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 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
~/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
- 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
- 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 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).
Streaming over ssh N900
Here is an alternative way of streaming video on the 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.