Hey all. Two topics:
First, I teach Computer Science at the high school level at a largish school
near Austin, Texas. For the past several years there's been a
"jukebox" in
my room where students could vote for albums to hear during programming lab
time, and random tracks off the winning albums play over the speakers in the
classroom.
This past week I changed the "player" portion of the system to play
oggs
instead of mp3s. So I've spent the past two days explaining to each of my
classes (over 100 students in CS-I, CS-II, and CS-III combined) about the
changes in the system and why I moved from mp3s to Ogg Vorbis.
Why not mp3?
1) Quality is lower than many current alternatives.
2) Patent situation is scary and I fear a recurrence of the whole Unisys/GIF
fiasco.
3) Saying I have a hard-drive full of mp3s just sounds shady, even when
they're all legal.
And why Ogg Vorbis?
1) Sound quality vs. file size is very nice. (I quoted for them that for
similar quality, oggs are about 10% smaller. (-q 3 ogg vs 160Kbps mp3))
2) Patent-free algorithms and open-source mean The Man can never take my oggs
from me. Also makes it easy to add functionality.
Just wanted to share that over a hundred kids in the "Silicon Hills"
just
basically got a well-informed lecture on why they should switch to Ogg Vorbis.
And previously I'd had 128Kbps mp3s; I replaced them with (slightly smaller)
-q 3 oggs and have already had a student or two remark about the improved
sound quality.
Second topic, somewhat related:
In order to replace my previous mp3 player (was xaudio wrapped in a bit of
custom code) with an ogg player, I needed to add a few options to ogg123, and
wanted to offer my changes if anyone wants them.
First major change: added simplistic playlist support. Now you can specify
oggs/URLs or text files containing names of oggs/URLs (one per line) on the
command line, and it will play all the files in order. Deciding whether a
given file is an ogg or a playlist is incredibly stupid at the moment (if it
doesn't end in ".ogg", it's a playlist), but is abstracted
enough to be
easily replaced with a smarter heuristic. This was the only
"modification";
all the others are additions which could be safely ignored.
I also added three command-line parameters.
-D, --daemonize - runs the player in the background automatically.
Also sets --quiet. This addition was the reason for
<A HREF="http://bugs.xiph.org/show_bug.cgi?id=116">bug
116</A>.
-S file, --status-file=file - writes the name/URL of the currently playing
track to the given file. Clears the file on quit.
-P file, --poll=file - reads the given playlist/file for tracks to play, but
also stats it between each track to see if it has changed. If so, it
reads in the playlist again and starts over at the top. If the
playlist is empty or has been expended, the program doesn't quit but
rather sleeps for ten seconds, and stats the playlist again every
time it wakes up. Using the parameter ignores any other
files/URLs/playlist supplied on the command line; it *only* reads the
list supplied with this parameter. Useful for radio station type
situations.
This would theoretically work for a single ogg which it would play, and
then sleep until the ogg file changed, when it would play it again. I
haven't tested this, but it should work and might be useful for
some.
I run my new program as:
% ogg123d -P /music/metafile.m3u -S /var/run/now_playing -D
After the kids' votes are collated, the winning playlist is written to
/music/metafile.m3u, and within ten seconds the player wakes up and starts
playing tracks without any explicit user intervention. As the tracks are
played, it writes the names to /var/run/now_playing, which I have another
daemon parse and display on a "Now Playing" screen. When the list is
expended, the player just quietly sleeps and waits for the playlist to change
again.
The code is in the "works for me" category. Download it at
http://cs.leander.isd.tenet.edu/~mitchell/ogg123d-0.1.0.tar.gz
I only touched a couple of files, and all my code is wrapped with
/* Graham Mitchell added this code. */
foo();
/* End of code added by Graham Mitchell. */
...mostly for my own sanity so I can remember which parts are mine if I want
to add something else in six months.
If there's interest I can separate out the code for each of the changes
individually and make four patches for the stock rc3 ogg123. (Assuming
someone can tell me how to appropriately run 'diff'.)
Sorry for the long message. I could probably have said all this in much
fewer words, but I tend to ramble in emails sometimes. Fortunately I don't
ramble when coding.
--
Graham Mitchell - computer science teacher, Leander High School
"Come thou no more for ransom, gentle herald. They shall have none, I
swear, but these my joints, which if they have as I will leave 'em them,
shall yield them little." - Henry the Fifth
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