View source for How to stream camera over network

== Overview ==
This article will explain how to stream camera content over network thanks to [[GStreamer overview|GStreamer]] application on top of [[V4L2_camera_overview|V4L2 Linux<sup>&reg;</sup> kernel framework]].

Capturing compressed JPEG pictures is an efficient way to send camera images to any local or remote player; JPEG pictures require a limited bandwidth while being fully interoperable.

Find below some examples of command lines allowing to capture a continuous JPEG stream while playing it using various multimedia players, either local or remote.

== Local streaming ==
Here is an example of a local preview involving [[V4l2-ctl]] for JPEG pictures capture and [[Gst-play|gst-play]] GStreamer player for JPEG decoding and display. JPEG pictures are sent over a standard Linux pipe.
 {{Board$}} v4l2-ctl --set-parm=30;v4l2-ctl --set-fmt-video=width=640,height=480,pixelformat=JPEG --stream-mmap --stream-count=-1 {{highlight|'''--stream-to{{=}}-'''}} {{HighlightParam|2>/dev/null}} {{highlight|'''<nowiki>|</nowiki>'''}} gst-play-1.0 {{highlight|'''"fd://0"'''}}
{{highlight|'''--stream-to{{=}}-'''}} tells [[V4l2-ctl]] to output binary captured content to standard output, which is then sent to pipe {{highlight|'''<nowiki>|</nowiki>'''}}.

Special URI {{highlight|'''fd://0'''}} tells [[Gst-play|gst-play]] GStreamer player to read data from the pipe.

Note the {{HighlightParam|2>/dev/null}} right after the [[V4l2-ctl]] command to remove the logs from console output.
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== UDP streaming ==
{{Info|An internet connection is required, for example by plugging an ethernet cable on the [[STM32MP157C-EV1 - hardware description#MB1262-CN3|STM32MP157C-EV1 Evaluation board CN3 ethernet connector]]}}{{UpdateNeededForNewBoard|Point to the ethernet connector (if any) of the new board}}
Get first the IP address {{highlight|'''aa.bb.cc.dd'''}} of the host PC using [[Ifconfig|ifconfig]] command:
 {{PC$}} ifconfig | grep "inet addr"
    inet addr:{{highlight|'''aa.bb.cc.dd'''}}  Bcast:10.201.23.255  Mask:255.255.252.0
    inet addr:127.0.0.1  Mask:255.0.0.0

Then fill the {{HighlightParam|'''host{{=}}'''}} udpsink property with this IP address on the remote side:
 {{Board$}} v4l2-ctl --set-parm=30;v4l2-ctl --set-fmt-video=width=640,height=480,pixelformat=JPEG --stream-mmap --stream-count=-1 --stream-to=- 2>/dev/null | gst-launch-1.0 fdsrc ! jpegparse ! rtpjpegpay ! udpsink {{HighlightParam|'''host{{=}}'''}}{{highlight|'''aa.bb.cc.dd'''}} port=5000

Then play the UDP stream on host PC:
 {{PC$}} gst-launch-1.0 udpsrc port=5000 ! application/x-rtp, encoding-name=JPEG ! rtpjpegdepay ! jpegparse ! decodebin ! autovideosink
A new window will popup on host PC displaying the camera content.
{{Info|Due to SDP protocol signaling, this solution is not fully interoperable because it needs a dedicated GStreamer command line to be played on host side}}


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== RTSP streaming ==
{{Warning| neet to explain gst-rtsp-server-launch-1.0 (derived from GStreamer example test_launch.c of rtsp libraries) and not yet documented}}
Prerequesite:
* Board connected to local network
* RTSP server [[GStreamer overview|GStreamer]] libraries (libgstrtspserver-1.0.so* to be put in /usr/lib/gstreamer-1.0/)
* gst-rtsp-server-launch-1.0 [[GStreamer overview|GStreamer]] utility
* Get the ip address of the board:
 {{Board$}} ifconfig

 eth0      Link encap:Ethernet  HWaddr 00:80:E1:42:42:D8  
          inet addr:{{blue|'''10.48.1.122'''}}  Bcast:10.48.3.255  Mask:255.255.252.0


Capture VGA jpeg pictures and stream them over network using RTSP streaming protocol:
 {{Board$}} gst-rtsp-server-launch-1.0 {{blue|'''10.48.1.122'''}} 8081 "/test" "( v4l2src do-timestamp=true device=/dev/video0  ! image/jpeg, width=640, height=480, framerate=(fraction)15/1 ! queue ! jpegparse ! rtpjpegpay name=pay0 pt=96 )"

 stream ready at {{green|'''rtsp://10.48.1.122:8081/test'''}}


Stream can then be played on host PC using any media player which support RTSP streaming such as [[GStreamer overview|GStreamer]] or VLC:
 {{PC$}} gst-play-1.0 {{green|'''rtsp://10.48.1.122:8081/test'''}}

 {{PC$}} cvlc {{green|'''rtsp://10.48.1.122:8081/test'''}}

Stream can also be played on another target with same [[Gst-play|gst-play]] [[GStreamer overview|GStreamer]] utility:
 {{Board$}} gst-play-1.0 {{green|'''rtsp://10.48.1.122:8081/test'''}}
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<noinclude>
{{ArticleBasedOnModel | How to article model}}
{{PublicationRequestId | 7962 | 2018-07-05 | AlainF}} 
[[Category:How to run use cases]]
[[Category:V4L2]]
[[Category:GStreamer]]
</noinclude>