Subject: Re: alternative for vat_play_audio for sending AU files?

From: "Alan J. Flavell" <[email-masked]>
Date: Fri, 6 Sep 1996 14:50:31 +0000

> For my "CBC Radio News Test" session I have been using a utility
> called "vat_play_audio" developed my Anders Klemets in 1993. 

(me 2  ;-)

> Does anyone know of, or is anyone developing, an alternative method
> for sending an AU file to a multicast audio session?

MboneVCR seems to be the current solution, and works well if the multicast
is under the control of the owner of the data.  

http://www.informatik.uni-mannheim.de/~whd/mbone-vcr/

However, in the form that I most recently encountered it, it was not
suitable for being remote-controlled by some arbitrary caller. 

Altavista gave me the following pointer to an on-demand design:

http://eratosthenes.informatik.uni-mannheim.de/~whd/mbone-vcrods/

Sadly, there doesn't seem to be anything behind this menu page ;-}
I'll copy this mail to the author in case he wants to fix that...

best regards

---

From: [email-masked] (Kevin C. Almeroth)
Date: Fri, 6 Sep 1996 13:03:53 -0400 (EDT)

>>called "vat_play_audio" developed my Anders Klemets in 1993.  This
>>utility will play an AU audio file into a multicast session, and I
>>have a little cron routine that records the news on the hour and then
>>plays the AU file repeatedly throughout the remainder of the hour
>>until the news is updated.

I have used Henning's rtp tools with great success.  You can find them
at http://www.cs.columbia.edu/~hgs/rtp/toc.html and follow the links
to rtpdump, etc.

The caveat here is that you'll need to record the audio as 
an RTP session.  Shouldn't be too difficult if you use vat to take
the radio broadcast and play it on a local session and then record it 
using RTP dump (rtpdump -fdump <vat addr> >/mass_storage/audio).  When
                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
you are ready to play it out to the MBone as a whole use:

rtpplay -t <ttl of new playout> 224.2.179.106:26206 </mass_storage/audio
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

radio -> vat -> local_multicast -> disk(rtpdump) -> MBone(rtpplay)

>>There are a number of limitations of vat_play_audio, including:
>>
>>- it uses the older VAT protocol instead of the modern RTPv2 protocol
>>
>>- it only supports PCM encoding of the AU file where DVI or something
>>  with lower bandwidth demands may be more appropriate here

Solves all of these problems...

-Kevin Almeroth