<link>http://people.skolelinux.org/pere/blog/</link>
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+ <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>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.m4u 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=0 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=0 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.</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>
+
<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>
</description>
</item>
- <item>
- <title>H, Ap, Frp og Venstre går for DNA-innsamling av hele befolkningen</title>
- <link>http://people.skolelinux.org/pere/blog/H__Ap__Frp_og_Venstre_g_r_for_DNA_innsamling_av_hele_befolkningen.html</link>
- <guid isPermaLink="true">http://people.skolelinux.org/pere/blog/H__Ap__Frp_og_Venstre_g_r_for_DNA_innsamling_av_hele_befolkningen.html</guid>
- <pubDate>Wed, 14 Mar 2018 14:15:00 +0100</pubDate>
- <description><p>I går kom det nok et argument for å holde seg unna det norske
-helsevesenet. Da annonserte et stortingsflertall, bestående av Høyre,
-Arbeiderpartiet, Fremskrittspartiet og Venstre, at de går inn for å
-samle inn og lagre DNA-prøver fra hele befolkningen i Norge til evig
-tid. Endringen gjelder innsamlede blodprøver fra nyfødte i Norge.
-Det vil dermed ta litt tid før en har hele befolkningen, men det er
-dit vi havner gitt nok tid. I dag er det nesten hundre prosent
-oppslutning om undersøkelsen som gjøres like etter fødselen, på
-bakgrunn av blodprøven det er snakk om å lagre, for å oppdage endel
-medfødte sykdommer. Blodprøven lagres i dag i inntil seks år.
-<a href="https://www.stortinget.no/no/Saker-og-publikasjoner/Publikasjoner/Innstillinger/Stortinget/2017-2018/inns-201718-182l/?all=true">Stortingets
-flertallsinnstilling</a> er at tidsbegrensingen skal fjernes, og mener
-at tidsubegrenset lagring ikke vil påvirke oppslutningen om
-undersøkelsen.</p>
-
-<p>Datatilsynet har ikke akkurat applaudert forslaget:</p>
-
-<p><blockquote>
-
- <p>«Datatilsynet mener forslaget ikke i tilstrekkelig grad
- synliggjør hvilke etiske og personvernmessige utfordringer som må
- diskuteres før en etablerer en nasjonal biobank med blodprøver fra
- hele befolkningen.»</p>
-
-</blockquote></p>
-
-<p>Det er flere historier om hvordan innsamlet biologisk materiale har
-blitt brukt til andre formål enn de ble innsamlet til, og historien om
-<a href="https://www.aftenposten.no/norge/i/Ql0WR/Na-ma-Folkehelsa-slette-uskyldiges-DNA-info">folkehelseinstituttets
-lagring på vegne av politiet (Kripos) av innsamlet biologisk materiale
-og DNA-informasjon i strid med loven</a> viser at en ikke kan være
-trygg på at lover og intensjoner beskytter de som blir berørt mot
-misbruk av slik privat og personlig informasjon.</p>
-
-<p>Det er verdt å merke seg at det kan forskes på de innsamlede
-blodprøvene uten samtykke fra den det gjelder (eller foreldre når det
-gjelder barn), etter en lovendring for en stund tilbake, med mindre
-det er sendt inn skjema der en reserverer seg mot forskning uten
-samtykke. Skjemaet er tilgjengelig fra
-<a href="https://www.fhi.no/arkiv/publikasjoner/for-pasienter-skjema-for-reservasjo/">folkehelseinstituttets
-websider</a>, og jeg anbefaler, uavhengig av denne saken, varmt alle å
-sende inn skjemaet for å dokumentere hvor mange som ikke synes det er
-greit å fjerne krav om samtykke.</p>
-
-<p>I tillegg bør en kreve destruering av alt biologisk materiale som
-er samlet inn om en selv, for å redusere eventuelle negative
-konsekvenser i fremtiden når materialet kommer på avveie eller blir
-brukt uten samtykke, men det er så vidt jeg vet ikke noe system for
-dette i dag.</p>
-
-<p>Som vanlig, hvis du bruker Bitcoin og ønsker å vise din støtte til
-det jeg driver med, setter jeg pris på om du sender Bitcoin-donasjoner
-til min adresse
-<b><a href="bitcoin:15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b">15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b</a></b>.</p>
-</description>
- </item>
-
</channel>
</rss>
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