[alsa-devel] Dsnoop-plugin buffer sizes

[Magnus Olsson]

This output is captured when running periods_min=4.

[root at axis /mnt/flash/root]1335# arecord -v -r 16000 -c1 -Daudiosource0 -fS16_LE /tmp/in.wav
Recording WAVE '/tmp/in.wav' : Signed 16 bit Little Endian, Rate 16000 Hz, Mono
Direct Snoop PCM
Its setup is:
  stream       : CAPTURE
  access       : RW_INTERLEAVED
  format       : S16_LE
  subformat    : STD
  channels     : 1
  rate         : 16000
  exact rate   : 16000 (16000/1)
  msbits       : 16
  buffer_size  : 8000
  period_size  : 2000
  period_time  : 125000
  tstamp_mode  : NONE
  period_step  : 1
  avail_min    : 2000
  period_event : 0
  start_threshold  : 1
  stop_threshold   : 8000
  silence_threshold: 0
  silence_size : 0
  boundary     : 2097152000
Hardware PCM card 0 'X4 AIC3104 Dual' device 0 subdevice 0
Its setup is:
  stream       : CAPTURE
  access       : MMAP_INTERLEAVED
  format       : S16_LE
  subformat    : STD
  channels     : 2
  rate         : 16000
  exact rate   : 16000 (16000/1)
  msbits       : 16
  buffer_size  : 8192
  period_size  : 2000
  period_time  : 125000
  tstamp_mode  : ENABLE
  period_step  : 1
  avail_min    : 2000
  period_event : 0
  start_threshold  : 1
  stop_threshold   : 1073741824
  silence_threshold: 0
  silence_size : 0
  boundary     : 1073741824
  appl_ptr     : 0
  hw_ptr       : 0


-----Original Message-----
From: alsa-devel-bounces at alsa-project.org [mailto:alsa-devel-bounces at alsa-project.org] On Behalf Of Jaroslav Kysela
Sent: den 14 mars 2011 11:08
To: Magnus Olsson
Cc: alsa-devel at alsa-project.org
Subject: Re: [alsa-devel] Dsnoop-plugin buffer sizes

On Mon, 14 Mar 2011, Magnus Olsson wrote:

> Hi,
>
> I'm having issues with garbage data in my audio stream, which I believe 
> is caused by incorrect buffer sizes somewhere in the audio pipeline. The 
> garbage occurs periodically and is always constant in length. This 
> problem only triggers when I use the dsnoo-plugin. If running directly 
> towards the device, the audio stream is fine (no garbage). I've not 
> tested if this occurs with any other plugin.
>
> I'm using Dsnoop to capture a mono stream from a stereo device using 
> arecord, arecord -v -r 16000 -c1 -Daudiosource0 -fS16_LE /tmp/in.wav 
> (where audiosource0 is my dsnoop-device, bound to channel 0)
>
> The verbose info from arecord shows me that ALSA has correctly created 
> the Dsnoop device, with a "buffer_size" of 8000. It also shows that it 
> has opened my Hardware device in MMAP-mode, with a "buffer_size" of 
> 8192.

Show us this output from 'arecord -v'.

 					Jaroslav

-----
Jaroslav Kysela <perex at perex.cz>
Linux Kernel Sound Maintainer
ALSA Project, Red Hat, Inc.

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