X-Git-Url: http://pere.pagekite.me/gitweb/homepage.git/blobdiff_plain/5aa9d156bcbd561acf67f4658ad00618cb128238..6621ff349d531b5887d38da305c6d1fde095b36d:/blog/index.rss diff --git a/blog/index.rss b/blog/index.rss index d326ab721f..cfcefdc156 100644 --- a/blog/index.rss +++ b/blog/index.rss @@ -6,6 +6,179 @@ http://people.skolelinux.org/pere/blog/ + + Time for an official MIME type for patches? + http://people.skolelinux.org/pere/blog/Time_for_an_official_MIME_type_for_patches_.html + http://people.skolelinux.org/pere/blog/Time_for_an_official_MIME_type_for_patches_.html + Thu, 1 Nov 2018 08:15:00 +0100 + <p>As part of my involvement in +<a href="https://gitlab.com/OsloMet-ABI/nikita-noark5-core">the Nikita +archive API project</a>, I've been importing a fairly large lump of +emails into a test instance of the archive to see how well this would +go. I picked a subset of <a href="https://notmuchmail.org/">my +notmuch email database</a>, all public emails sent to me via +@lists.debian.org, giving me a set of around 216 000 emails to import. +In the process, I had a look at the various attachments included in +these emails, to figure out what to do with attachments, and noticed +that one of the most common attachment formats do not have +<a href="https://www.iana.org/assignments/media-types/media-types.xhtml">an +official MIME type</a> registered with IANA/IETF. The output from +diff, ie the input for patch, is on the top 10 list of formats +included in these emails. At the moment people seem to use either +text/x-patch or text/x-diff, but neither is officially registered. It +would be better if one official MIME type were registered and used +everywhere.</p> + +<p>To try to get one official MIME type for these files, I've brought +up the topic on +<a href="https://www.ietf.org/mailman/listinfo/media-types">the +media-types mailing list</a>. If you are interested in discussion +which MIME type to use as the official for patch files, or involved in +making software using a MIME type for patches, perhaps you would like +to join the discussion?</p> + +<p>As usual, if you use Bitcoin and want to show your support of my +activities, please send Bitcoin donations to my address +<b><a href="bitcoin:15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b">15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b</a></b>.</p> + + + + + Measuring the speaker frequency response using the AUDMES free software GUI - nice free software + http://people.skolelinux.org/pere/blog/Measuring_the_speaker_frequency_response_using_the_AUDMES_free_software_GUI___nice_free_software.html + http://people.skolelinux.org/pere/blog/Measuring_the_speaker_frequency_response_using_the_AUDMES_free_software_GUI___nice_free_software.html + Mon, 22 Oct 2018 08:40:00 +0200 + <p><img src="http://people.skolelinux.org/pere/blog/images/2018-10-22-audmes-measure-speakers.png" align="right" width="40%"/></p> + +<p>My current home stereo is a patchwork of various pieces I got on +flee markeds over the years. It is amazing what kind of equipment +show up there. I've been wondering for a while if it was possible to +measure how well this equipment is working together, and decided to +see how far I could get using free software. After trawling the web I +came across an article from DIY Audio and Video on +<a href="https://www.diyaudioandvideo.com/Tutorial/SpeakerResponseTesting/">Speaker +Testing and Analysis</a> describing how to test speakers, and it listing +several software options, among them +<a href="https://sourceforge.net/projects/audmes/">AUDio MEasurement +System (AUDMES)</a>. It is the only free software system I could find +focusing on measuring speakers and audio frequency response. In the +process I also found an interesting article from NOVO on +<a href="http://novo.press/understanding-speaker-specifications-and-frequency-response/">Understanding +Speaker Specifications and Frequency Response</a> and an article from +ecoustics on +<a href="https://www.ecoustics.com/articles/understanding-speaker-frequency-response/">Understanding +Speaker Frequency Response</a>, with a lot of information on what to +look for and how to interpret the graphs. Armed with this knowledge, +I set out to measure the state of my speakers.</p> + +<p>The first hurdle was that AUDMES hadn't seen a commit for 10 years +and did not build with current compilers and libraries. I got in +touch with its author, who no longer was spending time on the program +but gave me write access to the subversion repository on Sourceforge. +The end result is that now the code build on Linux and is capable of +saving and loading the collected frequency response data in CSV +format. The application is quite nice and flexible, and I was able to +select the input and output audio interfaces independently. This made +it possible to use a USB mixer as the input source, while sending +output via my laptop headphone connection. I lacked the hardware and +cabling to figure out a different way to get independent cabling to +speakers and microphone.</p> + +<p>Using this setup I could see how a large range of high frequencies +apparently were not making it out of my speakers. The picture show +the frequency response measurement of one of the speakers. Note the +frequency lines seem to be slightly misaligned, compared to the CSV +output from the program. I can not hear several of these are high +frequencies, according to measurement from +<a href="http://freehearingtestsoftware.com">Free Hearing Test +Software</a>, an freeware system to measure your hearing (still +looking for a free software alternative), so I do not know if they are +coming out out the speakers. I thus do not quite know how to figure +out if the missing frequencies is a problem with the microphone, the +amplifier or the speakers, but I managed to rule out the audio card in my +PC by measuring my Bose noise canceling headset using its own +microphone. This setup was able to see the high frequency tones, so +the problem with my stereo had to be in the amplifier or speakers.</p> + +<p>Anyway, to try to role out one factor I ended up picking up a new +set of speakers at a flee marked, and these work a lot better than the +old speakers, so I guess the microphone and amplifier is OK. If you +need to measure your own speakers, check out AUDMES. If more people +get involved, perhaps the project could become good enough to +<a href="https://bugs.debian.org/910876">include in Debian</a>? And if +you know of some other free software to measure speakers and amplifier +performance, please let me know. I am aware of the freeware option +<a href="https://www.roomeqwizard.com/">REW</a>, but I want something +that can be developed also when the vendor looses interest.</p> + +<p>As usual, if you use Bitcoin and want to show your support of my +activities, please send Bitcoin donations to my address +<b><a href="bitcoin:15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b">15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b</a></b>.</p> + + + + + Web browser integration of VLC with Bittorrent support + http://people.skolelinux.org/pere/blog/Web_browser_integration_of_VLC_with_Bittorrent_support.html + http://people.skolelinux.org/pere/blog/Web_browser_integration_of_VLC_with_Bittorrent_support.html + Sun, 21 Oct 2018 09:50:00 +0200 + <p>Bittorrent is as far as I know, currently the most efficient way to +distribute content on the Internet. It is used all by all sorts of +content providers, from national TV stations like +<a href="https://www.nrk.no/">NRK</a>, Linux distributors like +<a href="https://www.debian.org/">Debian</a> and +<a href="https://www.ubuntu.com/">Ubuntu</a>, and of course the +<a href="https://archive.org/">Internet archive</A>. + +<p>Almost a month ago +<a href="https://tracker.debian.org/pkg/vlc-plugin-bittorrent">a new +package adding Bittorrent support to VLC</a> became available in +Debian testing and unstable. To test it, simply install it like +this:</p> + +<p><pre> +apt install vlc-plugin-bittorrent +</pre></p> + +<p>Since the plugin was made available for the first time in Debian, +several improvements have been made to it. In version 2.2-4, now +available in both testing and unstable, a desktop file is provided to +teach browsers to start VLC when the user click on torrent files or +magnet links. The last part is thanks to me finally understanding +what the strange x-scheme-handler style MIME types in desktop files +are used for. By adding x-scheme-handler/magnet to the MimeType entry +in the desktop file, at least the browsers Firefox and Chromium will +suggest to start VLC when selecting a magnet URI on a web page. The +end result is that now, with the plugin installed in Buster and Sid, +one can visit any +<a href="https://archive.org/details/CopyingIsNotTheft1080p">Internet +Archive page with movies</a> using a web browser and click on the +torrent link to start streaming the movie.</p> + +<p>Note, there is still some misfeatures in the plugin. One is the +fact that it will hang and +<a href="https://github.com/johang/vlc-bittorrent/issues/13">block VLC +from exiting until the torrent streaming starts</a>. Another is the +fact that it +<a href="https://github.com/johang/vlc-bittorrent/issues/9">will pick +and play a random file in a multi file torrent</a>. This is not +always the video file you want. Combined with the first it can be a +bit hard to get the video streaming going. But when it work, it seem +to do a good job.</p> + +<p>For the Debian packaging, I would love to find a good way to test +if the plugin work with VLC using autopkgtest. I tried, but do not +know enough of the inner workings of VLC to get it working. For now +the autopkgtest script is only checking if the .so file was +successfully loaded by VLC. If you have any suggestions, please +submit a patch to the Debian bug tracking system.</p> + +<p>As usual, if you use Bitcoin and want to show your support of my +activities, please send Bitcoin donations to my address +<b><a href="bitcoin:15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b">15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b</a></b>.</p> + + + Release 0.2 of free software archive system Nikita announced http://people.skolelinux.org/pere/blog/Release_0_2_of_free_software_archive_system_Nikita_announced.html @@ -492,172 +665,5 @@ them. I hope you too will do the same.</p> - - A bit more on privacy respecting health monitor / fitness tracker - http://people.skolelinux.org/pere/blog/A_bit_more_on_privacy_respecting_health_monitor___fitness_tracker.html - http://people.skolelinux.org/pere/blog/A_bit_more_on_privacy_respecting_health_monitor___fitness_tracker.html - Mon, 13 Aug 2018 09:00:00 +0200 - <p>A few days ago, I wondered if there are any privacy respecting -health monitors and/or fitness trackers available for sale these days. -I would like to buy one, but do not want to share my personal data -with strangers, nor be forced to have a mobile phone to get data out -of the unit. I've received some ideas, and would like to share them -with you. - -One interesting data point was a pointer to a Free Software app for -Android named -<a href="https://github.com/Freeyourgadget/Gadgetbridge/">Gadgetbridge</a>. -It provide cloudless collection and storing of data from a variety of -trackers. Its -<a href="https://github.com/Freeyourgadget/Gadgetbridge/#supported-devices">list -of supported devices</a> is a good indicator for units where the -protocol is fairly open, as it is obviously being handled by Free -Software. Other units are reportedly encrypting the collected -information with their own public key, making sure only the vendor -cloud service is able to extract data from the unit. The people -contacting me about Gadgetbirde said they were using -<a href="https://us.amazfit.com/shop/bip?variant=336750">Amazfit -Bip</a> and -<a href="http://www.xiaomimi6phone.com/xiaomi-mi-band-3-features-release-date-rumors/">Xiaomi -Band 3</a>.</p> - -<p>I also got a suggestion to look at some of the units from Garmin. -I was told their GPS watches can be connected via USB and show up as a -USB storage device with -<a href="https://www.gpsbabel.org/htmldoc-development/fmt_garmin_fit.html">Garmin -FIT files</a> containing the collected measurements. While -proprietary, FIT files apparently can be read at least by -<a href="https://www.gpsbabel.org">GPSBabel</a> and the -<a href="https://apps.nextcloud.com/apps/gpxpod">GpxPod</a> Nextcloud -app. It is unclear to me if they can read step count and heart rate -data. The person I talked to was using a -<a href="https://buy.garmin.com/en-US/US/p/564291">Garmin Forerunner -935</a>, which is a fairly expensive unit. I doubt it is worth it for -a unit where the vendor clearly is trying its best to move from open -to closed systems. I still remember when Garmin dropped NMEA support -in its GPSes.</p> - -<p>A final idea was to build ones own unit, perhaps by basing it on a -wearable hardware platforms like -<a href="https://learn.adafruit.com/flora-geo-watch">the Flora Geo -Watch</a>. Sound like fun, but I had more money than time to spend on -the topic, so I suspect it will have to wait for another time.</p> - -<p>While I was working on tracking down links, I came across an -inspiring TED talk by Dave Debronkart about -<a href="https://archive.org/details/DavedeBronkart_2010X">being a -e-patient</a>, and discovered the web site -<a href="https://participatorymedicine.org/epatients/">Participatory -Medicine</a>. If you too want to track your own health and fitness -without having information about your private life floating around on -computers owned by others, I recommend checking it out.</p> - -<p>As usual, if you use Bitcoin and want to show your support of my -activities, please send Bitcoin donations to my address -<b><a href="bitcoin:15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b">15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b</a></b>.</p> - - - - - Privacy respecting health monitor / fitness tracker? - http://people.skolelinux.org/pere/blog/Privacy_respecting_health_monitor___fitness_tracker_.html - http://people.skolelinux.org/pere/blog/Privacy_respecting_health_monitor___fitness_tracker_.html - Tue, 7 Aug 2018 16:00:00 +0200 - <p>Dear lazyweb,</p> - -<p>I wonder, is there a fitness tracker / health monitor available for -sale today that respect the users privacy? With this I mean a -watch/bracelet capable of measuring pulse rate and other -fitness/health related values (and by all means, also the correct time -and location if possible), which is <strong>only</strong> provided for -me to extract/read from the unit with computer without a radio beacon -and Internet connection. In other words, it do not depend on a cell -phone app, and do make the measurements available via other peoples -computer (aka "the cloud"). The collected data should be available -using only free software. I'm not interested in depending on some -non-free software that will leave me high and dry some time in the -future. I've been unable to find any such unit. I would like to buy -it. The ones I have seen for sale here in Norway are proud to report -that they share my health data with strangers (aka "cloud enabled"). -Is there an alternative? I'm not interested in giving money to people -requiring me to accept "privacy terms" to allow myself to measure my -own health.</p> - -<p>As usual, if you use Bitcoin and want to show your support of my -activities, please send Bitcoin donations to my address -<b><a href="bitcoin:15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b">15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b</a></b>.</p> - - - - - Sharing images with friends and family using RSS and EXIF/XMP metadata - http://people.skolelinux.org/pere/blog/Sharing_images_with_friends_and_family_using_RSS_and_EXIF_XMP_metadata.html - http://people.skolelinux.org/pere/blog/Sharing_images_with_friends_and_family_using_RSS_and_EXIF_XMP_metadata.html - Tue, 31 Jul 2018 23:30:00 +0200 - <p>For a while now, I have looked for a sensible way to share images -with my family using a self hosted solution, as it is unacceptable to -place images from my personal life under the control of strangers -working for data hoarders like Google or Dropbox. The last few days I -have drafted an approach that might work out, and I would like to -share it with you. I would like to publish images on a server under -my control, and point some Internet connected display units using some -free and open standard to the images I published. As my primary -language is not limited to ASCII, I need to store metadata using -UTF-8. Many years ago, I hoped to find a digital photo frame capable -of reading a RSS feed with image references (aka using the -&lt;enclosure&gt; RSS tag), but was unable to find a current supplier -of such frames. In the end I gave up that approach.</p> - -<p>Some months ago, I discovered that -<a href="https://www.jwz.org/xscreensaver/">XScreensaver</a> is able to -read images from a RSS feed, and used it to set up a screen saver on -my home info screen, showing images from the Daily images feed from -NASA. This proved to work well. More recently I discovered that -<a href="https://kodi.tv">Kodi</a> (both using -<a href="https://www.openelec.tv/">OpenELEC</a> and -<a href="https://libreelec.tv">LibreELEC</a>) provide the -<a href="https://github.com/grinsted/script.screensaver.feedreader">Feedreader</a> -screen saver capable of reading a RSS feed with images and news. For -fun, I used it this summer to test Kodi on my parents TV by hooking up -a Raspberry PI unit with LibreELEC, and wanted to provide them with a -screen saver showing selected pictures from my selection.</p> - -<p>Armed with motivation and a test photo frame, I set out to generate -a RSS feed for the Kodi instance. I adjusted my <a -href="https://freedombox.org/">Freedombox</a> instance, created -/var/www/html/privatepictures/, wrote a small Perl script to extract -title and description metadata from the photo files and generate the -RSS file. I ended up using Perl instead of python, as the -libimage-exiftool-perl Debian package seemed to handle the EXIF/XMP -tags I ended up using, while python3-exif did not. The relevant EXIF -tags only support ASCII, so I had to find better alternatives. XMP -seem to have the support I need.</p> - -<p>I am a bit unsure which EXIF/XMP tags to use, as I would like to -use tags that can be easily added/updated using normal free software -photo managing software. I ended up using the tags set using this -exiftool command, as these tags can also be set using digiKam:</p> - -<blockquote><pre> -exiftool -headline='The RSS image title' \ - -description='The RSS image description.' \ - -subject+=for-family photo.jpeg -</pre></blockquote> - -<p>I initially tried the "-title" and "keyword" tags, but they were -invisible in digiKam, so I changed to "-headline" and "-subject". I -use the keyword/subject 'for-family' to flag that the photo should be -shared with my family. Images with this keyword set are located and -copied into my Freedombox for the RSS generating script to find.</p> - -<p>Are there better ways to do this? Get in touch if you have better -suggestions.</p> - -<p>As usual, if you use Bitcoin and want to show your support of my -activities, please send Bitcoin donations to my address -<b><a href="bitcoin:15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b">15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b</a></b>.</p> - - -