音频单元开发（OS X）

Question

I'm quite new to Core Audio development. I did many google searches but so far I couldn't come up with something useful for bootstrapping the process.I looked through the Apple Audio Unit Guide but it is outdated and uses Core Audio SDK which I even cant find for downloading. Is there any useful resources with audio Unit development apart from the horrible Apple guide?

Answer 1

I feel that this book has a good beginning overview of Audio Units (better than any Apple provides) and equips the reader with the tools to build more complicated programs.

http://www.amazon.com/Learning-Core-Audio-Hands-On-Programming/dp/0321636848

Chapter 7 in the book has an example of adding a reverb effect. So you can use that to guide you on whatever audio effects you want to add. As for the equalizer functions, there are audio units for it, also located in Chapter 7. If none of these accomplish what you want, you can always intercept the PCM audio data in the callback and manipulate the raw data. Though that does require you to know some DSP, which is too advanced for me.

Here are some useful posts I found:

http://www.deluge.co/?q=content/coreaudio-iphone-creating-graphic-equalizer

http://www.musicdsp.org/files/Audio-EQ-Cookbook.txt

Getting started with programmatic audio

Answer 2

Audio Unit tutorials and the Learning Core Audio book are mostly about using the Core Audio API. If you want to know more about how to actually process the audio data inside an Audio Unit for some effect, the subject in which you may really be interested is Digital Signal Processing (DSP). It's a large non-trivial subject area. There are many entire university-level textbooks on the subject, as well as a specialty dsp.stackexchange site. For starters, try this answer or this answer .