function set_default_playback_device_next {
    # this number is useful when we are on the last soundcard:
    # if it can't find a next soundcard, it will try to find previous one
    inc=${1:-1}

    # how many devices do we have ?
	num_devices=$(pacmd list-sinks | grep -c index:)

	# make a list of devices numbers we found (the lines starting with index:)
    sink_arr=($(pacmd list-sinks | grep index: | grep -o '[0-9]\+'))

	# find which device is the currently active one
    default_sink_index=$(( $(pacmd list-sinks | grep index: | grep -no '*' | grep -o '^[0-9]\+') - 1 ))

	# remainder of the euclidian division : current device number + number of devices + 1 / number of devices
    # = next device , or = first device if we were using the last one
    default_sink_index=$(( ($default_sink_index + $num_devices + $inc) % $num_devices ))

    default_sink=${sink_arr[$default_sink_index]}

	# move the output
    pacmd set-default-sink $default_sink
	# move the inputs related to outputs
    move_sinks_to_new_default $default_sink
}



function move_sinks_to_new_default {
    DEFAULT_SINK=$1
    pacmd list-sink-inputs | grep index: | grep -o '[0-9]\+' | while read SINK
    do
        pacmd move-sink-input $SINK $DEFAULT_SINK
    done
}

set_default_playback_device_next