recording real time to QT file

detour's picture

Hi all. I'm looking for a solution to enable recording the output of my composition in real time as I run and manipulate it.

A little background. Back in the 90's I used to work in video studios and had a setup running video sources (tapes, cameras, etc.) through a video mixer with various effects. The workflow was that I could play around until I had something visually I liked, and then downstream on the output sat a video record deck that I could just hit record on and grab what I was doing.

Fast forward to 2009, I have a video mixing style composition which uses MIDI input from boxes of knobs and sliders to control all the parameters, and a GUI application I wrote in REALbasic to select media and control additional parameters, all sent via MIDI to the composition.

So now I'd like to be able to dump what I'm doing in real time out to a Quicktime file.

I've looked at a number of ways of doing this and I'm not sure that I've found something that will work as simply as pressing a record button, but here's a few ideas:

  1. The Kineme Value Historian patch, hooked up to every place. With this approach it looks like I'd have to save out files from every node where I use it which could get rather complicated. Perhaps there's some way to "gang" them all together and save it out. The problem that I see here is that I'm running the composition in my own player app built in Xcode and so I don't see how I would be able to tell the value historians when and where to save history files.

  2. A screen capture utility such as Snapz Pro. I've downloaded the demo but it still seems intrusive in terms of setting up the recording area (which it didn't seem to want to cooperate with on my full screen output on a second monitor).

  3. Feed another video stream in the player app out to Firewire and have another computer record it. I'm not sure how this would affect frame rate performance, plus I'd have to have another machine set up every time I decide to noodle around and do some video.

Has anyone else looked at issues like these? Is there an elegant way to have something like a record button :) ? Any feedback would be appreciated.



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gtoledo3's picture
Re: recording real time to QT file

It sounds like, if you need real time render to .mov, you might want to try compiling the movie maker(?, can't remember exactly what it's called) plugin in the example quartz composer plugins. When you use it, it's important that you make sure to enable/disable the render on the actual port of the plugin. If you simply stop render, the mov file will be unreadable. That said, it really hurts fps, and I personally can't use much beyond medium quality, and not too big of a render size. In fact, certain codec/quality settings will crash QC outright for me.

You should be able to use just one value historian in your composition by going to settings and adding more inputs. That said, you can also have multiple in your composition.

The value historian doesn't save the information to file so to speak, and you also can't save virtual information in your composition when you save your qtz and have it re-appear when you open it, but everything else should be fine.

Using the value historian to capture your "performance" data, and then rendering offline with Quartz Crystal is the best option as far as visual quality goes, and rendering the visual output of all plugins.

I've never found any screengrab to movie software that I thought was really awesome.... I use iGrabit though, and it is sometimes preferable to the movie to file plugin project.

detour's picture
Re: recording real time to QT file

Thanks for the response. I hadn't spent too much time playing with value historian so I think I will spend some time with it and see how I can integrate it. Didn't realize I can use just one with multiple inputs. Rendering after the face in higher quality would be preferable - it'll take some time to figure out a work approach, but that's part of the fun. I'll post back when I have some results!



hekxsa's picture
Re: recording real time to QT file

There's a nice screen grabber I have used called ScreenFlow. It basically records what goes on into a filetype of its own and later you have to export (render) it to a movie. You need a lot of disk space but it can keep up with whatever is going on rather nicely.