Hi guys,

I'm developing a webcam sampler with the help of Bryan Chung's Multimedia Programming in Pd book. I've created four points on the screen that uses changing colour hues to trigger samples, I've also used [switch~]ing to the four [readsf~] objects for each sample to minimise CPU usage on audio. All seems to work fine. However, when the GEM window is activated for the webcam, my CPU usage jumps up by about 30 % and creates audio errors! Is there a way to reduce CPU usage with GEM windows/webcams etc? Would FPS and other methods make a difference?

Patch is here webcam.pd

cheers

Casper

@casper Hello Casper.........
Unfortunately my mac webcam will always crash gem.........
...... however, looking at your patch I would guess that [pix_data] (which you have 4 times? in your patch) is outputting a huge amount of data.
I would try reducing both the repeat rate (does the 10ms metro sending to $0-m need to be running as fast)......... and the size of the data array that is being sent (by reducing as far as possible the size (pixel content) of the 4 sampled areas)...........
Sorry....... I can only guess as I cannot run your patch........
Changing the frame rate would help also, in the same way....... by reducing the sampling rate of the four hotspots........ but will ruin your visuals on screen....
David.

@whale-av Thanks David. I really appreciate all your points and will implement them. One quick question to you know how to reduce FPS and samplerate on the gem window?

cheers

Casper

Hi @casper,

do you mean the framerate with FPS? you can change it by sending a message to [gemwin]

[frame 2(
I
[gemwin]

for a framerate of 2. Also you can try to reduce CPU by changing settings of [pix_video]. check help patch for changing the resolution. Also you can try to use more Audio latency to avoid dropouts. There was a disscussion about all of that in the mailinglist few times and also very recently.
If the link doesn*t lead you google:
"DSP and Gem in the same instance of Pd"
for me cpu is quite fine ~12% (macbook pro 2012, osx 10.8.5, pd-0.46-7 + GEM)

Hi @whale-av
what version of pd are you using? i used to have that problem too, but it vanished with different Version. I just checked again, and it is only not working with pd-x-0.42.5..

@Johnny-Mauser I am using the latest (LAST?__ boo hoo....0.43) extended in windows 7 on an intel MacBook pro............ so it is unsurprising that my cam is "kaput". As I am almost entirely in the audio domain it does not bother me much............ except when I am trying to help someone else..........
.. Interestingly? I can force the cam to work by loading a quick time image into pix_image...... disconnecting [pix_texture] from the chain....... starting the render and reconnecting....... sometimes....... but sometimes = unreliable = useless = kaput.

I find "extended" to be so far superior to the "up to date" vanilla (sorry............ but "up to date" means???) that I cannot be tempted to change........... but.......... remember that I am using windows7........ maybe not the best platform for Pd......... but probably, in the archives of the hitchhikers guide to the galaxy............ the best OS ever to "hit the street"........ and on a block of aluminium that has to be one of the "prettiest" ever punched!!........ (shame about the os!!).........
David.

@whale-av i really have no clue about Windows7 on macbook. Out of interest, what color does it show, when its not working? do you have quicktime installed?

@Johnny-Mauser hello again Johnny, and thank you for the interest! If I create a window for the cam the window becomes grey and Pd crashes.... knock-out.......
It is strange because it works in Max and all other programs. My job for 40 years was sound, lights (including wobbly buckets) graphics and video....... so my computer has almost everything possible installed in win7 (my os of choice)....... and the only thing that I have not managed to fix is my webcam...... because I never use it.
However, every now and then I manage to "accidentally" make it work whilst working through some project or another........ and of course I don't manage to repeat the exercise (I am not motivated of course, because "suddenly" I see myself old and decrepit plastered all over the screen with bad lighting and an incorrect white balance!)
Anyway...... I don't think you will be able to help unless I send you a clone of my hard drive !!
David.

@whale-av you are right about my ability to help your webcam. I can not. Maybe that is also good, out of the reasons you exlained and for me it is also leaving some of my tasks open gives me a good feeling of the future.