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ORG.BLUEALSA.PCM1(7) D-Bus Interface ORG.BLUEALSA.PCM1(7)

NAME

org.bluealsa.PCM1 - Bluetooth Audio PCM D-Bus API

SYNOPSIS

org.bluealsa[.unique ID]
org.bluealsa.PCM1
[variable prefix]/{hci0,...}/dev_XX_XX_XX_XX_XX_XX/[type]/[mode]

DESCRIPTION

This page describes the D-Bus PCM interface of the bluealsa(8) service. The PCM interface gives access to individual PCM objects created by this service.

Methods

Open BlueALSA PCM stream. This method returns two file descriptors, respectively PCM stream PIPE and PCM controller SEQPACKET socket.

Controller socket commands: "Drain", "Drop", "Pause", "Resume"

Possible Errors:

dbus.Error.InvalidArguments
dbus.Error.NotSupported
dbus.Error.Failed


Return the array of additional PCM codecs. Client can switch to one of these codecs with the SelectCodec() D-Bus method call.
Select PCM codec. This call shall be made before PCM stream opening for given transport type, otherwise the ongoing stream (or PCM counterpart: sink, source) will be terminated.

For A2DP codecs, client can override built-in logic for selecting codec configuration by providing the configuration blob via the "Configuration" property. Provided configuration must be valid for given codec in respect to BlueALSA and peer device capabilities. Otherwise, the call will fail. It is possible to override this validation by setting the "NonConformant" property to true.

Possible Errors:

dbus.Error.InvalidArguments
dbus.Error.NotSupported
dbus.Error.Failed


Set an arbitrary adjustment (+/-) to the reported Delay in 1/10 of millisecond for a specific codec. This adjustment is applied to the Delay property when that codec is selected, and can be used to compensate for devices that do not report accurate Delay values.

Possible Errors:

dbus.Error.InvalidArguments


Return the array of currently set delay adjustments. Each entry of the array gives the name of a codec and the adjustment that the PCM will apply to the Delay property when that codec is selected.

Properties

BlueZ device object path.
This property indicates the sequence in which devices connected. The larger the value, the later the device was connected.
Underlying Bluetooth transport type.

Possible values:

"A2DP-sink"
"A2DP-source"
"HFP-AG"
"HFP-HF"
"HSP-AG"
"HSP-HS"


PCM stream operation mode (direction).

Possible values:

"sink"
"source"


This property is true when the Bluetooth transport for this PCM is acquired and able to transfer audio samples.
Stream format identifier. The highest two bits of the 16-bit identifier determine the signedness and the endianness. Next 6 bits determine the physical width of a sample in bytes. The lowest 8 bits are used to store the actual sample bit-width.

Examples:

0x4210 - unsigned 16-bit 2 bytes big-endian
0x8418 - signed 24-bit 4 bytes little-endian


Number of audio channels.
Sampling frequency.
Bluetooth transport codec. This property is available only when transport codec is selected.
Optional. Bluetooth transport codec configuration blob. This property is available only for transports which support codec configuration (e.g. A2DP).
Approximate PCM delay in 1/10 of millisecond.
An adjustment (+/-) included within the reported Delay in 1/10 of millisecond to compensate for devices that do not report accurate delay values.
This property determines whether BlueALSA will make volume control internally or will delegate this task to BlueALSA PCM client or connected Bluetooth device respectively for PCM sink or PCM source.
This property holds volume (loudness) value and mute information for channel 1 (left) and 2 (right). Data for channel 1 is stored in the upper byte, channel 2 is stored in the lower byte. The highest bit of both bytes determines whether channel is muted.

Possible values:

A2DP: 0-127
SCO:  0-15



COPYRIGHT

Copyright (c) 2016-2023 Arkadiusz Bokowy.

The bluez-alsa project is licensed under the terms of the MIT license.

SEE ALSO

bluealsa-cli(1), bluealsa-plugins(5), bluealsa(8)


<https://github.com/arkq/bluez-alsa>

January 2024 BlueALSA v4.2.0