Re: [9fans] audio standards -- too many to choose from

[James Tomaschke <james@orcasystems.com>]

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Russ Cox wrote:
> I've done audio on a handful of operating systems
> and all I ever want to do with the card is set it up
> to play X kHz 16-bit little-endian PCM stereo and
> then control the volume.  The rest can be done from
> user space.  This is exactly what Plan 9's audio
> driver already does, and I wish the others were so
> simple.
It is simple, and it limits you simple applications.

Having to set the sampling format or rate has never been a problem, in
fact it is a requirement.  The sample and format are chosen by the
application based on what the hardware internally supports to eliminate
any sample or rate conversion overhead.  Low latency is very important
for many audio applications.

> By analogy, Plan 9's kernel gives user space access to the
> raw disk bytes.  It doesn't implement the interpretation
> of those bytes as 9660, fat, ext2, kfs, venti, or other disk
> "file formats".  That can be done better and more easily
> in user space.
This is an incorrect analogy, audio hardware (DACs/ADCs/DSPs) are
engineered to function on a unit of information (sample) which varies
between audio hardware.  Perhaps if all audio hardware were
SoundBlaster-16s then the audio(3) interface would make sense.

Then there's the whole topic on multiple hardware mix buffers or
multiple channels.
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