Streaming video from built-in webcam

It is possible to use the N800 camera as a source of streaming video. This was originally described here, but the referenced example has an error which prevents it working.

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

1.

Install the necessary gstreamer packages. The following list may be excessive, but "works": * gstreamer-tools * gstreamer0.10-3gp-osso * gstreamer0.10-adpcm-osso * gstreamer0.10-ffmpeg-osso * gstreamer0.10-gnomevfs * gstreamer0.10-hantro * gstreamer0.10-id3lib-osso * gstreamer0.10-mpeg1demux-osso * gstreamer0.10-mpegstream-osso * gstreamer0.10-plugins-bad * gstreamer0.10-plugins-base * gstreamer0.10-plugins-base-extra * gstreamer0.10-plugins-base-kulve * gstreamer0.10-plugins-good * gstreamer0.10-plugins-good-extra * gstreamer0.10-plugins-good-kulve * gstreamer0.10-tools * gstreamer0.10-wma 2.

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 ~/bin/rtpstream.sh.

#!/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

3.

On the Linux box, the sample .sdp file from the original article, with the address of our VLC player, saved as a file i.e. /tmp/n800.sdp

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

4.

On the N800, pop out the camera and run:

$ ~/bin/rtpstream.sh # assume on PATH, +x etc.

5.

On Linux box (note VLC runs on other platforms as well):

$ vlc /tmp/n800.sdp

6.

Enjoy streaming video (and sound) from the N800.