#! /bin/sh

# Capture the audio player by any program on Linux.  This creates a dump
# of all the sounds sent to the audio card in raw format.
#
# Usage: alsacapture programname args...
#
# This will install sound capture, run the given program, and stop
# capturing when the program finishes.  Note that all sounds sent to
# the sound card are captured, not just the ones produced by the given
# program.

DUMPFILE=/dev/shm/out.raw

# The dump file is $DUMPFILE, which you can e.g. reencode in MP3 with
# (assuming 2-channels 16-bit low-endian):
#
#     ffmpeg -ac 2 -f s16le -i $DUMPFILE -acodec mp3 -ab 192k output.mp3


if [[ -e ~/.asoundrc ]] ; then
        echo "Move ~/.asoundrc out of the way..."
        exit 1
fi

cat > ~/.asoundrc <<EOF
pcm.!default {
    type file
    slave.pcm {
        type plug
        slave.pcm {
            type hw
            card 0
            device 0
            subdevice -1
        }
    }
    file $DUMPFILE
    format raw
}
EOF
echo "ALSA sound capture enabled"

"$@"

rm ~/.asoundrc
echo "ALSA sound capture disabled"