From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Alexander E. Patrakov" Subject: Re: Nodes, Widgets, ELD and Digital Surround 5.1 (HDMI) Output? Date: Thu, 04 Dec 2014 17:34:25 +0500 Message-ID: <548054D1.1000302@gmail.com> References: <499A51023C98481A9A8BE9EBEFDDFD70@Lyra> <547EBCFF.5030204@canonical.com> <547EC2BF.3080601@gmail.com> <46543BFB759444F4B56F5153F4727DEE@Lyra> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: Received: from mail-lb0-f179.google.com (mail-lb0-f179.google.com [209.85.217.179]) by alsa0.perex.cz (Postfix) with ESMTP id 2759926053E for ; Thu, 4 Dec 2014 13:34:28 +0100 (CET) Received: by mail-lb0-f179.google.com with SMTP id z11so13708240lbi.24 for ; Thu, 04 Dec 2014 04:34:27 -0800 (PST) In-Reply-To: <46543BFB759444F4B56F5153F4727DEE@Lyra> 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: bencoxdev@gmail.com, David Henningsson , ALSA Mailing list List-Id: alsa-devel@alsa-project.org 04.12.2014 15:55, bencoxdev@gmail.com wrote: > Hi Guys, > Thank you for your input it's much appreciated. > I have now produced the pulse audio log as suggested and it > appears that > when an attempt to open the Digital Surround 5.1 device, it fails with a > "No such file or directory" error. Here is a snippet of the log > showing the > error. > ( 0.456| 0.000) D: [pulseaudio] alsa-mixer.c: Looking at profile > output:iec958-ac3-surround-51 > ( 0.456| 0.000) D: [pulseaudio] alsa-mixer.c: Checking for > playback on Digital Surround 5.1 (IEC958/AC3) (iec958-ac3-surround-51) > ( 0.456| 0.000) D: [pulseaudio] alsa-util.c: Trying a52:1 with > SND_PCM_NO_AUTO_FORMAT ... > ( 0.456| 0.000) I: [pulseaudio] (alsa-lib)pcm.c: Unknown PCM a52:1 > ( 0.456| 0.000) I: [pulseaudio] alsa-util.c: Error opening PCM > device a52:1: No such file or directory > So I guess the next question is what is responsible for producing the > required device? This is not the correct device. This is a software encoder that is not installed on your computer. It will degrade audio quality by compression, eat CPU time, kill PulseAudio for exhausting the real-time budget, and is generally not needed on HDMI, because HDMI can transport PCM 5.1 streams just fine. Please see my earlier reply how to force PulseAudio into opening the correct HDMI device. -- Alexander E. Patrakov