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doc:howto:webcam

Webcam with the Linux UVC driver

Prerequisites

  1. follow usb.video
Name Depends Size Description
mjpg-streamer libpthread, libjpeg 33738 Streaming application for Linux-UVC compatible webcams

The package motion is not now available in the OpenWrt repositories. http://www.lavrsen.dk/foswiki/bin/view/Motion/WebHome

Installation

opkg install kmod-video-uvc mjpg-streamer

Configuration

/etc/config/mjpg-streamer

Don't forget change option enabled '0' to '1'.

Usage

  • start on boot
    /etc/init.d/mjpg-streamer enable
  • start mjpg-streamer right now
    /etc/init.d/mjpg-streamer start

NOTE: You will need to edit the mjpeg config to enable the mjpeg streamer. Manually edit the /etc/config/mjpeg-streamer file.

Now open the URL http://192.168.1.1:8080/ in the Firefox browser or VLC and watch the MJPEG stream (the default username/password is "openwrt"/"openwrt"). In other browsers, scripts, etc., you can use http://192.168.1.1:8080?action=snapshot for taking one image or http://192.168.1.1:8080?action=stream for stream of images.

Performance

mjpeg-streamer fps, CPU load, memory usage, bandwidth at different resolutions:

Embedding video stream into simple webpages

  • Download a package located here and unpack it into /www/webcam_www directory.
  • Edit /etc/init.d/mjpg-streamer - find this line in function start():

[ $enabled -gt 0 -a -c $device ] && sleep 3 && $SSD -S -m -p $PIDF -q -x $PROG -- --input "input_uvc.so --device $device --fps $fps --resolution $resolution" --output "output_http.so --port $port" &
and add -w /www/webcam_www behind –output "output_http.so. Now it should look like this:
[ $enabled -gt 0 -a -c $device ] && sleep 3 && $SSD -S -m -p $PIDF -q -x $PROG -- --input "input_uvc.so --device $device --fps $fps --resolution $resolution" --output "output_http.so -w /www/webcam_www --port $port" &

Controlling exposure, color balance, etc.

The opkg version of mjpg-streamer has no control options for the camera. If you want to control exposure, brightness and other options you'll need to install uvcdynctrl.

Install uvcdynctrl

opkg install uvcdynctrl

List available devices.

/usr/bin/uvcdynctrl -l

List available control options.

/usr/bin/uvcdynctrl -c

Listing available controls for device video0:
  Brightness
  Contrast
  Saturation
  Hue
  White Balance Temperature, Auto
  Gamma
  Power Line Frequency
  White Balance Temperature
  Sharpness
  Backlight Compensation

Create a configuration file based on the current running values.

/usr/bin/uvcdynctrl -W /etc/config/uvcdynctrl

Load a configuration file, which can be edited.

/usr/bin/uvcdynctrl -L /etc/config/uvcdynctrl

The above can be added to /etc/rc.local, via the GUI or command line to load settings required for your camera. I use the above to enable auto exposure and auto white balance which would otherwise be disabled from cold a start.

Webcam Pan and Tilt Example with Microprocessor

Here is a writeup of using openWrt for a pan and tilt camera. The devices were NSLU2 for openWrt and Picaxe for microcontroller, but the idea is the same with arduino as micro and other openWrt devices:

http://www.picaxeforum.co.uk/showthread.php?13705

Grey day today here in Nova Scotia, you can see at http://www.lyzby.com/cam.html

Troubleshooting

If the control page doesn't contain any of the controls, edit the file /etc/init.d/mjpg-streamer and replace these lines

service_start /usr/bin/mjpg_streamer --input "input_uvc.so \
                --device $device --fps $fps --resolution $resolution" \           
                --output "output_http.so --www $www --port $port"

by (on a single line )

service_start /usr/bin/mjpg_streamer --input "input_uvc.so --device $device --fps $fps --resolution $resolution" --output "output_http.so --www $www --port $port"

The command mjpg_streamer -h give you usage information and examples.

If your webcam is an uvc supported by V4L but you cannot get an image (white page), you may check that webcam output is not YUV only like output below:

root@OpenWrt:~# v4l2-ctl -V
Format Video Capture:
        Width/Height  : 320/240
        Pixel Format  : 'YUYV'
        Field         : None
        Bytes per Line: 640
        Size Image    : 153600
        Colorspace    : SRGB

The package uvc-streamer is no longer in the OpenWrt repositories.

Tags

doc/howto/webcam.txt · Last modified: 2016/07/11 16:43 by beard