From 8224e837ef60278a9a1140515d79650d9024757e Mon Sep 17 00:00:00 2001
From: Eric Wong <normalperson@yhbt.net>
Date: Sun, 16 Jul 2006 16:52:19 +0000
Subject: audioOutput_alsa: add use_mmap, period_time, buffer_time options

ALSA support in libao supports configuring of these variables,
and some hardware setups may benefit from having these things
as tweakable.

git-svn-id: https://svn.musicpd.org/mpd/trunk@4363 09075e82-0dd4-0310-85a5-a0d7c8717e4f
---
 doc/mpd.conf.5 | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

(limited to 'doc/mpd.conf.5')

diff --git a/doc/mpd.conf.5 b/doc/mpd.conf.5
index 7ff364b8b..88c9a6d85 100644
--- a/doc/mpd.conf.5
+++ b/doc/mpd.conf.5
@@ -236,6 +236,26 @@ separate options.  An example for oss: "dsp=/dev/dsp".  An example for alsa09:
 This specifies how many bytes to write to the audio device at once.  Used only
 by the ao output type.  This parameter is to work around a bug in older
 versions of libao on sound cards with very small buffers.  The default is 1024.
+.SH OPTIONAL ALSA OUTPUT PARAMETERS
+.TP
+.B use_mmap <yes or no>
+Setting this allows you to use memory-mapped I/O.  Certain hardware setups
+may benefit from this, but most do not.
+Most users do not need to set this.
+.TP
+.B buffer_time <time in microseconds>
+This sets the length of the hardware sample buffer in microseconds.
+Increasing it may help to reduce or eliminate skipping on certain setups.
+Most users do not need to change this.
+The default is 500000 microseconds (0.5 seconds).
+.TP
+.B period_time <time in microseconds>
+This sets the time between hardware sample transfers in microseconds.
+Increasing this can reduce CPU usage while lowering it can reduce underrun
+errors on bandwidth-limited devices.  Some users have reported good results
+with this set to 50000, but not all devices support values this high.
+Most users do not need to change this.
+The default is 256000000 / sample_rate(kHz), or 5804us for CD-quality audio.
 .SH REQUIRED SHOUT OUTPUT PARAMETERS
 .TP
 .B name <name>
-- 
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