[PD] GEM pix_buffer

Derek Holzer derek at umatic.nl
Wed Jul 25 16:58:09 CEST 2007

Hi Chris,

thanks again for helping me get this "codec issue" sorted out, and for 
taking it into consideration for the CVS GEM.

chris clepper wrote:

> Can you fit all 48 clips uncompressed into RAM?  A 1 second clip at 
> 640x480 30fps in YCbCr is about 18.5MB (double that for RGBA) which 
> would allow 3 and a half minutes of video to fit in 32bit address space. 

I didn't even think about addressing! I just assumed that if I had all 
my clips in buffers, then they would be more quickly accessible. Thanks 
for pointing that out. Guess I'll need to read a bit more about how 
buffers are accessed. Suggestions? Use the Source?

> Try creating a RAM disk and copy the uncompressed clips into that.  RAM 
> disks might even allow for greater than 32 bit sizes.

For shorter clips, loading direct from the HD is pleasantly faster than 
I expected. But when the clips get bigger, I might look into a RAMdisk. 
I found quite a few tutorials on making a RAM disk on OSX via Google, 
using everything from command line to Freeware.

One more question: if I use the "ram" message to [pix_film], does it 
stay in RAM when I load another one? My guess is no, of course. I 
suppose if I really needed speed I could make 48 [pix_film] instances, 
each with the clip loaded to RAM. But of course, using a RAM disk might 
be more efficient at that point anyways!


derek holzer ::: http://www.umatic.nl ::: http://blog.myspace.com/macumbista
---Oblique Strategy # 164:
"Twist the spine"

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