[school-discuss] icecast streaming test

[mikee <meschman@engima.com>]

hello,

first, apologies for posting 3 times to schoolforge et al.
we pulled an all nighter because of unforseen icecast problems.
i kept fumbling the keyboard.

the downloadable .mp3s on http://www.engima.com are
11026k/ sampled 16k-mono, which works and sounds fine.
but icecast bounces anything under 32k sampling in a case statement.
(grepping the source code turned that up).
we are going to try to fix this, because it cuts bandwidth requirement by 
half from what we used today. since we have the source, we can fix things.

piano and voice work fine with cutoff filters at 120 and 4800 hertz,
if the slope of the filter is 18 db per octave or better.
the best tactic for piano engineered with these cutoffs is to use music
with close hands or open chords (ref. "ruby my dear" by t.monk and
"the warriors" by percy grainger).
the trick is to use a steep cutoff slope so partial rise times are unaffected 
in the unfiltered frequency zone.

orchestral winds, etc. need the lowpass cutoff raised to about 8kh.

(the music IS important because it sets a tone for the readings, after all.)

we had to reburn everything before starting the broadcast this afternoon.  
haven't gotten to bed yet,
(have all the appeal of yesterday's lunch right now)
but will sleep well.

we had about 125+ visitors.  8 got bounced for "stupid headers" - looking 
into that.  23 got dropped for "too many errors on client side".
that should go away if we cut bandwidth by half (see beginning of e-mail on 
icecast sampling requirements).

there were an awful lot of .edu and k-12 in there,
thanks so much, we'll never get anything to work without
you good folks pushing on it, breaking it.  thanks.

i'm letting it play over night to probe for memory leaks, etc.

our isp (http://www.dsi-us.com) worked with us on this.  they are our
local linux sidekicks.  we did professional development and teacher 
recruiting web applications at caddo here in louisiana.  dsi wrote and 
designed the applications, which we ported to a s/390 redhat server 
in a day, so their stuff ran nt, intel linux and s/390 redhat without mods on
apache/php/mysql.  

our shooter on this is jonathan grimm, ace programmer.
steve smolen at dsi backed him up.

so this stuff is good to go at warren easton high school in new orleans :-)

back to gradebooks this weekend, look for a sunday post on that.

once again, thanks for stopping by.


mike eschman, etc...
"Not just an afterthought...
http://www.engima.com