Streaming video from built-in webcam

2014-03-19T08:46:40Z

216.151.137.34: /* Flumotion mention */

It is possible to use the [[Nokia N800|N800]] and [[Nokia N900|N900]] camera as a source of streaming video.

== N800 ==

This was originally described [https://maemo.org/community/wiki/howtostreamvideo/ here], but the referenced example has an error which prevents it from working.

This note describes how to stream video from the platform to an RTP sink, for example the [[VLC]] media player.

First, you must install the '''gstreamer-tools''' package from the diablo repo on repository.maemo.org.

* On the N800, the following script will stream video from the camera. Here, 172.31.0.244 is the Linux box with VLC installed, and 172.31.0.245 is the N800. I call this script <code>~/bin/rtpstream.sh</code>.
#!/bin/sh
VPORT=5434
APORT=5432
HOST=${1:-172.31.0.244}
gst-launch-0.10 v4l2src ! video/x-raw-yuv,width=176,height=144,framerate=$fraction$15/1 ! hantro4200enc stream-type=1 profile-and-level=1001 ! video/x-h263,framerate=$fraction$15/1 ! rtph263ppay mtu=1438 ! udpsink host=$HOST port=$VPORT dsppcmsrc ! queue ! audio/x-raw-int,channels=1,rate=8000 ! mulawenc ! rtppcmupay mtu=1438 ! udpsink host=$HOST port=$APORT

* On the Linux box, the sample .sdp file from [http://web.media.mit.edu/%7Elifton/snippets/n800_to_sl/ the original article], with the address of our VLC player, saved as a file i.e. <code>/tmp/n800.sdp</code>
v=0
o=- 37 614155991 IN IP4 127.0.0.0
s=QuickTime
t=0 0
a=range:npt=now-
m=audio 5432 RTP/AVP 0
c=IN IP4 172.31.0.245
b=AS:63
m=video 5434 RTP/AVP 96
c=IN IP4 172.31.0.245
a=rtpmap:96 H263-2000/90000
a=fmtp:96
a=cliprect:0,0,144,176
a=framesize:96 176-144
* On the N800, pop out the camera and run:
$ ~/bin/rtpstream.sh
assume on PATH, +x etc.
* On Linux box (note VLC runs on other platforms as well):
$ vlc /tmp/n800.sdp
* Enjoy streaming video (and sound) from the N800.

Thanks to [http://web.media.mit.edu/%7Elifton/snippets/n800_to_sl/ Josh Lifton] for the original leg wor

On a N800, to make the image vertically flip automatically when the camera's pointing backwards (so it's not upside-down), change the source name from "v4l2src" to "gconfv4l2src".

To adjust the video encoding quality, have a look at the parameters described by entering "gst-inspect hantro4200enc" at a shell prompt. Setting the "bit-rate" parameter to its maximum (515) and the "profile-and-level" parameter to 1007 produces a much better quality image. Also, I suspect the "stream-type" parameter should be "5" (H263), not "1" (MPEG4 Video).

== N900 ==

The instructions for the N900 are very similar to the N800.
First install gstreamer-tools.

$ apt-get install gstreamer-tools

To access the back camera use:
 ''/dev/video0''
 for the front
 ''/dev/video1''

In the example below the IP for the two devices are as follows
*PC IP 192.168.1.101
*N900 IP 192.168.1.105

On the N900 the command you want to run is:

$ gst-launch v4l2src device=/dev/video0 ! videoscale! video/x-raw-yuv,width=320,height=240 ! ffmpegcolorspace ! jpegenc ! tcpserversink host=192.168.1.101 port=5000

On the PC run

$ gst-launch tcpclientsrc host=192.168.1.105 port=5000 ! jpegdec ! autovideosink

The below also works
 '''N900'''

$ gst-launch v4l2camsrc device=/dev/video0 ! videoscale! video/x-raw-yuv,width=320,height=240 ! ffmpegcolorspace ! jpegenc ! tcpserversink host=192.168.1.101 port=5000

Another example using a different encoder/decoder and udp
 '''N900'''

$ gst-launch v4l2src device=/dev/video0 ! videoscale ! video/x-raw-yuv,width=320,height=240 ! ffmpegcolorspace ! smokeenc ! udpsink host=192.168.1.101 port=5000

 '''PC'''

$ gst-launch udpsrc port=5000 ! smokedec ! autovideosink

Another example using omap3cam driver
 '''N900'''

$ gst-launch-0.10 v4l2camsrc device=/dev/video0 driver-name=omap3cam ! videoscale ! video/x-raw-yuv,width=320,height=240 ! ffmpegcolorspace ! jpegenc ! tcpserversink host=192.168.1.101 port=5000

 '''PC'''

$ gst-launch tcpclientsrc host=192.168.1.105 port=5000 ! jpegdec ! autovideosink

There are many ways to skin this particular cat. Recommendations are to look at [http://www.gstreamer.net/ gstreamer] and familiarise yourself.

To stream from the N900 to VLC follow these [http://blog.pclewis.com/2010/02/streaming-nokia-n900-camera-to-vlc/ instructions]

=== For the future ===
=====vloopback=====
http://talk.maemo.org/showthread.php?t=26288
http://tektipsentriks.blogspot.com/2010/05/how-to-install-vloopback-on-ubuntu.html

===Webcam threads===
http://talk.maemo.org/showthread.php?t=31567
http://talk.maemo.org/showthread.php?t=46046

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== Streaming over ssh N900 ==

Here is an alternative way of streaming video on the [[Nokia N900|N900]] over ssh.

First get ssh to do X11 forwarding by installing xauth as follows:

# Install libxmuu1 (needed by xauth) by "apt-get install libxmuu1"
# Install the xauth from https://bugs.maemo.org/show_bug.cgi?id=2494

Now ssh to your N900 with the flag "-X" and then give the command:

gst-launch-0.10 v4l2src \
! videoscale ! video/x-raw-yuv,width=320,height=240 \
! xvimagesink

A 320x240 video window should now popup on your desktop.

[[Category:Connectivity]]
[[Category:Media]]
[[Category:Power users]]

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Streaming video from built-in webcam