ALSA Support in Rivendell

Rivendell can optionally be compiled to provide direct support for 
soundcards using the Advanced Linux Sound Architecture (ALSA).  
Instructions on enabling such support can be found in the INSTALL
file.  Information about ALSA itself can be found at:

    http://www.alsa-project.org/


STARTING UP RIVENDELL WITH ALSA
When Rivendell's audio daemon, caed(8) is started, and ALSA support is
enabled, caed(8) will look for PCM devices named rd<n>, where <n> is a
number between 0 and 7.  If it finds one or more, it will attempt to
open the devices(s) for both playback and capture.  If successful, the
devices will then be available as Rivendell virtual 'card' resources,
starting with the next available card number after any HPI or JACK
devices have been started.


CONFIGURING PCM DEVICE NAMES
PCM device names for ALSA can be configured by means of entries in the ALSA
configuration file.  The ALSA configuration file can either be an '.asoundrc'
file in the home directory of the user running the Rivendell daemons (normally
'root') or an '/etc/asound.conf' file which will apply to all users.  For the
simple case of a single ALSA soundcard to be made visible to Rivendell, one
would create an ALSA configuration file containing the following lines:

pcm.rd0 {
  type hw
  card 0
}
ctl.rd0 {
  type hw
  card 0
}

This would create an 'alias' for the first ALSA soundcard in the
system, called 'rd0'.

More details regarding the syntax and uses of .asoundrc can be found
on the ALSA web site in the documentation section.