Web cam capture Win 11 vs Mac OS

Processing Libraries
1

Hi

on a Win11 machine, to capture a web cam, it seems I need the following line of code:

  cam = new Capture(this, "pipeline:autovideosrc"); 
  cam.start();

as the following one returns an error that there is not a device

 String[] cameras = Capture.list();
 if (cameras.length != 0) { 
 cam = cameras[0]; 
 cam.start(); 
 }

(both codes works fine on a Mac).
Is it a known issue? How do i fix it on the Win machine?

2

Hello,

Related:

:)

3

I would just use pipeline:autovideosrc everywhere! Is there a reason you think you need to “fix” it?

4

Hi,

with the pipeline:autovideosrc code I am not sure how to list several webcam devices (i need at least two). Is there a way?
thanks cheers
mario

5

Hi

I see the solution by “Could not find any devices” error on Windows · Issue #168 · processing/processing-video · GitHub (lucasfredericks commented on Apr 1). Unfortunately I do not know what pipeline:autovideosrc, pipeline:ksvideosrc and so on, really refer to. How/where do I learn about those options? Thanks
m.

6

They are direct references to the underlying GStreamer pipeline elements and configuration - eg. ksvideosrc

Unfortunately, autovideosrc does not support device indexes. You need to use device-index=0 and device-index=1 etc. to pick up multiple cameras. And if you want the sketch to work across multiple OS you need to specifiy different pipelines on each. PraxisLIVE actually handles this for you, but if you don’t want to use that, our code for this may at least be useful to look at https://github.com/praxis-live/praxiscore/blob/master/praxiscore-video-gstreamer/src/main/java/org/praxislive/video/gstreamer/configuration/GStreamerSettings.java#L38

1 Like
7

hi. does the library ( praxiscore/GStreamerSettings.java at master · praxis-live/praxiscore · GitHub ) could handle multiple webcam input in processsing. thank you

8

@doni that is not a library, it’s a part of the PraxisCORE framework. Yes, via PraxisLIVE you can use multiple camera sources with Processing nodes, but it’s not a library you can use with Processing.

The Video library should support multiple cameras anyway.

1 Like