- <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>
+ <title>Time for an official MIME type for patches?</title>
+ <link>http://people.skolelinux.org/pere/blog/Time_for_an_official_MIME_type_for_patches_.html</link>
+ <guid isPermaLink="true">http://people.skolelinux.org/pere/blog/Time_for_an_official_MIME_type_for_patches_.html</guid>
+ <pubDate>Thu, 1 Nov 2018 08:15:00 +0100</pubDate>
+ <description><p>As part of my involvement in
+<a href="https://gitlab.com/OsloMet-ABI/nikita-noark5-core">the Nikita
+archive API project</a>, I've been importing a fairly large lump of
+emails into a test instance of the archive to see how well this would
+go. I picked a subset of <a href="https://notmuchmail.org/">my
+notmuch email database</a>, all public emails sent to me via
+@lists.debian.org, giving me a set of around 216 000 emails to import.
+In the process, I had a look at the various attachments included in
+these emails, to figure out what to do with attachments, and noticed
+that one of the most common attachment formats do not have
+<a href="https://www.iana.org/assignments/media-types/media-types.xhtml">an
+official MIME type</a> registered with IANA/IETF. The output from
+diff, ie the input for patch, is on the top 10 list of formats
+included in these emails. At the moment people seem to use either
+text/x-patch or text/x-diff, but neither is officially registered. It
+would be better if one official MIME type were registered and used
+everywhere.</p>
+
+<p>To try to get one official MIME type for these files, I've brought
+up the topic on
+<a href="https://www.ietf.org/mailman/listinfo/media-types">the
+media-types mailing list</a>. If you are interested in discussion
+which MIME type to use as the official for patch files, or involved in
+making software using a MIME type for patches, perhaps you would like
+to join the discussion?</p>
+
+<p>As usual, if you use Bitcoin and want to show your support of my
+activities, please send Bitcoin donations to my address
+<b><a href="bitcoin:15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b">15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b</a></b>.</p>
+</description>
+ </item>
+
+ <item>
+ <title>Measuring the speaker frequency response using the AUDMES free software GUI - nice free software</title>
+ <link>http://people.skolelinux.org/pere/blog/Measuring_the_speaker_frequency_response_using_the_AUDMES_free_software_GUI___nice_free_software.html</link>
+ <guid isPermaLink="true">http://people.skolelinux.org/pere/blog/Measuring_the_speaker_frequency_response_using_the_AUDMES_free_software_GUI___nice_free_software.html</guid>
+ <pubDate>Mon, 22 Oct 2018 08:40:00 +0200</pubDate>
+ <description><p><img src="http://people.skolelinux.org/pere/blog/images/2018-10-22-audmes-measure-speakers.png" align="right" width="40%"/></p>
+
+<p>My current home stereo is a patchwork of various pieces I got on
+flee markeds over the years. It is amazing what kind of equipment
+show up there. I've been wondering for a while if it was possible to
+measure how well this equipment is working together, and decided to
+see how far I could get using free software. After trawling the web I
+came across an article from DIY Audio and Video on
+<a href="https://www.diyaudioandvideo.com/Tutorial/SpeakerResponseTesting/">Speaker
+Testing and Analysis</a> describing how to test speakers, and it listing
+several software options, among them
+<a href="https://sourceforge.net/projects/audmes/">AUDio MEasurement
+System (AUDMES)</a>. It is the only free software system I could find
+focusing on measuring speakers and audio frequency response. In the
+process I also found an interesting article from NOVO on
+<a href="http://novo.press/understanding-speaker-specifications-and-frequency-response/">Understanding
+Speaker Specifications and Frequency Response</a> and an article from
+ecoustics on
+<a href="https://www.ecoustics.com/articles/understanding-speaker-frequency-response/">Understanding
+Speaker Frequency Response</a>, with a lot of information on what to
+look for and how to interpret the graphs. Armed with this knowledge,
+I set out to measure the state of my speakers.</p>
+
+<p>The first hurdle was that AUDMES hadn't seen a commit for 10 years
+and did not build with current compilers and libraries. I got in
+touch with its author, who no longer was spending time on the program
+but gave me write access to the subversion repository on Sourceforge.
+The end result is that now the code build on Linux and is capable of
+saving and loading the collected frequency response data in CSV
+format. The application is quite nice and flexible, and I was able to
+select the input and output audio interfaces independently. This made
+it possible to use a USB mixer as the input source, while sending
+output via my laptop headphone connection. I lacked the hardware and
+cabling to figure out a different way to get independent cabling to
+speakers and microphone.</p>
+
+<p>Using this setup I could see how a large range of high frequencies
+apparently were not making it out of my speakers. The picture show
+the frequency response measurement of one of the speakers. Note the
+frequency lines seem to be slightly misaligned, compared to the CSV
+output from the program. I can not hear several of these are high
+frequencies, according to measurement from
+<a href="http://freehearingtestsoftware.com">Free Hearing Test
+Software</a>, an freeware system to measure your hearing (still
+looking for a free software alternative), so I do not know if they are
+coming out out the speakers. I thus do not quite know how to figure
+out if the missing frequencies is a problem with the microphone, the
+amplifier or the speakers, but I managed to rule out the audio card in my
+PC by measuring my Bose noise canceling headset using its own
+microphone. This setup was able to see the high frequency tones, so
+the problem with my stereo had to be in the amplifier or speakers.</p>
+
+<p>Anyway, to try to role out one factor I ended up picking up a new
+set of speakers at a flee marked, and these work a lot better than the
+old speakers, so I guess the microphone and amplifier is OK. If you
+need to measure your own speakers, check out AUDMES. If more people
+get involved, perhaps the project could become good enough to
+<a href="https://bugs.debian.org/910876">include in Debian</a>? And if
+you know of some other free software to measure speakers and amplifier
+performance, please let me know. I am aware of the freeware option
+<a href="https://www.roomeqwizard.com/">REW</a>, but I want something
+that can be developed also when the vendor looses interest.</p>
+
+<p>As usual, if you use Bitcoin and want to show your support of my
+activities, please send Bitcoin donations to my address
+<b><a href="bitcoin:15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b">15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b</a></b>.</p>
+</description>
+ </item>
+
+ <item>
+ <title>Web browser integration of VLC with Bittorrent support</title>
+ <link>http://people.skolelinux.org/pere/blog/Web_browser_integration_of_VLC_with_Bittorrent_support.html</link>
+ <guid isPermaLink="true">http://people.skolelinux.org/pere/blog/Web_browser_integration_of_VLC_with_Bittorrent_support.html</guid>
+ <pubDate>Sun, 21 Oct 2018 09:50:00 +0200</pubDate>
+ <description><p>Bittorrent is as far as I know, currently the most efficient way to
+distribute content on the Internet. It is used all by all sorts of
+content providers, from national TV stations like
+<a href="https://www.nrk.no/">NRK</a>, Linux distributors like
+<a href="https://www.debian.org/">Debian</a> and
+<a href="https://www.ubuntu.com/">Ubuntu</a>, and of course the
+<a href="https://archive.org/">Internet archive</A>.
+
+<p>Almost a month ago
+<a href="https://tracker.debian.org/pkg/vlc-plugin-bittorrent">a new
+package adding Bittorrent support to VLC</a> became available in
+Debian testing and unstable. To test it, simply install it like
+this:</p>
+
+<p><pre>
+apt install vlc-plugin-bittorrent
+</pre></p>
+
+<p>Since the plugin was made available for the first time in Debian,
+several improvements have been made to it. In version 2.2-4, now
+available in both testing and unstable, a desktop file is provided to
+teach browsers to start VLC when the user click on torrent files or
+magnet links. The last part is thanks to me finally understanding
+what the strange x-scheme-handler style MIME types in desktop files
+are used for. By adding x-scheme-handler/magnet to the MimeType entry
+in the desktop file, at least the browsers Firefox and Chromium will
+suggest to start VLC when selecting a magnet URI on a web page. The
+end result is that now, with the plugin installed in Buster and Sid,
+one can visit any
+<a href="https://archive.org/details/CopyingIsNotTheft1080p">Internet
+Archive page with movies</a> using a web browser and click on the
+torrent link to start streaming the movie.</p>
+
+<p>Note, there is still some misfeatures in the plugin. One is the
+fact that it will hang and
+<a href="https://github.com/johang/vlc-bittorrent/issues/13">block VLC
+from exiting until the torrent streaming starts</a>. Another is the
+fact that it
+<a href="https://github.com/johang/vlc-bittorrent/issues/9">will pick
+and play a random file in a multi file torrent</a>. This is not
+always the video file you want. Combined with the first it can be a
+bit hard to get the video streaming going. But when it work, it seem
+to do a good job.</p>
+
+<p>For the Debian packaging, I would love to find a good way to test
+if the plugin work with VLC using autopkgtest. I tried, but do not
+know enough of the inner workings of VLC to get it working. For now
+the autopkgtest script is only checking if the .so file was
+successfully loaded by VLC. If you have any suggestions, please
+submit a patch to the Debian bug tracking system.</p>
projects / homepage.git / blobdiff