| by Steffen Klupsch <steffen@vlsi.informatik.tu-darmstadt.de>
 
Boundary Conditions (valid for transcode-0.5.0 and later):
 
   maximum image size is 1024x768
   The video frame operations ordering is fixed:
    "-j -I -X -B -Z -Y -r -z -l -k -K -G -C"
   (executed from left to right)
   Shrinking the image with '-B' is not possible
   if the image width/height is not a multiple of 32.
   Expanding the image with '-X' is not possible
   if the image width/height is not a multiple of 32.
   The final frame width/height should be a multiple of 8.
   (to avoid encoding problems with some divx codecs)
  
     Reducing the video height/width by 2,4,8
   Option '-r factor' can be used to shrink the video image by a
   constant factor, this factor can be 2,4 or 8.
     Clipping and changing the aspect ratio
   transcode uses 3 steps to produce the input image for the
   export modules
    
       Clipping of the input image.
       Changing the aspect ratio of the 1) output.
       Clipping of the 2) output.
     
   Used Options:
 
   The first clipping is defined by the option '-j top[,left[,bottom[,right]]]'
 if you don't specify all parameters, they will be assumed to be
      symmetric to the others.
 
          -j 80      is expanded to -j 80,0,80,0 (top,left,bottom,right)-j 80,8    is expanded to -j 80,8,80,8
 -j 80,8,10 is expanded to -j 80,8,10,8
 
 
 Changing the aspect ration can be done in 3 ways:
  
     (fast) shrinking the image with option '-B n[,m]'
     (fast) expanding the image with option '-X n,[m]'
     (high quality) resizing with option '-Z wxh'
   
 The 2nd clipping is defined by the option
'-Y top[,left[,bottom[,right]]]'
 if you don't specify all parameters, they will be assumed to be
      symmetric to the others.
 
Examples on Usage:
 
   Input data '16:9' 'widescreen' DVD data,
      output data should have 4:3 aspect ratio without black border.
      Analyze the input data, we assume a black border at the top and
      bottom of 66 pixel in a 720x576 pixel frame.
 
       
	 Using the fast resizing option  -B,
     shrinking the height to reach a correct aspect ratio:
     '-j 32,0 -B 4,0 -Y 24,0'
     Final image size: 720x336 Pixel
       Using the fast resizing options -X and -B,
     removing 1% at the left&right border, expanding the image width
     to PAL resolution, and shrinking the height to reach a
     correct aspect ratio:'-j 32,8 -X 0,2 -B 3,0 -Y 24,0'
 Final image size: 768x368 Pixel
 Using the fast -X resizing, expanding the image width,
     but removing 3% of the image at the left and the right border:'-j 64,24 -X 0,7'
 Final image size: 896x448 Pixel
 Using the slower -Z resizing, expanding the image width to PAL
     resolution:'-j 68,0 -Z 768x360'
 Final image size: 768x360 Pixel
 Using the slower -Z resizing, 800 Pixel image width:'-j 66,0 -Z 800x368'
 Final image size: 800x368 Pixel
 Using the slower -Z resizing, expanding the image width:'-j 64,0 -Z 960x448'
 Final image size: 960x448 Pixel
 
   Input data '16:9' DVD data without black borders,
   output data should have 4:3 aspect ratio.
   
     Using the fast resizing option  -B, shrinking the height to reach correct aspect ratio:
     '-B 4,0'
 Final image size: 720x448 Pixel
 Using the fast -X resizing, expanding the image width,
     but removing 3% of the image at the left and the right border:'-j 0,24 -X 0,7'
 Final image size: 896x576 Pixel
 Using the slower -Z resizing, expanding the image width
     to PAL resolution:'-Z 768x472'
 Final image size: 768x472 Pixel
 Using the slower -Z resizing, 800 Pixel image width:'-Z 800x480'
 Final image size: 800x480 Pixel
 Using the slower -Z resizing, expanding the image width:'-Z 960x576'
 Final image size: 960x576 Pixel
 
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