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Categories describing the post, video, pictures, audio…

Audio Processing Workflow

Monday, April 18, 2022

I prefer local control of media data, the rent-to-listen approach of various streaming services is certainly convenient, but pay-forever, you get what we think you should models don’t appeal to me. Over the decades, I’ve converted various eras of my physical media to digital formats using different standards that were in vogue at the time and with different emphasis on various metadata tags yielding a rather heterogeneous collection with some annoying incompatibilities that sometimes show up, for example using the Music plugin with NextCloud streaming via Subsonic to Sublime Music or Ultrasonic on Android.  I spent some time poking around to find a set of tools that satisfied my preferences for organization and structure and filled in a missing gap or two; this is what I’m doing these days and what with.

The steps outlined here are tuned to my particular use case:

• Linux-based process.
• I prefer mp3 to aac or flac because the format is widely compatible.  mp3 is pretty clearly inferior to aac for coding efficiency (aac produces better sound with less bits) and aac has some cool features that mp3 doesn’t but for my use compatibility wins.
• My ears ain’t what they used to be.  I’m not sure I could ever reliably have heard the difference between 320 CBR and 190 VBR, but I definitely can’t now and less data is less data.
• I like metadata and the flexibility in organization it provides, and like it standardized.

So to scratch that itch, I use the following steps:

• Convert FLAC/high-data rate mp3s to VBR (about 190 kbps) with ffmpeg
• Fix MP3 meta info wierdsies with MP3 Diags
• Add Replay Gain tags with loudness-scanner
• Add BPM tags with bpm-tag from bpm-tools
• Use Puddletag to:
• Clean any stray tags
• Assign Genre, Artist, Year, Album, Disk Number, Track, Title, & Cover
• Apply a standard replace function to clean text of weird characters
• Refile and re-name in a most-os-friendly way
• Clean up any stray data in the file system.

Links to the tools at the bottom.

Convert FLAC to MP3 with ffmpeg

The standard tool for media processing is ffmpeg.  This works for me:

find . -depth -type f -name "*.flac" -exec ffmpeg -i {} -q:a 2  -c:v copy -map_metadata 0 -id3v2_version 3 -write_id3v1 1  {}.mp3 \;

A summary:

find                  unix find command to return each found file one-by-one
.                     search from the current directory down
-depth                start at the bottom and work up
-type f               find only files (not directories)
-name "*.flac"        files that end with .flac
-exec ffmpeg          pass each found file to ffmpeg
-i {}                 ffmpeg takes the found file name as input
-q:a 2                VBR MP3 170-210 kbps
-c:v copy             copy the video stream (usually the cover image)
-id3v2_version 3      write ID3v2.3 tag format (more compatible than ID3v2.4)
-write_id3v1 1        also write old style ID3v1 tags (maybe useless)
{}.mp3 \;             write output file (which yields "/original/filename.flac.mp3")


For album encodes with a .cue or in other formats where the above would yield one giant file, Flacon is your friend.  I would use two steps: single flac -> exploded flac, then the ffmpeg encoder myself just for comfort with the encoding parameters.

Convert high data rate CBR MP3 to VBR

Converting high data rate CBR files requires a bit more code to detect that a given file is high data rate and CBR, for which I wrote a small bash script that leverages mediainfo to extract tags from the source file and validate.

#!/bin/bash

# first make sure at least some parameter was passed, if not echo some instructions
if [ $# -eq 0 ]; then echo "pass a file name or try: # find . -type f -name "*.mp3" -exec recomp.sh {} \;" exit 1 fi # assign input 1 to “file” to make it a little easier to follow file=$1

# get the media type, the bitrate, and the encoding mode and assign to variables
type=$(mediainfo --Inform='General;%Format/String%' "$file")
brate=$(mediainfo --Inform='General;%OverallBitRate/String%' "$file" |& grep -Eo [0-9]+)
mode=$(mediainfo --Inform='Audio;%BitRate_Mode/String%' "$file")

# first check: is the file an mpeg audio file, if not quit
if [[ "$type" != "MPEG Audio" ]]; then echo$file skipped, not valid audio
exit 0
fi

# second check: if the file is already VBR, move on.
if [[ "$mode" = "Variable" ]]; then echo$file skipped, already variable
exit 0
fi

# third check: the output will be 170-210, no reason to expand low bit rate files
if [[ "$brate" -gt 221 ]] then ffmpeg -hide_banner -loglevel error -i "$file"  -q:a 2  -c:v copy -map_metadata 0 -id3v2_version 3 -write_id3v1 1  "${file}.mp3" rm "${file}"
mv "${file}.mp3" "${file}"
echo $file recompressed to variable fi exit  I named this script “~/projects/recomp/recomp.sh” and call it with find . -depth -type f -name "*.mp3" -exec ~/projects/recomp/recomp.sh {} \;  which will scan down through all sub-directories and find files with .mp3 extensions, and if suitable, re-compress them to VBR as above. Yes, this is double lossy and not very audiophile, definitely prioritizing smaller files over acoustic fidelity which I cannot really hear anyway. Fix bad data with MP3 Diags MP3 Diags is a GUI tool for cleaning up bad tags. It is pretty solid and hasn’t mangled any of my files yet. It has two basic functions: passively highlight missing useful tags (replaygain, cover image, etc) and actively fix messed up tags which is a file-changing operation so make backups if needed. I generally just click the tools buttons “1”–”4″ and it seems to do the right thing. Thanks Ciobi! Install was easy on Ubuntu: sudo apt install mp3diags  Add ReplayGain Tags To bulk add (or update) ReplayGain tags, I find loudness-scanner very easy. I just use the droplet version and drop folders on it. The defaults do the right thing, computing track and album gain by folder. The droplet pops up a confirmation dialog which can be lost on a busy desktop, remember it. Click to apply the tags then wait for it to finish before closing that tag list window or it will seg fault. The only indication is in the command prompt window used to launch it, which shows “….” as it progresses and when the dots stop, you can close the tags window. I built it from source – these steps did the needful for me: git clone https://github.com/jiixyj/loudness-scanner.git cd loudness-scanner git submodule init git submodule update mkdir build cd build cmake .. make sudo make install  Then launch the droplet with ~/projects/loudness-scanner/build/loudness-drop-gtk  Add Beats Per Minute Tags Beats per minute calcs are mostly useful for DJ types, but I use them to easily sort music for different moods or for exercise. The calculation seems a bit arbitrary for things like speech or classical, but for those genres where BPM is relevant, bpm-tools seems to yield results that make sense. Install with sudo apt-get install libsox-fmt-mp3 bpm-tag  Then write tags with (the -f option overwrites existing tags). find . -name "*.mp3" -exec bpm-tag -f {} \;  Puddletag Back in my Windows days, I really liked MP3Tag. I was really happy to find puddletag, an mp3tag inspired linux variant. It’s great, does everything it should. I wish I had something like this for image metadata editing: the spreadsheet format is very easy to parse. One problem I had was the deunicode tool wasn’t decoding for me, so I wrote my own wee function to extend the functions.py by calling the unidecode function. only puddlestuff/functions.py needs to be patched to add this useful decode feature. UTF8 characters are well supported in tags, but not in all file structures and since the goal is compatibility, mapping them to fairly intelligible ASCII characters is useful. This works with the 2.1.1 version. Below is a patch file to show the very few changes needed. --- functions.py.bak 2022-04-14 13:58:47.937873000 +0300 +++ functions.py 2022-04-14 16:49:23.705786696 +0300 @@ -43,6 +43,7 @@ from mutagen.mp3 import HeaderNotFoundError from collections import defaultdict from functools import partial +from unidecode import unidecode import pyparsing @@ -769,6 +770,10 @@ cleaned_fn = unicodedata.normalize('NFKD', t_fn).encode('ASCII', 'ignore') return ''.join(chr(c) for c in cleaned_fn if chr(c) in VALID_FILENAME_CHARS) +# hack by David Gessel +def deunicode(text): + dutext = unidecode(text) + return (dutext) def remove_dupes(m_text, matchcase=False): """Remove duplicate values, "Remove Dupes:$0, Match Case $1" @@ -1126,7 +1131,8 @@ 'update_from_tag': update_from_tag, "validate": validate, 'to_ascii': to_ascii, - 'to_num': to_num + 'to_num': to_num, + 'deunicode': deunicode } no_fields = [filenametotag, load_images, move, remove_except,  I use the “standard” action to clean up file names with a few changes: • In “title” and “album” I replace ‘ – ‘ with ‘–‘ • in all, I RegExp replace ‘(\s)’ with ‘ ‘ – all blank space with a regular space. • I replace all %13 characters with a space • I RegExp ‘(\s)+’ with ‘ ‘ – all blank runs with a single space • Trim all to remove leading and ending spaces. My tag->filename function looks like this craziness which reduces the risk of filename misbehavior on most platforms: ~/$validate(%genre%,_,/\*?;”|: +<>=[])/$validate($deunicode(%artist%),_,/\*?;”|: +<>=[])/%year%--$left($validate($deunicode(%album%),_,/\*?;”|: +<>=[]),136)$if(%discnumber%, --D$num(%discnumber%,2),"")/$left($num(%track%,2)--$validate($deunicode(%title%),_,/\*?;”|: +<>=[]),132)  Puddletag is probably in your repository. To mod the code, I first installed from source per the puddletag instructions, but had to also add unidecode to my system with pip install unidecode  Last File System Cleanups The above steps should yield a clean file structure without leading or trailing spaces, indeed without any spaces at all, but in case it doesn’t the rename function can help. I installed it with sudo apt install rename  This is useful to, for example, normalize errant spelling of mp3 – for example Mp3 or MP3 or, I suppose, mP3. find . -depth -exec rename 's/\.mp3$/.mp3/i' {} +
aside from parameters explained previously
's/A/B/'            substitute B for each instance of A
\.                  escaped "." because "." has special meaning
$match end of string - so .mp3files won't match, but files.mp3 does i case insensitive match (.mp3 .MP3 .mP3 .Mp3 all match)  The following commands clean up errant spaces before after and repeated: find . -depth -exec rename 's/^ *//' {} + find . -depth -exec rename 's/ *$//' {} +
find . -depth -exec rename 's/\s+/_/g' {} +


If moving files around results in empty directories (or empty files, which shouldn’t happen) then they can be cleaned with

find . -depth -type d -empty -print -delete
find . -depth -type f -empty -print -delete


Players

If workflow preferences are highly personal, player prefs seem even more so.  Mine are as follows:

For Local Playback on a PC: Quod Libet

I like to sort by genre, artist, year, and album and Quod Libet makes that as easy as in foobar2000 did back in the olde days when Windows was still an acceptable desktop OS.  Those days are long, long over and while I am still fond of the foobar2000 approach, Quod Libet doesn’t need Wine.

Alas, one shortcoming still is that Quod Libet does not support subsonic or ampache.  That’s too bad because I really like the UI/UX.

For Subsonic Streaming on a PC: Sublime Music

Not the text editor, the music app.  It is pretty good, more pretty than Quod Libet and in a way that doesn’t entirely appeal to me, but it seems to work fairly well with NextCloud and is the best solution I’ve found so far.  It tends to flow quite a few errors and I see an odd bug where album tile selection jumps around, but it seems to work and a local program linking back to a server is generally more performant than in browser, but that’s also an option (see below) or run foobar2000 in Wine, perhaps even as an (ugh!) snap.

In Browser: NextCloud Music

Nextcloud’s Music app is one of those that imposes a sorting model that doesn’t work for me – not at all foobar2000ish – and so I don’t really use it much, but there are times, working on site for example, that a browser window is easiest.  I find I often have to rebuild the music database after changes.  Foam or Ample might be more satisfying choices functionally and aesthetically and can connect to the backend provided by Music.

Mobile: Ultrasonic

Ultrasonic works pretty well for me and seems to connect fairly reliably to my NextCloud server even in low bandwidth situations (though, obviously, not fast enough to actually listen to anything, but it doesn’t barf.)  Power Ampache might be another choice still currently developed (but I haven’t tried it myself).  Subsonic also worked with NextCloud, but I like Ultrasonic better and it is still actively developed.

If you’re on iOS instead of Android (congratulations on the envy your overpriced corporate icon inspires in the less fortunate) you almost certainly stick exclusively with your tribal allegiance and have no need for media outside of iTunes/Apple TV approved content.

Players:

Posted at 17:59:27 GMT-0700

Category: AudioHowToLinuxtechnology

South Lake Tahoe Caldor Fire Timelapse

Friday, September 3, 2021

Sentinalhub Playground is an excellent resource for near real time, albeit not quite google earth 1m resolution, satellite images.  One of the cool features is being able to adjust the mapping of the satellite bands to RGB outputs.  For example, using Sentinel-2 L2A image data of South Lake Tahoe between 2021-08-17 and 2021-09-01 and remapping the 2190nm (SWIR2) to red, which tends to highlight fires though isn’t thermal, 783nm to green, a vegetation band (though it is NIR to humans) to make vegetation cover more obvious, and 443nm to blue instead of 490nm as shorter wavelengths tend to be scattered more by aerosols and smoke the fire line (bright red) and smoke (obvs) is very visible while vegetation is (false) green. Burnt earth shows as dark red, compared to bare ground, which tends to show tan in this mapping, thus revealing the current line of fire, the recently burned areas, and the wind direction carrying smoke, which tends to correlate with the advancing line, and fuel (vegetation) still standing.

Then using the history controller to generate and save a sequence of stills, we can animate the progress of the fire with a simple FFMPEG command:

ffmpeg -framerate 1 -pattern_type glob -i '*.jpg' -vf crop=1754:1146 -c:v libx264 -r 30 -pix_fmt yuv420p fire.mp4


and you get:

Posted at 08:17:00 GMT-0700

Category: EventsGeopostmaptechnologyvideoweather

Compile and install Digikam on Ubuntu 20.04 Focal (21.10 too)

Friday, March 26, 2021

Digikam is an incredibly powerful media management tool that integrates a great collection of powerful media processing projects into a single, fairly nice and moderately intuitive user interface. The problem is that it make use of SO many projects and libraries that installation is quite fragile and most distributions are many years out of date – that is a typical sudo apt install digikam will yield version 4.5 while release is (as of this writing) 7.5.

In particular, this newer version has face detection that runs LOCALLY – not on Google or Facebook’s servers – meaning you don’t have to trade your personal photos and all the data implicit in them to a data broker to make use of such a useful tool.  Sure, Google once bought and then improved Picasa Desktop which gave you this function, but then they realized this was cutting into their data harvesting business and discontinued Picasa and tried to convince people to let them look at all their pictures with Google Photos.  We really, really need to make personal data a toxic asset, such an intolerable liability that any company that holds any personal data has negative value.  But until then, use FOSS software on your own hardware where ever possible.

You can compile the latest version on Ubuntu 20.04 Focal Fossa, though not exactly painlessly, or you can install the flatpak easily. I hate flatpaks with a passion, so I went through the exercise and found what appears to be stable success with the following procedure which yielded a fully featured digikam with zero dependency errors or warnings and all features enabled using MariaDB as a backend.

Updating Ubuntu from 20.04 to 21.10 (probably any other major update too) will (as typical) break a ton of stuff.  For “reasons” the updater uninstalls all sorts of things like MariaDB and many of the dependencies.  Generally, as libraries change versions, recompiling is required.  This is so easy with FreeBSD ports…

sudo apt update
sudo mysql_secure_installation

The secure options are all good, accept them unless you know better.

Start the server (if it isn’t)

sudo systemctl start mariadb.service


Do some really basic config:

sudo nano /etc/mysql/mariadb.conf.d/50-server.cnf


and set:

character-set-server = utf8mb4
collation-server = utf8mb4_general_ci
default_storage_engine = InnoDB


Switch to mariadb and create an admin user account and (I’d suggest) one for digikam.  It seems this has to be done before the first connect and can’t be fixed after.  You’ll probably want to use a different ‘user’ than I did, but feel free.

sudo mariadb
CREATE USER 'gessel'@'localhost' IDENTIFIED BY 'password';
GRANT ALL ON *.* TO 'gessel'@'localhost' IDENTIFIED BY 'password';
CREATE DATABASE digikam;
GRANT ALL PRIVILEGES ON digikam.* TO 'gessel'@'localhost';
FLUSH PRIVILEGES;


should correctly create the correct user – though check the instructions tab on the database connection options pane for any changes if you’re following these instructions for install of a later version. You will need the socket location to connect to the database so before exit; run:

mysqladmin -u admin -p version


Should yield something like:

Enter password:

Protocol version	10
Connection		Localhost via UNIX socket
UNIX socket		/var/run/mysqld/mysqld.sock
Uptime:			5 hours 26 min 6 sec

Threads: 29  Questions: 6322899  Slow queries: 0  Opens: 108  Flush tables: 1  Open tables: 74  Queries per second avg: 323.157


And note the value for UNIX socket, you’re going to need that later: /var/run/mysqld/mysqld.sock – yours might vary.

Install digiKam Dependencies

• Updated to libx264-163 and libx265-199
• Version change from 7.2.0 to 7.3.0

• Installing on Ubuntu 21.10 “impish”
• Version change to 7.5.0 (note camelcase used for file name now, “digiKam” not “digikam“)
• Problem with libopencv-dev required selecting a # sudo aptitude install solution to get past a libilmbase-dev but it is not installable error.

Digikam has just a few dependencies.just a few... the below command should install the needed for 7.30 on Ubuntu 21.10. Any other version combination might be different.:

sudo aptitude install \
bison \
checkinstall \
devscripts \
doxygen \
extra-cmake-modules \
ffmpeg \
ffmpegthumbnailer \
flex \
graphviz \
help2man \
jasper \
libavcodec-dev \
libavdevice-dev \
libavfilter-dev \
libavformat-dev \
libavutil-dev \
libboost-dev \
libboost-graph-dev \
libeigen3-dev \
libexiv2-dev \
libgphoto2-dev \
libjasper-dev \
libjasper-runtime \
libjasper4 \
libjpeg-dev \
libkf5calendarcore-dev \
libkf5contacts-dev \
libkf5doctools-dev \
libkf5kipi-dev \
libkf5notifyconfig-dev \
libkf5sane-dev \
libkf5solid-dev \
libkf5xmlgui-dev \
liblcms2-dev \
liblensfun-dev \
liblqr-1-0-dev \
libmagick++-6.q16-dev \
libmagick++-6.q16hdri-dev \
libmagickcore-dev \
libmarble-dev \
libqt5opengl5-dev \
libqt5sql5-mysql \
libqt5svg5-dev \
libqt5webkit5-dev \
libqt5webview5 \
libqt5webview5-dev \
libqt5x11extras5-dev \
libqt5xmlpatterns5-dev \
libqtav-dev \
libqtwebkit-dev \
libswscale-dev \
libtiff-dev \
libusb-1.0-0-dev \
libx264-163 \
libx264-dev \
libx265-199 \
libx265-dev \
libxml2-dev \
libxslt1-dev \
marble \
pkg-kde-tools \
qtbase5-dev \
qtbase5-dev-tools \
qtmultimedia5-dev \
qtwebengine5-dev \
libopencv-dev \
qtwebengine5-dev-tools


Compile Digikam

Switch to your projects directory (~/projects, say) and get the source, cross your fingers, and go to town. The make -j4 command will take a while to compile everything.  There are two basic mechanisms for getting the source code: wget the taball or git pull the repository.

wget https://download.kde.org/stable/digikam/7.5.0/digiKam-7.5.0.tar.xz
tar -xvf digiKam-7.5.0.tar.xz
cd digiKam-7.5.0.tar.xz


git pull the repository

Git uses branches/tags so check the pull down list of latest branches and tags at the top left, below the many, many branches is the tag list at https://invent.kde.org/graphics/digikam/-/tree/v7.5.0 , latest on top, and currently 7.5.0. This is currently a 1.4 GB git pull (!!).
There was an issue in the v7.3.0 tag that caused built to fail that was fixed in current, so building “stable” isn’t always the best choice for stability.

git clone -b v7.5.0 https://invent.kde.org/graphics/digikam.git
cd digikam


./bootstrap.linux
cd build
make -j4
sudo su
make install/fast


Compiling might take 15-30 minutes depending on CPU.  Adjust -jx to optimize build times, the normal rule of thumb is that x=# of cores or cores+1, YMMV, 4 is a reasonable number if you aren’t confident or interested in experimenting.

The ./bootstrap.linux result should be as below; if it indicates a something is missing then double check dependencies.  If you’ve never compiled anything before, you might need to install cmake and and some other basics not in the apt install list above:

-- ----------------------------------------------------------------------------------
--  digiKam 7.2.0 dependencies results   <https://www.digikam.org>
--
--  MySQL Database Support will be compiled.. YES (optional)
--  MySQL Internal Support will be compiled.. YES (optional)
--  DBUS Support will be compiled............ YES (optional)
--  App. Style Support will be compiled...... YES (optional)
--  QWebEngine Support will be compiled...... YES (optional)
--  libboostgraph found...................... YES
--  libexiv2 found........................... YES
--  libexpat found........................... YES
--  libjpeg found............................ YES
--  libkde found............................. YES
--  liblcms found............................ YES
--  libopencv found.......................... YES
--  libpng found............................. YES
--  libqt found.............................. YES
--  libtiff found............................ YES
--  bison found.............................. YES (optional)
--  doxygen found............................ YES (optional)
--  ccache found............................. YES (optional)
--  flex found............................... YES (optional)
--  libmagick++ found........................ YES (optional)
--  libeigen3 found.......................... YES (optional)
--  libgphoto2 found......................... YES (optional)
--  libjasper found.......................... YES (optional)
--  libkcalendarcore found................... YES (optional)
--  libkiconthemes found..................... YES (optional)
--  libkio found............................. YES (optional)
--  libknotifyconfig found................... YES (optional)
--  libksane found........................... YES (optional)
--  liblensfun found......................... YES (optional)
--  liblqr-1 found........................... YES (optional)
--  libmarble found.......................... YES (optional)
--  libqtav found............................ YES (optional)
--  libxml2 found............................ YES (optional)
--  libxslt found............................ YES (optional)
--  libx265 found............................ YES (optional)
--  OpenGL found............................. YES (optional)
--  libqtxmlpatterns found................... YES (optional)
--  digiKam can be compiled.................. YES
-- ----------------------------------------------------------------------------------


Launch and configure Digikam

(if you’re still root, exit root before launching # digikam)

The Configuration options are pretty basic, but note that to configure the Digikam back end you’ll need to use that MariaDB socket value you got before and the user you created like so UNIX_SOCKET=/var/run/mysqld/mysqld.sock:

On the first run, it will download about 350mb of code for the face recognition engine.  Hey – maybe a bit heavy, but you’re not giving the Google or Apple free lookie looks at all your personal pictures.  Also, if all this is a bit much (and, Frankly, it is) I’d consider Digikam one of the few applications that makes the whole flatpak thing seem somewhat justified.  Maybe.

I recommend mysqltuner highly, then maybe check this out (or just leave it default, default works well).

Tuning a database is application and computer specific, there’s no one size fits any, certainly not all, and it may change as your database grows. There are far more expert and complete tuning guides available, but here’s what I do:

Pre-Tuning Data Collection

Tuning at the most basic involves instrumenting the database to log problems, running it for a while, then parsing the performance logs for useful hints. The mysqltuner.pl script is far more expert at than I’ll ever be, so I pretty much just trust it. You have to modify your mysqld.cnf file to enable performance data collection (which, BTW, slows down operation, so undo this later) which, for MariaDB, means adding a few lines:

sudo nano /etc/mysql/mariadb.conf.d/50-server.cnf
# enable performance schema to allow optimization, but ironically hit performance, so disable after tuning.
# in the [mysqld] section insert
performance_schema=ON
performance-schema-instrument='stage/%=ON'
performance-schema-consumer-events-stages-current=ON
performance-schema-consumer-events-stages-history=ON
performance-schema-consumer-events-stages-history-long=ON


I rather like this guide’s helpful instructions for putting the script in /usr/local/sbin/ so it is in the execution path:

sudo wget https://raw.githubusercontent.com/major/MySQLTuner-perl/master/mysqltuner.pl -O /usr/local/sbin/mysqltuner.pl
sudo chmod 700 /usr/local/sbin/mysqltuner.pl
sudo mysqltuner.pl


Then restart with sudo service mariadb restart then go about your business with digikam – make sure you rack up some real hours to gather useful data on your performance. Things like ingesting a large collection should generate useful data. I’d suggest doing disk tuning first because that’s hardware not load dependent.

Disk tuning

Databases tend to hammer storage and SSDs, especially SLC/enterprise SSDs, massively improve DB performance over spinning disks – unless you have a massive array of really good rotating drives. I’m running this DB on one spinning disk, so performance is very MEH. MySQL and MariaDB make some assumptions about disk performance which is used to scale some pretty important parameters for write caching. You can meaningfully improve on the defaults by testing your disk with a great linux utility called “fio”.

sudo apt install fio
fio --randrepeat=1 --ioengine=libaio --direct=1 --gtod_reduce=1 --name=test --filename=test --bs=4k --iodepth=64 --size=4G --readwrite=randrw --rwmixread=75


This will take a while and will give some very detailed information about the performance of your disk subsystem, the key parameters being average and max write IOPS. I typically create a # performance tuning section at the end of my [mysqld] section and before [embedded] and I’ll put these values in as, say: (your IOPS values will be different):

# performance tuning

innodb_io_capacity              = 170
innodb_io_capacity_max          = 286


and sudo service mariadb restart

Using mysqltuner.pl

After you’ve collected some data, there may be a list of tuning options.

sudo nano /etc/mysql/mariadb.conf.d/50-server.cnf

Mine currently look like this, but they’ll change as the database stabilizes and my usage patterns change.

# performance tuning

innodb_io_capacity              = 170
innodb_io_capacity_max          = 286

innodb_buffer_pool_size         = 4G
innodb_log_file_size            = 512M
innodb_buffer_pool_instances    = 4
skip_name_resolve               = 1
query_cache_size                = 0
query_cache_type                = 0
query_cache_limit               = 2M
max_connections                 = 175
join_buffer_size                = 4M
tmp_table_size                  = 24M
max_heap_table_size             = 24M
innodb_buffer_pool_size         = 4G
max_allowed_packet              = 128M


and

sudo service mariadb restart

Note max_allowed_packet = 128M comes from this guide. I trust it, but it isn’t a mysqltuner suggestion.

Posted at 17:11:21 GMT-0700

Category: HowToLinuxphotoPositivereviewstechnology

Tagging MP3 Files with Puddletag on Linux Mint

Tuesday, March 23, 2021

A “fun” part of organizing an MP3 collection is harmonizing the tags so the datas work consistently with whatever management schema you prefer.  My preference is management by the file system—genre/artist/year/album/tracks works for me—but consistent metainformation is required and often disharmonious.  Finding metaharmony is a chore I find less taxing with a well structured tag editor and to my mind the ur-meta-tag manager is  MP3TAG.

The problem is that only works with that dead-end spyware riddled failing legacyware called “Windows.” Fortunately, in Linux-land we have puddletag, a very solid clone of MP3TAG.  The issues is that the version in repositories is (as of this writing) 1.20 and I couldn’t find a PPA for the latest, 2.0.1.  But compiling from source is super easy and works in both Linux Mint 19 and Ubuntu 20.04 (yay open source!):

1. Install pre-reqs to build (don’t worry, if they’re installed, they won’t be double installed)
2. get the tarball of the source code
3. expand it (into a reasonable directory, like ~/projects)
4. switch into that directory
5. run the python executable “puddletag” directly to verify it is working
6. install it
7. tell the desktop manager it’s there – and it should be in your window manager along with the rest of your applications.

sudo apt install python3-pyqt5 python3-pyqt5.qtsvg python3-pyparsing python3-mutagen python3-acoustid libchromaprint-dev libchromaprint-tools libchromaprint1
tar -xvf puddletag-2.0.1.tar.gz cd puddletag-2.0.1/
cd puddletag
./puddletag
sudo python3 setup.py install
sudo desktop-file-install puddletag.desktop


A nice feature is the configuration directory is portable and takes your complete customization with you – it is an extremely customizable program so you can generally configure it as fits your mental model.  Just copy the entire puddletag directory located at ~/.configure/puddletag.

Posted at 15:19:01 GMT-0700

Category: AudioHowToLinuxPositivereviewsuncategorized

WebP and SVG

Tuesday, September 1, 2020

Using WebP coded images inside SVG containers works.  I haven’t found any automatic way to do it, but it is easy enough manually and results in very efficiently coded images that work well on the internets.  The manual process is to Base64 encode the WebP image and then open the .svg file in a text editor and replace the

xlink:href="data:image/png;base64, ..."

with

xlink:href="data:image/webp;base64,..."

(“…” means the appropriate data, obviously).

Back in about 2010 Google released the spec for WebP, an image compression format that provides a roughly 2-4x coding efficiency over the venerable JPEG (vintage 1974), derived from the VP8 CODEC they bought from ON2. VP8 is a contemporary of and technical equivalent to H.264 and was developed during a rush of innovation to replace the aging MPEG-II standard that included Theora and Dirac. Both VP8 and H.264 CODECs are encumbered by patents, but Google granted an irrevocable license to all patents, making it “open,” while H.264s patents compel licensing from MPEG-LA.  One would think this would tend to make VP8 (and the WEBM container) a global standard, but Apple refused to give Google the win and there’s still no native support in Apple products.

A small aside on video and still coding techniques.

All modern “lossy” (throwing some data away like .mp3, as opposed to “lossless” meaning the original can be reconstructed exactly, as in .flac) CODECs are founded on either Discrete Cosine Transform (DCT) or Wavelet (DWT) encoding of “blocks” of image data.  There are far more detailed write ups online that explain the process in detail, but the basic concept is to divide an image into small tiles of data then apply a mathematical function that converts that data into a form which sorts the information from least human-perceptible to most human-perceptible and sets some threshold for throwing away the least important data while leaving the bits that are most important to human perception.

Wavelets are promising, but never really took off, as in JPEG2000 and Dirac (which was developed by the BBC).  It is a fairly safe bet that any video or still image you see is DCT coded thanks to Nasir Ahmed, T. Natarajan and K. R. Rao.  The differences between 1993’s MPEG-1 and 2013’s H.265 are largely around how the data that is perceptually important is encoded in each still (intra-frame coding) and some very important innovations in inter-frame coding that aren’t relevant to still images.

It is the application of these clever intra-frame perceptual data compression techniques that is most relevant to the coding efficiency difference between JPEG and WebP.

Back to the good stuff…

Way back in 2010 Google experimented with the VP8 intra-coding techniques to develop WebP, a still image CODEC that had to have two core features:

• better coding efficiency than JPEG,
• ability to handle transparency like .png or .tiff.

This could be the one standard image coding technique to rule them all – from icons to gigapixel images, all the necessary features and many times better coding efficiency than the rest.  Who wouldn’t love that?

Apple.

Of course it was Apple.  Can’t let Google have the win.  But, finally, with Safari 14 (June 22, 2020 – a decade late!) iOS users can finally see WebP images and websites don’t need crazy auto-detect 1974 tech substitution tricks.  Good job Apple!

It may not be a coincidence that Apple has just released their own still image format based on the intra-frame coding magic of H.265, .heif and maybe they thought it might be a good idea to suddenly pretend to be an open player rather than a walled-garden-screw-you lest iOS insta-users wall themselves off from the 90% of the world that isn’t willing to pay double to pose with a fashionable icon in their hands.  Not surprisingly, .heic, based on H.265 developments is meaningfully more efficient than WebP based on VP8/H.264 era techniques, but as it took WebP 10 years to become a usable web standard, I wouldn’t count on .heic  having universal support soon.

Oh well.  In the mean time, VP8 gave way to VP9 then to VP10, which has now AV1, arguably a generation ahead of HEVC/H.265.  There’s no hardware decode (yet, as of end of 2020) but all the big players are behind it, so I expect 2021 devices will and GPU decode will come in 2021. By then, expect VVC (H.266) to be replacing HEVC (H.265) with a ~35% coding efficiency improvement.

Along with AV1’s intra/inter-frame coding advance, the intra-frame techniques are useful for a still format called AVIF, basically AVIF is to AV1 (“VP11”) what WEBP is to VP8 and HEIF is to HEVC. So far (Dec 2020) only Chrome and Opera support AVIF images.

Then, of course, there’s JPEG XL on the way.  For now, the most broadly supported post-JPEG image codec is WEBP.

SVG support in browsers is a much older thing – Apple embraced it early (SVG was not developed by Google so….) and basically everything but IE has full support (IE…  the tool you use to download a real browser).  So if we have SVG and WebP, why not both together?

Oddly I can’t find support for this in any of the tools I use, but as noted at the open, it is pretty easy.  The workflow I use is to:

• generate a graphic in GIMP or Photoshop or whatever and save as .png or .jpg as appropriate to the image content with little compression (high image quality)
• Combine that with graphics in Inkscape.
• If the graphics include type, convert the type to SVG paths to avoid font availability problems or having to download a font file before rendering the text or having it render randomly.
• Save the file (as .svg, the native format of Inkscape)
• Convert the image file to WebP with a reasonable tool like Nomacs or Ifranview.
• Base64 encode the image file, either with base64 # base64 infile.webp > outfile.webp.b64 or with this convenient site
• If you use the command line option the prefix to the data is “data:image/webp;base64,
• Replace the … on the appropriate xlink:href="...." with the new data using a text editor like Atom.
• Drop the file on a browser page to see if it works.

WordPress blocks .svg uploads without a plugin, so you need one

The picture is 101.9kB and tolerates zoom quite well. (give it a try, click and zoom on the image).

Posted at 08:54:16 GMT-0700

Category: HowToLinuxphotoself-publishingtechnology

Dealing with Apple Branded HEIF .HEIC files on Linux

Saturday, August 22, 2020

Some of the coding tricks in H.265 have been incorporated into MPEG-H coding, an ISO standard introduced in 2017, which yields a roughly 2:1 coding efficiency gain over the venerable JPEG, which was introduced in 1992.  Remember that?  I do; I’m old.  I remember having a hardware NUBUS JPEG decoder card.   One of the reasons JPEG has lasted so long is that images have become a small storage burden (compared to 4k video, say) and that changing format standards is extremely annoying to everyone.

Apple has elected to make every rational person’s life difficult and put a little barbed wire around their high-fashion walled garden and do something a little special with their brand of a HEVC (h.265) profile for images.  Now normally seeing iOS user’s insta images of how fashionable they are isn’t really worth the effort, but now and then a useful correspondent joins the cult and forks over a ton of money to show off a logo and starts sending you stuff in their special proprietary format.  Annoying, but fixable.

Assuming you’re using an OS that is neither primarily spyware nor fashion forward, such as Linux Mint, you can install HEIF decode (including Apple Brand HEIC) with a few simple commands:

$sudo add-apt-repository ppa:jakar/qt-heif$ sudo apt update
\$ sudo apt install qt-heif-image-plugin

Once installed, various image viewers should be able to decode the images.  I rather like nomacs as a fairly tolerable replacement for Irfan Skiljan‘s still awesome irfanview.

Posted at 03:56:36 GMT-0700

Category: HowToLinuxphotoPositivereviewstechnology

1976 GMC Suburban

Friday, May 17, 2019

When I was a young child, my dad bought a brand new 1976 GMC Suburban. Yellow. No extras at all – no head liner, plastic seats, manual everything, 305 V8.

It became my car in high school, survived that. Came out to California with me; ended up in the service of SRL, survived that too.

Eventually, it escaped.

Posted at 13:18:33 GMT-0700

Category: photoSRL

The Daily, from the NYT, weirdly slow

Saturday, December 30, 2017

From my distant location overseas, listening to the news via podcasts is a great way to keep up: something I’m quite grateful to have access to on demand and via the internets.   Until the end of Net Neutrality means that only “Verizon Insights” and “Life at AT&T” are still accessible, I enjoy a range of news sources on a daily basis using a podcatcher called Beyond Pod.  One of the essential features it has is the ability to speed up the tempo of podcasts, some of which are a bit slow as recorded.  But one…. one is like dripping molasses on a winter day: The Daily from the NYT by Michael Barbaro.  I’m pretty sure silences are inserted in editing to draw out the drama to infuriating lengths and the tempo of the audio is selectively slowed to about half normal speed.  Nobody can actually talk that slowly.  I mean listen and try – like actually try to draw out a word that might take 1 second to pronounce to two full seconds.   It is a pretty good news summary and has some useful information, but there’s no way I’d suffer through it without setting the tempo to 2x.

Every time I accidentally stream the podcast, rather than downloading and playing, the tempo control is disabled and while I scramble to skip to the next podcast before my I start questioning reality I often wonder for a moment just how bad the pauses are.  Here’s my analysis:

I consider the BBC Global News to be a very professional, truly “broadcast quality” podcast.  The announcers are clear, comprehensible, and speak at a pace that is appropriate for a news broadcast.  I still speed it up because daily life is like that now, but if I listen at normal pace, it isn’t even slightly annoying.

The Economist Radio is fairly typical of a print publication’s efforts at presenting print journalists as audio stars.  it doesn’t always work out perfectly and the pacing varies a lot by who is speaking and the rather eclectic line-up.  In general it is annoyingly slow, but not interminably so.  It comes across as a bit amateur by broadcast standards, but well done and very informative.

But then there’s The Daily from the NYT.  This podcast was the reason I took the time to figure out how to speed up playback.  There was no other choice: either unsubscribe or speed it up to something not aneurysm inducing.  Looking at the waveforms, I suspect they might actually be inserting silences of around 500msec between words, perhaps for dramatic effect (there’s way too much dramatic effect in a lot of the stories, which speeding up only hastens rather than fully alleviating—never have you heard so many interviewees break into uncomfortable tears as they’re overwhelmed by whatever the day’s tragedy is, an artifice only slightly less annoying than broadcasting the sound of someone eatingOMG, that’s real.  Rule 34.)

Posted at 07:42:26 GMT-0700

Category: Audiotechnology

Kitty Poop

Tuesday, June 27, 2017

Many years ago (21 years, 9 months as of this post), I used some as-of-then only slightly out of date equipment to record a one week time lapse of the cats’ litter box.

I found the video on a CD-ROM (remember those?) and thought I’d see if it was still usable. It wasn’t – Quicktime had abandoned support for most of the 1990’s era codecs, and as it was pre-internet, there just wasn’t any support any more. I had to fire up my old Mac 9500, which booted just fine after years of sitting, even if most of the rubber feet on the peripherals had long since turned to goo. The OS9 version of QT let me resave as uncompressed, which of course was way too big for the massive dual 9GB drives in that machine. Youtube would eat the uncompressed format and this critical archival record is preserved for a little longer.

Posted at 15:16:46 GMT-0700

Category: catsfilmsfunnyoddself-publishingvanity sitesvideo

Green Lacewings

Sunday, January 10, 2016

I noticed that my avocado tree was developing brown spots on the leaves, which were almost certainly the result of Persea mites.

So I looked up some possible cures, and it seemed like introducing a predator would be the best option and the least hassle.  I’d had good luck with introduced ladybugs a few years back, which formed a stable population that survived for many years after introduction.  For this pest, green lacewings are recommended.  I found a nearby insectary that could provide larvae on cards and they shipped them overnight.

The little guys look cute just waiting to hatch…

I hung he cards on the leaves of the tree after incubating them overnight in a warm room, and they should hatch sometime in the next day or two, as long as the ants don’t find them first…

Update 8 Sept 2016:

The green lacewings seem to have eaten all the mites.  It has been 9 months and there aren’t any signs of damage to this spring’s leaves.  Yay!

The new leaves that grew seem to be developing without any bites at all.  The old leaves that were too damaged have fallen off, but the surviving older leaves still show the scars of the mites.  Green lacewings seem to have done the trick.

Posted at 14:40:47 GMT-0700

Category: photoPositivereviews