On Feb 23, 2011, at 5:39 PM, Kyle Sluder wrote: > On Wed, Feb 23, 2011 at 3:21 PM, Ken Thomases <k...@codeweavers.com> wrote: >> On Feb 23, 2011, at 4:40 PM, Kyle Sluder wrote: >> >>> On Wed, Feb 23, 2011 at 2:17 PM, eveningnick eveningnick >>> <eveningn...@gmail.com> wrote: >>>> i am trying to write a video grabber, CGWindow API seems pretty convenient >>>> (because it allows to select which window to "grab"), but i am worried >>>> about >>>> the speed, because i need to record the grabbed frames to the video file. >>> >>> http://developer.apple.com/library/mac/#samplecode/OpenGLScreenCapture/Introduction/Intro.html%23//apple_ref/doc/uid/DTS10004445-Intro-DontLinkElementID_2 >> >> Actually, I don't think that's an improvement over the CGWindow API that >> eveningnick was already using (CGWindowListCreateImage, I assume). In >> general, if a high-level (more abstract) API achieves the desired result, it >> will be at least as efficient as the low-level API -- because, if the >> low-level approach is faster, the high-level API would just use it. > > Except the high-level APIs are geared around taking a static > screenshot. Remember, the OP is trying to capture a video. > > The method in the sample project creates multiple pixel buffers and > asynchronously swaps the framebuffer contents into them. By design, > the synchronous screen capture APIs cannot be as fast as working at > this level.
My apologies. The URL has the name OpenGLScreenCapture in it, even though the sample project is actually called OpenGLCaptureToMovie. I only looked at the URL and thought it was for the sample code to capture a single screenshot using OpenGL -- there is such a sample that I've looked at previously. I guess I must have been thinking of <http://developer.apple.com/library/mac/#samplecode/OpenGLScreenSnapshot/>, which has a confusingly similar URL, if not title. Regards, Ken _______________________________________________ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) 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 arch...@mail-archive.com
