* Only works for single-tiled images --> will error out cleanly, as currently
in other cases
* Save re-reading the codestream for the tile, and re-use code-blocks of the
previous decoding pass.
* Future improvements might involve improving opj_decompress, and the image writing logic,
to use this strategy.
Instead of being the full tile size.
* Use a sparse array mechanism to store code-blocks and intermediate stages of
IDWT.
* IDWT, DC level shift and MCT stages are done just on that smaller array.
* Improve copy of tile component array to final image, by saving an intermediate
buffer.
* For full-tile decoding at reduced resolution, only allocate the tile buffer to
the reduced size, instead of the full-resolution size.
Currently we allocate at least 8192 bytes for each codeblock, and copy
the relevant parts of the codestream in that per-codeblock buffer as we
decode packets.
As the whole codestream for the tile is ingested in memory and alive
during the decoding, we can directly point to it instead of copying. But
to do that, we need an intermediate concept, a 'chunk' of code-stream segment,
given that segments may be made of data at different places in the code-stream
when quality layers are used.
With that change, the decoding of MAPA_005.jp2 goes down from the previous
improvement of 2.7 GB down to 1.9 GB.
New profile:
n4: 1885648469 (heap allocation functions) malloc/new/new[], --alloc-fns, etc.
n1: 1610689344 0x4E78287: opj_aligned_malloc (opj_malloc.c:61)
n1: 1610689344 0x4E71D7B: opj_alloc_tile_component_data (tcd.c:676)
n1: 1610689344 0x4E7272C: opj_tcd_init_decode_tile (tcd.c:816)
n1: 1610689344 0x4E4BDD9: opj_j2k_read_tile_header (j2k.c:8618)
n1: 1610689344 0x4E4C8A2: opj_j2k_decode_tiles (j2k.c:10349)
n1: 1610689344 0x4E4E36E: opj_j2k_decode (j2k.c:7847)
n1: 1610689344 0x4E52FA2: opj_jp2_decode (jp2.c:1564)
n0: 1610689344 0x40374E: main (opj_decompress.c:1459)
n1: 219232541 0x4E4BBF0: opj_j2k_read_tile_header (j2k.c:4685)
n1: 219232541 0x4E4C8A2: opj_j2k_decode_tiles (j2k.c:10349)
n1: 219232541 0x4E4E36E: opj_j2k_decode (j2k.c:7847)
n1: 219232541 0x4E52FA2: opj_jp2_decode (jp2.c:1564)
n0: 219232541 0x40374E: main (opj_decompress.c:1459)
n1: 39822000 0x4E727A9: opj_tcd_init_decode_tile (tcd.c:1219)
n1: 39822000 0x4E4BDD9: opj_j2k_read_tile_header (j2k.c:8618)
n1: 39822000 0x4E4C8A2: opj_j2k_decode_tiles (j2k.c:10349)
n1: 39822000 0x4E4E36E: opj_j2k_decode (j2k.c:7847)
n1: 39822000 0x4E52FA2: opj_jp2_decode (jp2.c:1564)
n0: 39822000 0x40374E: main (opj_decompress.c:1459)
n0: 15904584 in 52 places, all below massif's threshold (1.00%)
There are situations where, given a tile size, at a resolution level,
there are sub-bands with x0==x1 or y0==y1, that consequently don't have any
valid codeblocks, but the other sub-bands may be non-empty.
Given that we recycle the memory from one tile to another one, those
ghost codeblocks might be non-0 and thus candidate for packet inclusion.
This saves comparing the current pointer with the end of buffer pointer.
This results at least in tiny speed improvement for raw decoding, and
smaller code size for MQC as well.
This kills the remains of the raw.h/.c files that were only used for
decoding. Encoding using the mqc structure already.
Ported from Carl Hetherington work (actually through Matthieu Darbois's port
on top of OpenJPEG 2.1.0)
Can reduce total encoding time by 10-15%
WARNING: VSC mode is not implemented, and so is a temporary regression
that must be fixed.
Visual Studio 2015 does not pass regression tests with `__restrict` so kept disabled for MSVC.
Need to check proper usage of OPJ_RESTRICT (if correct then there’s
probably a bug in vc14)
Closes#661
Addition flag array such that colflags[1+0] is for state of col=0,row=0..3,
colflags[1+1] for col=1, row=0..3, colflags[1+flags_stride] for col=0,row=4..7, ...
This array avoids too much cache trashing when processing by 4 vertical samples
as done in the various decoding steps.
Even Rouault
Matthieu Darbois