[PD] Gem, speed of video

Thoralf Schulze thoralf_schulze at yahoo.de
Tue Nov 29 14:24:37 CET 2005


hi,

> >>Does using [auto $1< to play a video file with
> pix_film take less CPU
> >>than a counter that increments with every render?
> > On which platform?  The answer is often 'yes' on
> OSX.
> and on linux + w32 it is 'no' (being merely a
> shortcut for building your 
> own counter)

However, I found that pix_film seems to decode
frame(s) anytime a render command arrives at its
inlet, even if it is the same frame as with the last
render command (bah, twisted explanation ... )
i therefore made myself a little subpatch that decodes
frames only if they are different from the one decoded
at the last render command (using pix_buffer), which
proved to cut cpu usage by half or so, depending on
the frame rates. 
Thinking about this again - could it be that uploading
a texture to the gpu takes up some cpu cycles as well?
pix_buffer prevents these transfers as well, iirc.

hope I'm making sense here,
thoralf.



	
	
		
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