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I would like to build simple Quartz compositions that respond in real time to audio. Once I've done that, how can I record both the audio and video into a single video file for upload to youtube? I would prefer to work within Quartz Composer, iMovie and other software that is free or already included with OSX.

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Well, you can import the audio into quartz or play it through the mic input using Soundflower. SHOULD export it. Then you can go back and add and line up the music to the video with iMovie (or something better) and export it.

*Soundflower Instructions: Open soundflowerbed, in the menubar (top) a little flower will appear, click on it and go under "Soundflower (2ch)" and click "Built-in output." This will let you hear the audio when you do this. Then go to your system preferences, go to audio settings, and change the OUTPUT to "Soundflower (2ch)" When you go into Quartz Composer, drag the Audio Input (if you have not already) and wire it up. Then go to settings in the inspector and check "Select a specific audio source" and select "Soundcloud (2ch)." Then go and play whatever you want on your computer.

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That is what I'm already doing. The problem is that I can't find a way to record the video synchronized with the audio. The best I can do is screencapture tools intended for presentations, and that isn't good enough. – ObscureRobot Jan 13 '13 at 17:03
@ObscureRobot Screenflow has a good FPS, but you need to buy it. You can even use Garage Band for the audio. – b2550 Jan 13 '13 at 17:07
I'm doubtful - screenflow records the entire screen at record time, and only lets you crop after the fact. That is a lot of bandwidth to keep up with. – ObscureRobot Jan 13 '13 at 17:13
Well you have to look. There are many good screen recording pieces of software. I can look but Quartz is unfortunately not made for doing that kind of stuff. – b2550 Jan 13 '13 at 17:16
Quartz is very much designed for audio visualizations - one of the default templates is for iTunes visualizations. The problem is that I haven't been able to find a Quartz host that will take a snapshot of the window hosting the quartz composition every 1/30 of a second and keep it in sync with the audio. I could probably fire up XCode and solve this problem myself, but I'm a bit surprised that people in the A/V world don't have a ready-made solution that works well. – ObscureRobot Jan 13 '13 at 17:40

Since Quartz Composer renders directly on the graphics card (with openGL) there's no way to render a file in real-time.

Here's an alternative solution:

  • Display the Quartz video fullscreen on a second monitor output (HDMI preferably)
  • capture the HDMI signal with an HD capture device, like this one
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No - you can capture Quartz output with most screen recording tools, including UStream's broadcaster app. But I don't want Ustream's highly compressed video stream, I'd like higher quality output. A hardware solution is unnecessary. – ObscureRobot Aug 13 '13 at 0:18
Try Quicktime Player's screen capture--it seems to work pretty well for ripping youtube videos. Also, I never said you couldn't capture Quartz, but rather that you can't render (i.e. produce a full quality file version) Quartz output in real-time. – audiomason Aug 13 '13 at 3:07

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