From mboxrd@z Thu Jan 1 00:00:00 1970 From: Florian Schmidt Subject: Re: Re: [Alsa-user] ALSA, JACK, ASIO Date: Sat, 12 Feb 2005 13:32:06 +0100 Message-ID: <20050212133206.7f0dc7a7@mango.fruits.de> References: <9e47339105020710162d246fed@mail.gmail.com> <9e473391050208182623c5b3ea@mail.gmail.com> <1107982073.1806.10.camel@radium.gaugetheory.org> <87y8dxp9fm.fsf@sulphur.joq.us> <1108029414.1806.23.camel@radium.gaugetheory.org> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit In-Reply-To: <1108029414.1806.23.camel@radium.gaugetheory.org> Sender: alsa-devel-admin@lists.sourceforge.net Errors-To: alsa-devel-admin@lists.sourceforge.net List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , List-Archive: To: Brian L Scipioni Cc: Jack O'Quin , alsa-user@lists.sourceforge.net, alsa-devel@lists.sourceforge.net List-Id: alsa-devel@alsa-project.org On Thu, 10 Feb 2005 04:56:55 -0500 Brian L Scipioni wrote: > Thanks. A couple more ASIO questions: > > Could the ASIO protocol be implemented on top of ALSA or within JACK? > Would it provide for low(er) latency operation on cards that support it? > Would ASIO perhaps just provide some parallel functionality that is > already represented in ALSA and/or JACK? AFAIK ASIO was introduced because the win32 mm drivers sucked badly and didn't allow to use a soundcard to its full potential. As ALSA doesn't have the problem of being completely braindead (as the win 32 mm driver (architecture) were), there's no need for ASIO on linux.. To answer the other post: With a modern Realtime Preemption kernel and an M-Audio Delta 66 i can use buffersizes of 32 or even 16 frames without dropouts (except for those produced by badly coded apps) with jack using its ALSA driver. The cpu load goes up a bit though with such small periodsizes due to context switch overhead, etc. It's very well suited for noodling my guitar through jack-rack though :) At a samplerate of 48khz a buffersize of 16 frames corresponds to an input latency of 0.3ms. The same for output latency. Disregarding any processing latencies by effects i use this gives a total roundtrip latency of around 0.6ms. I find a buffer size of 32 frames (1.2ms roundtrip latency) still perfectly usable with no audible delay (at least for my ears),, Your results might differ greatly depending on the soundcard used. For example my CS46xx based terratec dmx xfire 1024 always produced some xruns, even at 512 frames. I suspect either a driver or a hardware problem. Flo -- Palimm Palimm! http://affenbande.org/~tapas/ ------------------------------------------------------- SF email is sponsored by - The IT Product Guide Read honest & candid reviews on hundreds of IT Products from real users. Discover which products truly live up to the hype. Start reading now. http://ads.osdn.com/?ad_id=6595&alloc_id=14396&op=click