Webcam faster?


Im wondering if there is a hidden, magic pin deep inside the videoin.node for faster my Usb2.0 webcam?
One says it can stream up to 25fps/640x480px but in fact it doesnt (in combination with massive other nodes). Some ideas of giving it a little push - like the feeling for it of having priority for me and how can I do it?
Or do you have a link to a side where camowners talk about their worries?

Ciao Frank

First thing to check - soory to state the obvious here - is: Do you get the full video performance out of any other aplication?
Note that USB cameras will likely auto-degrade their frame rates (without visible error messages) when you use the wrong, or too long, cables. Also, not all ports on a pc need to be equal. Hubs or additional devices can also slow down transfer rates, of course.

surely you do know the boost (VVVV) node already, and the various implications of the time mode pin of mainloop (VVVV) ?

would be interesting if a simple VideoIn -> VideoOut connection (with nothing else in the patch) has full 25fps (see VideoOuts output for framrate).

boost will rather not help here since it boosts vvvvs main thread possibly leaving even less time for the video (directshow) thread.

also note that webcams usually have an auto-exposure feature which will limit the frame rate to something like 5fps in dark rooms to get longer exposure times and less noise.


back to my webcam topic:
-I use a webcam (Creative Notebook Ultra) that can give me 640x480px at 25fps. Only with 4.5m Usb cable. I tried all Usb-Ports and found a fast one. I set all sttings in porperties manually and switched autostuff off.
-My second videodevice is a DvCam Sony Dsp 150 that gives me 720x576px at 25fps. Connected with 3m Firewire cable.
-Together in a simple patch (only videoin and some shaders and merge the image) both can give me the full 25fps at full res.
-But in my patch, it has got a bunch of textures and nodes, the webcam slows down at 14fps.

I played a little with some values and found an interesting point:
-The slow down of the webcam only occurs if I boost Vvvv (set prog priority to high). I think that reduces the power for the “system” process in taskbar, that obviously control the webcam datastream. Vvvv then runs at 20fps.
-Before boosting Vvvv the Webcam had gave me 20fps (what is quite enough for me), BUT Vvvv runned only at 8-14fps (what is like “Daumenkino”).
-Next step was to split the Cpu-Account. Give Vvvv just one Cpu (I have a 2 Cpu-System). Works better with boost mode: Vvvv 15fps AND Webcam with 20fps. Tada!
-But now the Dvcam has got a delay of 3-5 frames. 8-((((

So is there a way to change priority and Cpu-account of “System”-Process in taskbar? It just says me no way “Zugriff verweigert”.

Ciao Frank

Sometimes I feel like Indiana Jones in jungle of technics. Solving a quest is start of the next one. I hope I´ll find the lost pyramids :)

I found the lost pyramids!

Ok, I changed both videoin ref clock to system-mode (before webcam has system, dvcam not) and now they peacefully share the datarate at 20fps each. No delay anymore.

Had took a look at taskbar and Vvvv (Boost) and “System”-Process share the Cpu-Power at 50% each in harmony. That means “System” automatically take the second Cpu.

And Vvvv is at 13fps - think I have to reduce some textures.