- <title>Release 0.1.1 of free software archive system Nikita announced</title>
- <link>http://people.skolelinux.org/pere/blog/Release_0_1_1_of_free_software_archive_system_Nikita_announced.html</link>
- <guid isPermaLink="true">http://people.skolelinux.org/pere/blog/Release_0_1_1_of_free_software_archive_system_Nikita_announced.html</guid>
- <pubDate>Sat, 10 Jun 2017 00:40:00 +0200</pubDate>
- <description><p>I am very happy to report that the
-<a href="https://github.com/hiOA-ABI/nikita-noark5-core">Nikita Noark 5
-core project</a> tagged its second release today. The free software
-solution is an implementation of the Norwegian archive standard Noark
-5 used by government offices in Norway. These were the changes in
-version 0.1.1 since version 0.1.0 (from NEWS.md):
-
-<ul>
-
- <li>Continued work on the angularjs GUI, including document upload.</li>
- <li>Implemented correspondencepartPerson, correspondencepartUnit and
- correspondencepartInternal</li>
- <li>Applied for coverity coverage and started submitting code on
- regualr basis.</li>
- <li>Started fixing bugs reported by coverity</li>
- <li>Corrected and completed HATEOAS links to make sure entire API is
- available via URLs in _links.</li>
- <li>Corrected all relation URLs to use trailing slash.</li>
- <li>Add initial support for storing data in ElasticSearch.</li>
- <li>Now able to receive and store uploaded files in the archive.</li>
- <li>Changed JSON output for object lists to have relations in _links.</li>
- <li>Improve JSON output for empty object lists.</li>
- <li>Now uses correct MIME type application/vnd.noark5-v4+json.</li>
- <li>Added support for docker container images.</li>
- <li>Added simple API browser implemented in JavaScript/Angular.</li>
- <li>Started on archive client implemented in JavaScript/Angular.</li>
- <li>Started on prototype to show the public mail journal.</li>
- <li>Improved performance by disabling Sprint FileWatcher.</li>
- <li>Added support for 'arkivskaper', 'saksmappe' and 'journalpost'.</li>
- <li>Added support for some metadata codelists.</li>
- <li>Added support for Cross-origin resource sharing (CORS).</li>
- <li>Changed login method from Basic Auth to JSON Web Token (RFC 7519)
- style.</li>
- <li>Added support for GET-ing ny-* URLs.</li>
- <li>Added support for modifying entities using PUT and eTag.</li>
- <li>Added support for returning XML output on request.</li>
- <li>Removed support for English field and class names, limiting ourself
- to the official names.</li>
- <li>...</li>
-
-</ul>
-
-<p>If this sound interesting to you, please contact us on IRC (#nikita
-on irc.freenode.net) or email
-(<a href="https://lists.nuug.no/mailman/listinfo/nikita-noark">nikita-noark
-mailing list).</p>
+ <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>
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