From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Alexander E. Patrakov" Subject: Re: USB-Audio.conf routing and dmix Date: Fri, 15 May 2015 10:58:11 +0500 Message-ID: <55558AF3.8070804@gmail.com> References: <20150509002017.GB18945@freedom> <20150511195734.GA12233@freedom> <55531850.1020208@ladisch.de> <20150513113215.GA569@freedom> <20150515020715.GA418@freedom> <555589EF.60602@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: Received: from mail-wg0-f52.google.com (mail-wg0-f52.google.com [74.125.82.52]) by alsa0.perex.cz (Postfix) with ESMTP id 09DE726154E for ; Fri, 15 May 2015 07:58:15 +0200 (CEST) Received: by wgbhc8 with SMTP id hc8so67143914wgb.3 for ; Thu, 14 May 2015 22:58:14 -0700 (PDT) In-Reply-To: <555589EF.60602@gmail.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: alsa-devel-bounces@alsa-project.org Sender: alsa-devel-bounces@alsa-project.org To: sylvain.bertrand@gmail.com, Clemens Ladisch Cc: alsa-devel@alsa-project.org List-Id: alsa-devel@alsa-project.org 15.05.2015 10:53, Alexander E. Patrakov wrote: > 15.05.2015 07:07, sylvain.bertrand@gmail.com wrote: >> On Wed, May 13, 2015 at 11:32:15AM +0000, sylvain.bertrand@gmail.com >> wrote: >>> On Wed, May 13, 2015 at 11:24:32AM +0200, Clemens Ladisch wrote: >>>>>> I linked the surround51 and surround71 pcms with the >>>>>> 'disable-able' dmix >>>>>> section from the default pcm. >>>> >>>> These devices are not supposed to use plug or dmix. >>> >>> Ok. Then, there is no pcm to output 5.1 sound with dmix. >>> >>> Does it mean that the application is in charge to build a alsa-lib >>> pipeline >>> with dmix pcm and surround51 pcm, in order to let other applications >>> output 5.1 >>> sound at the same time? >> >> Then what is the "Right"(tm) way to do that? >> > > [this is my personal opinion, in no way official] > > The right way seems to be to use PulseAudio. Pure ALSA, in its default > configuration, just does not support mixing 5.1 audio, on any card. This > default cannot really be changed, because there are many people who use > 5.1 cards for output to stereo headphones only, i.e. who need automatic > downmixing if an app (such as VLC) starts a 5.1 stream. The default > plug/dmix setup provides such downmixing. I need to test things before posting. This is wrong, plug/dmix does not include the extra channels in the stereo mix. > As an application developer, just tell your users "your default device > needs to support 5.1, see you there", as mpv developers did. This will > be the case either with PulseAudio or with a hacked .asoundrc. This is still my position. -- Alexander E. Patrakov