Play, record, and configure audio streams.
Important
audio-driver-ctl is deprecated. Please use ffx audio device tool instead. For more information,
run ffx audio device --help from your host machine and see
README for ffx audio: //src/developer/ffx/plugins/audio/README.md
Usage
audio-driver-ctl [-d <id>] [-t (input|output)] agc (on|off)
audio-driver-ctl [-a <mask>] [-b (8|16|20|24|32)] [-c <channels>] \
[-d <id>] [-r <hertz>] duplex <playpath> <recordpath>
audio-driver-ctl [-d <id>] [-t (input|output)] gain <decibels>
audio-driver-ctl [-d <id>] [-t (input|output)] info
audio-driver-ctl [-a <mask>] [-b (8|16|20|24|32)] [-c <channels>] \
[-d <id>] loop <playpath>
audio-driver-ctl [-d <id>] [-t (input|output)] mute
audio-driver-ctl [-a <mask>] [-b (8|16|20|24|32)] [-c <channels>] \
[-d <id>] [-r <hertz>] noise [<seconds>] [<amplitude>]
audio-driver-ctl [-a <mask>] [-b (8|16|20|24|32)] [-c <channels>] \
[-d <id>] play <playpath>
audio-driver-ctl [-d <id>] [-t (input|output)] pmon [<seconds>]
audio-driver-ctl [-a <mask>] [-b (8|16|20|24|32)] [-c <channels>] \
[-d <id>] [-r <hertz>] record <recordpath> [<seconds>]
audio-driver-ctl [-a <mask>] [-b (8|16|20|24|32)] [-c <channels>] \
[-d <id>] [-r <hertz>] tone [<frequency>] [<seconds>] [<amplitude>
audio-driver-ctl [-d <id>] [-t (input|output)] unmute
Options
-a <mask>
Active channel mask. For example 0xf or 15 for channels 0, 1, 2, and 3.
Defaults to all channels.
-b (8|16|20|24|32)
Bits per sample. Defaults to 16.
-c <channels>
Number of channels to use when recording or generating tones/noises.
Does not affect WAV file playback because WAV files specify how many
channels to use in their headers. Defaults to the first driver-reported
value. Run info to see how many channels your target Fuchsia device
has. The number of channels must match what the audio driver expects
because audio-driver-ctl does not do any mixing.
-d <id>
The device node ID of the stream. Defaults to 0. To figure out <id> run
info. You'll see a path value like /dev/class/audio-input/000.
<id> in this example is 000.
-t (input|output)
The device type. Defaults to output. This option is ignored for commands like
play that only make sense for one of the types.
-r <hertz>
The frame rate in hertz. Defaults to 48000.
Commands
agc
audio-driver-ctl [-d <id>] [-t (input|output)] agc (on|off)
Enables or disables automatic gain control for the stream.
duplex
audio-driver-ctl [-a <mask>] [-b (8|16|20|24|32)] [-c <channels>] \
[-d <id>] [-r <hertz>] duplex <playpath> <recordpath>
Simultaneously plays the WAV file located at <playpath> and records
another WAV file into <recordpath> in order to analyze the delays in the
system. The -c option if provided applies to the recording side since the
number of channels for playback is taken from the WAV file header.
gain
audio-driver-ctl [-d <id>] [-t (input|output)] gain <decibels>
Sets the gain of the stream in decibels.
info
audio-driver-ctl [-d <id>] [-t (input|output)] info
Gets capability and status info for a stream.
loop
audio-driver-ctl [-a <mask>] [-b (8|16|20|24|32)] [-c <channels>] \
[-d <id>] loop <playpath>
Repeatedly plays the WAV file at <playpath> on the selected output until a key
is pressed.
mute
audio-driver-ctl [-d <id>] [-t (input|output)] mute
Mutes a stream.
noise
audio-driver-ctl [-a <mask>] [-b (8|16|20|24|32)] [-c <channels>] \
[-d <id>] [-r <hertz>] noise [<seconds>] [<amplitude>]
Plays pseudo-white noise. <seconds> controls how long the noise plays and must
be at least 0.001 seconds. If <seconds> is not provided the noise plays until
a key is pressed.
play
audio-driver-ctl [-a <mask>] [-b (8|16|20|24|32)] [-c <channels>] \
[-d <id>] play <playpath>
Plays a WAV file.
pmon
audio-driver-ctl [-d <id>] [-t (input|output)] pmon [<seconds>]
Monitors the plug state of a stream. <seconds> must be above 0.5 seconds
(default: 10.0 seconds).
record
audio-driver-ctl [-a <mask>] [-b (8|16|20|24|32)] [-c <channels>] \
[-d <id>] [-r <hertz>] record <recordpath> [<seconds>]
Records to the specified WAV file from the selected input. If <seconds> is not
provided the input is recorded until a key is pressed.
tone
audio-driver-ctl [-a <mask>] [-b (8|16|20|24|32)] [-c <channels>] \
[-d <id>] [-r <hertz>] tone [<frequency>] [<seconds>] [<amplitude>
Plays a sinusoidal tone. <frequency> must be between 15.0 and 96000.0 hertz
(default: 440.0 hertz). <seconds> must be above 0.001 seconds. If <amplitude> scales the
output if provided and must be an increment of 0.1 between 0.1 and 1.0.
unmute
audio-driver-ctl [-d <id>] [-t (input|output)] unmute
Unmutes a stream. Note that the gain of the stream will be reset to its default value.
Examples
Enable automatic gain control on a stream
$ audio-driver-ctl agc on
Get stream info
# Equivalent to `audio-driver-ctl -t output -d 000 info`
$ audio-driver-ctl info
Info for audio output at \"/dev/class/audio-output/000\"
Unique ID : 0100000000000000-0000000000000000
Manufacturer : Spacely Sprockets
Product : acme
Current Gain : 0.00 dB (unmuted, AGC on)
Gain Caps : gain range [-103.00, 24.00] in 0.50 dB steps; can mute; can AGC
Plug State : plugged
Plug Time : 12297829382473034410
PD Caps : hardwired
Number of channels : 1
Frame rate : 8000Hz
Bits per channel : 16
Valid bits per channel : 16
...
Set gain of a stream to -40 decibels
# Equivalent to `audio-driver-ctl -t output -d 000 gain -40`
$ audio-driver-ctl gain -40
Mute a stream
# Equivalent to `audio-driver-ctl -t output -d 000 mute`
$ audio-driver-ctl mute
Repeatedly play (loop) a WAV file on a stream
# Equivalent to `audio-driver-ctl -t output -d 000 loop /tmp/test.wav`
$ audio-driver-ctl loop /tmp/test.wav
Looping /tmp/test.wav until a key is pressed
Play a WAV file once on a stream
# Equivalent to `audio-driver-ctl -t output -d 000 play /tmp/test.wav`
$ audio-driver-ctl play /tmp/test.wav
Play a 450 hertz tone for 1 second at 50% amplitude on a stream
# Equivalent to `audio-driver-ctl -t output -d 000 tone 450 1 0.5`
$ audio-driver-ctl tone 450 1 0.5
Playing 450.00 Hz tone for 1.00 seconds at 0.50 amplitude
Unmute a stream
# Equivalent to `audio-driver-ctl -t output -d 000 unmute`
audio-driver-ctl unmute
Notes
Accessing this command
This command is only available on certain diagnostic and testing Fuchsia builds.
This is a device-side command, not a host-side command like fx or ffx.
In other words before calling this command you must first access the
shell of the Fuchsia device.
To interactively access the Fuchsia device's shell:
ffx component explore <component>
Replace <component> with the name of the component that has access to
the command documented on this page.
To call a single command and return the output to the host:
ffx component explore <component> -c "<command>"
Replace <command> with one of the commands documented on this page.
Supported builds for commands that exercise streams
Commands that exercise audio streams such as play are only supported
in diagnostic
product bundles
like core.
In other builds only the informational commands like info are supported.
Copying WAV files between a host and a target Fuchsia device
To copy WAV files from your host to your target Fuchsia device or
vice versa, run fx cp (--to-target|--to-host) <source> <destination>
on your host. <source> is the file you want to copy and <destination>
is where you want to put the copied file.
Example of copying from host to target Fuchsia device:
$ fx cp --to-target /path/on/host/source.wav /path/on/target/destination.wav
Example of copying from target Fuchsia device to host:
$ fx cp --to-host /path/on/target/source.wav /path/on/host/destination.wav
Both commands should be run from your host, not the target Fuchsia device.
Source code
Source code for audio-driver-ctl: //src/media/audio/tools/audio-driver-ctl/