From mboxrd@z Thu Jan 1 00:00:00 1970 From: Anssi Hannula Subject: Re: IEC61937/SPDIF Date: Tue, 14 Jun 2011 21:09:43 +0300 Message-ID: <4DF7A3E7.5080907@iki.fi> References: Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from tulikuusama.dnainternet.net (tulikuusama.dnainternet.net [83.102.40.132]) by alsa0.perex.cz (Postfix) with ESMTP id 41148244DA for ; Tue, 14 Jun 2011 20:09:49 +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: ajay khandelwal Cc: alsa-devel@alsa-project.org List-Id: alsa-devel@alsa-project.org On 14.06.2011 15:47, ajay khandelwal wrote: > Hi All, Hi! I've worked with IEC61937, but I'm no ALSA expert, so I hope others correct me if I'm wrong. > I have to develop driver for SPDIF output of my board connected to HDMI. > > I'm not sure for following (specially IEC61937) > 1) How should driver know if it is compressed audio or plain pcm You can look at the bit 1 (0x02) of AES0 IEC958 channel status. The driver generally provides IEC958 controls: http://www.alsa-project.org/~tiwai/writing-an-alsa-driver/ch10s03.html That are then used via hooks in "foo.pcm.hdmi.0" (or "foo.pcm.iec958.0" for non-hdmi) definition in /usr/share/alsa/cards/foo.conf (look at existing drivers for examples). Applications can then set these flags by e.g. opening the ALSA audio device as "hdmi:AES0=0x06,AES1=0x82" etc. > 2) Is their any plugin available for IEC61937, I could see only for IEC958 No. > 3) Who should create burst preamble, some plug in or driver. Currently they are created by the applications themselves. -- Anssi Hannula