XMOS USB and MPD and Linux

[roberth]

Hello

 

I have a Dac which uses the XMOS usb audio 2.0 chip, and I use linux and MPD to play music with it. So I am trying to achieve bitperfect playback. I am not sure if I am achieving that.

 

When I play a song, MPD shows this in the log:

 

[font=monospace][color=#000000]Apr 21 07:46 : playlist: play 0:"10cc/Bloody Tourists/01 - 10CC - Dreadlock Holiday.flac"[/color]
Apr 21 07:46 : client: [0] command returned 0
Apr 21 07:46 : decoder_thread: probing plugin flac
Apr 21 07:46 : playlist: queue song 1:"Twisted Sister/Stay Hungry/05 - I Wanna Rock.flac"
Apr 21 07:46 : decoder: audio_format=44100:16:2, seekable=true
Apr 21 07:46 : client: [0] process command "status"
Apr 21 07:46 : alsa_output: opened hw:2,0 type=HW
Apr 21 07:46 : alsa_output: format=S32_LE (Signed 32 bit Little Endian)
Apr 21 07:46 : alsa_output: buffer: size=16..131072 time=362..2972155
Apr 21 07:46 : alsa_output: period: size=8..65536 time=181..1486078
Apr 21 07:46 : alsa_output: default period_time = buffer_time/4 = 500000/4 = 125000
Apr 21 07:46 : alsa_output: buffer_size=22050 period_size=5513
Apr 21 07:46 : output: opened plugin=alsa name="My ALSA Device" audio_format=44100:32:2
Apr 21 07:46 : output: converting from 44100:16:2
[/font]

 

Does this info indicate that it resample the audio?

 

Some info:

 

[font=monospace][color=#000000]roberth@Magda [/color][color=#18B218]~[/color][color=#000000]> [/color][color=#005FD7]aplay[/color][color=#00AFFF]-l[/color]
**** List of PLAYBACK Hardware Devices ****
card 0: HDMI [HDA Intel HDMI], device 3: HDMI 0 [HDMI 0]
 Subdevices: 1/1
 Subdevice #0: subdevice #0
card 0: HDMI [HDA Intel HDMI], device 7: HDMI 1 [HDMI 1]
 Subdevices: 1/1
 Subdevice #0: subdevice #0
card 0: HDMI [HDA Intel HDMI], device 8: HDMI 2 [HDMI 2]
 Subdevices: 1/1
 Subdevice #0: subdevice #0
card 1: PCH [HDA Intel PCH], device 0: ALC1150 Analog [ALC1150 Analog]
 Subdevices: 1/1
 Subdevice #0: subdevice #0
card 1: PCH [HDA Intel PCH], device 1: ALC1150 Digital [ALC1150 Digital]
 Subdevices: 1/1
 Subdevice #0: subdevice #0
card 2: X20 [XMOS USB Audio 2.0], device 0: USB Audio [uSB Audio]
 Subdevices: 0/1
 Subdevice #0: subdevice #0
[/font]

 

[font=monospace][color=#000000]roberth@Magda [/color][color=#18B218]~[/color][color=#000000]> [/color][color=#005FD7]aplay[/color][color=#00AFFF]-L[/color]
null
   Discard all samples (playback) or generate zero samples (capture)
hdmi:CARD=HDMI,DEV=0
   HDA Intel HDMI, HDMI 0
   HDMI Audio Output
hdmi:CARD=HDMI,DEV=1
   HDA Intel HDMI, HDMI 1
   HDMI Audio Output
hdmi:CARD=HDMI,DEV=2
   HDA Intel HDMI, HDMI 2
   HDMI Audio Output
sysdefault:CARD=PCH
   HDA Intel PCH, ALC1150 Analog
   Default Audio Device
front:CARD=PCH,DEV=0
   HDA Intel PCH, ALC1150 Analog
   Front speakers
surround21:CARD=PCH,DEV=0
   HDA Intel PCH, ALC1150 Analog
   2.1 Surround output to Front and Subwoofer speakers
surround40:CARD=PCH,DEV=0
   HDA Intel PCH, ALC1150 Analog
   4.0 Surround output to Front and Rear speakers
surround41:CARD=PCH,DEV=0
   HDA Intel PCH, ALC1150 Analog
   4.1 Surround output to Front, Rear and Subwoofer speakers
surround50:CARD=PCH,DEV=0
   HDA Intel PCH, ALC1150 Analog
   5.0 Surround output to Front, Center and Rear speakers
surround51:CARD=PCH,DEV=0
   HDA Intel PCH, ALC1150 Analog
   5.1 Surround output to Front, Center, Rear and Subwoofer speakers
surround71:CARD=PCH,DEV=0
   HDA Intel PCH, ALC1150 Analog
   7.1 Surround output to Front, Center, Side, Rear and Woofer speakers
iec958:CARD=PCH,DEV=0
   HDA Intel PCH, ALC1150 Digital
   IEC958 (S/PDIF) Digital Audio Output
sysdefault:CARD=X20
   XMOS USB Audio 2.0, USB Audio
   Default Audio Device
front:CARD=X20,DEV=0
   XMOS USB Audio 2.0, USB Audio
   Front speakers
surround21:CARD=X20,DEV=0
   XMOS USB Audio 2.0, USB Audio
   2.1 Surround output to Front and Subwoofer speakers
surround40:CARD=X20,DEV=0
   XMOS USB Audio 2.0, USB Audio
   4.0 Surround output to Front and Rear speakers
surround41:CARD=X20,DEV=0
   XMOS USB Audio 2.0, USB Audio
   4.1 Surround output to Front, Rear and Subwoofer speakers
surround50:CARD=X20,DEV=0
   XMOS USB Audio 2.0, USB Audio
   5.0 Surround output to Front, Center and Rear speakers
surround51:CARD=X20,DEV=0
   XMOS USB Audio 2.0, USB Audio
   5.1 Surround output to Front, Center, Rear and Subwoofer speakers
surround71:CARD=X20,DEV=0
   XMOS USB Audio 2.0, USB Audio
   7.1 Surround output to Front, Center, Side, Rear and Woofer speakers
iec958:CARD=X20,DEV=0
   XMOS USB Audio 2.0, USB Audio
   IEC958 (S/PDIF) Digital Audio Output
[/font]

 

MPD output configuration:

 

[font=monospace][color=#000000]audio_output {[/color]
       type            "alsa"
       name            "My ALSA Device"
       device          "hw:2,0"
      auto_resample   "no"
       mixer_type      "no"
       auto_format     "no"
[/font]

 

I also noticed through alsamixer that it uses a mixer that controls the volume when using mpd, is that neccesary to disable?

 

[poalex]

Yes, the audio is converted. 44100:32:2 ->44100:16:2. Causes 2: 1.XMOS not support 32bit 2. MPD is configured to convert. The ALSA settings do not change.

[roberth]

Yes, the audio is converted. 44100:32:2 ->44100:16:2. Causes 2: 1.XMOS not support 32bit 2. MPD is configured to convert. The ALSA settings do not change.

 

Uhm... I am playing 16bit 44,1khz audio, the dac supports up to 32 bit.

[poalex]

Uhm... I am playing 16bit 44,1khz audio, the dac supports up to 32 bit.

Perhaps to see the entire file MPD CONFIG?

[roberth]

Here you go.

 

# An example configuration file for MPD.
# Read the user manual for documentation: http://www.musicpd.org/doc/user/
# or /usr/share/doc/mpd/user-manual.html




# Files and directories #######################################################
#
# This setting controls the top directory which MPD will search to discover the
# available audio files and add them to the daemon's online database. This 
# setting defaults to the XDG directory, otherwise the music directory will be
# be disabled and audio files will only be accepted over ipc socket (using
# file:// protocol) or streaming files over an accepted protocol.
#
music_directory		"/mnt/DATA/sync/musikk"
#
# This setting sets the MPD internal playlist directory. The purpose of this
# directory is storage for playlists created by MPD. The server will use 
# playlist files not created by the server but only if they are in the MPD
# format. This setting defaults to playlist saving being disabled.
#
playlist_directory		"/home/roberth/.config/mpd/playlists"
#
# This setting sets the location of the MPD database. This file is used to
# load the database at server start up and store the database while the 
# server is not up. This setting defaults to disabled which will allow
# MPD to accept files over ipc socket (using file:// protocol) or streaming
# files over an accepted protocol.
#
db_file			"/home/roberth/.config/mpd/database"
# 
# These settings are the locations for the daemon log files for the daemon.
# These logs are great for troubleshooting, depending on your log_level
# settings.
#
# The special value "syslog" makes MPD use the local syslog daemon. This
# setting defaults to logging to syslog, otherwise logging is disabled.
#
log_file			"/home/roberth/.config/mpd/mpd.log"
#
# This setting sets the location of the file which stores the process ID
# for use of mpd --kill and some init scripts. This setting is disabled by
# default and the pid file will not be stored.
#
pid_file			"/home/roberth/.config/mpd/pid"
#
# This setting sets the location of the file which contains information about
# most variables to get MPD back into the same general shape it was in before
# it was brought down. This setting is disabled by default and the server 
# state will be reset on server start up.
#
state_file			"/home/roberth/.config/mpd/state"
#
# The location of the sticker database.  This is a database which
# manages dynamic information attached to songs.
#
#sticker_file                   "/var/lib/mpd/sticker.sql"
#
###############################################################################




# General music daemon options ################################################
#
# This setting specifies the user that MPD will run as. MPD should never run as
# root and you may use this setting to make MPD change its user ID after
# initialization. This setting is disabled by default and MPD is run as the
# current user.
#
#user				"roberth"
#
# This setting specifies the group that MPD will run as. If not specified
# primary group of user specified with "user" setting will be used (if set).
# This is useful if MPD needs to be a member of group such as "audio" to
# have permission to use sound card.
#
#group                          "users"
#
# This setting sets the address for the daemon to listen on. Careful attention
# should be paid if this is assigned to anything other then the default, any.
# This setting can deny access to control of the daemon. Choose any if you want
# to have mpd listen on every address
#
# For network
bind_to_address		"localhost"
#
# And for Unix Socket
#bind_to_address		"/run/mpd/socket"
#
# This setting is the TCP port that is desired for the daemon to get assigned
# to.
#
port				"6600"
#
# This setting controls the type of information which is logged. Available 
# setting arguments are "default", "secure" or "verbose". The "verbose" setting
# argument is recommended for troubleshooting, though can quickly stretch
# available resources on limited hardware storage.
#
log_level			"verbose"
#
# If you have a problem with your MP3s ending abruptly it is recommended that 
# you set this argument to "no" to attempt to fix the problem. If this solves
# the problem, it is highly recommended to fix the MP3 files with vbrfix
# (available as vbrfix in the debian archive), at which
# point gapless MP3 playback can be enabled.
#
#gapless_mp3_playback			"yes"
#
# Setting "restore_paused" to "yes" puts MPD into pause mode instead
# of starting playback after startup.
#
#restore_paused "no"
#
# This setting enables MPD to create playlists in a format usable by other
# music players.
#
#save_absolute_paths_in_playlists	"no"
#
# This setting defines a list of tag types that will be extracted during the 
# audio file discovery process. The complete list of possible values can be
# found in the mpd.conf man page.
#metadata_to_use	"artist,album,title,track,name,genre,date,composer,performer,disc"
#
# This setting enables automatic update of MPD's database when files in 
# music_directory are changed.
#
auto_update    "yes"
#
# Limit the depth of the directories being watched, 0 means only watch
# the music directory itself.  There is no limit by default.
#
#auto_update_depth "3"
#
###############################################################################




# Symbolic link behavior ######################################################
#
# If this setting is set to "yes", MPD will discover audio files by following 
# symbolic links outside of the configured music_directory.
#
#follow_outside_symlinks	"yes"
#
# If this setting is set to "yes", MPD will discover audio files by following
# symbolic links inside of the configured music_directory.
#
#follow_inside_symlinks		"yes"
#
###############################################################################




# Zeroconf / Avahi Service Discovery ##########################################
#
# If this setting is set to "yes", service information will be published with
# Zeroconf / Avahi.
#
#zeroconf_enabled		"yes"
#
# The argument to this setting will be the Zeroconf / Avahi unique name for
# this MPD server on the network.
#
#zeroconf_name			"Music Player"
#
###############################################################################




# Permissions #################################################################
#
# If this setting is set, MPD will require password authorization. The password
# can setting can be specified multiple times for different password profiles.
#
#password                        "password@read,add,control,admin"
#
# This setting specifies the permissions a user has who has not yet logged in. 
#
#default_permissions             "read,add,control,admin"
#
###############################################################################




# Database #######################################################################
#


#database {
#       plugin "proxy"
#       host "other.mpd.host"
#       port "6600"
#}


# Input #######################################################################
#


input {
       plugin "curl"
#       proxy "proxy.isp.com:8080"
#       proxy_user "user"
#       proxy_password "password"
}


#
###############################################################################


# Audio Output ################################################################
#
# MPD supports various audio output types, as well as playing through multiple 
# audio outputs at the same time, through multiple audio_output settings 
# blocks. Setting this block is optional, though the server will only attempt
# autodetection for one sound card.
#
# An example of an ALSA output:
#
audio_output {
type		"alsa"
name		"My ALSA Device"
device     	"hw:2,0"
auto_resample   "no"
mixer_type      "no"
auto_format	"no"	
}
#
# An example of an OSS output:
#
#audio_output {
#	type		"oss"
#	name		"My OSS Device"
#	device		"/dev/dsp"	# optional
#	mixer_type      "hardware"      # optional
#	mixer_device	"/dev/mixer"	# optional
#	mixer_control	"PCM"		# optional
#}
#
# An example of a shout output (for streaming to Icecast):
#
#audio_output {
#	type		"shout"
#	encoding	"ogg"			# optional
#	name		"My Shout Stream"
#	host		"localhost"
#	port		"8000"
#	mount		"/mpd.ogg"
#	password	"hackme"
#	quality		"5.0"
#	bitrate		"128"
#	format		"44100:16:1"
#	protocol	"icecast2"		# optional
#	user		"source"		# optional
#	description	"My Stream Description"	# optional
#	url             "http://example.com"    # optional
#	genre		"jazz"			# optional
#	public		"no"			# optional
#	timeout		"2"			# optional
#	mixer_type      "software"              # optional
#}
#
# An example of a recorder output:
#
#audio_output {
#       type            "recorder"
#       name            "My recorder"
#       encoder         "vorbis"                # optional, vorbis or lame
#       path            "/var/lib/mpd/recorder/mpd.ogg"
##      quality         "5.0"                   # do not define if bitrate is defined
#       bitrate         "128"                   # do not define if quality is defined
#       format          "44100:16:1"
#}
#
# An example of a httpd output (built-in HTTP streaming server):
#
#audio_output {
#	type		"httpd"
#	name		"My HTTP Stream"
#	encoder		"vorbis"		# optional, vorbis or lame
#	port		"8000"
#	bind_to_address "0.0.0.0"               # optional, IPv4 or IPv6
#	quality		"5.0"			# do not define if bitrate is defined
#	bitrate		"128"			# do not define if quality is defined
#	format		"44100:16:1"
#	max_clients     "0"                     # optional 0=no limit
#}
#
# An example of a pulseaudio output (streaming to a remote pulseaudio server)
# Please see README.Debian if you want mpd to play through the pulseaudio
# daemon started as part of your graphical desktop session!
#
#audio_output {
#	type		"pulse"
#	name		"My Pulse Output"
#	server		"remote_server"		# optional
#	sink		"remote_server_sink"	# optional
#}
#
# An example of a winmm output (Windows multimedia API).
#
#audio_output {
#	type		"winmm"
#	name		"My WinMM output"
#	device		"Digital Audio (S/PDIF) (High Definition Audio Device)" # optional
#		or
#	device		"0"		# optional
#	mixer_type	"hardware"	# optional
#}
#
# An example of an openal output.
#
#audio_output {
#	type		"openal"
#	name		"My OpenAL output"
#	device		"Digital Audio (S/PDIF) (High Definition Audio Device)" # optional
#}
#
## Example "pipe" output:
#
#audio_output {
#	type		"pipe"
#	name		"my pipe"
#	command		"aplay -f cd 2>/dev/null"
## Or if you're want to use AudioCompress
#	command		"AudioCompress -m | aplay -f cd 2>/dev/null"
## Or to send raw PCM stream through PCM:
#	command		"nc example.org 8765"
#	format		"44100:16:2"
#}
#
## An example of a null output (for no audio output):
#
#audio_output {
#	type		"null"
#	name		"My Null Output"
#	mixer_type      "none"                  # optional
#}
#
# If MPD has been compiled with libsamplerate support, this setting specifies 
# the sample rate converter to use.  Possible values can be found in the 
# mpd.conf man page or the libsamplerate documentation. By default, this is
# setting is disabled.
#
#samplerate_converter		"Fastest Sinc Interpolator"
#
###############################################################################




# Normalization automatic volume adjustments ##################################
#
# This setting specifies the type of ReplayGain to use. This setting can have
# the argument "off", "album", "track" or "auto". "auto" is a special mode that
# chooses between "track" and "album" depending on the current state of
# random playback. If random playback is enabled then "track" mode is used.
# See <http://www.replaygain.org> for more details about ReplayGain.
# This setting is off by default.
#
#replaygain			"album"
#
# This setting sets the pre-amp used for files that have ReplayGain tags. By
# default this setting is disabled.
#
#replaygain_preamp		"0"
#
# This setting sets the pre-amp used for files that do NOT have ReplayGain tags.
# By default this setting is disabled.
#
#replaygain_missing_preamp	"0"
#
# This setting enables or disables ReplayGain limiting.
# MPD calculates actual amplification based on the ReplayGain tags
# and replaygain_preamp / replaygain_missing_preamp setting.
# If replaygain_limit is enabled MPD will never amplify audio signal
# above its original level. If replaygain_limit is disabled such amplification
# might occur. By default this setting is enabled.
#
#replaygain_limit		"yes"
#
# This setting enables on-the-fly normalization volume adjustment. This will
# result in the volume of all playing audio to be adjusted so the output has 
# equal "loudness". This setting is disabled by default.
#
#volume_normalization		"no"
#
###############################################################################




# Character Encoding ##########################################################
#
# If file or directory names do not display correctly for your locale then you 
# may need to modify this setting.
#
filesystem_charset		"UTF-8"
#
# This setting controls the encoding that ID3v1 tags should be converted from.
#
id3v1_encoding			"UTF-8"
#
###############################################################################




# SIDPlay decoder #############################################################
#
# songlength_database:
#  Location of your songlengths file, as distributed with the HVSC.
#  The sidplay plugin checks this for matching MD5 fingerprints.
#  See http://www.c64.org/HVSC/DOCUMENTS/Songlengths.faq
#
# default_songlength:
#  This is the default playing time in seconds for songs not in the
#  songlength database, or in case you're not using a database.
#  A value of 0 means play indefinitely.
#
# filter:
#  Turns the SID filter emulation on or off.
#
#decoder {
#       plugin                  "sidplay"
#       songlength_database     "/media/C64Music/DOCUMENTS/Songlengths.txt"
#       default_songlength      "120"
#       filter "true"
#}
#
###############################################################################


audio_buffer_size               "1024"
buffer_before_play              "10%"

[poalex]

Maximum quality. No resample. Enjoy :-)

[roberth]

So it then just fills up the remaining 16 bit with zeros when doing this converting?

[poalex]

So it then just fills up the remaining 16 bit with zeros when doing this converting?

The MPD does not converting.

up the remaining 16 bit with zeros or one :-)