14. Audio

(Most of the answers you will find here are taken from the vbox manual by Matthias Hessler hessler@wi-inf.uni-essen.de and Bernhard Hailer dl4mhk@lrz.uni-muenchen.de; you can get the manual at:

http://www.lrz-muenchen.de/~ui161ab/www/isdn/

- click on "Audio!" (still in German we're afraid - sorry...) They are currently outdated, but may give you a few hints?

14.1 audio_format: What is the format of the audio messages (.msg) vbox plays when it answers a call?

You can get the format from the messages with rmdgetheader. The samples messages in the packages are recorded using format 4 (the latest Zyxel-Compression)

14.2 audio_recordmsg: How can I record my own messages for vboxgetty?

First call yourself on the number you configured vboxgetty to answer and leave a message. Then rename the message to *.msg (standard.msg for the main answering message) and copy it to the directory where all the messages are kept (usually /var/spool/vbox/user/messages where user is the user for which vboxgetty is configured). You can also record a message using a microphone and the soundcard.

14.3 audio: How can I play audio messages locally using /dev/audio?

This is best achieved with vbox using format 6 (uLaw - must be compiled in). You can then easily play the messages using:

cat xxx  /dev/audio

14.4 audio: If vboxgetty has recorded a message in a format which can not be played using "cat xxx/dev/audio" how can I still hear the message?

See question audio_recordmsg .

14.5 audio: How can I convert audio messages which where recorded by vbox to other formats (i.e. from uLaw to WAV)?

The standard tool for converting all sound formats is SOX. SOX is available as source code for both UNIX and DOS. You can get it at:

http://www.powerweb.de/mpeg/util/msdos/sox10c.zip

(including sources that compile under Linux).

14.6 audio: How can I format WAV for uLaw (for my vbox announcement message)?

We receive the following tip form Christian Stueble stueble@ls6.informatik.uni-dortmund.de on 15 Jan 1997:

For me, the following (somewhat indirect) method works:

sox file.wav -r 8000 file.ul rate
rmdcatheader -u file.ul  file.msg
cat file.ul  file.msg

14.7 audio: My vboxgetty does not answer any incoming calls.

vboxgetty needs ".vboxrc" in the home directory of the user for which vboxgetty is configured. The number of rings is taken from this file.

14.8 audio: My vboxgetty answers at the first ring but the number of rings is set to 4.

The rings are created by a timer in the isdn module that doesn't necessarily set the delay accurately. If you configure vboxgetty with 30 rings, vboxgetty will wait about 5 rings before it picks up the line.

14.9 audio: My vbox 1.1 does not work together with HiSax.

Use HiSax =1.2. This version includes correct alerting.

14.10 audio: If vboxgetty has recorded a message in a format which can not be played using "cat xxx/dev/audio" how can I still hear the message?

Vboxgetty can play all formats. You could also copy the message as the standard message (standard.msg in the messages directory) and call yourself, the message will be played then. (Don't forget to copy back the original message when you are done :-) ).

14.11 audio: At the beginning of a message recorded by vboxgetty, there's often a part of my own announcement?

This is a known bug that occurs when switching between the playing of the announcement and recording the message. Up to now there is no known workaround.