#3 alsa09 ao support

[Hod McWuff]

Adds alsa09 ao output support to ao.c, mpg321.h, and
options.c.

It Works For Me, but if you want it to work for you
then you'll need a fixed libao alsa09 output driver.

I've submitted a patch for that to bugs.xiph.org, but
haven't heard back from anyone about it. I'm not quite
sure who the project maintainer is, so it couild be awhile.

[Hod McWuff]

patch for alsa09 libao support

[Joe Drew]

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I've mostly got this in CVS, but I'm not sure about your
alsa09 device settings. The only device setting that seems
to be needed with alsa09 is 'device', which defaults to
'default.' (I'm not entirely sure how you're to select
different cards.) I've made alsa09 do what I think is the
right thing, but if you would investigate I'd appreciate it.

Thanks a lot for the help :)

[Hod McWuff]

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I more or less copied those cold from the alsa05 driver;
mpg321 was my test harness to repair the libao alsa09
plugin, hence that code was done before I knew what the
options were going to be. Brainfart...

'device' is passed unmolested all the way to alsa-lib.

I have defined 'buffer_time' and 'period_time' to specify
the length of the output buffer in milliseconds, and the
length of a hardware transfer unit (period) in milliseconds.
libao_alsa09 will start transferring data to the sound card
when four periods of data are present. This gives a way to
influence prebuffer time.

By default, libao will set 1000ms of buffer and a 50ms
period time.

I'll get the updated libao alsa09 patch posted sometime
tonight. You'll need it for this to work at all.