if you are rendering out to the decklink, then you do not have any GL acceleration and are using software rendering. The Decklink and AJA sty;e cards do not have any GL facilities built in, so you will get CPU side rendering. That might account for some of the sluggishness that you are seeing.
You might be better off rendering to a CGLContext and an offscreen FBO, and doing readback yourself and sending that to your decklink's quicktime output session. Rendering directly to the Decklink and AJA will guarantee sup-par performance due to QCs OpenGL requirement and those cards lack of hardware acceleration for it. Good luck. On Dec 25, 2010, at 6:29 AM, Nisar Ahmed wrote: > Quartz crystal is not a plugin so I cannot use it in my xcode application, > but the processing it is doing on each frame can be done inside the xcode > application as I am using core video's display link to fetch a frame from > composition (QCRenderer's renderAtTime). CoreVideo's display link syncs with > the monitor's refresh rate which is 60Hz and renders smoothly on the desktop > but at 25fps the result is choppy on Decklink as well. The hops are not an > issue on the desktop but it is on the Decklink SDI output. > > I would like to know what quartz crystal does to each frame inside the code > so that I can do that to my composition frames too before sending it to SDI > card's memory. > > Dear Achim, > > I can understand the fps issue you are taking about but in my application I > have used displaylink which can be set to callback a function at 25fps as > well and inside that callback we can fetch next frame by using QCRendere's > renderAtTime function. Also hops are not an issue on computer's monitor, the > requirement is a smooth playback through the video card not the GPU which is > Decklink in my case. > > > Subject: Re: exporting a composition to a quicktime movie > From: dokt...@mac.com > Date: Fri, 24 Dec 2010 16:18:01 -0500 > CC: quartzcomposer-dev@lists.apple.com > To: nisar...@hotmail.com > > It might be helpful to describe why the movie is poor. What is the expected > result, what do you actually see, etc. > > If the issue is flickering text, then yes, Quartz Composer renders at 60fps, > DV @ 25 will make the title crawl look choppy since there are less frames to > show the text crawl between two positions. Doing smooth titles is not easy at > high speed, low framerate, there are some tricks you can do, but the best > thing is to adjust the speed of the scrolling until it looks good. > > Maybe look into Quartz Crystal from Kineme and use frame blending which will > help ease the "pops" in position between consecutive frames. > > Is that the issue you are noticing? > > > > On Dec 24, 2010, at 7:41 AM, Nisar Ahmed wrote: > > I am trying to export a quartz composition movie to a quicktime movie using > quicktime pro but the result is poor as compared to the original composition > file. > > I am attaching the composition you can try opening it with quicktime pro and > exporting it to dv-pal movie 25fps and see the result. I have also tried > other combinations but failed to reproduce the expected result. > > Thanks in advance > Nisar > <crawler.qtz> _______________________________________________ > Do not post admin requests to the list. They will be ignored. > Quartzcomposer-dev mailing list (Quartzcomposer-dev@lists.apple.com) > Help/Unsubscribe/Update your Subscription: > http://lists.apple.com/mailman/options/quartzcomposer-dev/doktorp%40mac.com > > This email sent to dokt...@mac.com > >
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