[vorbis] Realtime encoding at 44.1khz

Michael Smith msmith at labyrinth.net.au
Fri Sep 7 10:26:53 PDT 2001

At 12:03 AM 9/8/01 +1000, you wrote:
>I've been experimenting with streaming vorbis across my network from the
>windows box to an icecast2 server on my linux machine (the server I usually
>use is having some network issues at present).  I've tested both ostream
>0.7.1 and oddcast beta26.   It seems that neither can encode on the fly on
>my P2-266 at 44100 fast enough to be able to stream it.  Ostream looked the
>more promising of the two, with breaks in the audio but otherwise coping OK
>... until it crashed, presumably because it filled some buffer somewhere.
>It can maintain a 44.1khz mono stream at lowest bitrate (aprox. 40kbps) but
>only just.  I only tried oddcast once, at 64kbps stereo.  It sounded very
>weird, as if it was only recording half the data in a given time period.
>It sounded as if it was playing at about double speed but wasn't pitch
>What I want to know is this.  Am I expecting too much of my P2-266 to do
>44.1khz 64kbps stereo in real-time?  Assuming I'm not, is this an
>optimisation issue or should I be able to do it already?

With the current code - yes. Based on my experiences (i.e. developing ices2),
you'll need about a p2-333 at an absolute minimum to be able to do realtime
encoding with the current libvorbis - it's certainly optimisable, though.

However, if you're having problems with realtime encoding of a mono stream 
on a p2-266, then something else is wrong. For reference, ices2 takes about
60-70% of the cpu for encoding a stereo stream at 44.1kHz on my celeron 450.
Mono is about half this - so your hardware shouldn't have any problems.
Make sure you haven't accidently ended up with a debug build of libvorbis,
instead of an optimised one - that'll kill performance. 

If you really can't even manage mono reliably and with plenty of spare cpu,
then something else is wrong with the program you're using.


--- >8 ----
List archives:  http://www.xiph.org/archives/
Ogg project homepage: http://www.xiph.org/ogg/
To unsubscribe from this list, send a message to 'vorbis-request at xiph.org'
containing only the word 'unsubscribe' in the body.  No subject is needed.
Unsubscribe messages sent to the list will be ignored/filtered.

More information about the Vorbis mailing list