Talk:HOWTO ALSA Complete (includes dmix)

From Gentoo Linux Wiki

[edit] About real HOWTO

this is a great bunch of misc tidbits - someone should massage it into a real HowTo. Start by saying why you need dmix and how it differs from alsamixer.

ALSA already have all info, we (contributors) just put it together for gentoo, and i hope it will grow in terms of hardware specificity. Due to it constant changes i do not see any needs to convert it to the real old fashion HOWTO. Right now, on wiki, anybody who have an idea, can update it right away, compare to a hassel with real HOWTO, but if you want to, you are always welcome :.D'mitri

is it necessarily true that you need non-kernel alsa? I use dmix with alsa-in-kernel, seems to work fine - AlecZorab

No, that part is completely wrong as it is because they forgot to mention that this is for kernel 2.4 only. If you read to the end of that section it says something like "now that was for kernel 2.4, if you're on kernel 2.6 do...". Most users would expect something that important a little earlier then 3 pages into the document.

[edit] Article update

I update the article with a note in the Introduction.
Any ideas are welcome.
Thank you for appreciation.
ΩD'mitri 13:04, 17 Nov 2004 (GMT)

[edit] Music Player Daemon

Could someone add a section on configuring mpd for dmix?

Done

[edit] Consolidate ~/.asoundrc 's to a single file

I'm not sure if anyone really understands this, but all of the chipsets interface with alsa the same. We don't need all of these examples so much as we need one that integrates the comments from all of the others. If someone would like me to do this, I don't mind, but I don't want to edit a huge section of the page (about half the page is sample asoundrc's).

Email: pagerc@gmail.com

[edit] Correction for intel8x0/nforce2 .asoundrc

(Wiki first-timer so sorry if this should be on the front page) What I changed to get sound in Firefox (Flash) to work: (Firefox freezes up upon sound otherwise)

########
# AOSS #
########
# OSS dsp0 device
pcm.dsp0 {
     type plug
#    slave.pcm "duplex" #### DOESN'T WORK
     slave.pcm "dmix" #### WORKS
}

Someone please confirm this besides me... I tried hw:0,0 and that works fine all by itself (XMMS complains something else is using the soundcard while Firefox is doing audio). From my testing, THAT is what gets it working for me.

arkaine@cox.net

[edit] Refactoring

I've cleaned up this HOWTO, which should be less messy now.

It is basically split into: ALSA setup; Apps config; Hardware config.

[edit] alsa-lib not needed for 2.6?

This is mentioned twice, but it sounds to me like it should be *alsa-driver* is not needed for 2.6.

I'm on 2.6 and when I emerged alsa-oss, it depends upon alsa-libs.

== /etc/conf.d/alsasound seems to have changed :

bash-2.05b# cat /etc/conf.d/alsasound

1. SAVE_ON_STOP:
2. Do you want to save changes made to your mixer volumes when alsasound
3. stops?
4. no - Do not save state
5. yes - Save state

SAVE_ON_STOP="yes" bash-2.05b#

running equery depends alsa-lib gives following output on my system

linux-box root # equery depends alsa-lib [ Searching for packages depending on alsa-lib... ] gnome-base/control-center-2.8.2 kde-base/arts-1.3.2-r1 kde-base/kdemultimedia-3.3.2 kde-base/arts-3.4.0 kde-base/kdelibs-3.3.2-r9 media-libs/libao-0.8.5 media-libs/openal-20040817 media-libs/libsdl-1.2.8-r1 media-libs/libmikmod-3.1.11-r1 media-libs/xine-lib-1.0-r2 media-plugins/xmms-alsa-1.2.10 media-plugins/gst-plugins-alsa-0.8.8 media-sound/esound-0.2.34 media-sound/alsa-utils-1.0.8 media-sound/beep-media-player-0.9.7-r4 media-video/avifile-0.7.41.20041001-r1 media-video/mplayer-1.0_pre6-r4

so I assume alsa-lib is BADLY needed and what the author means is really alsa-driver that can be safely displayed. BTW, I uninstalled alsa-lib and Alsa immediately gave up. I needed to reinstall it in order to get sound working again.

[edit] Everything works well but still little discomfort

Thank you for the article, I was going to find out how to get sound mexied with Linux and at last I managed to tune everything (almost), but still experience some discomfort with that. I use kernel 2.6, external alsa-deivers, snd-intel8x0 driver on the Intel Corp. 82801DB/DBL/DBM chipset. Here are my problems:

1. If I drag a window with the mouse during having xmms running or mplayer, both - doesn't metter (I heven't tried anything else) all the sound stops and it resumes only after I release the window (by the way if this window is xmms one then the sound is ok despite the sound source). In addition, if I have the commands typed:
   alsaplayer -o alsa -d plug:dmix some.mp3
   or
   aoss mpg321 some.mp3
   again, all the sound is ok if I drag any of the windows. First I thought it was a problem of my win manager but after tests with these commands I'm not sure of that. Do I have to put option like NON-BLOCKING in the .asoundrc or something like that??? Might it be so that alsa api is used incorrectly by mplayer or xmms plugins?
2. ANSWER: I'm gonna take a guess that you're using fluxbox and should set "session.opaqueMove: false" in ~/.fluxbox/init. Let us know if that helps
3. ANSWER-addition-info: I using gentoo:2.6.10 on amd64 running enlightenment 0.16.7.2. I've had this problem with xmms freezing (playback stops) when I moved any window (not sure it included the xmms 'window' itself). I've just got the Alsa:dmix solution in place (xmms-1.2.10-r13; xmms-alsa-1.2.10; alsa-embedded-vanilla-sources-2.6.10; with alsa-lib-1.0.8) - and still the problem - alsaplayer is not affected. The above reply-answer; made me check; and I discovered that any 'Move&Resize Setting' other than 'Opaque' exhibited the problem - strange, but true.
4. RE:ANSWER: Yes, you're right, but it's set to false and doesn't work.
5. FIXED: I installed native kernel alsa driver and the problem disappeared.
6. If I have mplayer and xmms running simultaneously then I tune volume in the xmms, it's independent on the mlayer's, but if do so in the mplayer then it changes volume of the xmms' as well (it changes pcm value that can be seen via the alsamixer).
7. Before I set up dmix I'd read a few articles about Linux sound system, I've personally tried esound and jack. First one is qute drugged, the second I couldn't adjust properly (problems with mplayer - I have sound but no movie running itself, I couldn't start jackstart, only jackd, as I know jackstart is correct way to have jack working). I'm still confused - what is the best way to have sound mixed, should I play more with jack because it's "a low-latency audio server", why all the deamons are needed if there is the lowermost dmix capability???
8. ANSWER: jack is a sound mixer, if you intend to mix audio like you would with a mixer, you should use jack. If you're just trying to get multiple applications to play sound at the same time, and your soundcard doesn't support native hardware mixing, you want to enable dmix.

I needn't have set up external drivers as I'm a 2.6 kernel user but read about that too late, should I try internal ones to solve any of the problems???
Thank you.

12:21, 27 Mar 2005 (GMT)

[edit] This is a PITA

We really need to get some way of doing this in a reasonable manner for the end user.

I consider myself reasonably advanced, and following this HOWTO gives me a headache just looking at it. How in the world can I convince my less savvy friends leave windows if they can't play MP3s and get system sounds at the same time without doing this?

This is the problem with the sound-system today, what would work best (in my head atm atleast) would be support for mixing on kernel-level so the end-user doesnt need to play with configs just to get a basic soundsystem, then configs/userspace-tools for tweaking.

I didn't find it that hard to follow, just potentially confusing if you don't read the whole thing before starting. It should be reorganized. I'd do it myself but, considering how busy I am, someone else will probably have done it by the time I come back. --StephanSokolow 20:57, 5 Apr 2005 (GMT)

[edit] System-wide configuration

I should point out that all of this can be done using system-wide configuration files. For example, /etc/asound.conf instead of ~/.asoundrc

That's what I did when I put Gentoo on my brother's dual-boot system and it works very well.

My experience was that I couldn't get my mixing to work right unless I set it in the /etc/asound.conf file with the following dmixer device:

pcm.dmixer { 
    type dmix 
    ipc_key 1024
    ipc_key_add_uid false
    ipc_perm 0666			# mixing for all users
    slave { 
        pcm "hw:0,0" 
        period_time 0 
        period_size 1024 
        buffer_size 8192
        rate 44100
    }
    bindings { 
        0 0 
        1 1 
    } 
} 

pcm.dsp0 { 
    type plug 
    slave.pcm "dmixer" 
} 

pcm.!default { 
    type plug 
    slave.pcm "dmixer" 
} 

pcm.default { 
   type plug 
   slave.pcm "dmixer" 
} 

ctl.mixer0 { 
    type hw 
    card 0 
}

Note that this was because I am starting the Music Player Daemon (MPD) from init scripts and it is running as the "MPD" user. This configuration allows all users to share the dmix device. In case you want to know, this is on a nforce3 board.

[edit] Misc. Corrections and Observations

mmap mode works fine for xmms, I didn't need to use any of the special tweaks for mplayer, and I didn't need any of the via82xx tweaks either. The system in question uses Asus A7V8X-X on-board audio.

[edit] qpkg deprecated

"qpkg is now deprecated and has been removed from gentoolkit. It has been supplanted with equery." - Portage for RPM Users

I was going to fix the page myself but I've realized that I don't know how to translate the commands.

Alright, I've added the following paragraph to the article, feel free to correct it: Please note that qpkg has become deprecated and been replaced by equery. If after emerging gentoolkit gpkg still is not installed, try the following:

# equery -i list *alsa*
[ Searching for package '*alsa*' in all categories among: ]
 * installed packages
[I--] [  ] media-libs/alsa-lib-1.0.8 (0)
[I--] [  ] media-plugins/xmms-alsa-1.2.10 (0)
[I--] [  ] media-plugins/gst-plugins-alsa-0.8.7-r1 (0.8)
[I--] [  ] media-sound/alsa-headers-1.0.8 (0)

it's ok, but equery list alsa is sufficient. Dunno what -i stands for, but '*'s are surely not neccessary. -- ph

(-i = search installed packages, it's default) -- digits

[edit] Alsa and multiple soundcards?

There are two things that I can't find any good documentation on, and they are

- Use two soundcards, both play the same sound

- Use two soundcards as if they where one with a lot more speakers

85.167.53.16 13:04, 13 August 2006 (UTC): Found http://alsa.opensrc.org/TwoCardsAsOne that explains how to do this. The example given explains how to gain more channels, but by adjusting the routing table like this: pcm.ttable {

  type route;
  slave.pcm "multi";
  ttable.0.0 1;
  ttable.1.1 1;
  ttable.0.2 1;
  ttable.1.3 1;
}

> pmidi -l

> pmidi -p 128:0 some.mid

# Set default sound card
# Useful so that all settings can be changed to a differen card here.
pcm.snd_card {
    type hw
    card 0
    device 0
}

# Allow mixing of multiple output streams to this device
pcm.output {
    type dmix
    ipc_key 1024
    ipc_perm 0660 # Sound for everybody in your group!
    slave.pcm "snd_card"

    slave {
         # This stuff provides some fixes for latency issues.
         # buffer_size should be set for your audio chipset.
         period_time 0
         period_size 1024
         buffer_size 8192
    }

    bindings {
         0 0
         1 1
    }
}

# Allow reading from the default device.
# Also known as record or capture.
pcm.input {
    type dsnoop
    ipc_key 2048
    ipc_key_add_uid yes
    slave.pcm "snd_card"

## Possible artsd full duplex fix:
    slave {
         period_time 0
         period_size 1024
         buffer_size 8192
         rate 48000
    }

    bindings {
         0 0
         1 1
    }
}

# This is what we want as our default device
# a fully duplex (read/write) audio device.
#
# The "output" device seems to block all other sound requests
# of other users, e.g. the Timidity server started at boot time
# The "dmix" device works
pcm.duplex {
    type asym
#     playback.pcm "output" 
    playback.pcm "dmix"
    capture.pcm "input"
}

###################
# CONVERSION PLUG #
###################
# Setting the default pcm device allows the conversion
# rate to be selected on the fly.
# duplex mode allows any alsa enabled app to read/write
# to the dmix plug (Fixes a problem with wine).
pcm.!default {
    type plug
    slave.pcm "duplex"
}

# Apparently this is wrong (breaks mplayer for me opening the
# device)
#ctl.!default {
#     type plug
#     slave.pcm "snd_card"
#}

########
# AOSS #
########
# OSS dsp0 device (OSS needs only output support, duplex will 
# break some stuff)
pcm.dsp0 {
    type plug
    slave.pcm "output"
}

# OSS control for dsp0 (needed?...this might not be useful)
ctl.dsp0 {
    type plug
    slave.pcm "snd_card"
}

# OSS control for dsp0 (default old OSS is mixer0)
ctl.mixer0 {
    type plug
    slave.pcm "snd_card"
}

Device Drivers -> Generic Driver Options -> Userspace firmware loading support