Dacquery is a command-line utility that scans a Linux system's ALSA audio cards for Digital to Analog Converters -- "DACs" -- and lists the combinations of rates, sample formats and channels (with channel maps if available) they accept. (Interleaved audio is assumed.)
Dacquery only probes interfaces that begin with hw:, hdmi: or iec958:.
Dacquery also lists the mixers attached to the cards, listing their ranges, decibel-denominated ranges if provided and, if so, whether they accept a special decibel "volume" that causes them to mute.
The name on the command line is dacquery.
Note: As an alternative to building from source, Dacquery is available as a Docker image on the Docker Hub.
To build from source, ensure the system is up to date, install the tools and libraries needed and then build and install Dacquery.
In the commands below, note the convention that a # prompt means you are in superuser mode and a $ prompt means you are in a regular unprivileged user mode. You can use sudo ("SUperuser DO") to temporarily promote yourself from user to superuser, if permitted. For example, if you want to execute apt update in superuser mode and you are in user mode, enter sudo apt update.
Some of these tools and libraries may already be installed -- it does no harm to try to install them again.
# apt update
# apt upgrade # this is optional but recommended
# apt install --no-install-recommends build-essential git autoconf automake libasound2-dev
# yum update
# yum install git autoconf automake gcc alsa-lib-devel
Execute the following commands.
$ git clone https://github.com/mikebrady/dacquery.git
$ cd dacquery
$ autoreconf -fi
$ ./configure
$ make
# make install
$ dacquery
--- Alsa Version: 1.2.12.
--- Sound Cards: 1.
--- Card 0:
--- Name: "HD-Audio Generic".
--- Mixers:
--------------------------------------------------------------------------------------------------------
| Name | Index | Min | Max | Mute dB | Min dB | Max dB |
--------------------------------------------------------------------------------------------------------
| Master | 0 | 0 | 64 | No | -64.00 | 0.00 |
| PCM | 0 | 0 | 255 | No | -51.00 | 0.00 |
| Front | 0 | 0 | 64 | No | -64.00 | 0.00 |
| Surround | 0 | 0 | 64 | No | -64.00 | 0.00 |
| Center | 0 | 0 | 64 | No | -64.00 | 0.00 |
| LFE | 0 | 0 | 64 | No | -64.00 | 0.00 |
| Side | 0 | 0 | 64 | No | -64.00 | 0.00 |
| Mic Boost | 0 | 0 | 3 | No | 0.00 | 30.00 |
--------------------------------------------------------------------------------------------------------
--- Interfaces and Supported Formats:
>>> Interface "hw:Generic":
The interface listed above supports rate, format and channel combinations from the following table:
-------------------------------------------------------------------------------------------------------------
| Rate | Format | Channels | Channel Map |
-------------------------------------------------------------------------------------------------------------
| 44100 | S16_LE | 2 | FL FR |
| 48000 | S32_LE | 4 | FL FR RL RR |
| 96000 | | 8 | FL FR RL RR FC LFE SL SR |
| 192000 | | | |
-------------------------------------------------------------------------------------------------------------
-e Display some extra information, including information about devices, sub-devices and interfaces. The start of the example above would become:
$ dacquery -e
--- Alsa Version: 1.2.12.
--- Sound Cards: 1.
--- Card 0:
--- CTL name: "hw:CARD=Generic".
--- Name: "HD-Audio Generic".
--- Long name: "HD-Audio Generic at 0x3d400000 irq 72".
--- Devices: 1.
--- Device 0:
--- Name: "Generic Analog".
--- ID: "Generic Analog".
--- Subdevices: 1.
--- Subdevice: 0:
--- Name: "subdevice #0".
--- Interfaces:
>>> "hw:Generic"
--- Mixers:
...
-h Display help information and quit.
-V Display version information and quit.
Dacquery must have permission to access the ALSA sound system. It will complain if it does not.
For Dacquery to fully investigate a device, the device must be idle. If you can't free up a device, it may be an indication that it is being used by a sound server such as PulseAudio or PipeWire.
To test a HDMI interface, it is usually necessary to have a HDMI device connected to it and enabled. In addition, the HDMI device's source should be set to this device. Once this has been done, you should reboot this system to ensure the appropriate drivers are loaded. Otherwise, the HDMI interface may be listed as uninitialised.
Dacquery lists devices and mixers as they appear to programs and utilities running on the computer. Sometimes, however, these devices may not be functional in reality. For instance, they may not be hooked up to the outside world.
Another phenomenon to look out for is that the same audio hardware can appear in two or more different interfaces. That is, there might be two or more interfaces that present slightly different access to the same underlying hardware. If the interfaces are to the same subdevice (see the -e option), then it is likely that they refer to the same hardware.
aplay(1), amixer(1), alsamixer(1), speaker-test(1).
Mike Brady (https://github.com/mikebrady) wrote Dacquery.