Selecting audio devices by name

[Tim Roberts]

Hi All,

I'm using a script to launch extempore to save a heap of typing.  This is great, because I can easily launch extempore with the correct audio devices.  However, this is not so great because when another mac, that has airplay enabled, is nearby, airplay becomes device 0, shifting all other devices up by 1.  As a result, if I launch extempore the devices are no longer correct.

Is there a way to choose the device based on the name, rather than the device number?

I could turn wifi off, and for demonstrating I will do that, but it's a pain to enable and disable during development.  If the airplay is enumerated while extempore is running, I think everything continues as it should, but it may not.  Something for me to test.

Here are the device ID's and then the script that I run to launch extempore.

-----Available Audio Devices-----------------------------

audio device[0]:AirPlay api[0]:Core Audio inchan[0] outchan[2]

audio device[1]:Built-in Microph api[0]:Core Audio inchan[2] outchan[0]

audio device[2]:Built-in Input api[0]:Core Audio inchan[2] outchan[0]

audio device[3]:Built-in Output api[0]:Core Audio inchan[0] outchan[2]

----------------------------------------------------------

#!/bin/bash

#Script for loading extempore with default inputs and outputs

echo "Starting Extempore process"

echo "with Stereo in and Stereo out"

cd /Users/Tim/extempore/cmake-build

./extempore --device=2 --channels=2 --indevice=1 --inchannels=2 --frames=128

echo "Done"

[Tim Roberts]

For now, I've changed my script to the code below.  It lists the audio devices available and then allows the user to choose the one that they would prefer.  Ideally I would add error checking to the frame size, but this is good enough for me at the moment.

I have a bat file that I run on my PC that I might also update to do a similar thing.

#!/bin/bash

#Script for loading extempore with default inputs and outputs

echo "Listing audio devices available to extempore"

cd ~/extempore/cmake-build

./extempore --print-devices

echo "Which output device would you like to use?"

read out_device

echo "How many channels does it have?"

read out_channels

echo "Which input device would you like to use?"

read input_device

echo "How many channels does it have?"

read input_channels

echo "How large would you like the frame buffer to be? (Must be a power of 2)"

read frame_buffer_size

echo "Launching extempore"

./extempore --device=$out_device --channels=$out_channels --indevice=$input_device --inchannels=$input_channels --frames=$frame_buffer_size

[Ben Swift]

Hi Tim

I know the pain of having an errant airplay device throw the setup stuff
out of whack - that almost ruined a gig for me once.

The nicer solution is to integrate the "select device by name" stuff
into src/AudioDevice.cpp so that you could do it with the --device flag,
but I'm about to head off to china for a while and so probably won't get
around to it for a bit.

Having said that, it's a nice little community-sized project, if
anyone's keen.

Cheers,
Ben

[Jim Kuhn]

Tim,

I just committed and pushed a change to support this (lightly tested).

New command line options are "--device-name" and "--indevice-name".  They override their ID counterparts if both are specified.  Note that the full name must match.  For example, on my system one of the devices listed is:

audio device[1]:HDA Intel PCH: ALC662 rev3 Alt Analog (hw:0,2) api[0]:ALSA inchan[2] outchan[0]

I must specify the whole name:

$ ./extempore --device_name "HDA Intel PCH: ALC662 rev3 Alt Analog (hw:0,2)"

or an (appropriate) error will be generated.  Something like this (when I gave a shortened name):

*** Can't find named device: HDA Intel PCH: ALC662 rev3 Analo

Jim