Bluetooth mic routing fix by kikura · Pull Request #6436 · home-assistant/android

kikura · 2026-02-12T14:42:33Z

Description

Fixes an issue where the Bluetooth microphone was not being used when launching the voice assistant from a Bluetooth headset button. The app would fail to recognize voice commands unless the phone's microphone was within earshot.

Problem

When triggering the voice assistant from a Bluetooth headset (e.g., pressing the button on AirPods), the app would display "no text recognised" even though the Bluetooth headset was functioning correctly with other voice assistants like Google Gemini.

Solution

Enabled Bluetooth SCO (Synchronous Connection Oriented) audio routing by:

Changed audio source to VOICE_COMMUNICATION when Bluetooth SCO is available
Added startBluetoothSco() call in requestFocus() to enable SCO audio mode before recording
Added stopBluetoothSco() call in abandonFocus() to properly clean up SCO connection
Added API level checks to ensure compatibility with older Android versions

Testing

Launch the voice assistant by pressing the button on a Bluetooth headset
Give voice commands
Verify that the app now recognizes speech from the Bluetooth microphone

Files Changed

`common/src/main/kotlin/io/homeassistant/companion/android/common/util/AudioRecorder.kt

*Please not that the neccessary code has been generated by Co-Pilot, but has been tested and works.

…outing, replacing line 33 with dynamic audio source selection.

Updated AudioRecorder to dynamically select audio source based on connected Bluetooth devices, enhancing audio recording functionality.

Refactor audio source selection to prioritize VOICE_COMMUNICATION for Bluetooth audio. Enable and disable Bluetooth SCO as needed based on API level.

home-assistant

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Thanks!

home-assistant · 2026-02-12T14:42:40Z

Please take a look at the requested changes, and use the Ready for review button when you are done, thanks 👍

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Copilot

Pull request overview

This PR aims to fix voice-assistant speech recognition when invoked from a Bluetooth headset button by routing input through Bluetooth SCO and selecting an appropriate AudioRecord source in the shared :common audio recording utility.

Changes:

Update AudioRecorder to select AudioSource.VOICE_COMMUNICATION when Bluetooth SCO is available
Start/stop Bluetooth SCO around audio focus acquisition/release
(Accidental) Adds a repository-root AudioRecorder.kt file containing non-compilable pseudo-code

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 5 comments.

File	Description
common/src/main/kotlin/io/homeassistant/companion/android/common/util/AudioRecorder.kt	Adds Bluetooth SCO routing and dynamic audio source selection for voice recording
AudioRecorder.kt	New file at repo root that appears to be Copilot-generated pseudo-code and will break compilation

Copilot · 2026-02-12T14:46:33Z

+    /**
+     * Determine the appropriate audio source based on connected devices.
+     * Prefers Bluetooth SCO if available, falls back to VOICE_COMMUNICATION,
+     * and finally defaults to MIC if neither is available.
+     */
+    private fun getAudioSource(): Int {
+        if (audioManager == null) {
+            return AudioSource.MIC
+        }
+
+        // Check if Bluetooth SCO is available
+        return if (audioManager.isBluetoothScoAvailableOffCall()) {
+            // Use VOICE_COMMUNICATION which is the standard for Bluetooth audio
+            AudioSource.VOICE_COMMUNICATION
+        } else {
+            AudioSource.MIC
+        }
+    }


The KDoc for getAudioSource() doesn't match the actual behavior: the function returns VOICE_COMMUNICATION only when Bluetooth SCO is available, otherwise MIC (there is no separate “fallback to VOICE_COMMUNICATION” path). Please update the documentation (or adjust the logic) so it accurately reflects what the code does.

Copilot · 2026-02-12T14:46:34Z

+        // Enable Bluetooth SCO if available (requires API 11+)
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) {
+            if (audioManager.isBluetoothScoAvailableOffCall()) {
+                audioManager.startBluetoothSco()
+            }
+        }


startBluetoothSco() is guarded by an API 11 check, but this project’s minSdk is 23, so the version guard is redundant. Also, consider tracking whether this instance actually started SCO so you can stop it deterministically (rather than relying on a global stop later).

Copilot · 2026-02-12T14:46:34Z

+
+        // Disable Bluetooth SCO (requires API 11+)
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) {
+            audioManager.stopBluetoothSco()
+        }
+


abandonFocus() calls stopBluetoothSco() unconditionally (only gated by the redundant API-level check), even if this AudioRecorder never started SCO. Since SCO is a global AudioManager state, this can interfere with other audio usage. Please gate the stop call on a local “SCO started” flag and/or the same condition used to start SCO.

Suggested change

// Disable Bluetooth SCO (requires API 11+)

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) {

audioManager.stopBluetoothSco()

}

// Disable Bluetooth SCO (requires API 11+)

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB &&

audioManager.isBluetoothScoAvailableOffCall()

) {

audioManager.stopBluetoothSco()

}

Copilot · 2026-02-12T14:46:34Z

+import android.media.AudioManager;
+import android.telecom.Call;
+import android.bluetooth.BluetoothAdapter;
+import android.bluetooth.BluetoothDevice;
+
+// Function to detect connected Bluetooth devices
+private AudioDevice getAudioSource() {
+    BluetoothAdapter bluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
+    if (bluetoothAdapter != null && bluetoothAdapter.isEnabled()) {
+        for (BluetoothDevice device : bluetoothAdapter.getBondedDevices()) {
+            if (device.getType() == BluetoothDevice.DEVICE_TYPE_AUDIO) {
+                // return audio source associated with the Bluetooth device
+                return AudioDevice.BLUETOOTH;
+            }
+        }
+    }
+    // Fallback to default audio source if no Bluetooth devices are connected
+    return AudioDevice.DEFAULT;


This AudioRecorder.kt at the repository root is Java-like pseudo-code (semicolon imports, non-Kotlin function syntax, unknown types like AudioDevice) and will not compile in this Kotlin/Gradle project. It looks like an accidentally committed Copilot-generated snippet—please remove it from the PR (or convert it into valid Kotlin in the correct module/package if it’s actually needed).

Suggested change

import android.media.AudioManager;

import android.telecom.Call;

import android.bluetooth.BluetoothAdapter;

import android.bluetooth.BluetoothDevice;

// Function to detect connected Bluetooth devices

private AudioDevice getAudioSource() {

BluetoothAdapter bluetoothAdapter = BluetoothAdapter.getDefaultAdapter();

if (bluetoothAdapter != null && bluetoothAdapter.isEnabled()) {

for (BluetoothDevice device : bluetoothAdapter.getBondedDevices()) {

if (device.getType() == BluetoothDevice.DEVICE_TYPE_AUDIO) {

// return audio source associated with the Bluetooth device

return AudioDevice.BLUETOOTH;

}

}

}

// Fallback to default audio source if no Bluetooth devices are connected

return AudioDevice.DEFAULT;

import android.media.AudioManager

import android.telecom.Call

import android.bluetooth.BluetoothAdapter

import android.bluetooth.BluetoothDevice

private enum class AudioDevice {

BLUETOOTH,

DEFAULT,

}

// Function to detect connected Bluetooth devices

private fun getAudioSource(): AudioDevice {

val bluetoothAdapter: BluetoothAdapter? = BluetoothAdapter.getDefaultAdapter()

if (bluetoothAdapter?.isEnabled == true) {

val bondedDevices: Set<BluetoothDevice>? = bluetoothAdapter.bondedDevices

if (!bondedDevices.isNullOrEmpty()) {

// Return audio source associated with any bonded Bluetooth device

return AudioDevice.BLUETOOTH

}

}

// Fallback to default audio source if no Bluetooth devices are connected

return AudioDevice.DEFAULT

Copilot · 2026-02-12T14:46:34Z

@@ -17,6 +18,7 @@ import kotlinx.coroutines.flow.MutableSharedFlow
 import kotlinx.coroutines.flow.asSharedFlow
 import kotlinx.coroutines.isActive
 import kotlinx.coroutines.launch
+import android.os.Build


AudioDeviceInfo is imported but never used, and Build is imported after non-Android imports. This will fail ktlint/unused-import checks—please remove the unused import and keep imports grouped/ordered consistently.

Co-authored-by: kikura <37535682+kikura@users.noreply.github.com>

Fix Bluetooth SCO state management in AudioRecorder

TimoPtr

Thanks for proposing this change, but I'm not sure it actually works. The API documentation is mentioning that when using startBluetoothSco that you should wait for a given state

As the SCO connection establishment can take several seconds, applications should not rely on the connection to be available when the method returns but instead register to receive the intent ACTION_SCO_AUDIO_STATE_UPDATED and wait for the state to be SCO_AUDIO_STATE_CONNECTED.

And I don't see that in your code.

For the next steps you should do the modification yourself and test, and only use AI to help you on the issues you have.

TimoPtr · 2026-02-13T12:57:32Z

+        }
+
+        // Check if Bluetooth SCO is available
+        return if (audioManager.isBluetoothScoAvailableOffCall()) {


Use the property instead of the function

Suggested change

return if (audioManager.isBluetoothScoAvailableOffCall()) {

return if (audioManager.isBluetoothScoAvailableOffCall) {

TimoPtr · 2026-02-13T12:58:05Z

 /**
 * Wrapper around [AudioRecord] providing pre-configured audio recording functionality.
 */
 class AudioRecorder(private val audioManager: AudioManager?) {


I would like a small update of the documentation that explains the behavior of the recorder.

TimoPtr · 2026-02-13T13:01:02Z

+        // Check if Bluetooth SCO is available
+        return if (audioManager.isBluetoothScoAvailableOffCall()) {
+            // Use VOICE_COMMUNICATION which is the standard for Bluetooth audio
+            AudioSource.VOICE_COMMUNICATION


Any reason to not use that all the time, it might be beneficial to other scenario than only Bluetooth.

Microphone audio source tuned for voice communications such as VoIP. It will for instance take advantage of echo cancellation or automatic gain control if available.

TimoPtr · 2026-02-13T13:10:44Z


    companion object {
        // Docs: 'currently the only rate that is guaranteed to work on all devices'
        const val SAMPLE_RATE = 44100


From the documentation

Even if a SCO connection is established, the following restrictions apply on audio output streams so that they can be routed to SCO headset:
the stream type must be STREAM_VOICE_CALL
the format must be mono
the sampling must be 16kHz or 8kHz
The following restrictions apply on input streams:
the format must be mono
the sampling must be 8kHz

It means we should not use 44100 when we are going to use Bluetooth but 8000 otherwise you might get weird behavior.

TimoPtr · 2026-02-13T13:11:25Z

+
+        // Enable Bluetooth SCO if available
+        if (audioManager.isBluetoothScoAvailableOffCall()) {
+            audioManager.startBluetoothSco()


This method is deprecated and the documentation suggest to use setCommunicationDevice instead can you adjust and try again?

TimoPtr · 2026-02-13T13:11:57Z

@@ -0,0 +1,20 @@
+// Other existing imports


Remove this file.

Refactor audio recording logic to support dynamic sample rates based on Bluetooth SCO availability. Update methods to use currentSampleRate and improve Bluetooth handling.

…o make changes as this is beyond my capabilities.

TimoPtr · 2026-02-16T08:55:44Z

Take the time to review my comments, but also the code generated before asking for review.

kikura added 5 commits February 12, 2026 11:24

Update AudioRecorder to support Bluetooth audio input routing

6d7a9f9

Updated AudioRecorder.kt to add Bluetooth audio input detection and r…

fc4a2cd

…outing, replacing line 33 with dynamic audio source selection.

Update AudioRecorder.kt for Bluetooth audio input detection

757a469

Fix AudioRecorder to properly support Bluetooth microphone input routing

f950461

Updated AudioRecorder to dynamically select audio source based on connected Bluetooth devices, enhancing audio recording functionality.

Refactor audio source handling for Bluetooth support

fc24d6b

Refactor audio source selection to prioritize VOICE_COMMUNICATION for Bluetooth audio. Enable and disable Bluetooth SCO as needed based on API level.

Copilot AI review requested due to automatic review settings February 12, 2026 14:42

home-assistant Bot added the cla-needed label Feb 12, 2026

home-assistant Bot previously requested changes Feb 12, 2026

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home-assistant Bot marked this pull request as draft February 12, 2026 14:42

Copilot started reviewing on behalf of kikura February 12, 2026 14:43 View session

home-assistant Bot added cla-recheck cla-signed and removed cla-recheck cla-needed labels Feb 12, 2026

Merge branch 'main' into bluetooth-mic-routing-fix

4040f30

kikura marked this pull request as ready for review February 12, 2026 14:44

Copilot AI reviewed Feb 12, 2026

View reviewed changes

Copilot AI and others added 3 commits February 12, 2026 16:59

Initial plan

c081dfa

Fix Bluetooth SCO state tracking and code review issues

5e39f18

Co-authored-by: kikura <37535682+kikura@users.noreply.github.com>

Merge pull request #1 from kikura/copilot/address-code-review-comments

99574db

Fix Bluetooth SCO state management in AudioRecorder

TimoPtr reviewed Feb 13, 2026

View reviewed changes

TimoPtr self-requested a review February 13, 2026 13:14

TimoPtr requested changes Feb 13, 2026

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home-assistant Bot marked this pull request as draft February 13, 2026 13:14

kikura added 2 commits February 15, 2026 08:52

Enhance AudioRecorder for dynamic sample rate support

74cc0ce

Refactor audio recording logic to support dynamic sample rates based on Bluetooth SCO availability. Update methods to use currentSampleRate and improve Bluetooth handling.

Refine Bluetooth SCO implementation. Sadly have had to use AI again t…

33bcb89

…o make changes as this is beyond my capabilities.

kikura marked this pull request as ready for review February 15, 2026 09:55

home-assistant Bot requested a review from TimoPtr February 15, 2026 09:55

Merge branch 'main' into bluetooth-mic-routing-fix

9c76ad4

TimoPtr marked this pull request as draft February 16, 2026 08:55

jpelgrom linked an issue Feb 16, 2026 that may be closed by this pull request

Bluetooth headset microphone not used for Assistant voice input (audio input remains on phone mic) #6433

Open

	return if (audioManager.isBluetoothScoAvailableOffCall()) {
	return if (audioManager.isBluetoothScoAvailableOffCall) {

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kikura commented Feb 12, 2026

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