Compiling Alsa Modules from Takashi Iwai’s GIT Repository

Download your current kernel headers: Bash | view plain | copy to clipboard by clicking on icon (via flash)  sudo aptitude install linux-headers-$(uname -r) If the command fails with “not found” error, install headers package appropriate for your running kernel. Or install whole kernel source by Bash | view plain | copy to clipboard by clicking on icon (via flash)  sudo apt-get source linux-image-$(uname -r) Download development software stack: Bash | view plain | copy to clipboard by clicking on icon (via flash)  sudo aptitude install kernel-package Clone git sound tree: Bash | view plain | copy to clipboard by clicking on icon (via flash)  git clone https://kernel.googlesource.com/pub/scm/linux/kernel/git/tiwai/sound.git If needed, switch to another branch: Bash | view plain | copy to clipboard by clicking on icon (via flash)  cd soundgit checkout -b ak411x-fix remotes/origin/topic/ak411x-fixcd .. Clone git alsa-driver-build tree: Bash | view plain | copy to clipboard by clicking on icon (via flash)  git … Continue reading

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Pulseaudio with LD_PRELOADing libsoxr-lsr

Pulseaudio with default-sample-rate=192000 and resample-method=src-sinc-best-quality takes about 90% CPU on my i5, aplay via default (pulse plugin) complains about xruns, pulseaudio gets killed eventually (I do not know what kills it, CPU ulimit is unlimited, probably some laptop service watching CPU hogs). Simply starting pulseaudio with LD_PRELOAD LD_PRELOAD=/usr/lib/x86_64-linux-gnu/libsoxr-lsr.so.0 pulseaudio drops pulseaudio CPU load down to 6-9% while resampling running (checked in the card’s hw_params). That was simple Integrating with client-spawn pulseaudio Tested on Mint15: 1. Create executable script /usr/local/bin/pulseaudio.sh. Make sure to use correct path to your libsoxr-lsr library: Bash | view plain | copy to clipboard by clicking on icon (via flash)  #! /bin/bashexport LD_PRELOAD=/usr/lib/x86_64-linux-gnu/libsoxr-lsr.so.0exec /usr/bin/pulseaudio $@ Do … Continue reading

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Using libsoxr-lsr in Alsa Rate Plugin with LD_PRELOAD

Since my previous post the great libsoxr library incl. the libsoxr-lsr variant has become part of debian testing/ubuntu repositories. It means we can easily use it instead of libsamplerate now. Just install the package: pavel@samsung ~ $ aptitude search libsoxr p libsoxr-dev – High quality 1D sample-rate conversion lib p libsoxr-dev:i386 – High quality 1D sample-rate conversion lib p libsoxr-lsr0 – High quality 1D sample-rate conversion lib p libsoxr-lsr0:i386 – High quality 1D sample-rate conversion lib p libsoxr0 – High quality 1D sample-rate conversion lib p libsoxr0:i386 – High quality 1D sample-rate conversion lib sudo aptitude install libsoxr-lsr0 Check contents … Continue reading

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DTS SPDIF input decoder

DTS only, DD does not work (mplayer does not detect the format) arecord -q -t raw -c2 -r 48000 -f S16_LE -D plughw:0,1 | mplayer – -channels 6 -ao alsa:device=plughw=0

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Support for libsoxr in alsa rate plugin

Preliminary results of libsoxr integration Plugin rate API modified to allow float. This avoids the information loss of int24->int16 conversion currently occuring in alsa-lib (int24->float32 is bit perfect). Libsamplerate (and libsoxr) use float internally. The sweep file generated by: Bash | view plain | copy to clipboard by clicking on icon (via flash)  sox -V -r 44100 -c 2 -s -b 24 -n sweep.wav synth 10 sine 1:22000 vol -6dB Spectrum of the sweep Bash | view plain | copy to clipboard by clicking on icon (via flash)  sox sweep.wav -n spectrogram -w Kaiser -z 180 -o spectrum-sweep.png Devices defined in .asoundrc: Bash | view plain | copy to clipboard by clicking on icon (via flash)  pcm.raw { type hw card 0 device 0 format S32_LE} pcm.flexibleraw { … Continue reading

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Tool for A/B Testing

Here is a simple script for A/B testing. Just modify the CONFIG section to your needs, or feel free to rewrite completely :) Continue reading

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Offline Copies for Central BackupPC server

Making offline copies of a large backuppc server is a backuppc mailing list evergreen. Here is a brief decription of what we have been using for a few years now. Continue reading

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Simple Centralized WakeOnLAN Service

Company-wide systems serving individual computers need a centralized WakeOnLAN service to turn them on in a simple and scriptable way. Here is a simple PHP script its authors generously shared on internet. I did only minor modifications. The tool has proven useful for nightly backups, data updates of our workstations, as well as remote access to already shut-down computers. Continue reading

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BackupPC with Locking and WOL

The wonderful BackupPC project has been serving us well for many years. Since backups occur preferably at night and energy costs rise, the machines should be shutdown as soon as the backup finishes. However, apart of backups, other nightly services run on the backed-up machines, requiring centralized locking/synchronization. Throughout the years we have enhanced our BackupPC installation with WOL capability, simple centralized locks, config templates, and other features. Continue reading

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