From mboxrd@z Thu Jan 1 00:00:00 1970 From: Clemens Ladisch Subject: Re: 24 bit sample embedded in 32 bits Date: Mon, 02 Jul 2012 13:01:21 +0200 Message-ID: <4FF17F81.8070300@ladisch.de> References: <4FF173D4.7060401@st.com> 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 5A3E21041FE for ; Mon, 2 Jul 2012 13:01:23 +0200 (CEST) In-Reply-To: <4FF173D4.7060401@st.com> 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: Vipin Kumar Cc: "alsa-devel@alsa-project.org" , Mark Brown List-Id: alsa-devel@alsa-project.org Vipin Kumar wrote: > I assume that the alsa framework expects the 24 bit sample data to be > packed one after the other. ALSA expects the sample data to conform to whatever sample format has been configured. Most hardware uses 32-bit sample words in memory to make the interface to the PCI bus easier. > I need to find a way to tell the framework that the data is 24bit > but is embedded in 32 bit. (HH = highest byte, LL = lowest byte, MM = middle byte) LL MM HH SNDRV_PCM_FORMAT_S24_3LE xx LL MM HH SNDRV_PCM_FORMAT_S32_LE LL MM HH xx SNDRV_PCM_FORMAT_S24_LE HH MM LL SNDRV_PCM_FORMAT_S24_3BE HH MM LL xx SNDRV_PCM_FORMAT_S32_BE xx HH MM LL SNDRV_PCM_FORMAT_S24_BE Regards, Clemens