Subject: Re: [linux-audio-dev] ALSA => OSS compatibility
From: Paul Davis (pbd_AT_Op.Net)
Date: Fri Mar 15 2002 - 20:54:43 EET
>In an earlier mail, you said that PortAudio would soon support JACK and
>perhaps ALSA. Are you planning to write these yourself? I planned to
>write an ALSA layer a few months ago, but ALSA didn't work for me at that
>time and I lost interest. In any case, your intimate knowledge of ALSA
>would definitely make for superior implmementation.
>
>If you aren't planning to write an ALSA layer yourself, do you have any
>suggestions for the person who does?
ALSA: not at this time. it might take me a morning to write the PortAudio
stuff. unfortunately, thats a morning away from stuff i'm trying to
make a living from ...
JACK: well, perhaps. But I'd rather get the implementation of jackd
completely "finished" first. there are still a couple of important
outstanding issues that cramp its style just a bit right now. they
don't affect 90% of all potential clients, however.
>The JACK FAQ says that "it is not clear that [PortAudio] works at
>hardware-level latencies." Do you still hold this view? (I'm assuming
>your wrote the FAQ). What in the API would prevent it from achieving
>hardware-level performance?
its not stuff in the API, its stuff in the implementation. running at
64 frames/interrupt or less requires more-or-less real-time coding and
design. last time i looked at PortAudio, it wasn't clear to me that
this had been carefully paid attention. it may be that its OK, or it
might fall apart under pressure. i don't know.
the API is great, and is essentially very very similar to JACK's,
except that it allows the user to set sample rates and formats, which
JACK doesn't permit (sample rate is a property of jackd, and all audio
is mono 32 bit floating point throughout).
--p
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