usage

外国人写的一个很好的嵌入式视频采集源程序。

- Command line options:


Options you need:
 
  h - help
  x - width
  y - height
  w - depth ( in bytes )
  d - device
  p - pnm output (24 or 8 bits only )
  t - targa output
  r - raw output
  f - filename (needed: - means stdout, + means timestamp-sequence-input)
  
  Optional:
 
  i - Input (if its set to -1, cycle input in loop mode)
  m - Mode <NTSC|PAL|SECAM>
  j - jpeg output
  u - Hue
  c - Contrast
  b - Brightness
  l - Colour
  s - show device report
  n - no capture, just setup and exit clean
  q - if set, toggle loop capture on 
 
 Stamp

 S - stamp text (if it doesn`t exists, there will be no stamp)
 X - stamp X coordinate inside the image
 Y - stamp Y coordinate inside the image
 W - stamp weight font scale (zoom)
 H - stamp height font scale (zoom)
 
 
- Optional effects:
  Note: I had no formal education in image processing, so, 
        much of this are an effort to learn more about his topic and help 
	those who mailed me asking about how to implement these kind of 
	functions in videodog. see video.c and effects.c to more details.
  	If you got something about this subject, please drop me a line.
 
I left the effects remarked in video.c, grab_one function, i
because isn`t everybody who needs it. In a future release, there will be an 
interface to it in the config file.
Effects are detailed in the EFFECTS file. 
They are implemented in ANSI C, with no asm optimization, so, should work well in any arch.

   sobel transformation (works better in 8 bpp)
   laplace transformation (works better in 8 bpp)
   gamma correction to <value>
   set threshold to the image (funny effects in RGB24).
   and more effects ( see CHANGELOG and EFFECTS )

   
  For Now these effects are enabled only in the single frame capture. Its easy to enable them in the loop, but seems not interesting.
  They are not included in the command line options too, because are experimental and educational code, so, enable them for yourself in video.c, inside the grab_one function. see EFFECTS for reference.



- Command line examples:
 	
	
	./videodog (will look for /etc/vd.conf and starts smoothly)
	
	./videodog -s -d /dev/video0 
 			- query the device about settings.
 
 
 	./videodog -x 320 -y 240 -w 3 -d /dev/video0 -p -f lelel.pnm ; 
						cjpeg lelel.pnm > lelel.jpg
 
 	./videodog -x 640 -y 480 -w 3 -i 1 -m NTSC -d /dev/video -p -f out.pnm
 			- uses input 1 and NTSC mode to grab image
 
 	./videodog -s -d /dev/video0 -u 200 
 			- set Hue == 200 and query the device
 
	./videodog -x 320 -y 240 -w 3 -d /dev/video0 -j -f leee.jpg 
			- uses the internal jpeg compressor ( aka jpeglib ).
		 	just edit the Makefile to disable it
	
	./videodog -x 320 -y 240 -w 3 -d /dev/video0 -j -q
			- loop capture at maximum possible rate.
			this will record in the current folder, lots of 
			img-xx.ext, where xx is a number, and ext is 
			one of {raw, pnm, jpg}.

	./videodog -x 320 -y 240 -w 3 -d /dev/video0 -j -f -
			- dumps the image to stdout ( any format )
			 just change the filename by -
	
	./videodog -x 320 -y 240 -w 3 -d /dev/video0 -j -f +
			- image name will be timestamp-sequence-input.( any format )
			 sequence is needed due to loop capture ( more than 1 fps)
	
	./videodog -x 320 -y 240 -w 3 -d /dev/video0 -j -f leee.jpg -S "oi %Y" -X 2 -Y 10
			- generate an jpeg image called leee.jpg, with a stamp containing oi and the year, at the 2, 10 coordinates.
	
	./videodog -x 320 -y 240 -w 3 -d /dev/video0 -j -f leee.jpg -S "oi %Y" -X 2 -Y 10 -W 2 -H 2
			- same as above, but scale the fonts by a factor of 2 ( experimental )
 	
	./videodog -x 640 -y 480 -w 3 -i -1  -d /dev/video -j -f + -q
 			- cycle inputs and grab images as timestamp-seq-input in a loop

NOTE: inside the stamp text, you should use the same simbols than strftime. Check out "man strftime" to see all the possibilities.