Fix noisy microphone's left channel

extension.js

/**
 * Gnome Extension (tested on Gnome 46 and with previous exact configuration).
 */
import {Extension} from 'resource:///org/gnome/shell/extensions/extension.js';
import * as Main from 'resource:///org/gnome/shell/ui/main.js';
const { GLib } = imports.gi;

const DEBUG_LOG_TAG = 'mic-hider';
function log(message) {
    console.log(`[${DEBUG_LOG_TAG}] ${message}`);
}

export default class MicHiderExtension extends Extension {
    enable() {
        log('Starting');

        // Adapted from: https://discourse.gnome.org/t/main-panel-statusarea-quicksettings-system-is-undefined/16827/2
        if (Main.panel.statusArea.quickSettings._volumeInput) {
            this._initMicControllers();
        } else {
            GLib.idle_add(GLib.PRIORITY_DEFAULT, () => {
                if (!Main.panel.statusArea.quickSettings._volumeInput)
                    return GLib.SOURCE_CONTINUE;
    
                this._initMicControllers();
                return GLib.SOURCE_REMOVE;
            });
        }
    }

    _initMicControllers() {
        this.micIndicator = Main.panel.statusArea.quickSettings._volumeInput;
        log(`micIndicator: ${this.micIndicator}`);
        this.controlHandlerIds = [];
        
        this.controlHandlerIds.push(this.micIndicator._control.connect('stream-added', () => this.updateVisibility()));
        this.controlHandlerIds.push(this.micIndicator._control.connect('stream-removed', () => this.updateVisibility()));
        this.controlHandlerIds.push(this.micIndicator._control.connect('input-added', () => this.updateVisibility()));
        this.controlHandlerIds.push(this.micIndicator._control.connect('input-removed', () => this.updateVisibility()));
        log(`controlHandlerIds: ${this.controlHandlerIds.join(', ')}`);

        this.inputHandlerId = this.micIndicator._input.connect('notify::visible', () => this.updateVisibility());
        log(`inputHandlerId: ${this.inputHandlerId}`);

        this.updateVisibility();
    }

    disable() {
        // Revert whatever we did in enable()
        for (const handlerId of this.controlHandlerIds) {
            this.micIndicator._control.disconnect(handlerId);
        }
        this.micIndicator._input.disconnect(this.inputHandlerId);
        this.micIndicator.visible = this.micIndicator._input._shouldBeVisible();
    }

    isMicActive() {
        const allOutputs = this.micIndicator._control.get_source_outputs();
        log('Listing all outputs:');
        for (const output of allOutputs) {
            log(`  Application ID: ${output.get_application_id()}`);
            log(`  Description: ${output.get_description()}`);
            log(`  ID: ${output.get_id()}`);
            log(`  Name: ${output.get_name()}`);
            log(`  State: ${output.get_state()}`);
            log(` ------------------------ `);
        }

        // Return true if there is an input that doesn't match the pattern of our virtual mic
        // However, this may be a security risk, as it could be possible to spoof the name of the virtual mic!
        for (const output of allOutputs) {
            const expectedDescription = 'Remapped alsa_input.pci-0000_03_00.6.analog-stereo source input';
            const expectedName = null;
            const expectedApplicationId = null;

            // In general, none of our virtual sinks have a name or application ID
            if (output.get_name() !== expectedName || output.get_application_id() !== expectedApplicationId) {
                log(`Showing mic (name: ${output.get_name()}, application ID: ${output.get_application_id()})`);
                return true;
            }

            // Check for all of our virtual sinks, based on the description
            const isVirtualMic = output.get_description() === expectedDescription;
            const loopbackSinkRegex = /^loopback-1[0-9]{3}-1[0-9] input$/g;
            const isLoopbackSink = loopbackSinkRegex.test(output.get_description());

            if (!isVirtualMic && !isLoopbackSink) {
                log(`Showing mic (description: ${output.get_description()})`);
                return true;
            }
        }

        return false;
    }

    updateVisibility() {
        const expectedVisibility = this.micIndicator._input._shouldBeVisible() && this.isMicActive();
        if (this.micIndicator.visible != expectedVisibility) {
            this.micIndicator.visible = expectedVisibility;
        }
    }
}

metadata.json

{
  "name": "Hide useless Mic indicator",
  "description": "Hide the Mic indicator from Gnome status bar if it is useless at the moment",
  "uuid": "1297f1ec-e681-491c-93d2-3da7bb487e90",
  "shell-version": [
    "46"
  ],
  "url": "https://gist.github.com/simonesestito/ef4ea0c1af420d474d29a9a20d375d80"
}

mic_noise_fix.env

DEFAULT_MIC_ID=alsa_input.pci-0000_03_00.6.analog-stereo

mic_noise_fix.service

[Unit]
Description=Mic Noise Fix

[Service]
Type=oneshot
RemainAfterExit=yes
ExecStart=/home/simone/.config/systemd/user/mic_noise_fix_start.sh
ExecStop=/home/simone/.config/systemd/user/mic_noise_fix_stop.sh

[Install]
WantedBy=default.target

mic_noise_fix_start.sh

#!/bin/sh --
set -e
set -x

source /home/simone/.config/systemd/user/mic_noise_fix.env

# Create the new virtual microphone, with correct noise suppression and ignoring the broken channel
pactl load-module module-switch-on-connect
pactl load-module module-remap-source \
    source_name=virtual_mic_remapped \
    master=${DEFAULT_MIC_ID} \
    channels=1 \
    master_channel_map=front-right \
    channel_map=mono
pactl set-default-source virtual_mic_remapped
pactl set-source-volume ${DEFAULT_MIC_ID} '32%'
pactl set-source-volume virtual_mic_remapped '75%'

mic_noise_fix_stop.sh

#!/bin/sh --
set -e
set -x

source /home/simone/.config/systemd/user/mic_noise_fix.env

# Revert the modifications made in mic_noise_fix_start.sh
pactl unload-module module-remap-source
pactl unload-module module-switch-on-connect
pactl set-default-source "${DEFAULT_MIC_ID}"

stylesheet.css

/* Add your custom extension styling here */
#panel .microphone-indicator {
    display: none;
}