Date: Wed, 03 Sep 1997 19:54:04 -0700 From: Amancio Hasty <hasty@rah.star-gate.com> To: Andrew Reilly <reilly@zeta.org.au> Cc: luigi@labinfo.iet.unipi.it, multimedia@FreeBSD.ORG Subject: Re: snd970903.tgz and pnp970903.tgz Message-ID: <199709040254.TAA06160@rah.star-gate.com> In-Reply-To: Your message of "Thu, 04 Sep 1997 09:16:54 %2B1000." <199709032316.JAA02065@gurney.reilly.home>
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For short burst audio streams you probably want to do programmed i/o and we don't support that right now however you can modify one the ad1848 driver to do it. It sounds like what you may want is something similar to an analog's dsp 2181 and I intent to order their development kit sometime this week. It would be nice if we can start a project to support dsp like algorithms for FreeBSD. My first cut at a full integrated package is to write a driver for Omnimedia's Z-Lite which has a DEC 21230 which is somewhat programmable, for video input decoding it has a Phillips SAA 7111 and for audio an Analog DSP 2181. If anyone knows of ISA or better yet a PCI sound card which just has an Analog's DSP 2181 please let me know. Why the dsp 2181? It is currently used in Omnimedia's real time mpeg encoder/decoder and it will propably not be hard to support full duplex via its ad1849 mode. I own a mediatrix's audiotrix pro which is a high quality sound card and it has a cs4231 which is fully capable of doing full duplex I/O with the guspnp driver and I suspect that with a little tweaking Luigi's sound driver it will also work. If you are interested check out http://www.mediatrix.com Amancio >From The Desk Of Andrew Reilly : > Hi Luigi, > > Sorry to be a bother, but I think you probably know more about this > than most by now. > > On 3 Sep, Luigi Rizzo wrote: > > * fixed SB16 PnP operation, now works in 8 and 16bit, both > > capture and playback; > > > > not recognised/not working (although the SB16 driver still needs > > refinements in order to support full duplex operation). > > I haven't bought a sound card yet because I want to be sure that I can > do full-duplex, full bandwidth (48kHz preferably, 44.1kHz is OK) signal > processing. All I've heard about the SB16 (and by extension the SB32, > AWE32, and AWE64) says that the closest it comes to full-duplex is 16 > bits out/8 bits in. Is that the case? > > Are there any inexpensive sound cards with good AD/DA quality that can > do full duplex 16-bit? > > In any case, do you have an idea of the minimum latency you could get > with a program that just did un-buffered reads and writes to the audio > device? Are we talking about <= 20ms? > > (I'm a DSP guy, and I would very much like to be able to prototype > algorithms on my workstation, before I have to cut them into DSP code.) > > -- > Andrew > > "The steady state of disks is full." > -- Ken Thompson >
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