All of lore.kernel.org
 help / color / mirror / Atom feed
From: Steve Longerbeam <stevel@embeddedalley.com>
To: Jaroslav Kysela <perex@suse.cz>
Cc: Takashi Iwai <tiwai@suse.de>,
	"J. Scott Merritt" <alsauser@pragmasoft.com>,
	ALSA development <alsa-devel@alsa-project.org>
Subject: Re: non-interleaved mode
Date: Wed, 11 Jul 2007 11:12:49 -0700	[thread overview]
Message-ID: <46951DA1.9000500@embeddedalley.com> (raw)
In-Reply-To: <Pine.LNX.4.61.0707111935470.7300@tm8103.perex-int.cz>

Jaroslav Kysela wrote:
> On Wed, 11 Jul 2007, Steve Longerbeam wrote:
>
>   
>> Last night I ran an experiment.  I created a 16-bit stereo .wav file 
>> with all left samples = 0x5555, and all right samples = 0xAAAA. I then 
>> played the .wav using aplay, and just before trigger start in my driver 
>> I searched the DMA buffer for the first occurrence of 0xAAAA. The right 
>> samples didn't start until exactly half-way through the entire DMA buffer!
>>     
>
> Yes, it's the right non-interleaved behaviour. You can imagine this layout 
> as separate "mono" ring buffers for each channels - see 
> snd_pcm_lib_ioctl_channel_info() in pcm_lib.c . Driver might modify 
> info->offset if required (see hdsp.c driver for example).
>   

thanks, that cleared everything up for me.

Steve

      reply	other threads:[~2007-07-11 18:12 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-07-10 18:08 non-interleaved mode Steve Longerbeam
2007-07-11  8:47 ` Takashi Iwai
2007-07-11 13:13   ` J. Scott Merritt
2007-07-11 13:35     ` Takashi Iwai
2007-07-11 16:23       ` Steve Longerbeam
2007-07-11 17:44         ` Jaroslav Kysela
2007-07-11 18:12           ` Steve Longerbeam [this message]

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=46951DA1.9000500@embeddedalley.com \
    --to=stevel@embeddedalley.com \
    --cc=alsa-devel@alsa-project.org \
    --cc=alsauser@pragmasoft.com \
    --cc=perex@suse.cz \
    --cc=tiwai@suse.de \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.