For some reason playback speed is only about 1.6x (probably due to
slowing down accesses to the I/O page to 1MHz, so as not to mess up
hardware timings), but happily this comes within 3% of being 44100/2.
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
IIGS palettes.
Move the palette diff_matrix generation into make_data_tables.py since
that is the only place it is used.
Demand-load the edit distance matrices when transcoding.
Add a test case that the bmp2dhr output of input filenames containing
'.' are handled correctly.
Break out video.Mode into video_mode.VideoMode to resolve circular
dependency.
- Extract out a (File)FrameSequencer class from Video to encapsulate
the generation of still frames. This also makes Video easier to test.
- Fix FileFrameSequencer.frames() to correctly handle filenames
containing '.'
- Temporarily switch to the BMP2DHR NTSC palette (#5) for evaluation.
Video:
- Temporarily hardcode DHGR decoding
- Optimize _heapify_priorities() by using numpy to vectorize the
construction of the list of tuples. This requires changing the
random nonce to an int so the intermediate array has a uniform type.
- Use the efficient 28-bit representation of DHGR (aux, main, aux,
main) tuples introduced in DHGRBitmap to evaluate diffs
- Switch to np.int type for accumulating diffs, and random.randint(0,
10000) instead of float for nonce values.
- Fix/improve some of the error evaluation in _index_changes:
- skip offsets whose diffs have already been cleared
- hoist some stuff out of _compute_error into the parent
- Add some validation that when we run out of work to do with a frame,
the source and target memory maps should be equal. This isn't
happening sometimes, i.e. there is a bug.
- can't emit Terminate opcode in the middle of the bytestream
- pad the TCP stream to next 2k boundary when emitting terminate opcode,
since the player will block until receiving this much data.
