To Investigate

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This page contains interesting tools that might be useful for future inclusion in the Network Security Toolkit.

Data Visualizer

Gephi is a generic visualizer that allows one to look at node/edge based graphs visually. Might be useful for visualized network traffic, intrusion detection data, etc.

Web Cam Image Capturing

The v4l-utils package includes a lot of web cam utilities. Including the v4l2-ctl command line tool which allows you to query and adjust the web cam settings from the command line. Try:

 yum install v4l-utils
 v4l2-ctl --all
 v4l2-ctl --list-ctrls

Here are some examples which query and then change the frame size:

[root@cayenne image-capture]# v4l2-ctl --all
Driver Info (not using libv4l2):
	Driver name   : uvcvideo
	Card type     : USB 2.0 Camera
	Bus info      : usb-0000:00:1d.7-2
	Driver version: 3.6.11
	Capabilities  : 0x04000001
		Video Capture
Format Video Capture:
	Width/Height  : 640/480
	Pixel Format  : 'YUYV'
	Field         : None
	Bytes per Line: 1280
	Size Image    : 614400
	Colorspace    : SRGB
Crop Capability Video Capture:
	Bounds      : Left 0, Top 0, Width 640, Height 480
	Default     : Left 0, Top 0, Width 640, Height 480
	Pixel Aspect: 1/1
Video input : 0 (Camera 1: ok)
Streaming Parameters Video Capture:
	Capabilities     : timeperframe
	Frames per second: 30.000 (30/1)
	Read buffers     : 0
[root@cayenne image-capture]# v4l2-ctl --list-framesizes=YUYV
	Size: Discrete 640x480
	Size: Discrete 352x288
	Size: Discrete 320x240
	Size: Discrete 176x144
	Size: Discrete 160x120
	Size: Discrete 640x480
[root@cayenne image-capture]# v4l2-ctl --set-fmt-video=width=352,height=288,pixelformat=YUYV
[root@cayenne image-capture]# v4l2-ctl --get-fmt-videoFormat Video Capture:
	Width/Height  : 352/288
	Pixel Format  : 'YUYV'
	Field         : None
	Bytes per Line: 704
	Size Image    : 202752
	Colorspace    : SRGB
[root@cayenne image-capture]# 

The streamer tool from the xawtv package can be used to capture still frames at periodic intervals. For example, the following will capture 10 frames total at a capture rate of 0.2 seconds per frame (5 seconds between each image):

streamer -w 2.0 -t 10 -r 0.2 -s 640x480 -o /var/nst/image-capture/image-00.jpeg

NOTE: It's been hit and miss for me related to the use of the streamer rate parameter (often is seems like it is ignored and images are captured very quickly - especially at the initial start of the capture).

The mplayer and ffmpeg packages can be used to capture still frames like:

yum install mplayer ffmpeg
mplayer -tv device=/dev/video0:width=640:height=480:outfmt=rgb24 -frames 60 -vo jpeg:outdir=/var/nst/image-capture2 tv:// 

This definitely is a simple method to grab a snapshot or two. Here are some things to note:

  • The user be a member of the video group.
  • The first couple of frames may be completely bad (on my netbook I see two solid green frames before the images start coming in).
  • It may take many frames until the web camera's "auto adjustments" (white balance, etc) result in decent pictures (on my web cam things started looking decent at frame 10 and by frame 20 things looked like they had stabilized).

Ideally, this sounds to me like if you were using the mplayer approach it would be best if you could leave the web cam in a on state after capture (I think this would reduce the number of frames required to get a good image the next time).

The ZoneMinder package ( is available under Fedora and creating a setup/management page in the NST WUI would be possible.