Spent the better part of today reverse engineering gridflow's "multiblob" example patch -- time well spent, actually, as I now have a much better idea what it's actually doing than I would if I had just cribbed the example.

The only trouble is, it's s-s-l-l-l-l-o-o-o-o-o-o-w-w-w-w-w-w-w-w-w, chewing anywhere from 30-60% CPU according to Ubuntu system monitor. So I'm wondering how to pick up the pace. My patch is attached.

First obvious thing is, reduce the image size by another factor of two. After [#downscale_by 4 smoothly], the image is 320x256. I may not need that much resolution, but I'd prefer to keep that as a last resort.

Second thing -- I'm not sure how much efficiency I'm losing by reading the webcam using gem and then converting to gridflow. I ended up doing it that way because I simply could not get [#camera] to grab images at all. The #camera panel does identify the laptop's built-in webcam (BisonCam,_NB_Pro) but 'bang'ing a [#camera 0] only produces this error.

error: [#io.videodev in /dev/video0 0] inlet 0 method bang: alloc_image: ioctl VIDIOCGMBUF: Invalid argument

(Ubuntu Lucid (2.6.33-29-realtime), 64-bit, pd 0.42.5-extended, installed gridflow from the puredyne PPA https://launchpad.net/~puredyne-team/+archive/ppa/+files/gridflow_9.12-1%7Eppa1%7Elucid1_amd64.deb)

Beyond that, I don't know enough about what gridflow is doing under the hood to use it more efficiently. Any pointers?

Thanks,
James

http://www.pdpatchrepo.info/hurleur/labelling-to-osc-blur9.pd

Found the bottleneck - it's [pix_video] --> [#from_pix].

[#camera] works if you choose the API, then the device. This is, of course, not documented anywhere -- I had to go directly to Mathieu Bouchard to find that out. So now my patch is working with #camera by doing

[loadbang]
|
[api libv4l1, device 0(
|
[#camera]

Using #camera cut CPU down by at least a factor of 2, maybe even 3.

James

when I installed gridflow, it caused my old patches to lag massively, even though they weren't using any gridflow nodes at all, had to completely uninstall PD and re-install it without gridflow to get them working fine again.. Isn't that strange? I am on vista though..