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# Here is an example of a successive-approximation script.
# This is equivalent to the default script used by
# "cjpeg -progressive" for YCbCr images:
# Initial DC scan for Y,Cb,Cr (lowest bit not sent)
0,1,2: 0-0, 0, 1 ;
# First AC scan: send first 5 Y AC coefficients, minus 2 lowest bits:
0: 1-5, 0, 2 ;
# Send all Cr,Cb AC coefficients, minus lowest bit:
# (chroma data is usually too small to be worth subdividing further;
# but note we send Cr first since eye is least sensitive to Cb)
2: 1-63, 0, 1 ;
1: 1-63, 0, 1 ;
# Send remaining Y AC coefficients, minus 2 lowest bits:
0: 6-63, 0, 2 ;
# Send next-to-lowest bit of all Y AC coefficients:
0: 1-63, 2, 1 ;
# At this point we've sent all but the lowest bit of all coefficients.
# Send lowest bit of DC coefficients
0,1,2: 0-0, 1, 0 ;
# Send lowest bit of AC coefficients
2: 1-63, 1, 0 ;
1: 1-63, 1, 0 ;
# Y AC lowest bit scan is last; it's usually the largest scan
0: 1-63, 1, 0 ;
# It may be worth pointing out that this script is tuned for quality
# settings of around 50 to 75. For lower quality settings, you'd
# probably want to use a script with fewer stages of successive
# approximation (otherwise the initial scans will be really bad).
# For higher quality settings, you might want to use more stages of
# successive approximation (so that the initial scans are not too large).
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