[PD] a flawed Gem (Was: Re: pdp/pidip on win32?)

[cyrille henry]

hello,

1-> i don't know where the problem is. But i don't think it is in Gem, since Gem does only control the graphic card.
upgrade you graphic card could help.

2-> Yes, the Gemhead concept in Gem is different than pd concept. it is this way because Gem is very close to openGL concept, and that's why Gem works so efficiently. See documentation about OpenGL for more info.

3-> what you describe is a missing sinc to vblank. Be aware that once you set this parametter on the driver, you have to choose on wich screen to sinc, and to restart pd/Gem. 
Nvidia driver are the same for lot's of different hardware, it's possible that you have this option in your drivers, but your hardware is not able to do it.

3b-> i don't have a firwire cam to test, but i saw strange thing in you patch : 
-why do you use spigot?
-why do you connect many time on the same camera?
can you try the attached patch, and tell us if it is still crashing?

4-> i think there was some bug report about this issue regarding pix_record on linux.
don't have time to check.


6-> pix_motionblur does affect images in the buffer, because Gem did not copy images from the buffer before using them. This is the way to have good performance. of course, you can force Gem to copy the image, using pix_separator.


Sending 1 mail for 1 problem would be easier to discuss.

Cyrille

John Harrison a écrit :
> As promised, here's a couple of patches to show a few of my concerns 
> about Gem. Interestingly, after creating the patches on the target 
> machine, I tried the same patches on my laptop and got slightly better 
> results (recording suddenly started working again and I was able to 
> avoid one referenced segfault in the patch. I made a note of both of 
> these changes inside the patch.)
> 
> I'd love to get these concerns addressed and would like to help to 
> accomplish this in whatever would be most effective. It would be amazing 
> to really get this tool ready for artists ready to explore this medium 
> in the classes I teach.
> 
> I built these patches on ubuntu 8.10 32 bit on Pd-extended 0.40.3 with 
> video card referred to by lspci as nVidia GeForce 6150SE nForce 430 
> (a2). You'll need a firewire video capture device to try them. The 
> patches also create and reference a recorded video file: /tmp/test.mov. 
> Perhaps the name would need to be changed if trying on OSX or Windows.
> 
> This is just a start on some of the problems I have had. If it is 
> helpful I can provide more feedback like this.
> 
> Thanks,
> 
> -John
> 
> 
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