Hi, well if you look at the entire pipeline, it may well be something like this:
yuv->resize to 640x480->RGB->GL texture upload->lanczos filtering to 320->(either on screen, or bus reading for file writing) You may have 2 resize ops and a GPU upload (and download?) which are all expansive. I can see 2 possible options for making that faster: - directly ask Quicktime for the expected size - use a software CIContext for avoiding GPU upload. Raphael On Wed, Apr 15, 2009 at 1:41 AM, Dev <[email protected]> wrote: > Hello, > > I use QTKit to grab an image from my webcam. Then i need to resize it into > a smaller image. > > Going from My CIImage, i use two filter "CILanczosScaleTransform" and > "CICrop" > to get my image at the correct size. (640x480 to 320x240+crop). > Doing only that, my CPU go up to 30% of usage while it is at 12% > without the transformations. > > I have a set of C function that works on Bitmaps that is very > specialized to what i m doing, and would > allow me to earn a lots of unnecessary transformations (on windows > that makes my CPU usage to raise to +5% max only) ... > but here the problem, the rendering of CIImage to a bitmap is worse > than the filter usage. > > here my question, Is there a way of accessing directly the CIImage > representation so that i can pick my pixels very quickly ? > the aim is to be very efficient of course ... > > thanks to all that will help me. > -- > Dev > _______________________________________________ > > Cocoa-dev mailing list ([email protected]) > > Please do not post admin requests or moderator comments to the list. > Contact the moderators at cocoa-dev-admins(at)lists.apple.com > > Help/Unsubscribe/Update your Subscription: > http://lists.apple.com/mailman/options/cocoa-dev/raphael.sebbe%40gmail.com > > This email sent to [email protected] > _______________________________________________ Cocoa-dev mailing list ([email protected]) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to [email protected]
