Bluetooth Audio Utility

Windows 10, 11  ·  Version 1.0.0  ·  Free

See which codec your Bluetooth headphones are using.

Bluetooth Audio Utility is a native Windows app. It shows which codec your Bluetooth audio device is using, plus its bitrate, sample rate, latency and supported codecs.

Use it to troubleshoot wireless headphones or to force a particular codec. The app stays small, using less than 2.5 MB of resident memory.

Platform
Windows 10, Windows 11AAC needs 11
Version
1.0.0
Builds
x64, ARM64
Price
Free
Download for x64 .msi installer for 64-bit Windows

Windows on ARM: ARM64 installer

Administrator rights

The app reads the connection state, the codec in use and the device's supported codec list without elevated rights. Everything else comes from Bluetooth driver ETW events, and reading those needs administrator privileges. If you start the app unelevated, it offers to restart itself as an administrator. Without administrator rights, streaming state, bitrate, sample rate and latency stay empty, and codec configuration settings cannot be changed.

01

Start it as an administrator

To switch codecs on or off and see streaming state, bitrate and latency, answer Yes when the app asks at startup to restart itself as an administrator.

Readout 1 The elevation prompt, first runFull size
The app showing a dialog that reads: Administrator rights are needed to read Bluetooth driver events. Restart this program as an administrator? with Yes and No buttons.

ReadingNo driver events · connection and codec in use still shown · streaming, bitrate and latency need elevation

02

The status panel

The left half of the window is measurement. The fields in it come from the Bluetooth driver on this PC. Here a Tribit FlyBuds C1 has just connected.

Readout 2 Tribit FlyBuds C1, connected on AACFull size
The app window. Status reads Connected, codec in use AAC, 88 Kbps, 48000 Hz, 2 channels, 16 bit, this PC encodes. Latency 200 ms reported by device.
Device
The drop down across the top lets you select the device to query from every paired audio device on this PC.
Connected
Device state, under STATUS. It reads Disconnected, Connected or Streaming. Streaming means audio is playing through this device right now.
AAC  codec in use
Indicates what Windows and Bluetooth device negotiated for audio transmission. Windows encodes audio using this codec.
88 Kbps
The bitrate the Windows encoder reported for this stream. Here, the remote device is a generic Bluetooth dongle, so the bitrare is relatively low.
48000 Hz · 2 ch · 16 bit · this PC encodes
Sample rate, channels, bit depth, and which layer does the encoding: this PC encodes (software), or Bluetooth radio encodes (hardware). On SBC this line starts with the bitpool.
Supported
Codecs advertised by the device during pairing. What Windows driver cannot use are marked (not supported by Windows).
Latency
The delay the device itself reports, in milliseconds. It is the device's claim, not a measured value.

ReadingTribit FlyBuds C1 · AAC · 48 000 Hz · 2 ch · 16 bit · 88 Kbps · 200 ms · this PC encodes

03

The configuration panel

The right half holds four controls. They write Windows A2DP driver settings to the registry. These are machine settings, so they apply to every user on this PC. Your changes take effect after you reload the profile.

Readout 3 Configuration panel, same windowFull size
The configuration panel. AAC codec and aptX codec both checked, AAC maximum bitrate set to 256 Kbps, SBC quality set to High with a bitpool of 53. Buttons: Reset to Defaults and Reload Profile.
AAC codec
Whether to offer AAC to remote devices.
aptX codec
Whether to offer aptX to remote devices.
AAC maximum bitrate, Kbps
The highest bitrate the driver's software AAC encoder may use. Default 256.
SBC quality, bitpool
Medium, High or Ultra, which set the maximum bitpool to 35, 53 or 76. The number beside the label shows the stored ceiling. A higher bitpool means a higher bitrate on the link.

Few devices support bitpool higher than 53.

Reset to Defaults
Sets all four settings back to what Windows ships with.
Reload Profile
Applies your changes. It reloads the Bluetooth audio profile and restarts the A2DP driver, which then reads the new settings. Until you press it, the changes are not in effect. Without this button you would need to restart the PC after each change.

StoredAAC codec on · aptX codec on · AAC ceiling 256 Kbps · SBC ceiling bitpool 53

04

The codec priority order

Windows walks the list below, takes the first codec that both ends support, and uses it to encode audio for Bluetooth transmission.

1AACWindows starts here. It picks AAC when the device offers it and the AAC checkbox is checked.
2aptXReached only when AAC is unavailable or switched off.
3SBCThe default. Every Bluetooth audio device supports it, so the list ends here.

Windows makes the choice, so the app has no codec picker. You can switch a codec off, and Windows moves down the list. Windows does not support aptX HD, aptX Low Latency, LDAC or LHDC. When a device offers them, the app marks them in the Supported list. AAC encoding needs Windows 11, build 22000 or later. On Windows 10 the list starts at aptX.

Windows 11 supports aptX Adaptive on some hardware and ranks it above AAC.

05

Forcing aptX by switching AAC off

To move a device from AAC to aptX, clear the AAC codec checkbox. he device keeps using AAC until you reload the profile.

Readout 4 AAC cleared, not yet appliedFull size
The AAC codec checkbox is now clear, aptX stays checked. The status still shows AAC at 88 Kbps, and a note under the configuration panel reads Reload Profile to apply.

ReadingTribit FlyBuds C1 · still AAC · 88 Kbps · change stored, not applied

06

Reload the profile

Reload Profile disables and re-enables the A2DP sink for the selected device. The device disconnects and reconnects, which is what forces a fresh codec negotiation. Expect a short silence.

Readout 5 Mid reloadFull size
During the reload the status drops to Disconnected and reads Waiting for a device, while the Reload Profile button is greyed out and labelled Reload Profile with an ellipsis.
Disconnected  /  Waiting for a device
The device is disconnected for a moment.
Reload Profile…
The button greys out and gains an ellipsis while the reload runs, so a second click cannot start an overlapping one.

ReadingLink down · reload in progress · no codec negotiated yet

07

Confirm the new codec

The device comes back on aptX. Check the sample rate: aptX on Windows runs at 44 100 Hz, and AAC ran at 48 000 Hz.

Readout 6 Reconnected on aptXFull size
After the reload the status reads Connected with aptX as the codec in use, at 44100 Hz, 2 channels, 16 bit, this PC encodes.
aptX  codec in use
Negotiated on the new connection. The same spot read AAC before the reload.
44100 Hz · 2 ch · 16 bit
44 100 Hz now, against 48 000 Hz on AAC.

ReadingTribit FlyBuds C1 · aptX · 44 100 Hz · 2 ch · 16 bit · 200 ms · connected, idle

Readout 7 Playing, aptXFull size
With audio playing the state changes to Streaming, still on aptX at 44100 Hz.
Streaming
Start playing and the state changes from Connected to Streaming.

Note: Windows does not report the bitrate for aptX.

ReadingTribit FlyBuds C1 · aptX · 44 100 Hz · 2 ch · 16 bit · 200 ms · streaming

08

Forcing SBC

Here is a Shanling MW200 with AAC and aptX both cleared. Windows walks past both and negotiates SBC. SBC is also the one codec whose quality you can set, through the bitpool.

Readout 8 Shanling MW200 streaming SBC, both codecs offFull size
Shanling MW200 streaming SBC at 206 Kbps with bitpool 30 of 53. The supported list includes aptX Low Latency, LHDC, aptX HD and LDAC, each marked as not supported by Windows.
AAC codec  /  aptX codec
Both checkboxes are clear, so Windows offers neither codec.
SBC  codec in use
The codec every A2DP device must support, which is why the list ends here.
206 Kbps
The encoder reports this number, as it did for AAC.
bitpool 30 of 53
On SBC the detail line starts with the bitpool. The first number is the bitpool the link uses. The second is your ceiling from step 03. If the first number sits well below the second, the device or the radio conditions set the limit, and your setting does not.
(not supported by Windows)
This label appears several times in the Supported list. This device also offers aptX Low Latency, LHDC, aptX HD and LDAC. Windows supports none of them, and the app marks each one.

ReadingShanling MW200 · SBC · bitpool 30 of 53 · 44 100 Hz · 2 ch · 16 bit · 206 Kbps · 267 ms · streaming

09

aptX Adaptive needs specific PC hardware

The vivo TWS 3 below supports aptX Adaptive, but this PC and its generic Bluetooth dongle do not. The vivo TWS 3 does not list plain aptX among its supported codecs, so switching AAC off drops the link to SBC. The Supported list in the app shows this.

Readout 9 vivo TWS 3, aptX on, still SBCFull size
vivo TWS 3 connected on SBC at 206 Kbps with bitpool 30 of 53, while the aptX codec checkbox is checked. Its supported list reads AAC, SBC, aptX Adaptive.

Readingvivo TWS 3 · SBC · bitpool 30 of 53 · 44 100 Hz · 2 ch · 16 bit · 206 Kbps · 200 ms · connected

Visual theming

The app supports main window look customization under View > Theme. System follows the Windows light and dark setting. Light, Dark and Amber CRT are fixed. Below, the same device streams aptX in each of the three.

The app in the Light theme, streaming aptX.
Light
The app in the Dark theme, streaming aptX.
Dark
The app in the Amber CRT theme, amber text on black with a monospaced face, streaming aptX.
Amber CRT

Configuration reference

Whatever you set here stays set until you change it or press Reset to Defaults.

Control Options Default
AAC codec on, off on
aptX codec on, off on
AAC maximum bitrate 192000, 256000, 352000 256000
SBC quality, bitpool Medium 35, High 53, Ultra 76 53

Machine wide

These settings belong to the driver, so they apply to every user and every paired device on this PC. Changing them needs elevation.

In the tray

View > Close to tray closes the app to the notification area. It then tells you when the codec changes, when a device disconnects, and when the SBC bitpool drops on a link that was running higher.

Diagnostics

Help > Collect diagnostic info shows you the report contents, then writes one file to your desktop. The report leaves out your user name, computer name and file paths. The app does not send the file anywhere; you decide who gets it.

Languages

English, French, Spanish, German and Italian, under View > Language. System default follows Windows.