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<rss version='2.0' xmlns:lj='http://www.livejournal.org/rss/lj/1.0/' xmlns:atom="http://www.w3.org/2005/Atom">
        <channel>
                <title>Petter Reinholdtsen</title>
                <description></description>
                <link>http://people.skolelinux.org/pere/blog/</link>
                <atom:link href="http://people.skolelinux.org/pere/blog/index.rss" rel="self" type="application/rss+xml" />
        
        <item>
                <title>Software created using taxpayers’ money should be Free Software</title>
                <link>http://people.skolelinux.org/pere/blog/Software_created_using_taxpayers__money_should_be_Free_Software.html</link>
                <guid isPermaLink="true">http://people.skolelinux.org/pere/blog/Software_created_using_taxpayers__money_should_be_Free_Software.html</guid>
                <pubDate>Thu, 30 Aug 2018 13:50:00 +0200</pubDate>
                <description>&lt;p&gt;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
&lt;a href=&quot;https://publiccode.eu/&quot;&gt;Public Money, Public Code&lt;/a&gt; to help
them. I hope you too will do the same.&lt;/p&gt;
</description>
        </item>
        
        <item>
                <title>A bit more on privacy respecting health monitor / fitness tracker</title>
                <link>http://people.skolelinux.org/pere/blog/A_bit_more_on_privacy_respecting_health_monitor___fitness_tracker.html</link>
                <guid isPermaLink="true">http://people.skolelinux.org/pere/blog/A_bit_more_on_privacy_respecting_health_monitor___fitness_tracker.html</guid>
                <pubDate>Mon, 13 Aug 2018 09:00:00 +0200</pubDate>
                <description>&lt;p&gt;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&#39;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
&lt;a href=&quot;https://github.com/Freeyourgadget/Gadgetbridge/&quot;&gt;Gadgetbridge&lt;/a&gt;.
It provide cloudless collection and storing of data from a variety of
trackers.  Its
&lt;a href=&quot;https://github.com/Freeyourgadget/Gadgetbridge/#supported-devices&quot;&gt;list
of supported devices&lt;/a&gt; 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
&lt;a href=&quot;https://us.amazfit.com/shop/bip?variant=336750&quot;&gt;Amazfit
Bip&lt;/a&gt; and
&lt;a href=&quot;http://www.xiaomimi6phone.com/xiaomi-mi-band-3-features-release-date-rumors/&quot;&gt;Xiaomi
Band 3&lt;/a&gt;.&lt;/p&gt;

&lt;p&gt;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
&lt;a href=&quot;https://www.gpsbabel.org/htmldoc-development/fmt_garmin_fit.html&quot;&gt;Garmin
FIT files&lt;/a&gt; containing the collected measurements.  While
proprietary, FIT files apparently can be read at least by
&lt;a href=&quot;https://www.gpsbabel.org&quot;&gt;GPSBabel&lt;/a&gt; and the
&lt;a href=&quot;https://apps.nextcloud.com/apps/gpxpod&quot;&gt;GpxPod&lt;/a&gt; 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
&lt;a href=&quot;https://buy.garmin.com/en-US/US/p/564291&quot;&gt;Garmin Forerunner
935&lt;/a&gt;, 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.&lt;/p&gt;

&lt;p&gt;A final idea was to build ones own unit, perhaps by basing it on a
wearable hardware platforms like
&lt;a href=&quot;https://learn.adafruit.com/flora-geo-watch&quot;&gt;the Flora Geo
Watch&lt;/a&gt;.  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.&lt;/p&gt;

&lt;p&gt;While I was working on tracking down links, I came across an
inspiring TED talk by Dave Debronkart about
&lt;a href=&quot;https://archive.org/details/DavedeBronkart_2010X&quot;&gt;being a
e-patient&lt;/a&gt;, and discovered the web site
&lt;a href=&quot;https://participatorymedicine.org/epatients/&quot;&gt;Participatory
Medicine&lt;/a&gt;.  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.&lt;/p&gt;

&lt;p&gt;As usual, if you use Bitcoin and want to show your support of my
activities, please send Bitcoin donations to my address
&lt;b&gt;&lt;a href=&quot;bitcoin:15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b&quot;&gt;15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b&lt;/a&gt;&lt;/b&gt;.&lt;/p&gt;
</description>
        </item>
        
        <item>
                <title>Privacy respecting health monitor / fitness tracker?</title>
                <link>http://people.skolelinux.org/pere/blog/Privacy_respecting_health_monitor___fitness_tracker_.html</link>
                <guid isPermaLink="true">http://people.skolelinux.org/pere/blog/Privacy_respecting_health_monitor___fitness_tracker_.html</guid>
                <pubDate>Tue, 7 Aug 2018 16:00:00 +0200</pubDate>
                <description>&lt;p&gt;Dear lazyweb,&lt;/p&gt;

&lt;p&gt;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 &lt;strong&gt;only&lt;/strong&gt; 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 &quot;the cloud&quot;).  The collected data should be available
using only free software.  I&#39;m not interested in depending on some
non-free software that will leave me high and dry some time in the
future.  I&#39;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 &quot;cloud enabled&quot;).
Is there an alternative?  I&#39;m not interested in giving money to people
requiring me to accept &quot;privacy terms&quot; to allow myself to measure my
own health.&lt;/p&gt;

&lt;p&gt;As usual, if you use Bitcoin and want to show your support of my
activities, please send Bitcoin donations to my address
&lt;b&gt;&lt;a href=&quot;bitcoin:15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b&quot;&gt;15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b&lt;/a&gt;&lt;/b&gt;.&lt;/p&gt;
</description>
        </item>
        
        <item>
                <title>Sharing images with friends and family using RSS and EXIF/XMP metadata</title>
                <link>http://people.skolelinux.org/pere/blog/Sharing_images_with_friends_and_family_using_RSS_and_EXIF_XMP_metadata.html</link>
                <guid isPermaLink="true">http://people.skolelinux.org/pere/blog/Sharing_images_with_friends_and_family_using_RSS_and_EXIF_XMP_metadata.html</guid>
                <pubDate>Tue, 31 Jul 2018 23:30:00 +0200</pubDate>
                <description>&lt;p&gt;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
&amp;lt;enclosure&amp;gt; RSS tag), but was unable to find a current supplier
of such frames.  In the end I gave up that approach.&lt;/p&gt;

&lt;p&gt;Some months ago, I discovered that
&lt;a href=&quot;https://www.jwz.org/xscreensaver/&quot;&gt;XScreensaver&lt;/a&gt; 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
&lt;a href=&quot;https://kodi.tv&quot;&gt;Kodi&lt;/a&gt; (both using
&lt;a href=&quot;https://www.openelec.tv/&quot;&gt;OpenELEC&lt;/a&gt; and
&lt;a href=&quot;https://libreelec.tv&quot;&gt;LibreELEC&lt;/a&gt;) provide the
&lt;a href=&quot;https://github.com/grinsted/script.screensaver.feedreader&quot;&gt;Feedreader&lt;/a&gt;
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.&lt;/p&gt;

&lt;p&gt;Armed with motivation and a test photo frame, I set out to generate
a RSS feed for the Kodi instance.  I adjusted my &lt;a
href=&quot;https://freedombox.org/&quot;&gt;Freedombox&lt;/a&gt; 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.&lt;/p&gt;

&lt;p&gt;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:&lt;/p&gt;

&lt;blockquote&gt;&lt;pre&gt;
exiftool -headline=&#39;The RSS image title&#39; \
  -description=&#39;The RSS image description.&#39; \
  -subject+=for-family photo.jpeg
&lt;/pre&gt;&lt;/blockquote&gt;

&lt;p&gt;I initially tried the &quot;-title&quot; and &quot;keyword&quot; tags, but they were
invisible in digiKam, so I changed to &quot;-headline&quot; and &quot;-subject&quot;.  I
use the keyword/subject &#39;for-family&#39; 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.&lt;/p&gt;

&lt;p&gt;Are there better ways to do this?  Get in touch if you have better
suggestions.&lt;/p&gt;

&lt;p&gt;As usual, if you use Bitcoin and want to show your support of my
activities, please send Bitcoin donations to my address
&lt;b&gt;&lt;a href=&quot;bitcoin:15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b&quot;&gt;15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b&lt;/a&gt;&lt;/b&gt;.&lt;/p&gt;
</description>
        </item>
        
        <item>
                <title>Simple streaming the Linux desktop to Kodi using GStreamer and RTP</title>
                <link>http://people.skolelinux.org/pere/blog/Simple_streaming_the_Linux_desktop_to_Kodi_using_GStreamer_and_RTP.html</link>
                <guid isPermaLink="true">http://people.skolelinux.org/pere/blog/Simple_streaming_the_Linux_desktop_to_Kodi_using_GStreamer_and_RTP.html</guid>
                <pubDate>Thu, 12 Jul 2018 17:55:00 +0200</pubDate>
                <description>&lt;p&gt;Last night, I wrote
&lt;a href=&quot;http://people.skolelinux.org/pere/blog/Streaming_the_Linux_desktop_to_Kodi_using_VLC_and_RTSP.html&quot;&gt;a
recipe to stream a Linux desktop using VLC to a instance of Kodi&lt;/a&gt;.
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.&lt;/p&gt;

&lt;p&gt;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
&lt;a href=&quot;https://kodi.wiki/view/JSON-RPC_API/v8&quot;&gt;the JSON-RPC API in
Kodi&lt;/a&gt; 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.&lt;/p&gt;

&lt;blockquote&gt;&lt;pre&gt;
#!/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=&quot;$1&quot;
    cmd=&quot;$2&quot;
    params=&quot;$3&quot;
    curl --silent --header &#39;Content-Type: application/json&#39; \
         --data-binary &quot;{ \&quot;id\&quot;: 1, \&quot;jsonrpc\&quot;: \&quot;2.0\&quot;, \&quot;method\&quot;: \&quot;$cmd\&quot;, \&quot;params\&quot;: $params }&quot; \
         &quot;http://$host/jsonrpc&quot;
}
cleanup() {
    if [ -n &quot;$kodihost&quot; ] ; then
        # Stop the playing when we end
        playerid=$(kodicmd &quot;$kodihost&quot; Player.GetActivePlayers &quot;{}&quot; |
                            jq .result[].playerid)
        kodicmd &quot;$kodihost&quot; Player.Stop &quot;{ \&quot;playerid\&quot; : $playerid }&quot; &gt; /dev/null
    fi
    if [ &quot;$gstpid&quot; ] &amp;&amp; kill -0 &quot;$gstpid&quot; &gt;/dev/null 2&gt;&amp;1; then
        kill &quot;$gstpid&quot;
    fi
}
trap cleanup EXIT INT

if [ -n &quot;$1&quot; ]; then
    kodihost=$1
    shift
else
    kodihost=kodi.local
fi

mcast=239.255.0.1
mcastport=1234
mcastttl=1

pasrc=$(pactl list | grep -A2 &#39;Source #&#39; | grep &#39;Name: .*\.monitor$&#39; | \
  cut -d&quot; &quot; -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. \
  &gt; /dev/null 2&gt;&amp;1 &amp;
gstpid=$!

# Give stream a second to get going
sleep 1

# Ask kodi to start streaming using its JSON-RPC API
kodicmd &quot;$kodihost&quot; Player.Open \
        &quot;{\&quot;item\&quot;: { \&quot;file\&quot;: \&quot;udp://@$mcast:$mcastport\&quot; } }&quot; &gt; /dev/null

# wait for gst to end
wait &quot;$gstpid&quot;
&lt;/pre&gt;&lt;/blockquote&gt;

&lt;p&gt;I hope you find the approach useful.  I know I do.&lt;/p&gt;

&lt;p&gt;As usual, if you use Bitcoin and want to show your support of my
activities, please send Bitcoin donations to my address
&lt;b&gt;&lt;a href=&quot;bitcoin:15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b&quot;&gt;15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b&lt;/a&gt;&lt;/b&gt;.&lt;/p&gt;
</description>
        </item>
        
        <item>
                <title>Streaming the Linux desktop to Kodi using VLC and RTSP</title>
                <link>http://people.skolelinux.org/pere/blog/Streaming_the_Linux_desktop_to_Kodi_using_VLC_and_RTSP.html</link>
                <guid isPermaLink="true">http://people.skolelinux.org/pere/blog/Streaming_the_Linux_desktop_to_Kodi_using_VLC_and_RTSP.html</guid>
                <pubDate>Thu, 12 Jul 2018 02:00:00 +0200</pubDate>
                <description>&lt;p&gt;PS: See
&lt;ahref=&quot;http://people.skolelinux.org/pere/blog/Simple_streaming_the_Linux_desktop_to_Kodi_using_GStreamer_and_RTP.html&quot;&gt;the
followup post&lt;/a&gt; for a even better approach.&lt;/p&gt;

&lt;p&gt;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.&lt;/p&gt;

&lt;p&gt;I had a look at several approaches, for example
&lt;a href=&quot;https://github.com/mfoetsch/dlna_live_streaming&quot;&gt;using uPnP
DLNA as described in 2011&lt;/a&gt;, 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.&lt;/p&gt;

&lt;p&gt;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.&lt;/p&gt;

&lt;p&gt;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.&lt;/p&gt;

&lt;p&gt;I did not spend much time investigating codeces.  I combined the
rtp and rtsp recipes from
&lt;a href=&quot;https://wiki.videolan.org/Documentation:Streaming_HowTo/Command_Line_Examples/&quot;&gt;the
VLC Streaming HowTo/Command Line Examples&lt;/a&gt;, and was able to get
this working on the desktop/streaming end.&lt;/p&gt;

&lt;blockquote&gt;&lt;pre&gt;
vlc screen:// --sout \
  &#39;#transcode{vcodec=mp4v,acodec=mpga,vb=800,ab=128}:rtp{dst=projector.local,port=1234,sdp=rtsp://192.168.11.4:8080/test.sdp}&#39;
&lt;/pre&gt;&lt;/blockquote&gt;

&lt;p&gt;I ssh-ed into my Kodi box and created a file like this with the
same IP address:&lt;/p&gt;

&lt;blockquote&gt;&lt;pre&gt;
echo rtsp://192.168.11.4:8080/test.sdp \
  &gt; /storage/videos/screenstream.m3u
&lt;/pre&gt;&lt;/blockquote&gt;

&lt;p&gt;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. :)&lt;/p&gt;

&lt;p&gt;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.&lt;/p&gt;

&lt;p&gt;&lt;strong&gt;Update 2018-07-12&lt;/strong&gt;: Johannes Schauer send me a few
succestions and reminded me about an important step.  The &quot;screen:&quot;
input source is only available once the vlc-plugin-access-extra
package is installed on Debian.  Without it, you will see this error
message: &quot;VLC is unable to open the MRL &#39;screen://&#39;.  Check the log
for details.&quot;  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

&lt;blockquote&gt;&lt;pre&gt;
cvlc screen:// --sout \
  &#39;#transcode{vcodec=mp4v,acodec=mpga,vb=800,ab=128}:rtp{sdp=rtsp://:8080/}&#39;
&lt;/pre&gt;&lt;/blockquote&gt;

&lt;p&gt;and this on the Kodi end&lt;p&gt;

&lt;blockquote&gt;&lt;pre&gt;
echo rtsp://192.168.11.4:8080/ \
  &gt; /storage/videos/screenstream.m3u
&lt;/pre&gt;&lt;/blockquote&gt;

&lt;p&gt;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&#39;ve tried to change the vb and ab
parameters to use more bandwidth, but it did not make a
difference.&lt;/p&gt;

&lt;p&gt;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:

&lt;blockquote&gt;&lt;pre&gt;
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=$(pactl list | grep -A2 &#39;Source #&#39; | \
    grep &#39;Name: .*\.monitor$&#39; |  cut -d&quot; &quot; -f2|head -1) ! \
  audioconvert ! queue2 ! avenc_aac ! queue2 ! mux.
&lt;/pre&gt;&lt;/blockquote&gt;

&lt;p&gt;and this on the Kodi end&lt;p&gt;

&lt;blockquote&gt;&lt;pre&gt;
echo udp://@239.255.0.1:1234 \
  &gt; /storage/videos/screenstream.m3u
&lt;/pre&gt;&lt;/blockquote&gt;

&lt;p&gt;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 &quot;hop&quot; for each increase (read up on
multicast to learn more. :)!&lt;/p&gt;

&lt;p&gt;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.&lt;/p&gt;

&lt;blockquote&gt;&lt;pre&gt;
cvlc screen:// --sout &#39;#transcode{vcodec=mp4v,acodec=mpga,vb=800,ab=128}:rtp{mux=ts,dst=239.255.0.1,port=1234,sdp=sap}&#39;
&lt;/pre&gt;&lt;/blockquote&gt;

&lt;p&gt;As usual, if you use Bitcoin and want to show your support of my
activities, please send Bitcoin donations to my address
&lt;b&gt;&lt;a href=&quot;bitcoin:15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b&quot;&gt;15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b&lt;/a&gt;&lt;/b&gt;.&lt;/p&gt;
</description>
        </item>
        
        <item>
                <title>What is the most supported MIME type in Debian in 2018?</title>
                <link>http://people.skolelinux.org/pere/blog/What_is_the_most_supported_MIME_type_in_Debian_in_2018_.html</link>
                <guid isPermaLink="true">http://people.skolelinux.org/pere/blog/What_is_the_most_supported_MIME_type_in_Debian_in_2018_.html</guid>
                <pubDate>Mon, 9 Jul 2018 08:05:00 +0200</pubDate>
                <description>&lt;p&gt;Five years ago,
&lt;a href=&quot;http://people.skolelinux.org/pere/blog/What_is_the_most_supported_MIME_type_in_Debian_.html&quot;&gt;I
measured what the most supported MIME type in Debian was&lt;/a&gt;, 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:

&lt;p&gt;&lt;strong&gt;Debian Unstable:&lt;/strong&gt;&lt;/p&gt;

&lt;pre&gt;
  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
&lt;/pre&gt;

&lt;p&gt;The list was created like this using a sid chroot: &quot;cat
/var/lib/apt/lists/*sid*_dep11_Components-amd64.yml.gz| zcat | awk &#39;/^
- \S+\/\S+$/ {print $2 }&#39; | sort | uniq -c | sort -nr | head -20&quot;&lt;/p&gt;

&lt;p&gt;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 &quot;file --mime &amp;lt;filename&amp;gt;&quot;, and then
look up all packages announcing support for this format in their
AppStream metadata (XML or .desktop file) using &quot;appstreamcli
what-provides mimetype &amp;lt;mime-type&amp;gt;.  For example if you, like
me, want to know which packages support inode/directory, you can get a
list like this:&lt;/p&gt;

&lt;p&gt;&lt;blockquote&gt;&lt;pre&gt;
% 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
%
&lt;/pre&gt;&lt;/blockquote&gt;&lt;/p&gt;

&lt;p&gt;Using the same method, I can quickly discover that the Sketchup file
format is not yet supported by any package in Debian:&lt;/p&gt;

&lt;p&gt;&lt;blockquote&gt;&lt;pre&gt;
% appstreamcli what-provides mimetype  application/vnd.sketchup.skp
Could not find component providing &#39;mimetype::application/vnd.sketchup.skp&#39;.
%
&lt;/pre&gt;&lt;/blockquote&gt;&lt;/p&gt;

&lt;p&gt;Yesterday I used it to figure out which packages support the STL 3D
format:&lt;/p&gt;

&lt;p&gt;&lt;blockquote&gt;&lt;pre&gt;
% appstreamcli what-provides mimetype  application/sla|grep Package
Package: cura
Package: meshlab
Package: printrun
%
&lt;/pre&gt;&lt;/blockquote&gt;&lt;/p&gt;

&lt;p&gt;PS: A new version of Cura was uploaded to Debian yesterday.&lt;/p&gt;

&lt;p&gt;As usual, if you use Bitcoin and want to show your support of my
activities, please send Bitcoin donations to my address
&lt;b&gt;&lt;a href=&quot;bitcoin:15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b&quot;&gt;15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b&lt;/a&gt;&lt;/b&gt;.&lt;/p&gt;
</description>
        </item>
        
        <item>
                <title>Debian APT upgrade without enough free space on the disk...</title>
                <link>http://people.skolelinux.org/pere/blog/Debian_APT_upgrade_without_enough_free_space_on_the_disk___.html</link>
                <guid isPermaLink="true">http://people.skolelinux.org/pere/blog/Debian_APT_upgrade_without_enough_free_space_on_the_disk___.html</guid>
                <pubDate>Sun, 8 Jul 2018 12:10:00 +0200</pubDate>
                <description>&lt;p&gt;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 &#39;apt upgrade&#39;.  I normally
would resolve the issue by doing &#39;apt install &amp;lt;somepackages&amp;gt;&#39; 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 &#39;apt-in-chunks&#39;:&lt;/p&gt;

&lt;p&gt;&lt;blockquote&gt;&lt;pre&gt;
#!/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 [ &quot;$1&quot; ]; then
        grep -v &quot;$1&quot;
    else
        cat
    fi
}

for p in $(apt list --upgradable | ignore &quot;$@&quot; |cut -d/ -f1 | grep -v &#39;^Listing...&#39;); do
    echo &quot;Upgrading $p&quot;
    apt clean
    apt install --download-only -y $p
    for f in /var/cache/apt/archives/*.deb; do
        if [ -e &quot;$f&quot; ]; then
            dpkg -i /var/cache/apt/archives/*.deb
            break
        fi
    done
done
&lt;/pre&gt;&lt;/blockquote&gt;&lt;/p&gt;

&lt;p&gt;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
&#39;apt install -f&#39; 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.&lt;/p&gt;

&lt;p&gt;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
&#39;ghc&#39;, but I have run into other large packages causing similar
problems earlier (like TeX).&lt;/p&gt;

&lt;p&gt;Update 2018-07-08: Thanks to Paul Wise, I am aware of two
alternative ways to handle this.  The &quot;unattended-upgrades
--minimal-upgrade-steps&quot; 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, &quot;aptutude upgrade&quot; can upgrade single packages, thus avoiding
the need for using &quot;dpkg -i&quot; in the script above.&lt;/p&gt;

&lt;p&gt;As usual, if you use Bitcoin and want to show your support of my
activities, please send Bitcoin donations to my address
&lt;b&gt;&lt;a href=&quot;bitcoin:15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b&quot;&gt;15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b&lt;/a&gt;&lt;/b&gt;.&lt;/p&gt;
</description>
        </item>
        
        <item>
                <title>The worlds only stone power plant?</title>
                <link>http://people.skolelinux.org/pere/blog/The_worlds_only_stone_power_plant_.html</link>
                <guid isPermaLink="true">http://people.skolelinux.org/pere/blog/The_worlds_only_stone_power_plant_.html</guid>
                <pubDate>Sat, 30 Jun 2018 10:35:00 +0200</pubDate>
                <description>&lt;p&gt;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
&lt;a href=&quot;https://en.wikipedia.org/wiki/Bremanger&quot;&gt;Bremanger&lt;/a&gt; i
Norway, where
&lt;a href=&quot;https://www.bontrup.com/en/activities/raw-materials/bremanger-quarry/&quot;&gt;the
Bremanger Quarry&lt;/a&gt; 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?&lt;/p&gt;

&lt;p&gt;As usual, if you use Bitcoin and want to show your support of my
activities, please send Bitcoin donations to my address
&lt;b&gt;&lt;a href=&quot;bitcoin:15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b&quot;&gt;15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b&lt;/a&gt;&lt;/b&gt;.&lt;/p&gt;
</description>
        </item>
        
        <item>
                <title>Add-on to control the projector from within Kodi</title>
                <link>http://people.skolelinux.org/pere/blog/Add_on_to_control_the_projector_from_within_Kodi.html</link>
                <guid isPermaLink="true">http://people.skolelinux.org/pere/blog/Add_on_to_control_the_projector_from_within_Kodi.html</guid>
                <pubDate>Tue, 26 Jun 2018 23:55:00 +0200</pubDate>
                <description>&lt;p&gt;My movie playing setup involve &lt;a href=&quot;https://kodi.tv/&quot;&gt;Kodi&lt;/a&gt;,
&lt;a href=&quot;https://openelec.tv&quot;&gt;OpenELEC&lt;/a&gt; (probably soon to be
replaced with &lt;a href=&quot;https://libreelec.tv/&quot;&gt;LibreELEC&lt;/a&gt;) 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, &lt;a href=&quot;https://www.infocus.com/&quot;&gt;InFocus&lt;/a&gt;, 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
&lt;a href=&quot;https://github.com/petterreinholdtsen/infocus-projector-control&quot;&gt;a
small script to control the projector&lt;/a&gt;.  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.&lt;/p&gt;

&lt;p&gt;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.&lt;/p&gt;

&lt;p&gt;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
&lt;a href=&quot;https://github.com/pyserial/pyserial&quot;&gt;pyserial module&lt;/a&gt; in
the add-on.  The long term solution is to make a &quot;script&quot; type
pyserial module for Kodi, that can be pulled in as a dependency in
Kodi.  But until that in place, I embed it.&lt;/p&gt;

&lt;p&gt;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.

&lt;p&gt;If this sound interesting to you, check out
&lt;a href=&quot;https://github.com/fredrik-eriksson/kodi_projcontrol&quot;&gt;the
project github repository&lt;/a&gt;.  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.&lt;/p&gt;

&lt;p&gt;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.&lt;/p&gt;

&lt;p&gt;As usual, if you use Bitcoin and want to show your support of my
activities, please send Bitcoin donations to my address
&lt;b&gt;&lt;a href=&quot;bitcoin:15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b&quot;&gt;15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b&lt;/a&gt;&lt;/b&gt;.&lt;/p&gt;
</description>
        </item>
        
        </channel>
</rss>