pi@raspberrypi:~ $ ./ffmpeg-bin/bin/ffmpeg -f alsa -i hw:CARD=CODEC -t 30 out.wav
ffmpeg version N-80955-g5939878 Copyright (c) 2000-2016 the FFmpeg developers
  built with gcc 4.9.4 (crosstool-NG crosstool-ng-1.22.0) 20150629 (prerelease)
  configuration: --enable-cross-compile --cross-prefix=/home/user/x-tools/arm-unknown-linux-gnueabihf/bin/arm-unknown-linux-gnueabihf- --arch=armhf --target-os=linux --prefix=/home/user/ffmpeg-bin --enable-gpl --enable-nonfree --enable-libfdk-aac --extra-cflags=-I/home/user/fdk-aac-bin/include --extra-ldflags=-L/home/user/fdk-aac-bin/lib --extra-libs=-ldl
  libavutil      55. 28.100 / 55. 28.100
  libavcodec     57. 50.100 / 57. 50.100
  libavformat    57. 41.100 / 57. 41.100
  libavdevice    57.  0.102 / 57.  0.102
  libavfilter     6. 47.100 /  6. 47.100
  libswscale      4.  1.100 /  4.  1.100
  libswresample   2.  1.100 /  2.  1.100
  libpostproc    54.  0.100 / 54.  0.100
Unknown input format: 'alsa'