Audio Input Buggy?

jersmi's picture

This would be a question for the mailing list, but not sure it's up and running yet.

I haven't used the built-in Audio Input much and wish to explore it a bit. Looking at the Audio Input.qtz developer example patch and getting buggy results out of the box. No matter what input I select, the three far right bars (high freqs) randomly peak or show signal when they should be 0 or close to 0. Turning on and off the viewer produces random results. Any clues?

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dwskau's picture
Re: Audio Input Buggy?

I get the same issues. I have seen it happen on multiple different hardware configurations, even PowerPC machines running Leopard.

cwright's picture
Re: Audio Input Buggy?

long-standing known bug. There's a radar for it (not that it'd help anyone)

cybero's picture
Re: Audio Input Buggy?

I still say it, despite the initial CPU hit, Kineme Audio Tools are your friend :-)

jersmi's picture
Re: Audio Input Buggy?

Bug, ok. Thanks, Chris. If it's just the three high freq bands, reducing to twelve bands is workable for me. Another question: how are the freqs divided, ie, what range is each freq band?

@cybero -- I don't see anything in Kineme Audio Tools to compute frequency spectrum like with the built-in Audio Input. Am I missing something?

cwright's picture
Re: Audio Input Buggy?

The bands are undefined - they're free to change with various things (OS releases, audio input hardware, etc). As an implementation detail, Accelerate.framework is used to do an FFT on the samples (256 band I believe?) and then does some kind of bucketing similar to one of the Kineme Audio Tools methods (Sorry I'm hazy on the details, I haven't looked at the code for this patch in a while).

If you need specific frequency characteristics, you should commission a patch for it or file a radar (or both, and start a race to see who wins -- I'd expect kineme to win though because they have a much looser release cycle than Apple does ;)

jersmi's picture
Re: Audio Input Buggy?

I'll keep that in mind. Thanks, Chris. :)

harrisonpault's picture
Re: Audio Input Buggy?

Check out the file audio-frequency.qtz that is zipped up with other examples on the Kineme Audio Tools page. I am pretty certain you can get what you need out of that.

jersmi's picture
Re: Audio Input Buggy?

Thanks for the tip -- I had Audio Tools v0.4 and I don't when I would have noticed.... oy.

harrisonpault's picture
Re: Audio Input Buggy?

Hey Chris,

When is that multi-billion-dollar behemoth you work for going to get the quartz_composer_dev listserve going again?

Should we file a radar?