On Sat, 7 Mar 2015 17:46:12 +0000 Fons Adriaensen <[email protected]> wrote:
> On Sat, Mar 07, 2015 at 05:18:41PM +0000, Will Godfrey wrote: > > > I've just been reading the ALSA Programming HOWTO by Matthias Nagorni and > > one > > detail caught my attention immediately. This is the idea of using plughw > > instead > > of directly addressing your soundcard. > > > > On the face of it this seems *much* easier, but there surely must be a > > catch. > > Can anyone explain what the downside of doing this might be? > > That HOWTO must be at least ten years old now. > > It is not 'much easier', the API is the still the same. > The difference is that the plug layer will try to hide > the real configuration space of your HW, allowing you > to use almost any combination of sample rate, sample format, > period size, etc. The downside is that you have no control > over what is really happening. It also seems to interfere > with the strict timing that low-latency period-synchronous > systems such as Jack more or less require. > > In theory it should be possible to stack or combine the > various ALSA 'plugins' in arbitrary ways. In practice most > combinations do not work very well or at all. IMHO this > part of ALSA is a failure. > > If the ALSA API seems too much too handle, use a library > such as zita-alsa-pcmi to take care of the complexity, and > use it with a hw: device, not a plughw: one. All my apps > that provide access to ALSA directly (rather than via Jack) > use it - it replaces around a thousand lines of code in each > of them and provides a very easy to use interface. > > Ciao, > That was fast :) Thanks for the info. Just tried the examples. They certainly seem to be lightweight. ... they also proved that I was 'doing it wrong' and a KA6 USB card is accessible! -- Will J Godfrey http://www.musically.me.uk Say you have a poem and I have a tune. Exchange them and we can both have a poem, a tune, and a song. _______________________________________________ Linux-audio-dev mailing list [email protected] http://lists.linuxaudio.org/listinfo/linux-audio-dev
