stream2beamer.md

   1 # Stream Desktop/Video/Webcam to Kodi/Beamer/other PCs
   2 Gregor and I had a closer look at the following projects:
   3
   4 # Laplace
   5 Simple WebRTC implementation in GO: https://github.com/adamyordan/laplace.git
   6 Simple to compile and just works.
   7 WebRTC actually uses SRTP (Secure Real-time Transport Protocol).
   8
   9 IPv6+IPv4, and no TLS:
  10
  11     ./laplace -addr "[::]:8080" -tls=false
  12
  13 # gstreamer
  14 * Supports RTP
  15 * Supports webcam capture via v4l (video for linux)
  16 * Supports screen capture via xmanager/ximagesrc
  17 * Interesting URLs:
  18   * WebRTC in one direction only: https://stackoverflow.com/questions/57430215/how-to-use-webrtcbin-create-offer-only-receive-video
  19   * gstreamer to VLC via RTP: https://stackoverflow.com/questions/13154983/gstreamer-rtp-stream-to-vlc
  20   * https://github.com/intel/gstreamer-media-SDK/issues/138
  21   * https://developer.ridgerun.com/wiki/index.php?title=GstWebRTC_Pipelines
  22   * https://developer.ridgerun.com/wiki/index.php?title=GstWebRTC_-_H264-Opus_Examples#Receive_Pipeline
  23
  24 ## WebRTC
  25 gstreamer has a WebRTC implementation.
  26 The examples at https://github.com/centricular/gstwebrtc-demos.git work once
  27
  28     export OPENSSL_CONF=''
  29
  30 has been set (see https://gitlab.freedesktop.org/gstreamer/gst-plugins-bad/issues/811)
  31
  32 ## websockets
  33
  34 connecting to websockets (plus gstreamer and v4l2sink)
  35
  36 https://michael.stapelberg.ch/posts/2020-06-06-iphone-camera-linux-v4l2loopback/
  37
  38 ## gstreamer examples
  39     gst-launch-1.0 -v playbin uri=file:///home/philipp/tmp/GerisGame.mp4
  40
  41     # send
  42     gst-launch-1.0 ximagesrc ! videoconvert ! videoscale ! video/x-raw,width=800,height=600 ! vp8enc ! rtpvp8pay ! udpsink host=239.255.12.42 port=5004
  43     # receive
  44     gst-launch-1.0 udpsrc address=239.255.12.42 port=5004 caps="application/x-rtp, media=(string)video, clock-rate=(int)90000, encoding-name=(string)VP8-DRAFT-IETF-01, payload=(int)96, ssrc=(uint)2990747501, clock-base=(uint)275641083, seqnum-base=(uint)34810" ! rtpvp8depay ! vp8dec ! autovideosink
  45
  46     # send
  47     gst-launch-1.0 -v ximagesrc ! videoconvert ! videoscale ! video/x-raw,format=I420,width=800,height=600,framerate=25/1 ! jpegenc ! rtpjpegpay ! udpsink host=239.255.12.42 port=5004
  48     # receive
  49     gst-launch-1.0 udpsrc address=239.255.12.42 port=5004 ! application/x-rtp,encoding-name=JPEG,payload=26 ! rtpjpegdepay ! jpegdec ! autovideosink
  50
  51
  52 * https://stackoverflow.com/questions/33747500/using-gstreamer-to-capture-screen-and-show-it-in-a-window/33822024#33822024
  53 * http://www.einarsundgren.se/gstreamer-basic-real-time-streaming-tutorial/
  54 * https://gist.github.com/tetkuz/0c038321d05586841897
  55 * https://gist.github.com/esrever10/7d39fe2d4163c5b2d7006495c3c911bb
  56 * https://gist.github.com/nebgnahz/26a60cd28f671a8b7f522e80e75a9aa5
  57 * https://salsa.debian.org/debconf-video-team/ansible/-/blob/master/roles/voctomix/templates/videoteam-stream.j2
  58 * https://github.com/xfxf/video-scripts/blob/master/michael/youtube-live.sh
  59   (and others in the same repo)
  60
  61 # VLC
  62 Note that you have to close VLC and open it again for new streaming as VLC leaves the connections
  63 open (I spent hours figuring out why http based streaming doesn't work - `netstat -4 --ip` is nice
  64 for debugging in that respect).
  65
  66 ## RTP
  67 ### Source
  68 The address has to be the address where the video should be streamed **to**. In the following
  69 examples, a multicast address is used. It is either the IP address of the device receiving the video (unicast address) or a multicast address
  70 like 239.255.12.42 (multicast addresses are between 224.0.0.0 and 239.255.255.255, some of
  71 them being reserved, 239.0.0.0 to 239.255.255.255 are Organization-Local Scope so they are
  72 good candidates, see
  73 https://www.iana.org/assignments/multicast-addresses/multicast-addresses.xhtml).
  74
  75     cvlc -vv --sout '#transcode{vcodec=h264,acodec=mpga,channels=2,vb=800,ab=128}:rtp{mux=ts,dst=239.255.12.42,sdp=sap,name="Geris Game"}' GerisGame.mp4
  76     cvlc -vv --sout '#transcode{vcodec=h264,acodec=mpga,ab=128,channels=2,samplerate=44100,scodec=none}:rtp{dst=239.255.12.42,port=5004,mux=ts,sap,name=Geris Game}' :no-sout-all :sout-keep GerisGame.mp4
  77     cvlc -vv --sout '#transcode{vcodec=h264,acodec=mpga,channels=2}:rtp{mux=ts,dst=239.255.12.42,sdp=sap,name="Videokamera"}' v4l2:///dev/video0 # long latency
  78     cvlc -vv --sout '#transcode{vcodec=h264,acodec=mpga,channels=2}:rtp{mux=ts,dst=239.255.12.42,sdp=sap,name="Desktop"}' screen:// # not convincing
  79
  80 ### Player
  81     cvlc rtp://239.255.12.42
  82
  83
  84 ## RTSP
  85 For VLC, RTSP means RTSP combined with RTP.
  86
  87 ### Source
  88 We assume that the video source computer has the external IP 192.168.1.54.
  89 Instead of rtsp://192.168.1.54:8554/ we could also use rtsp://192.168.1.54:8554/mystream.sdp
  90
  91     cvlc -vv --sout '#transcode{vcodec=h264,acodec=mpga,ab=128,channels=2,samplerate=44100,scodec=none}:rtp{sdp=rtsp://:8554/}' :no-sout-all :sout-keep GerisGame.mp4
  92     cvlc -vv --sout '#rtp{dst=239.255.12.42,port=1234,sdp=rtsp://192.168.1.54:8554/}' :no-sout-all :sout-keep GerisGame.mp4
  93
  94
  95 ### Player
  96 The address needs to be the address of the source. Note the backslash at the end.
  97
  98     vlc rtsp://192.168.1.54:8554/
  99
 100
 101 ## VLC Remarks
 102 * Latency: The following options are said to reduce latency:
 103
 104       --network-caching=150 --clock-jitter=0 --clock-synchro=0
 105
 106 * Duplicating a stream is nice for debugging:
 107
 108       cvlc -vv --sout '#duplicate{dst=display,dst="transcode{vcodec=h264,acodec=mpga,channels=2,vb=800,ab=128}:rtp{mux=ts,dst=239.255.12.42,sdp=sap,name=Geris Game}"}' GerisGame.mp4
 109       cvlc rtp://239.255.12.42
 110
 111
 112 ## HTTP
 113 The address at the source side has to be the external one of the local computer.
 114
 115 ### Source (server)
 116     cvlc -vv --sout '#transcode{vcodec=mp4v,acodec=mpga,vb=800,ab=128}:standard{access=http,mux=ogg,dst=0.0.0.0:8080}' GerisGame.mp4
 117
 118 ### Player (client)
 119
 120     vlc http://192.168.1.54:8080
 121
 122
 123 # Kodi
 124 The player built into code knows at least the following streaming protocols: http, rtsp.
 125
 126 https://kodi.wiki/index.php?title=Internet_video_and_audio_streams