2 ms·

I'm really struggling to understand why a monitor would be designed this way. It's already receiving a pixel clock and all the pixels, horizontal fields, and en

I'm really struggling to understand why a monitor would be designed this way. It's already receiving a pixel clock and all the pixels, horizontal fields, and entire frames at 59.95Hz. There's absolutely no need for the monitor to be keeping track of a separate 60Hz clock anywhere. All I can figure is that it might have some motion blur or other interpolation feature and it's holding frames back after receiving them and displaying them from an internal buffer at 60Hz. In this case, you'll get occasional (but rare) tearing/stuttering no matter what since the computer's clock and the LCDs hypothetical clock are not syncronized.

gambiting 4y ago
So I'm only guessing, but I think it's because the internal display driver was actually working at 60Hz, but the monitor was just advertising the refresh speed incorrectly to any connected device as 59.95Hz. The error would accumulate and after about 20 seconds the monitor had to "stop" and resynchronize the clock.
londons_explore 4y ago
It's kinda hard to design hardware driven by someone else's clock. The easy and lazy solution is to generate your own clock signal at the rate you want, and then to buffer the data from their closeish-clock to your own. Obviously this has the downside of an extra frames latency and the occasional dropped frame when the clocks drift.
- russdill 4y ago
  An LCD monitor that buffers frames? That would be really bad. The typically HDMI receiver chip does the lazy thing. Which is simply to receive pixels on one end, and transmit them out the other at the same rate that it receives them at. No buffering. https://www.analog.com/en/products/adv7613.html https://www.analog.com/en/products/adv7613.html
  - londons_explore 4y ago
    Typically monitors buffer frames because the LCD matrix itself has a maximum and minimum refresh rate - and the user may provide an input signal outside that rate. Even so, the anti-ghosting compensation algorithms typically only work at one rate.

gambiting 4y ago

So I'm only guessing, but I think it's because the internal display driver was actually working at 60Hz, but the monitor was just advertising the refresh speed incorrectly to any connected device as 59.95Hz. The error would accumulate and after about 20 seconds the monitor had to "stop" and resynchronize the clock.

londons_explore 4y ago

It's kinda hard to design hardware driven by someone else's clock. The easy and lazy solution is to generate your own clock signal at the rate you want, and then to buffer the data from their closeish-clock to your own. Obviously this has the downside of an extra frames latency and the occasional dropped frame when the clocks drift.

russdill 4y ago
An LCD monitor that buffers frames? That would be really bad. The typically HDMI receiver chip does the lazy thing. Which is simply to receive pixels on one end, and transmit them out the other at the same rate that it receives them at. No buffering. https://www.analog.com/en/products/adv7613.html https://www.analog.com/en/products/adv7613.html
- londons_explore 4y ago
  Typically monitors buffer frames because the LCD matrix itself has a maximum and minimum refresh rate - and the user may provide an input signal outside that rate. Even so, the anti-ghosting compensation algorithms typically only work at one rate.