analyze a .wav or .mp3 file

[Terry Klarich]

Hello All:

I would like to see if anyone has an idea how to analyze a wav or mp3 file in a shell script to see if there is any audio present;
or, it is a blank file.

The story:
I have used a script for several years called xmonline to listen to xmradio over the internet.  Actually, I mostly used it to
record shows I wanted to listen to later.  Since, the original script used mplayer to play the stream, I modified the script to
write to a file on disk.  It worked well and I could listen to those shows on xm I had to miss for one reason or another.  (my own
xm audio recorder.

Recently, XM has changed their interface such that the xmonline script will no longer work.  I originally thought I cold use
firefox, and the analysis of the network trafic to write a new script.  Using curl as the xmonline script did, I am able to get
logged into the site.  But, when I dig out the stream and try and play it with mplayer, it doesn't work.  I know I'm missing some
simple little cookie or authorization parameter.  (Who knows)

Basically, I have given up on the streaming approach for now.  And, will use the brute force method.  I have my xmradio hooked up
via a sound card.  I am able to listen to xm on my computer with aplay just fine.  I even have a lirc config file that will turn
and off the unit and change channels.  Works great.

My problem is I have no way of knowing if the unit is on or off.  There is only a power toggle ir code.  If there was a power-on,
my problems would be over.

To get around this problem, I will first record a 10 second clip and see if there is anything there or not.  If there isn't, I know
the unit is off.

So, does anyone know a way to discover if there is any audio in a wav or mp3 file using a shell script running in the background?

Any suggestions wellcome.

THANKS!
Terry

P.S.
If anyone wants my failed xmrip script, they are welcome to see what they can do with it.