ii-vision/transcoder/video_mode.py
kris f3d03a1b87 Update comments and fix some bugs
make_edit_distance
- use MASKED_DOTS since it does not have a simple relationship to the
  HEADER_BITS/BODY_BITS for HGR
- try disabling transposition distances for Damerau-Levenshtein, this
  may give better quality

screen
- introduce separate notion of MASKED_DOTS which is the number of
  (coloured) pixels we can extract from MASKED_BITS.  For HGR this is
  not the same.
- fix bug in _fix_array_neighbours that was not fixing headers for HGR
- don't cache everything in byte_pair_differences, it's effectively
  unbounded.  Using 1M for LRU size seems to work just as well in
  practise, without leaking memory.
- fix bug in _diff_weights when comparing content, we want to evaluate
  the effect of storing content byte in each offset separately, not
  cumulatively.
- add a consistency check function (not currently wired up) to assert
  that headers/footers are in sync across columns
- HGR should have 16 body bits, this was causing headers not to
  propagate correctly to/from neighbouring column
- add test case for this bug

video
- Use 8 random bits consistently, using 16 in some places may have
  introduced bias
- ignore palette bit when comparing 0x00 and 0x7f in sanity check
2019-07-11 23:40:00 +01:00

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Python

"""Enum representing video encoding mode."""
import enum
class VideoMode(enum.Enum):
HGR = 0 # Hi-Res
DHGR = 1 # Double Hi-Res