Script to change audio output defaults

[developer1105]

I have reconfigured my system (do not remember exactly how) to make HDMI as the default sound output. I am using my laptop nowadays detached from the HDMI monitor I used formerly, so I would like my default to be P2 plug now. Since pavucontrol does not save the last config as the default, one needs to reconfigure it every reboot. I would like a script to change the audio output, so when I am using an HDMI monitor, I would type “snd-default-output hdmi” and when I am using my laptop unplugged, I would use “snd-default-output p2”. Thanks in advance for your help.

[nikgnomic]

Please post more information about your PulseAudio output sinks

pactl list short sinks

pacmd dump | grep default-sink

If the default-sink is set to the hdmi output, audio will try to use it for audio output
But if the monitor is unplugged and hdmi output not available PulseAudio will use a fallback sink

[developer1105]

[P2 HEADPHONES - ANALOG STEREO OUTPUT]

pactl list short sinks 

1 combined module-combine-sink.c s16le 2ch 16624Hz IDLE
3 ladspa_output.mbeq_1197.mbeq module-ladspa-sink.c float32le 2ch 16624Hz IDLE
4 alsa_output.pci-0000_00_1b.0.analog-stereo module-alsa-card.c s16le 2ch 44100Hz RUNNING

[HDMI]

pactl list short sinks

1 combined module-combine-sink.c s16le 2ch 16624Hz RUNNING
2 alsa_output.pci-0000_00_1b.0.hdmi-stereo module-alsa-card.c s16le 2ch 32000Hz RUNNING
3 ladspa_output.mbeq_1197.mbeq module-ladspa-sink.c float32le 2ch 16624Hz IDLE

[BOTH]

pacmd dump | grep default-sink

set-default-sink ladspa_output.mbeq_1197.mbeq

[nikgnomic]

You have 4 sinks for audio output not just the 2 I expected
and the default-sink ladspa_output.mbeq_1197.mbeq is pulseaudio-ladspa-equalizer

If you want to continue using the equalizer, leave the default-sink set to ladspa_output.mbeq_1197.mbeq
Changing the default-sink will bypass the equalizer

If you are no longer using HDMI you should remove module-combine-sink
That module may have been loaded by enabling the setting for simultaneous output in paprefs
Or it may have been added to the PulseAudio configuration file default.pa

[developer1105]

With your help, I was able to write this script. Thanks.

#!/bin/bash

#no-argument
if [ "$1" == "" ]; then
    echo "No argument provided. Please inform an option: [hdmi|analog]"
    exit 1
fi

#hdmi
if [ "$1" == "hdmi" ]; then
    PARAM_REGEX='s/output:analog-stereo/output:hdmi-stereo/'
    PARAM_PATH=/etc/pulse/default.pa
    sed -i $PARAM_REGEX $PARAM_PATH
    echo "done"
    exit 0
fi

#analog
if [ "$1" == "analog" ]; then
    PARAM_REGEX='s/output:hdmi-stereo/output:analog-stereo/'
    PARAM_PATH=/etc/pulse/default.pa
    sed -i $PARAM_REGEX $PARAM_PATH
    echo "done"
    exit 0
fi

#invalid-argument
echo "Invalid argument provided. Please inform an option: [hdmi|analog]"
exit 1

To use it, just type:

sudo snd-default-output hdmi

or

sudo snd-default-output analog

This way, one can travel some weeks with your laptop and use the analog output. Coming back home, one can use the hdmi monitor.