Jitter Technical Questions
How do I make Jitter output to a 2nd (or 3rd or 4th) screen?
If your video card supports extra displays (like on a
PowerBook, or a dual-headed video card), or if you have multiple video cards, you can use those extra outputs for Jitter display (depending on your hardware, you can output to a video monitor or tv, video projector or computer monitor). The simplest way to do it is to create a jit.window object and drag the window to the display you want to use. Sending the message 'fullscreen 1' to the jit.window object will cause the window to resize to fill the entire screen of that display.
If you want to get fancy, you can use the 'jit.displays' object to determine how many displays you have attached, and where they are. Then, you can auto-position windows and fullscreen them without having to drag windows around. The 'autodetect_monitor2.pat' example patch that ships with Jitter demonstrates one such method.
On Windows, jit.window must be floating, in order to leave the Max Application MDI Frame. Floating is turned on by sending jit.window the message "floating 1".
If you're running under OS9, you may need to update your Open GL software or reinstall your video drivers. We've seen several cases where the wrong
OpenGL or video driver software was installed on a user's computer because they used an install CD that came from a different model Mac (e.g. you have a
PowerBook, but used an iMac install CD to update to OS9). For best results, you should use the install CD that came with your computer, or a retail copy of the OS.
My computer won't support a 2nd display, but it has a FireWire port. Can I use jit.qt.videoout to send video data to a DV camera, and then display it on a 2nd screen?
On Macintosh you can, but it will be a lot slower than using a real 2nd display because the data has to be DV-compressed before it can stream over the port. Even with a fast computer, this is a slow process.
On Windows, jit.qt.videoout is not currently supported.
Why don't my Jitter objects show up in the New Object List?
For a couple of reasons, we didn't ship a new Max Object List file with Jitter for OS 9. But due to popular demand, we've abandoned our sruples, and made a version of the default list, with all of the Jitter objects added, which you can download
here. Just drop it into your Max application folder. It will overwrite any modifications you've made to the list. Note that the Max Object List is just a text file, though, and you can edit it manually, and add any objects you want, in any categories you like.
With the release of Max/MSP 4.3 and Jitter 1.1.2, the New Object List is dealt with in a new fashion, using text files found in the init folder in
MaxMSP's directory. Users of these versions should find their Jitter objects appearing in the New Object List.
Do you have any tips for maximizing Jitter's framerate?
We can't possibly answer this question completely in this space. There are many ways of optimizing your Jitter patches for greater performance. Here are two to get you started:
If your patches use little jit.pwindow objects as monitors, and the data being displayed on them is larger than the dimensions of the jit.pwindow objects (e.g. you're monitoring a 320x240 matrix on an 80x60 jit.pwindow object), turn OFF 'use onscreen' in the object's inspector. (Why? Onscreen mode uses Apple's copy routines, which feature a slow averaging filter when downscaling images. Offscreen mode uses custom routines which are faster, in this case).
If your patches use Jitter objects with multiple inputs (such as jit.chromakey), you can eliminate a copy step by using the @in2_name (or @in3_name, etc.) attribute to force the object to use the specified matrix in-place (don't forget to disconnect the patchcord from the right inlet of the object). Look at the 'jit.chromakey-pile.pat' example for a demonstration of this technique.
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