5 ms·

As a nerd I love numbers, 'Latency is minimal' doesnt do it for me. Display this http://tft.vanity.dk/inputlag.html http://tft.vanity.dk/inputlag.html or any ot

by rasz_pl 11y ago

As a nerd I love numbers, 'Latency is minimal' doesnt do it for me. Display this http://tft.vanity.dk/inputlag.html http://tft.vanity.dk/inputlag.html or any other stopwatch, and record both screens. What is the bitrate and cpu overhead at hd/fullhd resolutions 30/60hz? Some very slow MVA monitors lag as much as full frame behind input, so in extreme cases you could get equal delay on your laptop.

dharma1 11y ago
would like to see latency numbers too. Gstreamer with h264 is about 150ms ish
phoboslab 11y ago
For my system it hovers around 50-70ms[1][2]. Tested with an 800x600 window at ~7% cpu utilization on a Core i5. My desktop monitor is a Dell u2711, which seems to add about 15ms latency itself[3]. I'm not sure how much latency OSX or Chrome adds (at least a frame more than Firefox[4]); Mobile Safari seems to be a bit faster, as evident in the video. I don't have a second Windows machine for comparison. Edit: When connecting on the same machine, latency is 2 frames (33ms) exactly[5]. [1] http://phoboslab.org/files/jsmpeg/jsmpeg-vnc-latency.mp4 http://phoboslab.org/files/jsmpeg/jsmpeg-vnc-latency.mp4 [2] http://phoboslab.org/files/jsmpeg/jsmpeg-vnc-latency.jpg http://phoboslab.org/files/jsmpeg/jsmpeg-vnc-latency.jpg [3] http://www.anandtech.com/show/2922/4 http://www.anandtech.com/show/2922/4 [4] http://phoboslab.org/log/2012/06/measuring-input-lag-in-browsers http://phoboslab.org/log/2012/06/measuring-input-lag-in-brow... [5] http://phoboslab.org/up/B2u6w.png http://phoboslab.org/up/B2u6w.png
isaacremuant 11y ago
> 'Latency is minimal' Tell me about it, I've been trying to gather info about a solution where I can record with a camera, probably 1080p (via ethernet or via hdmi to capture card) and use the frame information as inputs in a simulation with a latency around 20 ms and am unable to get hard data on the actual latencies. Nobody cares about input lag because practically no one records as a real time input. Incidentally, if anyone knows or has experienced with a similar setup I'd be forever grateful.
- ramses0 11y ago
  http://superuser.com/questions/419070/transatlantic-ping-faster-than-sending-a-pixel-to-the-screen http://superuser.com/questions/419070/transatlantic-ping-fas...
- frik 11y ago
  Gamer care about input lag. Pro gamer on PC don't use wireless input devices, they prefer cable based ones for exactly that reason. The input lag is also what (afaik) almost killed Gaikai. Sony recently bought it for some older PS3 titles. https://en.wikipedia.org/wiki/Gaikai https://en.wikipedia.org/wiki/Gaikai
  - scoggs 11y ago
    I never played at the pro level but I did play competitively and I would never use wireless internet, mice, or keyboards. These days there are some great mice, keyboards, and headphones but most people I know won't leave it up to chance and always go with wires.
  - isaacremuant 11y ago
    Yes. I'm aware they do and manufacturers of those devices often provide options and information but cameras are seldom used as input devices so they're not usually measured and that's a shame.
- sdenton4 11y ago
  Here's a dumb idea I just came up with: Attach a bright light that the computer can blink programatically. Write a program which: a) blinks the light, b) Blinks the light again 0.01 seconds after the camera sees the light blink, and c) repeat b a thousand times. d) Measure how long the process took relative to ten seconds, divide by 1000 to get your latency (including latency for sending the signal to the light, but hey, it's at least an upper bound). Another thought that occurs to me is that people who work with music equipment (especially usb synths and such) care about latency a lot. It maybe worthwhile to hook into that scene and see what kind of insights can be gleaned. Here's a link to get you started: http://www.mathworks.com/help/dsp/examples/measuring-audio-latency.html http://www.mathworks.com/help/dsp/examples/measuring-audio-l... Looks like they're basically using a feedback model as well.

by rasz_pl 11y ago

dharma1 11y ago

would like to see latency numbers too. Gstreamer with h264 is about 150ms ish

phoboslab 11y ago

For my system it hovers around 50-70ms[1][2]. Tested with an 800x600 window at ~7% cpu utilization on a Core i5. My desktop monitor is a Dell u2711, which seems to add about 15ms latency itself[3]. I'm not sure how much latency OSX or Chrome adds (at least a frame more than Firefox[4]); Mobile Safari seems to be a bit faster, as evident in the video. I don't have a second Windows machine for comparison. Edit: When connecting on the same machine, latency is 2 frames (33ms) exactly[5]. [1] http://phoboslab.org/files/jsmpeg/jsmpeg-vnc-latency.mp4 http://phoboslab.org/files/jsmpeg/jsmpeg-vnc-latency.mp4 [2] http://phoboslab.org/files/jsmpeg/jsmpeg-vnc-latency.jpg http://phoboslab.org/files/jsmpeg/jsmpeg-vnc-latency.jpg [3] http://www.anandtech.com/show/2922/4 http://www.anandtech.com/show/2922/4 [4] http://phoboslab.org/log/2012/06/measuring-input-lag-in-browsers http://phoboslab.org/log/2012/06/measuring-input-lag-in-brow... [5] http://phoboslab.org/up/B2u6w.png http://phoboslab.org/up/B2u6w.png

isaacremuant 11y ago

> 'Latency is minimal' Tell me about it, I've been trying to gather info about a solution where I can record with a camera, probably 1080p (via ethernet or via hdmi to capture card) and use the frame information as inputs in a simulation with a latency around 20 ms and am unable to get hard data on the actual latencies. Nobody cares about input lag because practically no one records as a real time input. Incidentally, if anyone knows or has experienced with a similar setup I'd be forever grateful.

ramses0 11y ago
http://superuser.com/questions/419070/transatlantic-ping-faster-than-sending-a-pixel-to-the-screen http://superuser.com/questions/419070/transatlantic-ping-fas...
frik 11y ago
Gamer care about input lag. Pro gamer on PC don't use wireless input devices, they prefer cable based ones for exactly that reason. The input lag is also what (afaik) almost killed Gaikai. Sony recently bought it for some older PS3 titles. https://en.wikipedia.org/wiki/Gaikai https://en.wikipedia.org/wiki/Gaikai
- scoggs 11y ago
  I never played at the pro level but I did play competitively and I would never use wireless internet, mice, or keyboards. These days there are some great mice, keyboards, and headphones but most people I know won't leave it up to chance and always go with wires.
- isaacremuant 11y ago
  Yes. I'm aware they do and manufacturers of those devices often provide options and information but cameras are seldom used as input devices so they're not usually measured and that's a shame.
sdenton4 11y ago
Here's a dumb idea I just came up with: Attach a bright light that the computer can blink programatically. Write a program which: a) blinks the light, b) Blinks the light again 0.01 seconds after the camera sees the light blink, and c) repeat b a thousand times. d) Measure how long the process took relative to ten seconds, divide by 1000 to get your latency (including latency for sending the signal to the light, but hey, it's at least an upper bound). Another thought that occurs to me is that people who work with music equipment (especially usb synths and such) care about latency a lot. It maybe worthwhile to hook into that scene and see what kind of insights can be gleaned. Here's a link to get you started: http://www.mathworks.com/help/dsp/examples/measuring-audio-latency.html http://www.mathworks.com/help/dsp/examples/measuring-audio-l... Looks like they're basically using a feedback model as well.