[Vorbis] libao NAS compilation and playback issues

[Matt Prazak]

--- Matt Prazak <prazak_lists at yahoo.com> wrote:
> ...
>
> One work-around that I found works well is to use the playRaw example
> program provided with NAS via a UNIX pipe.  For example,
>
>   ogg123 --device=raw --file=- filename.ogg |
> ..../nas-1.6/clients/audio/examples/playRaw -
>
> I had to edit playRaw.c to make sure its sample rate matched that
> coming from ogg123.  The downside to this work-around is that CPU
> utilization of playRaw is very high (probably due to pushing the data
> across the pipe).
>
> ...

I did a little profiling, and I'm fairly convinced that the UNIX pipe
itself isn't causing the high CPU usage in playRaw.  Rather, it is the
event handler loop in playRaw.  cat-ting a CD-ROM iso file from the
hard drive through a pipe and timing it shows the pipe can push at
least 25MB/sec with low CPU utilization (2-channels at 44KHz is merely
~176KB/sec).


Matt




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