From mboxrd@z Thu Jan 1 00:00:00 1970 MIME-version: 1.0 Content-transfer-encoding: 7BIT Content-type: text/plain Date: Thu, 13 Aug 2009 19:45:15 -0700 From: "Roman V. Shaposhnik" In-reply-to: To: Fans of the OS Plan 9 from Bell Labs <9fans@9fans.net> Message-id: <1250217915.26729.63.camel@goose.sun.com> References: <38fa4d234fa7ff8613123fe9a6921943@quanstro.net> <13426df10908112014y49c5a89dpd616ce4529c1efe1@mail.gmail.com> <7DD19FED-D73E-44A3-8710-4F70D9293F34@sun.com> Subject: Re: [9fans] audio standards -- too many to choose from Topicbox-Message-UUID: 48ad108a-ead5-11e9-9d60-3106f5b1d025 On Wed, 2009-08-12 at 17:36 +0200, hiro wrote: > > This sounds like exactly the kind of thing one wants > > from an audio driver for playback. For recording things > > get slightly more complicated. > > What exactly do you mean? Now that I understand what Tim is trying to do my original concern makes no sense. Sorry for this little bit of noise. > > > Even for playback if you want to do passthrough (via > > SPDIF or some such) things get slightly more complicated. > > Of course, one can disregard passthrough as not > > being an audio at all, but rather a datalink issue. > > What's so special about things like SPDIF? Two things: the data traveling over the link can be any data, not just some form of PCM (it can be AC-3, it can be DTS, it can even be MP3). In that respect the audio card acts as a pass-through device. It is not really supposed to do anything with the data. And that brings us to the second point -- the pass-through APIs can be as ugly as hell, depending on the type of the device (follow the link to the MPlayer docs I provided in this thread). > Why would it be not suitible for the kernel audio driver? Because it has very little to do with the PCM audio, and that's what the driver discussed in this thread was supposed to be all about. Now, I'm not saying that there's shouldn't be a special driver just for pass-through type of functionality, all I'm saying is that lumping this functionality together with the PCM one would confuse things. > For me it's clearly an audio and > not a datalink issue, but perhaps I have only limited use cases. Perhaps, everywhere in this thread I should've prefixed the word audio with "some form of PCM". Thanks, Roman.