From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tanu Kaskinen Subject: Re: Logical device name for 4-channel microphones? Date: Tue, 24 Apr 2012 18:28:14 +0300 Message-ID: <1335281294.4604.19.camel@laptop> References: <1335011052.2268.18.camel@laptop> <4F96B3ED.3070007@ladisch.de> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from out3-smtp.messagingengine.com (out3-smtp.messagingengine.com [66.111.4.27]) by alsa0.perex.cz (Postfix) with ESMTP id 8267F24433 for ; Tue, 24 Apr 2012 17:28:17 +0200 (CEST) In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: alsa-devel-bounces@alsa-project.org Errors-To: alsa-devel-bounces@alsa-project.org To: Takashi Iwai Cc: alsa-devel@alsa-project.org, Clemens Ladisch List-Id: alsa-devel@alsa-project.org On Tue, 2012-04-24 at 16:09 +0200, Takashi Iwai wrote: > At Tue, 24 Apr 2012 16:08:45 +0200, > Clemens Ladisch wrote: > > > > Tanu Kaskinen wrote: > > > My problem is that I'd like to make Pulseaudio handle 4-channel webcam > > > microphones[2], but I'm not aware of any input device names for > > > 4-channel devices. Are there such device names? > > > > These device name are useful only for device types that are generic > > enough. Four-channel microphones aren't. > > Hm, we have already surround51 or such specific one, so it's not too > bad to have a definition for multi-channel mics. OTOH, surround51 & > co were the possible cause of confusions, as there are way too many > surround types. A generic type with the channels argument might be > more generic? > > In anyway, I think it's fine to define some new generic name. >>From Pulseaudio point of view using "hw" should be fine if you can guarantee that any current or future 4-channel mics can be opened in the 4-channel mode using the "hw:CARD" device name. I'm just worried that there might be cards that split the four channels to e.g. two stereo devices, "hw:CARD,0" and "hw:CARD,1", and then "hw:CARD" won't work. I might be mistaken, but aren't there some such cases with playback, which have to be opened with the "surround" device names to get all the channels? The "surround" devices also guarantee some specific channel mapping, which may not match what "hw" uses, which is another reason to prefer "surround" over "hw", but I don't think this applies to input side. Therefore, the only possible problem that I can see with "hw" is that it might not provide all channels. -- Tanu