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From: Clemens Ladisch <clemens@ladisch.de>
To: Vipin Kumar <vipin.kumar@st.com>
Cc: "alsa-devel@alsa-project.org" <alsa-devel@alsa-project.org>,
	Mark Brown <broonie@opensource.wolfsonmicro.com>
Subject: Re: 24 bit sample embedded in 32 bits
Date: Mon, 02 Jul 2012 13:01:21 +0200	[thread overview]
Message-ID: <4FF17F81.8070300@ladisch.de> (raw)
In-Reply-To: <4FF173D4.7060401@st.com>

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

  reply	other threads:[~2012-07-02 11:01 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-07-02 10:11 24 bit sample embedded in 32 bits Vipin Kumar
2012-07-02 11:01 ` Clemens Ladisch [this message]
2012-07-02 11:11   ` Vipin Kumar
2012-07-02 11:02 ` Jaroslav Kysela

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