| Date: | July 2021 |
|---|---|
| Manual section: | 8 |
| Manual group: | System Manager's Manual |
| Version: |
bluealsa [OPTION] ...
bluealsa is a Linux daemon to give applications access to Bluetooth audio streams using the Bluetooth A2DP, HFP and/or HSP profiles. It provides a D-Bus API to applications, and can be used by ALSA applications via libasound plugins.
| -h, --help | Output a usage message and exit. |
| -V, --version | Output the version number and exit. |
| -B NAME, --dbus=NAME | |
| BlueALSA D-Bus service name suffix. Without this option, bluealsa registers itself as an "org.bluealsa" D-Bus service. For more information see the EXAMPLE below. | |
| -S, --syslog | Send output to system logger (syslogd(8)).
By default, log output is sent to stderr. |
| -i hciX, --device=hciX | |
HCI device to use. Can be specified multiple times to select more than one HCI.
Because HCI numbering can change after a system reboot, this option also accepts
HCI MAC address for the hciX value, e.g: Without this option, the default is to use all available HCI devices. | |
| -p NAME, --profile=NAME | |
Enable NAME Bluetooth profile. May be given multiple times to enable multiple profiles. If this option is given, then only those profiles explicitly mentioned will be enabled. Without this option, bluealsa enables a2dp-source, hfp-ag and hsp-ag. For the list of supported profiles see the PROFILES section below. | |
| --initial-volume=NB | |
Set the initial volume to NB % when the device is connected. NB must be an integer in the range from 0 to 100. The default value is 100 (full volume). Having headphones volume reset to max whenever they connect can lead to an unpleasant experience. This option allows the user to choose an alternative initial volume level. Only one value can be specified and each device on connect will have the volume level of all its PCMs set to this value (%). However, a device with native volume control may then immediately override this level. | |
| --keep-alive=SEC | |
| Keep Bluetooth transport alive for SEC number of seconds after streaming was closed. This option can be useful when playing short audio files in quick succession. It will reduce the gap between playbacks caused by Bluetooth audio transport acquisition. | |
| --a2dp-force-mono | |
| Force monophonic sound for A2DP profile. | |
| --a2dp-force-audio-cd | |
| Force 44.1 kHz sampling frequency for A2DP profile. Some bluetooth devices can handle streams sampled at either 48kHz or 44.1kHz, in which case they normally default to using 48kHz. With this option, bluealsa will request such a device uses only 44.1 kHz sample rate. | |
| --a2dp-volume | Enable native A2DP volume control. By default bluealsa will use its own internal scaling algorithm to attenuate the volume. This option disables that internal scaling and instead passes the volume change request to the A2DP device. This feature can also be controlled during runtime via BlueALSA D-Bus API. Note that this feature might not work with all Bluetooth headsets. |
| --sbc-quality=NB | |
Set SBC encoder quality, where NB can be one of:
| |
| --mp3-quality=NB | |
| Selects LAME encoder internal algorithm. The NB can be in the range from 0 to 9, where 0 is the best quality but requires a lot of CPU power. Default value is 5. | |
| --mp3-vbr-quality=NB | |
| Specifies variable bit rate (VBR) quality, where NB can be in the range from 0 to 9. For best VBR quality use 0. Default value is 2 (high quality VBR mode). | |
| --aac-afterburner | |
| Enables Fraunhofer AAC afterburner feature, which is a type of analysis by synthesis algorithm. This feature increases the audio quality at the cost of increased processing power and overall memory consumption. | |
| --aac-bitrate=BPS | |
| Set the target bit rate for constant bit rate (CBR) mode or the maximum peak bit rate for variable bit rate (VBR) mode. Default value is 220000 bits per second. | |
| --aac-latm-version=NB | |
Select LATM syntax version used for AAC audio transport. Default value is 1. The NB can be one of:
| |
| --aac-true-bps | Enable true "bit per second" bit rate. A2DP AAC specification requires that for the constant bit rate (CBR) mode every RTP frame has the same bit rate and for the variable bit rate (VBR) mode the maximum peak bit rate limit is also per RTP frame. However, a single RTP frame does not contain a single full second of audio. This option enables true bit rate calculation (per second), which means that per RTP frame bit rate may vary even for CBR mode. This feature is not enabled by default, because it violates A2DP AAC specification. Enabling it should result in an enhanced audio quality, but will for sure produce fragmented RTP frames. If RTP fragmentation is not supported by used A2DP sink device (e.g. headphones) one might hear clearly audible clicks in the playback audio. In such case, please do not enable this option. |
| --aac-vbr | Prefer variable bit rate mode over constant bit rate mode. Please note, that this option does not necessarily mean that the variable bit rate (VBR) mode will be used. Used AAC configuration depends on a remote Bluetooth device capabilities. |
| --ldac-abr | Enables LDAC adaptive bit rate, which will dynamically adjust encoder quality based on the connection stability. |
| --ldac-eqmid=NB | |
Specifies LDAC encoder quality, where NB can be one of:
| |
| --xapl-resp-name=NAME | |
| Set the product name send in the XAPL response message. By default, the name is set as "BlueALSA". However, some devices (reported with e.g.: Sony WM-1000XM4) will not provide battery level notification unless the product name is set as "iPhone". | |
BlueALSA provides support for Bluetooth Advanced Audio Distribution Profile (A2DP), Hands-Free Profile (HFP) and Headset Profile (HSP). A2DP profile is dedicated for streaming music (i.e. stereo, 48 kHz or more sampling frequency), while HFP and HSP for two-way voice transmission (mono, 8 kHz or 16 kHz sampling frequency). With A2DP, BlueALSA includes mandatory SBC codec and various optional codecs like AAC, aptX, and other. The full list of available optional codecs, which depends on selected compilation options, will be shown with bluealsa command-line help message.
The list of profile NAME-s accepted by the --profile=NAME option:
- a2dp-source - Advanced Audio Source (streaming audio to connected device)
- a2dp-sink - Advanced Audio Sink (receiving audio from connected device)
- hfp-ofono - Hands-Free handled by oFono
- hfp-hf - Hands-Free
- hfp-ag - Hands-Free Audio Gateway
- hsp-hs - Headset
- hsp-ag Headset Audio Gateway
The hfp-ofono is available only when bluealsa was compiled with oFono support. Enabling HFP over oFono will automatically disable hfp-hf and hfp-ag.
- /etc/dbus-1/system.d/bluealsa.conf
- BlueALSA service D-Bus policy file. D-Bus will deny all access to the org.bluealsa service (even to root) unless permission is granted by a policy file. The default file permits only root to own this service, and only members of the audio group to exchange messages with it.
Emulate Bluetooth headset with A2DP and HSP support:
bluealsa -p a2dp-sink -p hsp-hsOn systems with more than one HCI device, it is possible to expose different profiles on different HCI devices. A system with three HCI devices might (for example) use hci0 for an A2DP sink service named "org.bluealsa.sink" and both hci1 and hci2 for an A2DP source service named "org.bluealsa.source". Such a setup might be created as follows:
bluealsa -B sink -i hci0 -p a2dp-sink &
bluealsa -B source -i hci1 -i hci2 -p a2dp-source &Setup like this will also require a change to the BlueALSA D-Bus configuration file in order to allow connection with BlueALSA services with suffixed names. Please add following lines to the BlueALSA D-Bus policy:
...
<allow send_destination="org.bluealsa.sink" />
<allow send_destination="org.bluealsa.source" />
...bluetoothd(8), bluealsa-aplay(1), bluealsa-rfcomm(1)
Project web site at https://github.com/Arkq/bluez-alsa
Copyright (c) 2016-2021 Arkadiusz Bokowy.
The bluez-alsa project is licensed under the terms of the MIT license.