- <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><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>
-</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><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>
-</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><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>
-</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><p>Last night, I wrote
-<a href="http://people.skolelinux.org/pere/blog/Streaming_the_Linux_desktop_to_Kodi_using_VLC_and_RTSP.html">a
-recipe to stream a Linux desktop using VLC to a instance of Kodi</a>.
-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.</p>
-
-<p>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
-<a href="https://kodi.wiki/view/JSON-RPC_API/v8">the JSON-RPC API in
-Kodi</a> 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.</p>
-
-<blockquote><pre>
-#!/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"
-</pre></blockquote>
-
-<p>I hope you find the approach useful. I know I do.</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>
-</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><p>PS: See
-<ahref="http://people.skolelinux.org/pere/blog/Simple_streaming_the_Linux_desktop_to_Kodi_using_GStreamer_and_RTP.html">the
-followup post</a> for a even better approach.</p>
-
-<p>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.</p>
-
-<p>I had a look at several approaches, for example
-<a href="https://github.com/mfoetsch/dlna_live_streaming">using uPnP
-DLNA as described in 2011</a>, 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.</p>
-
-<p>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.</p>
-
-<p>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.</p>
-
-<p>I did not spend much time investigating codeces. I combined the
-rtp and rtsp recipes from
-<a href="https://wiki.videolan.org/Documentation:Streaming_HowTo/Command_Line_Examples/">the
-VLC Streaming HowTo/Command Line Examples</a>, and was able to get
-this working on the desktop/streaming end.</p>
-
-<blockquote><pre>
-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}'
-</pre></blockquote>
-
-<p>I ssh-ed into my Kodi box and created a file like this with the
-same IP address:</p>
-
-<blockquote><pre>
-echo rtsp://192.168.11.4:8080/test.sdp \
- > /storage/videos/screenstream.m3u
-</pre></blockquote>
-
-<p>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. :)</p>
-
-<p>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.</p>
-
-<p><strong>Update 2018-07-12</strong>: 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
-
-<blockquote><pre>
-cvlc screen:// --sout \
- '#transcode{vcodec=mp4v,acodec=mpga,vb=800,ab=128}:rtp{sdp=rtsp://:8080/}'
-</pre></blockquote>
-
-<p>and this on the Kodi end<p>
-
-<blockquote><pre>
-echo rtsp://192.168.11.4:8080/ \
- > /storage/videos/screenstream.m3u
-</pre></blockquote>
-
-<p>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.</p>
-
-<p>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:
-
-<blockquote><pre>
-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.
-</pre></blockquote>
-
-<p>and this on the Kodi end<p>
-
-<blockquote><pre>
-echo udp://@239.255.0.1:1234 \
- > /storage/videos/screenstream.m3u
-</pre></blockquote>
-
-<p>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. :)!</p>
-
-<p>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.</p>
-
-<blockquote><pre>
-cvlc screen:// --sout '#transcode{vcodec=mp4v,acodec=mpga,vb=800,ab=128}:rtp{mux=ts,dst=239.255.0.1,port=1234,sdp=sap}'
-</pre></blockquote>
-
-<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>
-</description>
- </item>
-
projects / homepage.git / blobdiff