- <div class="title"><a href="http://people.skolelinux.org/pere/blog/Epost_inn_som_arkivformat_i_Riksarkivarens_forskrift_.html">Epost inn som arkivformat i Riksarkivarens forskrift?</a></div>
- <div class="date">27th April 2017</div>
- <div class="body"><p>I disse dager, med frist 1. mai, har Riksarkivaren ute en høring på
-sin forskrift. Som en kan se er det ikke mye tid igjen før fristen
-som går ut på søndag. Denne forskriften er det som lister opp hvilke
-formater det er greit å arkivere i
-<a href="http://www.arkivverket.no/arkivverket/Offentleg-forvalting/Noark/Noark-5">Noark
-5-løsninger</a> i Norge.</p>
-
-<p>Jeg fant høringsdokumentene hos
-<a href="https://www.arkivrad.no/aktuelt/riksarkivarens-forskrift-pa-horing">Norsk
-Arkivråd</a> etter å ha blitt tipset på epostlisten til
-<a href="https://github.com/hiOA-ABI/nikita-noark5-core">fri
-programvareprosjektet Nikita Noark5-Core</a>, som lager et Noark 5
-Tjenestegresesnitt. Jeg er involvert i Nikita-prosjektet og takket
-være min interesse for tjenestegrensesnittsprosjektet har jeg lest en
-god del Noark 5-relaterte dokumenter, og til min overraskelse oppdaget
-at standard epost ikke er på listen over godkjente formater som kan
-arkiveres. Høringen med frist søndag er en glimrende mulighet til å
-forsøke å gjøre noe med det. Jeg holder på med
-<a href="https://github.com/petterreinholdtsen/noark5-tester/blob/master/docs/hoering-arkivforskrift.tex">egen
-høringsuttalelse</a>, og lurer på om andre er interessert i å støtte
-forslaget om å tillate arkivering av epost som epost i arkivet.</p>
-
-<p>Er du igang med å skrive egen høringsuttalelse allerede? I så fall
-kan du jo vurdere å ta med en formulering om epost-lagring. Jeg tror
-ikke det trengs så mye. Her et kort forslag til tekst:</p>
-
-<p><blockquote>
-
- <p>Viser til høring sendt ut 2017-02-17 (Riksarkivarens referanse
- 2016/9840 HELHJO), og tillater oss å sende inn noen innspill om
- revisjon av Forskrift om utfyllende tekniske og arkivfaglige
- bestemmelser om behandling av offentlige arkiver (Riksarkivarens
- forskrift).</p>
-
- <p>Svært mye av vår kommuikasjon foregår i dag på e-post. Vi
- foreslår derfor at Internett-e-post, slik det er beskrevet i IETF
- RFC 5322,
- <a href="https://tools.ietf.org/html/rfc5322">https://tools.ietf.org/html/rfc5322</a>. bør
- inn som godkjent dokumentformat. Vi foreslår at forskriftens
- oversikt over godkjente dokumentformater ved innlevering i § 5-16
- endres til å ta med Internett-e-post.</p>
-
-</blockquote></p>
-
-<p>Som del av arbeidet med tjenestegrensesnitt har vi testet hvordan
-epost kan lagres i en Noark 5-struktur, og holder på å skrive et
-forslag om hvordan dette kan gjøres som vil bli sendt over til
-arkivverket så snart det er ferdig. De som er interesserte kan
-<a href="https://github.com/petterreinholdtsen/noark5-tester/blob/master/docs/epostlagring.md">følge
-fremdriften på web</a>.</p>
-
-<p>Oppdatering 2017-04-28: I dag ble høringuttalelsen jeg skrev
- <a href="https://www.nuug.no/news/NUUGs_h_ringuttalelse_til_Riksarkivarens_forskrift.shtml">sendt
- inn av foreningen NUUG</a>.</p>
+ <div class="title"><a href="http://people.skolelinux.org/pere/blog/Streaming_the_Linux_desktop_to_Kodi_using_VLC_and_RTSP.html">Streaming the Linux desktop to Kodi using VLC and RTSP</a></div>
+ <div class="date">12th July 2018</div>
+ <div class="body"><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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