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Frequently Asked Questions

working with Pd

Why do I get clicks in the audio?

If you are getting a constant stream of clicks in your audio, then it is probably because you are trying to do graphics and audio in the same process.

Rendering a graphics frame usually takes longer than the size of the audio buffer, which is why you get clicks (the clicks are usually at 20Hz...the typical frame rate).

One way around this is to use two computers, one for graphics and one for audio. If you have enough processing power (or dual processors), then you can run two versions of Pd, one for graphics and one for audio. Just use [netsend] and [netreceive] to have the two versions of Pd talk to each other.

How do I get audio data to GEM?

One simple way to get raw audio values right now is to use [snapshot~] . Just set up a metro which bangs [snapshot~] and use the floating point value.

If you want "musical" information, then use objects such as [env~] .

You could write audio-data into tables and use that to control things via [tabread] .

You might also have a look at the [pix_sig2pix~] which interprets audio-data as pixels and its counterpart [pix_pix2sig~]

Why can't GEM find an image/model file?

This means that GEM can't locate the file. If you use an absolute path (with / for instance), then GEM will look there. Otherwise, GEM will look in the directory of where the patch is. Then pd/GEM will search the paths you specified at pd-startup with the -path flag.

Check the following:

  1. Does the file exist?
  2. Did you make a typo in the filename?
  3. Is the file in the search-path ?

How can I optimize my patches?

One of the biggest performance hits is having UI elements in your patch which have to be updated.

The biggest performance hog is the number box. While the number box is great for debugging, make sure that they are all gone from your "release" patch.

If you run a performance meter, you will see that whenever Tcl/Tk has to update the user interface, it sucks the entire processor. Another examples of this is when you move a lot of objects at once, everything jerks and slides across the screen. There are probably ways to improve this...

Another problem is doing unneccessary calculations. When you are throwing lots of numbers around, especially packing/unpacking, doing vector math, etc., they add up. If the calculations are going unused (for instance, that part of the patch is turned off), then do not trigger the math objects.

Use [spigot] and block the events early. This is especially important with objects that send a lot of numbers, like ~-objects or [line]/[tripleLine].

Why does Gem crash when closing the Gem-window? !

I made am running Gem in fullscreen mode. In order to be able to still access my patch after the Gem-window has taken full control over my desktop, i use [gemmouse] to trigger a [destroy( message whenever i click the right mouse-button. While this closes the Gem-window, it also crashes Pd :-(

This happened with older versions of Gem, and should be fixed at least since 0.91. Please upgrade!

The reason for this is, that [gemmouse] sends out all the events immediately when they appear, which is on the stack of a method from the Gem-window itself. Destroying the window in this instance of time will invalidate the stack. A quick fix is to use a [delay 0] message between the trigger event and the [destroy( message.

But again, this hack is unnecessary with recent versions of Gem.

This FAQ applies to: 0.888

by IOhannes m zmoelnig last modified 2007-07-18 11:49 AM

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