X-Git-Url: http://pere.pagekite.me/gitweb/homepage.git/blobdiff_plain/b6b6575e368fa0e8d3ac34a3a09aa1e21132be0e..eb973c52f2e5a325c7ca6df9b9ff95d4f0dc3100:/blog/index.html diff --git a/blog/index.html b/blog/index.html index 7cee2eb902..caec1056c6 100644 --- a/blog/index.html +++ b/blog/index.html @@ -20,83 +20,19 @@
-
Some notes on fault tolerant storage systems
-
1st November 2017
-

If you care about how fault tolerant your storage is, you might -find these articles and papers interesting. They have formed how I -think of when designing a storage system.

- - - -

Several of these research papers are based on data collected from -hundred thousands or millions of disk, and their findings are eye -opening. The short story is simply do not implicitly trust RAID or -redundant storage systems. Details matter. And unfortunately there -are few options on Linux addressing all the identified issues. Both -ZFS and Btrfs are doing a fairly good job, but have legal and -practical issues on their own. I wonder how cluster file systems like -Ceph do in this regard. After, all the old saying, you know you have -a distributed system when the crash of a compyter you have never heard -of stops you from getting any work done. The same holds true if fault -tolerance do not work.

- -

Just remember, in the end, it do not matter how redundant, or how -fault tolerant your storage is, if you do not continuously monitor its -status to detect and replace failed disks.

+
Software created using taxpayers’ money should be Free Software
+
30th August 2018
+

It might seem obvious that software created using tax money should +be available for everyone to use and improve. Free Software +Foundation Europe recentlystarted a campaign to help get more people +to understand this, and I just signed the petition on +Public Money, Public Code to help +them. I hope you too will do the same.

- Tags: english, raid, sysadmin. + Tags: english, opphavsrett.
@@ -104,41 +40,66 @@ status to detect and replace failed disks.

-
Web services for writing academic LaTeX papers as a team
-
31st October 2017
-

I was surprised today to learn that a friend in academia did not -know there are easily available web services available for writing -LaTeX documents as a team. I thought it was common knowledge, but to -make sure at least my readers are aware of it, I would like to mention -these useful services for writing LaTeX documents. Some of them even -provide a WYSIWYG editor to ease writing even further.

- -

There are two commercial services available, -ShareLaTeX and -Overleaf. They are very easy to -use. Just start a new document, select which publisher to write for -(ie which LaTeX style to use), and start writing. Note, these two -have announced their intention to join forces, so soon it will only be -one joint service. I've used both for different documents, and they -work just fine. While -ShareLaTeX is free -software, while the latter is not. According to a -announcement from Overleaf, they plan to keep the ShareLaTeX code -base maintained as free software.

- -But these two are not the only alternatives. -Fidus Writer is another free -software solution with the -source available on github. I have not used it myself. Several -others can be found on the nice -alterntiveTo -web service. - -

If you like Google Docs or Etherpad, but would like to write -documents in LaTeX, you should check out these services. You can even -host your own, if you want to. :)

- +
A bit more on privacy respecting health monitor / fitness tracker
+
13th August 2018
+

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 +Gadgetbridge. +It provide cloudless collection and storing of data from a variety of +trackers. Its +list +of supported devices 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 +Amazfit +Bip and +Xiaomi +Band 3.

+ +

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 +Garmin +FIT files containing the collected measurements. While +proprietary, FIT files apparently can be read at least by +GPSBabel and the +GpxPod 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 +Garmin Forerunner +935, 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.

+ +

A final idea was to build ones own unit, perhaps by basing it on a +wearable hardware platforms like +the Flora Geo +Watch. 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.

+ +

While I was working on tracking down links, I came across an +inspiring TED talk by Dave Debronkart about +being a +e-patient, and discovered the web site +Participatory +Medicine. 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.

+ +

As usual, if you use Bitcoin and want to show your support of my +activities, please send Bitcoin donations to my address +15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b.

@@ -151,288 +112,36 @@ host your own, if you want to. :)

-
Locating IMDB IDs of movies in the Internet Archive using Wikidata
-
25th October 2017
-

Recently, I needed to automatically check the copyright status of a -set of The Internet Movie database -(IMDB) entries, to figure out which one of the movies they refer -to can be freely distributed on the Internet. This proved to be -harder than it sounds. IMDB for sure list movies without any -copyright protection, where the copyright protection has expired or -where the movie is lisenced using a permissive license like one from -Creative Commons. These are mixed with copyright protected movies, -and there seem to be no way to separate these classes of movies using -the information in IMDB.

- -

First I tried to look up entries manually in IMDB, -Wikipedia and -The Internet Archive, to get a -feel how to do this. It is hard to know for sure using these sources, -but it should be possible to be reasonable confident a movie is "out -of copyright" with a few hours work per movie. As I needed to check -almost 20,000 entries, this approach was not sustainable. I simply -can not work around the clock for about 6 years to check this data -set.

- -

I asked the people behind The Internet Archive if they could -introduce a new metadata field in their metadata XML for IMDB ID, but -was told that they leave it completely to the uploaders to update the -metadata. Some of the metadata entries had IMDB links in the -description, but I found no way to download all metadata files in bulk -to locate those ones and put that approach aside.

- -

In the process I noticed several Wikipedia articles about movies -had links to both IMDB and The Internet Archive, and it occured to me -that I could use the Wikipedia RDF data set to locate entries with -both, to at least get a lower bound on the number of movies on The -Internet Archive with a IMDB ID. This is useful based on the -assumption that movies distributed by The Internet Archive can be -legally distributed on the Internet. With some help from the RDF -community (thank you DanC), I was able to come up with this query to -pass to the SPARQL interface on -Wikidata: - -

-SELECT ?work ?imdb ?ia ?when ?label
-WHERE
-{
-  ?work wdt:P31/wdt:P279* wd:Q11424.
-  ?work wdt:P345 ?imdb.
-  ?work wdt:P724 ?ia.
-  OPTIONAL {
-        ?work wdt:P577 ?when.
-        ?work rdfs:label ?label.
-        FILTER(LANG(?label) = "en").
-  }
-}
-

- -

If I understand the query right, for every film entry anywhere in -Wikpedia, it will return the IMDB ID and The Internet Archive ID, and -when the movie was released and its English title, if either or both -of the latter two are available. At the moment the result set contain -2338 entries. Of course, it depend on volunteers including both -correct IMDB and The Internet Archive IDs in the wikipedia articles -for the movie. It should be noted that the result will include -duplicates if the movie have entries in several languages. There are -some bogus entries, either because The Internet Archive ID contain a -typo or because the movie is not available from The Internet Archive. -I did not verify the IMDB IDs, as I am unsure how to do that -automatically.

- -

I wrote a small python script to extract the data set from Wikidata -and check if the XML metadata for the movie is available from The -Internet Archive, and after around 1.5 hour it produced a list of 2097 -free movies and their IMDB ID. In total, 171 entries in Wikidata lack -the refered Internet Archive entry. I assume the 70 "disappearing" -entries (ie 2338-2097-171) are duplicate entries.

- -

This is not too bad, given that The Internet Archive report to -contain 5331 -feature films at the moment, but it also mean more than 3000 -movies are missing on Wikipedia or are missing the pair of references -on Wikipedia.

- -

I was curious about the distribution by release year, and made a -little graph to show how the amount of free movies is spread over the -years:

- -

- -

I expect the relative distribution of the remaining 3000 movies to -be similar.

- -

If you want to help, and want to ensure Wikipedia can be used to -cross reference The Internet Archive and The Internet Movie Database, -please make sure entries like this are listed under the "External -links" heading on the Wikipedia article for the movie:

- -

-* {{Internet Archive film|id=FightingLady}}
-* {{IMDb title|id=0036823|title=The Fighting Lady}}
-

- -

Please verify the links on the final page, to make sure you did not -introduce a typo.

- -

Here is the complete list, if you want to correct the 171 -identified Wikipedia entries with broken links to The Internet -Archive: Q1140317, -Q458656, -Q458656, -Q470560, -Q743340, -Q822580, -Q480696, -Q128761, -Q1307059, -Q1335091, -Q1537166, -Q1438334, -Q1479751, -Q1497200, -Q1498122, -Q865973, -Q834269, -Q841781, -Q841781, -Q1548193, -Q499031, -Q1564769, -Q1585239, -Q1585569, -Q1624236, -Q4796595, -Q4853469, -Q4873046, -Q915016, -Q4660396, -Q4677708, -Q4738449, -Q4756096, -Q4766785, -Q880357, -Q882066, -Q882066, -Q204191, -Q204191, -Q1194170, -Q940014, -Q946863, -Q172837, -Q573077, -Q1219005, -Q1219599, -Q1643798, -Q1656352, -Q1659549, -Q1660007, -Q1698154, -Q1737980, -Q1877284, -Q1199354, -Q1199354, -Q1199451, -Q1211871, -Q1212179, -Q1238382, -Q4906454, -Q320219, -Q1148649, -Q645094, -Q5050350, -Q5166548, -Q2677926, -Q2698139, -Q2707305, -Q2740725, -Q2024780, -Q2117418, -Q2138984, -Q1127992, -Q1058087, -Q1070484, -Q1080080, -Q1090813, -Q1251918, -Q1254110, -Q1257070, -Q1257079, -Q1197410, -Q1198423, -Q706951, -Q723239, -Q2079261, -Q1171364, -Q617858, -Q5166611, -Q5166611, -Q324513, -Q374172, -Q7533269, -Q970386, -Q976849, -Q7458614, -Q5347416, -Q5460005, -Q5463392, -Q3038555, -Q5288458, -Q2346516, -Q5183645, -Q5185497, -Q5216127, -Q5223127, -Q5261159, -Q1300759, -Q5521241, -Q7733434, -Q7736264, -Q7737032, -Q7882671, -Q7719427, -Q7719444, -Q7722575, -Q2629763, -Q2640346, -Q2649671, -Q7703851, -Q7747041, -Q6544949, -Q6672759, -Q2445896, -Q12124891, -Q3127044, -Q2511262, -Q2517672, -Q2543165, -Q426628, -Q426628, -Q12126890, -Q13359969, -Q13359969, -Q2294295, -Q2294295, -Q2559509, -Q2559912, -Q7760469, -Q6703974, -Q4744, -Q7766962, -Q7768516, -Q7769205, -Q7769988, -Q2946945, -Q3212086, -Q3212086, -Q18218448, -Q18218448, -Q18218448, -Q6909175, -Q7405709, -Q7416149, -Q7239952, -Q7317332, -Q7783674, -Q7783704, -Q7857590, -Q3372526, -Q3372642, -Q3372816, -Q3372909, -Q7959649, -Q7977485, -Q7992684, -Q3817966, -Q3821852, -Q3420907, -Q3429733, -Q774474

+
Privacy respecting health monitor / fitness tracker?
+
7th August 2018
+

Dear lazyweb,

+ +

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 only 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.

+ +

As usual, if you use Bitcoin and want to show your support of my +activities, please send Bitcoin donations to my address +15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b.

- Tags: english, opphavsrett. + Tags: english.
@@ -440,26 +149,75 @@ Archive: Q1140317,
-
A one-way wall on the border?
-
14th October 2017
-

I find it fascinating how many of the people being locked inside -the proposed border wall between USA and Mexico support the idea. The -proposal to keep Mexicans out reminds me of -the -propaganda twist from the East Germany government calling the wall -the “Antifascist Bulwark” after erecting the Berlin Wall, claiming -that the wall was erected to keep enemies from creeping into East -Germany, while it was obvious to the people locked inside it that it -was erected to keep the people from escaping.

- -

Do the people in USA supporting this wall really believe it is a -one way wall, only keeping people on the outside from getting in, -while not keeping people in the inside from getting out?

+
Sharing images with friends and family using RSS and EXIF/XMP metadata
+
31st July 2018
+

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 +<enclosure> RSS tag), but was unable to find a current supplier +of such frames. In the end I gave up that approach.

+ +

Some months ago, I discovered that +XScreensaver 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 +Kodi (both using +OpenELEC and +LibreELEC) provide the +Feedreader +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.

+ +

Armed with motivation and a test photo frame, I set out to generate +a RSS feed for the Kodi instance. I adjusted my Freedombox 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.

+ +

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:

+ +
+exiftool -headline='The RSS image title' \
+  -description='The RSS image description.' \
+  -subject+=for-family photo.jpeg
+
+ +

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.

+ +

Are there better ways to do this? Get in touch if you have better +suggestions.

+ +

As usual, if you use Bitcoin and want to show your support of my +activities, please send Bitcoin donations to my address +15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b.

- Tags: english. + Tags: debian, english.
@@ -467,48 +225,105 @@ while not keeping people in the inside from getting out?

-
Generating 3D prints in Debian using Cura and Slic3r(-prusa)
-
9th October 2017
-

At my nearby maker space, -Sonen, I heard the story that it -was easier to generate gcode files for theyr 3D printers (Ultimake 2+) -on Windows and MacOS X than Linux, because the software involved had -to be manually compiled and set up on Linux while premade packages -worked out of the box on Windows and MacOS X. I found this annoying, -as the software involved, -Cura, is free software -and should be trivial to get up and running on Linux if someone took -the time to package it for the relevant distributions. I even found -a request for adding into -Debian from 2013, which had seem some activity over the years but -never resulted in the software showing up in Debian. So a few days -ago I offered my help to try to improve the situation.

- -

Now I am very happy to see that all the packages required by a -working Cura in Debian are uploaded into Debian and waiting in the NEW -queue for the ftpmasters to have a look. You can track the progress -on -the -status page for the 3D printer team.

- -

The uploaded packages are a bit behind upstream, and was uploaded -now to get slots in the NEW -queue while we work up updating the packages to the latest -upstream version.

- -

On a related note, two competitors for Cura, which I found harder -to use and was unable to configure correctly for Ultimaker 2+ in the -short time I spent on it, are already in Debian. If you are looking -for 3D printer "slicers" and want something already available in -Debian, check out -slic3r and -slic3r-prusa. -The latter is a fork of the former.

+
Simple streaming the Linux desktop to Kodi using GStreamer and RTP
+
12th July 2018
+

Last night, I wrote +a +recipe to stream a Linux desktop using VLC to a instance of Kodi. +During the day I received valuable feedback, and thanks to the +suggestions I have been able to rewrite the recipe into a much simpler +approach requiring no setup at all. It is a single script that take +care of it all.

+ +

This new script uses GStreamer instead of VLC to capture the +desktop and stream it to Kodi. This fixed the video quality issue I +saw initially. It further removes the need to add a m3u file on the +Kodi machine, as it instead connects to +the JSON-RPC API in +Kodi and simply ask Kodi to play from the stream created using +GStreamer. Streaming the desktop to Kodi now become trivial. Copy +the script below, run it with the DNS name or IP address of the kodi +server to stream to as the only argument, and watch your screen show +up on the Kodi screen. Note, it depend on multicast on the local +network, so if you need to stream outside the local network, the +script must be modified. Also note, I have no idea if audio work, as +I only care about the picture part.

+ +
+#!/bin/sh
+#
+# Stream the Linux desktop view to Kodi.  See
+# http://people.skolelinux.org/pere/blog/Streaming_the_Linux_desktop_to_Kodi_using_VLC_and_RTSP.html
+# for backgorund information.
+
+# Make sure the stream is stopped in Kodi and the gstreamer process is
+# killed if something go wrong (for example if curl is unable to find the
+# kodi server).  Do the same when interrupting this script.
+kodicmd() {
+    host="$1"
+    cmd="$2"
+    params="$3"
+    curl --silent --header 'Content-Type: application/json' \
+	 --data-binary "{ \"id\": 1, \"jsonrpc\": \"2.0\", \"method\": \"$cmd\", \"params\": $params }" \
+	 "http://$host/jsonrpc"
+}
+cleanup() {
+    if [ -n "$kodihost" ] ; then
+	# Stop the playing when we end
+	playerid=$(kodicmd "$kodihost" Player.GetActivePlayers "{}" |
+			    jq .result[].playerid)
+	kodicmd "$kodihost" Player.Stop "{ \"playerid\" : $playerid }" > /dev/null
+    fi
+    if [ "$gstpid" ] && kill -0 "$gstpid" >/dev/null 2>&1; then
+	kill "$gstpid"
+    fi
+}
+trap cleanup EXIT INT
+
+if [ -n "$1" ]; then
+    kodihost=$1
+    shift
+else
+    kodihost=kodi.local
+fi
+
+mcast=239.255.0.1
+mcastport=1234
+mcastttl=1
+
+pasrc=$(pactl list | grep -A2 'Source #' | grep 'Name: .*\.monitor$' | \
+  cut -d" " -f2|head -1)
+gst-launch-1.0 ximagesrc use-damage=0 ! video/x-raw,framerate=30/1 ! \
+  videoconvert ! queue2 ! \
+  x264enc bitrate=8000 speed-preset=superfast tune=zerolatency qp-min=30 \
+  key-int-max=15 bframes=2 ! video/x-h264,profile=high ! queue2 ! \
+  mpegtsmux alignment=7 name=mux ! rndbuffersize max=1316 min=1316 ! \
+  udpsink host=$mcast port=$mcastport ttl-mc=$mcastttl auto-multicast=1 sync=0 \
+  pulsesrc device=$pasrc ! audioconvert ! queue2 ! avenc_aac ! queue2 ! mux. \
+  > /dev/null 2>&1 &
+gstpid=$!
+
+# Give stream a second to get going
+sleep 1
+
+# Ask kodi to start streaming using its JSON-RPC API
+kodicmd "$kodihost" Player.Open \
+	"{\"item\": { \"file\": \"udp://@$mcast:$mcastport\" } }" > /dev/null
+
+# wait for gst to end
+wait "$gstpid"
+
+ +

I hope you find the approach useful. I know I do.

+ +

As usual, if you use Bitcoin and want to show your support of my +activities, please send Bitcoin donations to my address +15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b.

- Tags: 3d-printer, debian, english. + Tags: debian, english, video.
@@ -516,30 +331,152 @@ The latter is a fork of the former.

-
Mangler du en skrue, eller har du en skrue løs?
-
4th October 2017
-
Når jeg holder på med ulike prosjekter, så trenger jeg stadig ulike -skruer. Det siste prosjektet jeg holder på med er å lage -en boks til en -HDMI-touch-skjerm som skal brukes med Raspberry Pi. Boksen settes -sammen med skruer og bolter, og jeg har vært i tvil om hvor jeg kan -få tak i de riktige skruene. Clas Ohlson og Jernia i nærheten har -sjelden hatt det jeg trenger. Men her om dagen fikk jeg et fantastisk -tips for oss som bor i Oslo. -Zachariassen Jernvare AS i -Hegermannsgate -23A på Torshov har et fantastisk utvalg, og åpent mellom 09:00 og -17:00. De selger skruer, muttere, bolter, skiver etc i løs vekt, og -så langt har jeg fått alt jeg har lett etter. De har i tillegg det -meste av annen jernvare, som verktøy, lamper, ledninger, etc. Jeg -håper de har nok kunder til å holde det gående lenge, da dette er en -butikk jeg kommer til å besøke ofte. Butikken er et funn å ha i -nabolaget for oss som liker å bygge litt selv. :)

+
Streaming the Linux desktop to Kodi using VLC and RTSP
+
12th July 2018
+

PS: See +the +followup post for a even better approach.

+ +

A while back, I was asked by a friend how to stream the desktop to +my projector connected to Kodi. I sadly had to admit that I had no +idea, as it was a task I never had tried. Since then, I have been +looking for a way to do so, preferable without much extra software to +install on either side. Today I found a way that seem to kind of +work. Not great, but it is a start.

+ +

I had a look at several approaches, for example +using uPnP +DLNA as described in 2011, but it required a uPnP server, fuse and +local storage enough to store the stream locally. This is not going +to work well for me, lacking enough free space, and it would +impossible for my friend to get working.

+ +

Next, it occurred to me that perhaps I could use VLC to create a +video stream that Kodi could play. Preferably using +broadcast/multicast, to avoid having to change any setup on the Kodi +side when starting such stream. Unfortunately, the only recipe I +could find using multicast used the rtp protocol, and this protocol +seem to not be supported by Kodi.

+ +

On the other hand, the rtsp protocol is working! Unfortunately I +have to specify the IP address of the streaming machine in both the +sending command and the file on the Kodi server. But it is showing my +desktop, and thus allow us to have a shared look on the big screen at +the programs I work on.

+ +

I did not spend much time investigating codeces. I combined the +rtp and rtsp recipes from +the +VLC Streaming HowTo/Command Line Examples, and was able to get +this working on the desktop/streaming end.

+ +
+vlc screen:// --sout \
+  '#transcode{vcodec=mp4v,acodec=mpga,vb=800,ab=128}:rtp{dst=projector.local,port=1234,sdp=rtsp://192.168.11.4:8080/test.sdp}'
+
+ +

I ssh-ed into my Kodi box and created a file like this with the +same IP address:

+ +
+echo rtsp://192.168.11.4:8080/test.sdp \
+  > /storage/videos/screenstream.m3u
+
+ +

Note the 192.168.11.4 IP address is my desktops IP address. As far +as I can tell the IP must be hardcoded for this to work. In other +words, if someone elses machine is going to do the steaming, you have +to update screenstream.m3u on the Kodi machine and adjust the vlc +recipe. To get started, locate the file in Kodi and select the m3u +file while the VLC stream is running. The desktop then show up in my +big screen. :)

+ +

When using the same technique to stream a video file with audio, +the audio quality is really bad. No idea if the problem is package +loss or bad parameters for the transcode. I do not know VLC nor Kodi +enough to tell.

+ +

Update 2018-07-12: Johannes Schauer send me a few +succestions and reminded me about an important step. The "screen:" +input source is only available once the vlc-plugin-access-extra +package is installed on Debian. Without it, you will see this error +message: "VLC is unable to open the MRL 'screen://'. Check the log +for details." He further found that it is possible to drop some parts +of the VLC command line to reduce the amount of hardcoded information. +It is also useful to consider using cvlc to avoid having the VLC +window in the desktop view. In sum, this give us this command line on +the source end + +

+cvlc screen:// --sout \
+  '#transcode{vcodec=mp4v,acodec=mpga,vb=800,ab=128}:rtp{sdp=rtsp://:8080/}'
+
+ +

and this on the Kodi end

+ +

+echo rtsp://192.168.11.4:8080/ \
+  > /storage/videos/screenstream.m3u
+
+ +

Still bad image quality, though. But I did discover that streaming +a DVD using dvdsimple:///dev/dvd as the source had excellent video and +audio quality, so I guess the issue is in the input or transcoding +parts, not the rtsp part. I've tried to change the vb and ab +parameters to use more bandwidth, but it did not make a +difference.

+ +

I further received a suggestion from Einar Haraldseid to try using +gstreamer instead of VLC, and this proved to work great! He also +provided me with the trick to get Kodi to use a multicast stream as +its source. By using this monstrous oneliner, I can stream my desktop +with good video quality in reasonable framerate to the 239.255.0.1 +multicast address on port 1234: + +

+gst-launch-1.0 ximagesrc use-damage=0 ! video/x-raw,framerate=30/1 ! \
+  videoconvert ! queue2 ! \
+  x264enc bitrate=8000 speed-preset=superfast tune=zerolatency qp-min=30 \
+  key-int-max=15 bframes=2 ! video/x-h264,profile=high ! queue2 ! \
+  mpegtsmux alignment=7 name=mux ! rndbuffersize max=1316 min=1316 ! \
+  udpsink host=239.255.0.1 port=1234 ttl-mc=1 auto-multicast=1 sync=0 \
+  pulsesrc device=$(pactl list | grep -A2 'Source #' | \
+    grep 'Name: .*\.monitor$' |  cut -d" " -f2|head -1) ! \
+  audioconvert ! queue2 ! avenc_aac ! queue2 ! mux.
+
+ +

and this on the Kodi end

+ +

+echo udp://@239.255.0.1:1234 \
+  > /storage/videos/screenstream.m3u
+
+ +

Note the trick to pick a valid pulseaudio source. It might not +pick the one you need. This approach will of course lead to trouble +if more than one source uses the same multicast port and address. +Note the ttl-mc=1 setting, which limit the multicast packages to the +local network. If the value is increased, your screen will be +broadcasted further, one network "hop" for each increase (read up on +multicast to learn more. :)!

+ +

Having cracked how to get Kodi to receive multicast streams, I +could use this VLC command to stream to the same multicast address. +The image quality is way better than the rtsp approach, but gstreamer +seem to be doing a better job.

+ +
+cvlc screen:// --sout '#transcode{vcodec=mp4v,acodec=mpga,vb=800,ab=128}:rtp{mux=ts,dst=239.255.0.1,port=1234,sdp=sap}'
+
+ +

As usual, if you use Bitcoin and want to show your support of my +activities, please send Bitcoin donations to my address +15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b.

- Tags: norsk. + Tags: debian, english, video.
@@ -547,64 +484,121 @@ nabolaget for oss som liker å bygge litt selv. :)

-
Visualizing GSM radio chatter using gr-gsm and Hopglass
-
29th September 2017
-

Every mobile phone announce its existence over radio to the nearby -mobile cell towers. And this radio chatter is available for anyone -with a radio receiver capable of receiving them. Details about the -mobile phones with very good accuracy is of course collected by the -phone companies, but this is not the topic of this blog post. The -mobile phone radio chatter make it possible to figure out when a cell -phone is nearby, as it include the SIM card ID (IMSI). By paying -attention over time, one can see when a phone arrive and when it leave -an area. I believe it would be nice to make this information more -available to the general public, to make more people aware of how -their phones are announcing their whereabouts to anyone that care to -listen.

- -

I am very happy to report that we managed to get something -visualizing this information up and running for -Oslo Skaperfestival 2017 -(Oslo Makers Festival) taking place today and tomorrow at Deichmanske -library. The solution is based on the -simple -recipe for listening to GSM chatter I posted a few days ago, and -will show up at the stand of Åpen -Sone from the Computer Science department of the University of -Oslo. The presentation will show the nearby mobile phones (aka -IMSIs) as dots in a web browser graph, with lines to the dot -representing mobile base station it is talking to. It was working in -the lab yesterday, and was moved into place this morning.

- -

We set up a fairly powerful desktop machine using Debian -Buster/Testing with several (five, I believe) RTL2838 DVB-T receivers -connected and visualize the visible cell phone towers using an -English version of -Hopglass. A fairly powerfull machine is needed as the -grgsm_livemon_headless processes from -gr-gsm converting -the radio signal to data packages is quite CPU intensive.

- -

The frequencies to listen to, are identified using a slightly -patched scan-and-livemon (to set the --args values for each receiver), -and the Hopglass data is generated using the -patches -in my meshviewer-output branch. For some reason we could not get -more than four SDRs working. There is also a geographical map trying -to show the location of the base stations, but I believe their -coordinates are hardcoded to some random location in Germany, I -believe. The code should be replaced with code to look up location in -a text file, a sqlite database or one of the online databases -mentioned in -the github -issue for the topic. - -

If this sound interesting, visit the stand at the festival!

+
What is the most supported MIME type in Debian in 2018?
+
9th July 2018
+

Five years ago, +I +measured what the most supported MIME type in Debian was, by +analysing the desktop files in all packages in the archive. Since +then, the DEP-11 AppStream system has been put into production, making +the task a lot easier. This made me want to repeat the measurement, +to see how much things changed. Here are the new numbers, for +unstable only this time: + +

Debian Unstable:

+ +
+  count MIME type
+  ----- -----------------------
+     56 image/jpeg
+     55 image/png
+     49 image/tiff
+     48 image/gif
+     39 image/bmp
+     38 text/plain
+     37 audio/mpeg
+     34 application/ogg
+     33 audio/x-flac
+     32 audio/x-mp3
+     30 audio/x-wav
+     30 audio/x-vorbis+ogg
+     29 image/x-portable-pixmap
+     27 inode/directory
+     27 image/x-portable-bitmap
+     27 audio/x-mpeg
+     26 application/x-ogg
+     25 audio/x-mpegurl
+     25 audio/ogg
+     24 text/html
+
+ +

The list was created like this using a sid chroot: "cat +/var/lib/apt/lists/*sid*_dep11_Components-amd64.yml.gz| zcat | awk '/^ +- \S+\/\S+$/ {print $2 }' | sort | uniq -c | sort -nr | head -20"

+ +

It is interesting to see how image formats have passed text/plain +as the most announced supported MIME type. These days, thanks to the +AppStream system, if you run into a file format you do not know, and +want to figure out which packages support the format, you can find the +MIME type of the file using "file --mime <filename>", and then +look up all packages announcing support for this format in their +AppStream metadata (XML or .desktop file) using "appstreamcli +what-provides mimetype <mime-type>. For example if you, like +me, want to know which packages support inode/directory, you can get a +list like this:

+ +

+% appstreamcli what-provides mimetype inode/directory | grep Package: | sort
+Package: anjuta
+Package: audacious
+Package: baobab
+Package: cervisia
+Package: chirp
+Package: dolphin
+Package: doublecmd-common
+Package: easytag
+Package: enlightenment
+Package: ephoto
+Package: filelight
+Package: gwenview
+Package: k4dirstat
+Package: kaffeine
+Package: kdesvn
+Package: kid3
+Package: kid3-qt
+Package: nautilus
+Package: nemo
+Package: pcmanfm
+Package: pcmanfm-qt
+Package: qweborf
+Package: ranger
+Package: sirikali
+Package: spacefm
+Package: spacefm
+Package: vifm
+%
+

+ +

Using the same method, I can quickly discover that the Sketchup file +format is not yet supported by any package in Debian:

+ +

+% appstreamcli what-provides mimetype  application/vnd.sketchup.skp
+Could not find component providing 'mimetype::application/vnd.sketchup.skp'.
+%
+

+ +

Yesterday I used it to figure out which packages support the STL 3D +format:

+ +

+% appstreamcli what-provides mimetype  application/sla|grep Package
+Package: cura
+Package: meshlab
+Package: printrun
+%
+

+ +

PS: A new version of Cura was uploaded to Debian yesterday.

+ +

As usual, if you use Bitcoin and want to show your support of my +activities, please send Bitcoin donations to my address +15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b.

- Tags: debian, english, personvern, surveillance. + Tags: debian, english, isenkram.
@@ -612,83 +606,83 @@ issue for the topic.
-
Easier recipe to observe the cell phones around you
-
24th September 2017
-

A little more than a month ago I wrote -how -to observe the SIM card ID (aka IMSI number) of mobile phones talking -to nearby mobile phone base stations using Debian GNU/Linux and a -cheap USB software defined radio, and thus being able to pinpoint -the location of people and equipment (like cars and trains) with an -accuracy of a few kilometer. Since then we have worked to make the -procedure even simpler, and it is now possible to do this without any -manual frequency tuning and without building your own packages.

- -

The gr-gsm -package is now included in Debian testing and unstable, and the -IMSI-catcher code no longer require root access to fetch and decode -the GSM data collected using gr-gsm.

- -

Here is an updated recipe, using packages built by Debian and a git -clone of two python scripts:

- -
    - -
  1. Start with a Debian machine running the Buster version (aka - testing).
    2. - -
  2. Run 'apt install gr-gsm python-numpy python-scipy - python-scapy' as root to install required packages.
    3. - -
  3. Fetch the code decoding GSM packages using 'git clone - github.com/Oros42/IMSI-catcher.git'.
    4. - -
  4. Insert USB software defined radio supported by GNU Radio.
    5. - -
  5. Enter the IMSI-catcher directory and run 'python - scan-and-livemon' to locate the frequency of nearby base - stations and start listening for GSM packages on one of them.
    6. - -
  6. Enter the IMSI-catcher directory and run 'python - simple_IMSI-catcher.py' to display the collected information.
    7. - -
- -

Note, due to a bug somewhere the scan-and-livemon program (actually -its underlying -program grgsm_scanner) do not work with the HackRF radio. It does -work with RTL 8232 and other similar USB radio receivers you can get -very cheaply -(for example -from ebay), so for now the solution is to scan using the RTL radio -and only use HackRF for fetching GSM data.

- -

As far as I can tell, a cell phone only show up on one of the -frequencies at the time, so if you are going to track and count every -cell phone around you, you need to listen to all the frequencies used. -To listen to several frequencies, use the --numrecv argument to -scan-and-livemon to use several receivers. Further, I am not sure if -phones using 3G or 4G will show as talking GSM to base stations, so -this approach might not see all phones around you. I typically see -0-400 IMSI numbers an hour when looking around where I live.

- -

I've tried to run the scanner on a -Raspberry Pi 2 and 3 -running Debian Buster, but the grgsm_livemon_headless process seem -to be too CPU intensive to keep up. When GNU Radio print 'O' to -stdout, I am told there it is caused by a buffer overflow between the -radio and GNU Radio, caused by the program being unable to read the -GSM data fast enough. If you see a stream of 'O's from the terminal -where you started scan-and-livemon, you need a give the process more -CPU power. Perhaps someone are able to optimize the code to a point -where it become possible to set up RPi3 based GSM sniffers? I tried -using Raspbian instead of Debian, but there seem to be something wrong -with GNU Radio on raspbian, causing glibc to abort().

+
Debian APT upgrade without enough free space on the disk...
+
8th July 2018
+

Quite regularly, I let my Debian Sid/Unstable chroot stay untouch +for a while, and when I need to update it there is not enough free +space on the disk for apt to do a normal 'apt upgrade'. I normally +would resolve the issue by doing 'apt install <somepackages>' to +upgrade only some of the packages in one batch, until the amount of +packages to download fall below the amount of free space available. +Today, I had about 500 packages to upgrade, and after a while I got +tired of trying to install chunks of packages manually. I concluded +that I did not have the spare hours required to complete the task, and +decided to see if I could automate it. I came up with this small +script which I call 'apt-in-chunks':

+ +

+#!/bin/sh
+#
+# Upgrade packages when the disk is too full to upgrade every
+# upgradable package in one lump.  Fetching packages to upgrade using
+# apt, and then installing using dpkg, to avoid changing the package
+# flag for manual/automatic.
+
+set -e
+
+ignore() {
+    if [ "$1" ]; then
+	grep -v "$1"
+    else
+	cat
+    fi
+}
+
+for p in $(apt list --upgradable | ignore "$@" |cut -d/ -f1 | grep -v '^Listing...'); do
+    echo "Upgrading $p"
+    apt clean
+    apt install --download-only -y $p
+    for f in /var/cache/apt/archives/*.deb; do
+	if [ -e "$f" ]; then
+	    dpkg -i /var/cache/apt/archives/*.deb
+	    break
+	fi
+    done
+done
+

+ +

The script will extract the list of packages to upgrade, try to +download the packages needed to upgrade one package, install the +downloaded packages using dpkg. The idea is to upgrade packages +without changing the APT mark for the package (ie the one recording of +the package was manually requested or pulled in as a dependency). To +use it, simply run it as root from the command line. If it fail, try +'apt install -f' to clean up the mess and run the script again. This +might happen if the new packages conflict with one of the old +packages. dpkg is unable to remove, while apt can do this.

+ +

It take one option, a package to ignore in the list of packages to +upgrade. The option to ignore a package is there to be able to skip +the packages that are simply too large to unpack. Today this was +'ghc', but I have run into other large packages causing similar +problems earlier (like TeX).

+ +

Update 2018-07-08: Thanks to Paul Wise, I am aware of two +alternative ways to handle this. The "unattended-upgrades +--minimal-upgrade-steps" option will try to calculate upgrade sets for +each package to upgrade, and then upgrade them in order, smallest set +first. It might be a better option than my above mentioned script. +Also, "aptutude upgrade" can upgrade single packages, thus avoiding +the need for using "dpkg -i" in the script above.

+ +

As usual, if you use Bitcoin and want to show your support of my +activities, please send Bitcoin donations to my address +15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b.

- Tags: debian, english, personvern, surveillance. + Tags: debian, english.
@@ -696,54 +690,32 @@ with GNU Radio on raspbian, causing glibc to abort().

-
Datalagringsdirektivet kaster skygger over Høyre og Arbeiderpartiet
-
7th September 2017
-

For noen dager siden publiserte Jon Wessel-Aas en bloggpost om -«Konklusjonen om datalagring som -EU-kommisjonen ikke ville at vi skulle få se». Det er en -interessant gjennomgang av EU-domstolens syn på snurpenotovervåkning -av befolkningen, som er klar på at det er i strid med -EU-lovgivingen.

- -

Valgkampen går for fullt i Norge, og om noen få dager er siste -frist for å avgi stemme. En ting er sikkert, Høyre og Arbeiderpartiet -får ikke min stemme -denne -gangen heller. Jeg har ikke glemt at de tvang igjennom loven som -skulle pålegge alle data- og teletjenesteleverandører å overvåke alle -sine kunder. En lov som er vedtatt, og aldri opphevet igjen.

- -

Det er tydelig fra diskusjonen rundt grenseløs digital overvåkning -(eller "Digital Grenseforsvar" som det kalles i Orvellisk nytale) at -hverken Høyre og Arbeiderpartiet har noen prinsipielle sperrer mot å -overvåke hele befolkningen, og diskusjonen så langt tyder på at flere -av de andre partiene heller ikke har det. Mange av -de som stemte -for Datalagringsdirektivet i Stortinget (64 fra Arbeiderpartiet, -25 fra Høyre) er fortsatt aktive og argumenterer fortsatt for å radere -vekk mer av innbyggernes privatsfære.

- -

Når myndighetene demonstrerer sin mistillit til folket, tror jeg -folket selv bør legge litt innsats i å verne sitt privatliv, ved å ta -i bruk ende-til-ende-kryptert kommunikasjon med sine kjente og kjære, -og begrense hvor mye privat informasjon som deles med uvedkommende. -Det er jo ingenting som tyder på at myndighetene kommer til å være vår -privatsfære. -Det -er mange muligheter. Selv har jeg litt sans for -Ring, som er basert på p2p-teknologi -uten sentral kontroll, er fri programvare, og støtter meldinger, tale -og video. Systemet er tilgjengelig ut av boksen fra -Debian og -Ubuntu, og det -finnes pakker for Android, MacOSX og Windows. Foreløpig er det få -brukere med Ring, slik at jeg også bruker -Signal som nettleserutvidelse.

+
The worlds only stone power plant?
+
30th June 2018
+

So far, at least hydro-electric power, coal power, wind power, +solar power, and wood power are well known. Until a few days ago, I +had never heard of stone power. Then I learn about a quarry in a +mountain in +Bremanger i +Norway, where +the +Bremanger Quarry company is extracting stone and dumping the stone +into a shaft leading to its shipping harbour. This downward movement +in this shaft is used to produce electricity. In short, it is using +falling rocks instead of falling water to produce electricity, and +according to its own statements it is producing more power than it is +using, and selling the surplus electricity to the Norwegian power +grid. I find the concept truly amazing. Is this the worlds only +stone power plant?

+ +

As usual, if you use Bitcoin and want to show your support of my +activities, please send Bitcoin donations to my address +15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b.

- Tags: dld, norsk, personvern, stortinget, surveillance, valg. + Tags: english.
@@ -751,96 +723,66 @@ brukere med Ring, slik at jeg også bruker
-
Simpler recipe on how to make a simple $7 IMSI Catcher using Debian
-
9th August 2017
-

On friday, I came across an interesting article in the Norwegian -web based ICT news magazine digi.no on -how -to collect the IMSI numbers of nearby cell phones using the cheap -DVB-T software defined radios. The article refered to instructions -and a recipe by -Keld Norman on Youtube on how to make a simple $7 IMSI Catcher, and I decided to test them out.

- -

The instructions said to use Ubuntu, install pip using apt (to -bypass apt), use pip to install pybombs (to bypass both apt and pip), -and the ask pybombs to fetch and build everything you need from -scratch. I wanted to see if I could do the same on the most recent -Debian packages, but this did not work because pybombs tried to build -stuff that no longer build with the most recent openssl library or -some other version skew problem. While trying to get this recipe -working, I learned that the apt->pip->pybombs route was a long detour, -and the only piece of software dependency missing in Debian was the -gr-gsm package. I also found out that the lead upstream developer of -gr-gsm (the name stand for GNU Radio GSM) project already had a set of -Debian packages provided in an Ubuntu PPA repository. All I needed to -do was to dget the Debian source package and built it.

- -

The IMSI collector is a python script listening for packages on the -loopback network device and printing to the terminal some specific GSM -packages with IMSI numbers in them. The code is fairly short and easy -to understand. The reason this work is because gr-gsm include a tool -to read GSM data from a software defined radio like a DVB-T USB stick -and other software defined radios, decode them and inject them into a -network device on your Linux machine (using the loopback device by -default). This proved to work just fine, and I've been testing the -collector for a few days now.

- -

The updated and simpler recipe is thus to

- -
    - -
  1. start with a Debian machine running Stretch or newer,
    2. - -
  2. build and install the gr-gsm package available from -http://ppa.launchpad.net/ptrkrysik/gr-gsm/ubuntu/pool/main/g/gr-gsm/,
    3. - -
  3. clone the git repostory from https://github.com/Oros42/IMSI-catcher,
    4. - -
  4. run grgsm_livemon and adjust the frequency until the terminal -where it was started is filled with a stream of text (meaning you -found a GSM station).
    5. - -
  5. go into the IMSI-catcher directory and run 'sudo python simple_IMSI-catcher.py' to extract the IMSI numbers.
    6. - -
- -

To make it even easier in the future to get this sniffer up and -running, I decided to package -the gr-gsm project -for Debian (WNPP -#871055), and the package was uploaded into the NEW queue today. -Luckily the gnuradio maintainer has promised to help me, as I do not -know much about gnuradio stuff yet.

- -

I doubt this "IMSI cacher" is anywhere near as powerfull as -commercial tools like -The -Spy Phone Portable IMSI / IMEI Catcher or the -Harris -Stingray, but I hope the existance of cheap alternatives can make -more people realise how their whereabouts when carrying a cell phone -is easily tracked. Seeing the data flow on the screen, realizing that -I live close to a police station and knowing that the police is also -wearing cell phones, I wonder how hard it would be for criminals to -track the position of the police officers to discover when there are -police near by, or for foreign military forces to track the location -of the Norwegian military forces, or for anyone to track the location -of government officials...

- -

It is worth noting that the data reported by the IMSI-catcher -script mentioned above is only a fraction of the data broadcasted on -the GSM network. It will only collect one frequency at the time, -while a typical phone will be using several frequencies, and not all -phones will be using the frequencies tracked by the grgsm_livemod -program. Also, there is a lot of radio chatter being ignored by the -simple_IMSI-catcher script, which would be collected by extending the -parser code. I wonder if gr-gsm can be set up to listen to more than -one frequency?

+
Add-on to control the projector from within Kodi
+
26th June 2018
+

My movie playing setup involve Kodi, +OpenELEC (probably soon to be +replaced with LibreELEC) and an +Infocus IN76 video projector. My projector can be controlled via both +a infrared remote controller, and a RS-232 serial line. The vendor of +my projector, InFocus, had been +sensible enough to document the serial protocol in its user manual, so +it is easily available, and I used it some years ago to write +a +small script to control the projector. For a while now, I longed +for a setup where the projector was controlled by Kodi, for example in +such a way that when the screen saver went on, the projector was +turned off, and when the screen saver exited, the projector was turned +on again.

+ +

A few days ago, with very good help from parts of my family, I +managed to find a Kodi Add-on for controlling a Epson projector, and +got in touch with its author to see if we could join forces and make a +Add-on with support for several projectors. To my pleasure, he was +positive to the idea, and we set out to add InFocus support to his +add-on, and make the add-on suitable for the official Kodi add-on +repository.

+ +

The Add-on is now working (for me, at least), with a few minor +adjustments. The most important change I do relative to the master +branch in the github repository is embedding the +pyserial module in +the add-on. The long term solution is to make a "script" type +pyserial module for Kodi, that can be pulled in as a dependency in +Kodi. But until that in place, I embed it.

+ +

The add-on can be configured to turn on the projector when Kodi +starts, off when Kodi stops as well as turn the projector off when the +screensaver start and on when the screesaver stops. It can also be +told to set the projector source when turning on the projector. + +

If this sound interesting to you, check out +the +project github repository. Perhaps you can send patches to +support your projector too? As soon as we find time to wrap up the +latest changes, it should be available for easy installation using any +Kodi instance.

+ +

For future improvements, I would like to add projector model +detection and the ability to adjust the brightness level of the +projector from within Kodi. We also need to figure out how to handle +the cooling period of the projector. My projector refuses to turn on +for 60 seconds after it was turned off. This is not handled well by +the add-on at the moment.

+ +

As usual, if you use Bitcoin and want to show your support of my +activities, please send Bitcoin donations to my address +15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b.

- Tags: debian, english, personvern, surveillance. + Tags: english, multimedia, video.
@@ -855,6 +797,25 @@ one frequency?

Archive