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I want to create an iOS app that records or takes audio from a file, gives the use the choice to apply a filter and plays said audio back with the filter applied.

I'm however completely unsure about how to approach this project. How do I best modify the sound of an audio file?

Should I go with Core Audio, OpenAL or are there other audio engines out there that make this even easier? Where would be a good place to start learning about stuff like this?

Thanks for any advice you can give me! :)

Mauin
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Core Audio is the Apple way and there are lots of examples online for working with it. To apply filters you would use AudioUnits

A new audio engine called The Amazing Audio Engine has just been released built on top of CoreAudio which might be useful.

A good book is Chris Adamson's Learning Core Audio: A Hands-on Guide to Audio Programming for Mac and iOS

iain
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OpenAL is not designed for this purpose. It is primarily for playing back audio without any effects other than pitch-shifting (which also results in speed up or speed down) and other very basic manipulations of audio. If you want to apply more robust audio filters and effects, Core Audio and the Audio Unit technology is the way to go. There is a good (and one of the few) books released last year on learning Core Audio, but also recently released is the audio engine already mentioned in your answers.

Jerome Baldridge
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Well, i once worked with audio in C# and used Bass audio library If you are working in Visual C++, i think you can try DirectSound libraries from DirectX, but it only supports wav file format (uncompressed audio), so if you want to play a mp3, you have to decompress "on-the-fly" and send the stream to a directsound buffer.

Give more details, please.

kristi_io
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