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[vox] [vox][ot] KDVS audio streaming (was: Bill on the radio!
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[vox] [vox][ot] KDVS audio streaming (was: Bill on the radio!



On Wed, 5 Dec 2001, Ryan wrote:

> You can listen to the live stream with xmms/winamp/any-decent-mp3-player by
> connecting to http://kdvs.org:8000

That reminds me of the good ol' days...  In case anyone is interested in
history of KDVS' Internet streaming (and its relationship to Linux, though
it's minor):

Professor Soderstrand and I used to do the Internet streaming of KDVS way
back in the beginning.  Actually, it was originally Professor Soderstrand
who set it up, and Justin Cable (who was in high school at the time, and
became the general manager of KDVS for several years after he came to UCD)
was there to help; I jumped in a few months later.  Then the Prof. went
on Sabbatical, then left UCD right after -- so I ended up with all the
work, and a couple keys to the EUII building.  (The keys came in handy
many times over the years.)

We only had a single SparcStation2000 to do the RealAudio serving and two
stream encodings at the same time, one at 28.8kbps and one at ISDN speed
(I don't recall if it was full or half duplex ISDN).  That darn thing was
so underpowered -- it couldn't do 14.4kbps because it took more CPU power
to do 14.4kbps compression than 28.8kbps.  We chose ISDN and 28.8kbps
speeds because the professor had an ISDN line (and so did I) and 28.8kbps
for those less fortunate than us.  At the time, I think 33.6kbps was the
best and the greatest consumer-level modem so we wanted to go with
14.4kbps to cover wider audiences, but the power just wasn't there.

Later, we took a PC from another project the professor was overseeing, the
robot-soccer project, and used it as an extra RealAudio encoder.  The
robot soccer people weren't too happy with that...  I had a mixed feeling
since I was involved in both projects :P

At first, the PC was running Windows and connected to a stereo to receive
the KDVS signal.  The stereo was the same stereo used by the NATCAR and
Micromouse students to listen to music while working... NATCAR and
Micromouse people weren't too happy about that.  Perhaps the biggest
mistake was leaving the PC in the robot soccer lab where the NATCAR,
Micromouse, and the robot soccer people had full access to -- they kept on
disconnecting the stereo from the PC to listen to music.  So I ended up
coming into the lab in the middle of the nights to reconnect it whenever I
got a complaint e-mail from KDVS HQ.

Anyway, Windows was too underpowered so I had to use the "reset whenever
buffer is XX% full" option on the encoder to keep the audio buffer from
overflowing and killing the encoder software.

Soon, the people disconnecting the stereo got lame, and I was getting
tired of coming in during nights to reconnect the stereo.  I got
permission to move the PC to Professor Soderstrand's office, and put Linux
on the box so I could connect to the machine remotely should I need to fix
something.  I also got the key to the office in case I needed to get
access to the hardware, too.

It turned out Linux was underpowered, too, and unfortunately the encoder
on Linux didn't have the reset option.  I ended up creating a cron job to
kill and restart the encoder at midnight every night.

That worked flawlessly with very little intervention from me for a long
time.  Then the ECE department wanted to move Dr.  Soderstrand's office;
by this time, the professor left the university and had only an emeritus
status, and that nice office in the prime spot was going to a waste, so
the department wanted to move his office to some dinky corner office to
some remote spot.  Unfortunately, the Sparcstation and the PC couldn't be
moved to the dinky office because it was the ECE department providing the
bandwidth, IP address, and the domain name for the RealAudio project. But
we did get permission from the ECE computer staff to move the machines to
a router closet, and that's what I ended up doing.  But that meant I no
longer had hardware access and could connect only remotely :(

Some weeks later, the ethernet connection was silently killed on the
Sparcstation and the PC, and I wasn't even told about it.  By the time I
found out the connection was killed, KDVS was ready to get a system into
the studio.  I gave them the RealAudio CDs I had (which were their
property) and the and the license #.  The Sparcstation and the PC were
absorbed into the ECE's computer accounting.

A couple weeks later I visited KDVS and checked out their setup -- a rack
with two (or was it three?) PCs (all running Linux, I think), a
monitor/keyboard/mouse + switch.  I stood on the threshold between studio
1 and the office (where a PC played the audio stream) and checked the
sound latency and found it to be about 45 or so seconds.  This latency
check made me realize that, even if I were to call the radio station as
soon as the radio announcer tells the listeners to "call in and the 10th
caller gets the prize", I'll already have been way past the 10th caller.

I've peeked many times to see how many connections there were and from
where.  I've on couple occasions connected a microphone on the back of the
computer to tell the listeners "I'm disconnecting the machine and it'll be
back online in a few minutes".  It was fun while it lasted :)

-Mark

--
Mark K. Kim
http://www.cbreak.org/mark/
PGP key available upon request.


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