CPU or GPU ?
Hi,
I'm currently in the process of updating my vj patch who is now 8 years old 8D
I was thinking going to GPU but after some quick tests the performance is not there. In fact I've got better fps with CPU !.
In my patch I use movies that are driven by an audio signal (i.e. if the audio signal volume is high the movie is speedy, if the audio volume is low, the movie is slow-mo).
I've made a patch to test the performance with GPU and CPU and the CPU fps is nearly twice the gpu when the movie rate is driven by audio. Do I miss something ? I've used vade's tips and my movies are 320*240 photojpeg.
Another problem appeared during my test who seemed to be more a quicktime issue. When the video rate is more than -2. the video freeze. Any clue ?
Pierre
This is not a very reliable performance test, since you are comparing jit.qt.movie displaying directly to jit.window without any processing with a jit.qt.movie->slab->videoplane setup. Where you may start to see a difference is with more complex processing chains and larger video frames.
Andrew B.
Thanks Andrew.
If i understand correctly, GPU will outperform CPU only if I use shader to program also my effects.
Pierre
it also depends on your graphics card, which you haven't mentioned.
I've got a 512 mo GeForce 8600M GT. Any good tutorial to learn about shader programming ? I've already check Andrew's on ths site.
Pierre
eh
the metro for the qt.movie is at speed 2
and the metro for the videoplane is at speed 16
....
if i put them both at 2
i get 59 fps for both ways
which would mean the cpu is slower , it doesnot do an extra slab
(eh yeah its on a 8coremacpro with max5 )
There is a common misconception that you have to be a GLSL wizard to start taking advantage of jit.gl.slab. The truth is, Jitter ships with an exceptional collection of basic video processing shaders, ready to use in jit.gl.slab. Look in Cycling '74/jitter-shaders and examples/jitter-examples/render/slab-helpers/.
Also, have a look at the "Video Processing System" tutorial series on this site for an example of real-world usage of GPU processing for video.
Best,
Andrew B.
Thanks mj, I feel so stupid on this one!
I've got the same fps when the metro are the same...
@andrew yes I've checked that, with p.jit.gl.shader and you own tutorials I've realized that it's really easy to integrate some slab fx. And I've also discovered the nice vOO1 shaders from vade.
So now I'm going mostly gpl for my new app.
Pierre