:40 PM
                        The benefits of (non-perceived) flickerMax2013/01/07 06:16 PM
                          The benefits of (non-perceived) flickerAnon2013/01/09 09:50 PM
                            The benefits of (non-perceived) flickerMax2013/01/10 06:18 AM
                              The benefits of (non-perceived) flickerSM2013/01/10 12:37 PM
                        The benefits of (non-perceived) flickerdmsc2013/01/07 07:36 PM
                          The benefits of (non-perceived) flickerEBFE2013/01/07 11:08 PM
                          The benefits of (non-perceived) flickerAnon2013/01/09 10:07 PM
                            The benefits of (non-perceived) flickerdmsc2013/01/10 04:41 PM
                              The benefits of (non-perceived) flickerUngo2013/01/11 05:20 PM
                    perception of flickerCarlie Coats2013/01/08 04:39 PM
                      perception of flickerDoug S2013/01/08 10:25 PM
                        perception of flickerAnon2013/01/09 10:09 PM
        Games at 2048 x 1536? Can you tell?anongamer2013/01/03 04:31 AM
      Games at 2048 x 1536? Can you tell?Richard Cownie2013/01/02 02:56 PM
        Tablet vs. console GPUsDoug S2013/01/02 04:09 PM
          Tablet vs. console GPUsRicardo B2013/01/02 04:50 PM
      Games at 2048 x 1536? Can you tell?Anon2013/01/03 12:13 AM
        Games at 2048 x 1536? Can you tell?anon2013/01/03 12:54 AM
          The Hobbit is at 48 fpsRichard Cownie2013/01/03 07:02 AM
            Thanks for the interesting data point! (NT)Paul A. Clayton2013/01/03 09:26 AM
            The Hobbit is at 48 fpsRicardo B2013/01/03 11:17 AM
              The Hobbit is at 48 fpsRichard Cownie2013/01/03 11:55 AM
                The Hobbit is at 48 fpsRichard Cownie2013/01/03 12:44 PM
                  The Hobbit is at 48 fpsRicardo B2013/01/03 01:42 PM
                    The Hobbit is at 48 fpsRichard Cownie2013/01/03 02:31 PM
                      The Hobbit is at 48 fpsy2013/01/04 07:47 PM
                        Exposure time traditionsNathan Monson2013/01/05 12:21 PM
                          Exposure time traditionsy2013/01/05 09:59 PM
                            Exposure time traditionsanon2013/01/06 01:46 AM
                              Exposure time traditionsJukka Larja2013/01/07 08:52 AM
                            Exposure time traditionsdmsc2013/01/06 09:34 AM
                              Exposure time traditionsy2013/01/06 09:11 PM
                                Exposure time traditionsdmsc2013/01/07 07:42 PM
                                  Exposure time traditionsRichard Cownie2013/01/09 08:23 AM
                        The Hobbit is at 48 fpsMichael S2013/01/05 12:30 PM
                          The Hobbit is at 48 fpsRichard Cownie2013/01/05 03:45 PM
                            The Hobbit is at 48 fpsAnon2013/01/06 02:03 AM
                              The Hobbit is at 48 fpsRichard Cownie2013/01/06 06:43 AM
                                The Hobbit is at 48 fpsJukka Larja2013/01/07 09:18 AM
                                  The Hobbit is at 48 fpsRichard Cownie2013/01/07 05:21 PM
                                    The Hobbit is at 48 fpsJukka Larja2013/01/08 09:29 AM
                                      The Master 65mm/70mmRichard Cownie2013/01/08 12:52 PM
                                        The Master 65mm/70mmJukka Larja2013/01/11 02:07 PM
                                          The Master 65mm/70mmRichard Cownie2013/01/11 07:05 PM
                                            The Master 65mm/70mmJukka Larja2013/01/11 11:35 PM
                                              The Master 65mm/70mmDoug S2013/01/12 02:16 PM
                                                Pixar and 3DRichard Cownie2013/01/13 07:07 AM
                                            The Master 65mm/70mmDavid Hess2013/01/12 02:06 PM
                                            The Master 65mm/70mmMegol2013/01/16 01:02 PM
                                        The Master 65mm/70mmRakesh Malik2013/01/23 12:28 PM
                                    The Hobbit is at 48 fpsAnon2013/01/09 10:18 PM
                                      The Hobbit is at 48 fpsRichard Cownie2013/01/10 01:07 PM
                                        The Hobbit is at 48 fpsAnon2013/01/10 03:50 PM
                                          The Hobbit is at 48 fpsRichard Cownie2013/01/10 06:05 PM
                                            The Hobbit is at 48 fpsAnon2013/01/13 12:48 AM
                                              I don't care about workflowRichard Cownie2013/01/13 06:55 AM
                                                I don't care about workflowAnon2013/01/13 04:15 PM
                                                  I don't care about workflowRichard Cownie2013/01/13 08:02 PM
                                            The Hobbit is at 48 fpsRakesh Malik2013/01/23 01:38 PM
                              The Hobbit is at 48 fpsRakesh Malik2013/01/23 12:15 PM
                  The Hobbit is at 48 fpsJukka Larja2013/01/05 07:00 AM
                    Realism and fiction?Paul A. Clayton2013/01/05 09:42 AM
                      Realism and fiction?Jukka Larja2013/01/06 02:32 AM
                        Or the second factor?Paul A. Clayton2013/01/06 04:35 AM
                          Or the second factor?Jukka Larja2013/01/07 09:07 AM
                        further reading (was: Realism and fiction?)hobold2013/01/06 04:47 PM
                          Thanks. I'll probably check that out soon. (NT)Jukka Larja2013/01/07 09:13 AM
            The Hobbit is at 48 fpsrwessel2013/01/03 09:57 PM
            VR and latencyCarlie Coats2013/01/04 05:30 PM
              VR and latencyRicardo B2013/01/04 07:49 PM
                VR and latencyJoe2013/01/05 02:01 AM
            The Hobbit is at 48 fpsBernd Schmidt2013/01/08 03:42 AM
        Games at 2048 x 1536? Can you tell?anongamer2013/01/03 05:01 AM
        Games at 2048 x 1536? Can you tell?Ricardo B2013/01/03 08:06 AM
    Games at 2048 x 1536? Can you tell?Marco Salvi2013/01/02 10:31 AM
    Games at 2048 x 1536? Can you tell?Ungo2013/01/02 04:28 PM
    Games at 2048 x 1536? Can you tell?Jukka Larja2013/01/05 07:13 AM
  Lessons in Technology and Innovation from the iPad 3 Graphics and DisplayRichard Cownie2013/01/02 10:29 AM
  iPad GPU Clock Speedsltcommander.data2013/01/05 12:32 PM
    iPad GPU Clock SpeedsBrett2013/01/06 11:48 PM
      iPad GPU Clock SpeedsDoug S2013/01/07 10:17 AM
      iPad GPU Clock SpeedsDavid Kanter2013/01/09 01:48 PM
    iPad GPU Clock SpeedsUngo2013/01/07 04:26 PM
      iPad GPU Clock SpeedsDavid Kanter2013/01/09 01:42 PM
  Lessons in Technology and Innovation from the iPad 3 Graphics and Displaympx2013/01/06 05:35 AM
    Lessons in Technology and Innovation from the iPad 3 Graphics and DisplayMegol2013/01/07 04:45 AM
      Lessons in Technology and Innovation from the iPad 3 Graphics and Displaympx2013/01/07 12:56 PM
        Lessons in Technology and Innovation from the iPad 3 Graphics and DisplayDoug S2013/01/07 04:53 PM
        Lessons in Technology and Innovation from the iPad 3 Graphics and Displayanon2013/01/07 06:26 PM
      Lessons in Technology and Innovation from the iPad 3 Graphics and DisplayMaynard Handley2013/02/13 12:19 PM
  Lessons in Technology and Innovation from the iPad 3 Graphics and DisplayVincent Diepeveen2013/01/06 03:29 PM
    Lessons in Technology and Innovation from the iPad 3 Graphics and DisplayDoug S2013/01/07 10:53 AM
      Lessons in Technology and Innovation from the iPad 3 Graphics and Displaympx2013/01/07 12:48 PM
      Lessons in Technology and Innovation from the iPad 3 Graphics and DisplayVincent Diepeveen2013/01/08 09:53 AM
        Lessons in Technology and Innovation from the iPad 3 Graphics and DisplayDoug S2013/01/08 01:29 PM
          Lessons in Technology and Innovation from the iPad 3 Graphics and DisplayLlew2013/01/26 12:06 PM
            Lessons in Technology and Innovation from the iPad 3 Graphics and DisplayDavid Kanter2013/01/26 01:43 PM
              Lessons in Technology and Innovation from the iPad 3 Graphics and DisplayLlew2013/01/26 02:09 PM
            Wii U has three cores clocked at about 1.2 ghz or so. (NT)I.S.T.2013/01/29 07:37 PM
Reply to this Topic
Name:
Email:
Topic:
Body: No Text
How do you spell avocado?