ALAC is a tool using the ALSA API to capture the Raspberry Pi's pcm audio and convert it to aac format using faac.
sudo apt-get install libasound2-dev
wget ftp://ftp.alsa-project.org/pub/lib/alsa-lib-1.1.7.tar.bz2
tar xjf alsa-lib-1.1.7.tar.bz2
cd alsa-lib-1.1.7/
./configure --prefix=$(pwd)/build
make -j4
make install
see alacSample.c.
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