high speed video frame rate?

Question

high speed video frame rate?

spincraft opened this issue 4 years ago · comments

I ordered a high speed camera to test with your pupil code.
This camera has a frame rate up to 120 fps.
I also want to run your ExperimentRecorder.js
Please let me know what parameters to change to match the camera frame rate.
THX

Bourry Xavier · Answer 1 · Mon May 25 2020 23:33:56 GMT+0800 (China Standard Time)

Hi @spincraft

Do you manage to get the 120 FPS video in the web browser using getUserMedia API?
I noticed that the highest level camera parameters are often not accessible in the web browser.

Currently the rendering loop is based on the refresh rate of the display since window.requestAnimationFrame is used to launch each iteration. What is the refresh rate of your display device ? You should try with a 144Hz monitor to not have a bottleneck on this side.

Also you need quite powerful hardware (especially the GPU) to be sure it won't be the bottleneck.

spincraft · Answer 2 · Tue May 26 2020 01:43:33 GMT+0800 (China Standard Time)

Thanks for your reply.
You mention several good points.
RE: getUserMedia API
My guess is that the response of this method is hardware dependant but I haven't tested it.

RE: display refresh rate
Yes, most monitors are 50/60 Hz refresh. That means the reporting ExperimentRecorder.js needs to keep up with the frame rate. The display will not keep up with the frame rate. The results will be provided after the experiment has concluded by the Recorder. It's code needs to modified to handle this high speed.

RE: 144 Hz monitor
The observer will not perceive the experiment since it happens too fast. I hope the ExperimentRecorder.js can handle this high speed.

RE: CPU vs. GPU
Yes, the GPU is capable of supporting the experiment.

spincraft · Answer 3 · Tue May 26 2020 01:45:13 GMT+0800 (China Standard Time)

closed by mistake, please reopen.
sorry

Bourry Xavier · Answer 4 · Tue May 26 2020 01:47:24 GMT+0800 (China Standard Time)

Hi,

Plz first test if getUserMedia is able to handle your camera at 120FPS, and if yes, with which mediaConstraints. Which camera is it exactly?

spincraft · Answer 5 · Tue May 26 2020 01:52:16 GMT+0800 (China Standard Time)

I ordered a custom PCB & components. It's a DIY camera project.
I'm waiting on the parts to arrive here.
How would I test getUserMedia without the camera?

Bourry Xavier · Answer 6 · Tue May 26 2020 01:57:33 GMT+0800 (China Standard Time)

I am not in a hurry

spincraft · Answer 7 · Tue May 26 2020 02:00:05 GMT+0800 (China Standard Time)

Sorry, I didn't understand your reply.

Bourry Xavier · Answer 8 · Tue May 26 2020 02:14:44 GMT+0800 (China Standard Time)

I want you to test it with the real device.
I am not in a hurry, I can wait that you received your stuffs.

Bourry Xavier · Answer 9 · Tue May 26 2020 02:16:01 GMT+0800 (China Standard Time)

And also, if you want me to help you here, please provide more information about your project. If what you are doing is strictly confidential, okay, I can also provide private support & development service but I charge for that.