From owner-freebsd-multimedia@FreeBSD.ORG Sun Feb 8 21:48:41 2015 Return-Path: Delivered-To: freebsd-multimedia@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id D7B0D217 for ; Sun, 8 Feb 2015 21:48:41 +0000 (UTC) Received: from mail-wg0-x241.google.com (mail-wg0-x241.google.com [IPv6:2a00:1450:400c:c00::241]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 7F1CAF4D for ; Sun, 8 Feb 2015 21:48:41 +0000 (UTC) Received: by mail-wg0-f65.google.com with SMTP id x12so7786996wgg.0 for ; Sun, 08 Feb 2015 13:48:39 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; bh=UtTslBxT56+X0jkYlgz7vTxf6QwVW0aaGSgIRpgRRaY=; b=kR7o7tlH5ZllA99z75S2TarbtUkmjWnlFWW03bLzcM9yjg1sfX3ccuBpdrzKw8m+07 a/cxelB4EY5aoY3XsKpJR4kUDgfmla5rCGe4i/sROwXdUyOXVZG1eqwE+g5A2CSK8aer Bypkf2P0+rOpkqLO+d8qIWLWCgWp12Cnpcrr6N9LEBDUj6oMXTooLISjdPGGrGFxlqsV JVWSG5mjpoMRyTsCPSWGVtfHT14ladkmCpknHqmHvOV8L8smZIN6lKxUXYwZBiHRs/ow a3ghJYAjvNh/dM3V6sKi9jLfIXRmULtd+gibfI4z3wlAwp01HsCzjj7p5P07DeRFkU8N brbQ== MIME-Version: 1.0 X-Received: by 10.181.29.168 with SMTP id jx8mr9326608wid.8.1423432119756; Sun, 08 Feb 2015 13:48:39 -0800 (PST) Received: by 10.27.14.167 with HTTP; Sun, 8 Feb 2015 13:48:39 -0800 (PST) In-Reply-To: <54D7D53D.2020504@selasky.org> References: <54D7D53D.2020504@selasky.org> Date: Sun, 8 Feb 2015 22:48:39 +0100 Message-ID: Subject: Re: Sound reasoning From: =?UTF-8?B?0JXQstCz0LXQvdC40Lkg0JEuINCh0L/QsNC80LDQutC+0LLRgdC60LjQuQ==?= To: Hans Petter Selasky Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-Content-Filtered-By: Mailman/MimeDel 2.1.18-1 Cc: freebsd-multimedia@freebsd.org X-BeenThere: freebsd-multimedia@freebsd.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: Multimedia discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 08 Feb 2015 21:48:41 -0000 On Sun, Feb 8, 2015 at 10:29 PM, Hans Petter Selasky wrote: > On 02/08/15 22:22, =D0=95=D0=B2=D0=B3=D0=B5=D0=BD=D0=B8=D0=B9 =D0=91. =D0= =A1=D0=BF=D0=B0=D0=BC=D0=B0=D0=BA=D0=BE=D0=B2=D1=81=D0=BA=D0=B8=D0=B9 wrote= : > >> Hi. >> >> Is there a point to writing a pcm device to have multiple "channel"s in >> the >> same direction? >> Say, two SND_FORMAT(AFMT_S16_LE, 1, 0) for record and two for playback, >> vs. >> just one SND_FORMAT(AFMT_S16_LE, 2, 0) in each direction. >> >> pcm_register() has so prominently two arguments 'numrec' and 'numplay' a= nd >> even if they are ignored, one can do pcm_addchan() any number of times. >> How is this expressed to the user-land programmer? >> >> "Read the code" is a fine answer, but it would be nice if someone can >> readily explain the idea behind the options. >> > > Hi, > > > Sounds similar to what my "virtual_oss" is doing. See: > > svn --username anonsvn --password anonsvn \ > checkout svn://svn.turbocat.net/i4b/trunk/ports >From the description it looks like virtual_oss is trying to do what VCHANs already succeed at doing. No offense, but this still does not explain what the difference is between a pcm unit collecting its physical streams in one channel vs. having a channel for each... Let's say I'm five years old? > > --HPS >