Image transformation, compression, and decompression codecs
Imagecodecs is a Python library that provides block-oriented, in-memory buffer
transformation, compression, and decompression functions for use in Tifffile,
Czifile, Zarr 2, kerchunk, and other scientific image input/output packages.
Decode and/or encode functions are implemented for Zlib (DEFLATE), GZIP, LZMA,
ZStandard (ZSTD), Blosc, Brotli, Snappy, BZ2, LZ4, LZ4F, LZ4HC, LZ4H5, LZW,
LZO, LZF, LZFSE, LZHAM, PGLZ (PostgreSQL LZ), RCOMP (Rice), ZFP, SZ3, Pcodec,
SPERR, AEC, SZIP, LERC, EER, NPY, BCn, DDS, BMP, PNG, APNG, GIF, TIFF, WebP,
JPEG (2 to 16-bit), Lossless JPEG (LJPEG, LJ92, JPEGLL), JPEG 2000 (JP2, J2K),
JPEG LS, JPEG XL, JPEG XS, JPEG XR (WDP, HD Photo), Ultra HDR (JPEG_R),
MOZJPEG, AVIF, HEIF, QOI, RGBE (HDR), Jetraw, DICOMRLE, PackBits,
Packed Integers, Delta, XOR Delta, Floating Point Predictor, Bitorder reversal,
Byteshuffle, Bitshuffle, Float24 (24-bit floating point),
Quantize (Scale, BitGroom, BitRound, GranularBR), and
CMS (color space transformations).
Checksum functions are implemented for crc32, adler32, fletcher32, and
Jenkins lookup3.
:Author: Christoph Gohlke <https://www.cgohlke.com>
_
:License: BSD 3-Clause
:Version: 2024.12.30
:DOI: 10.5281/zenodo.6915978 <https://doi.org/10.5281/zenodo.6915978>
_
Quickstart
Install the imagecodecs package and all dependencies from the
Python Package Index <https://pypi.org/project/imagecodecs/>
_::
python -m pip install -U "imagecodecs[all]"
Imagecodecs is also available in other package repositories such as
Anaconda <https://anaconda.org/conda-forge/imagecodecs>
,
MSYS2 <https://packages.msys2.org/base/mingw-w64-python-imagecodecs>
, and
MacPorts <https://ports.macports.org/port/py-imagecodecs/summary>
_.
See Requirements
_ and Notes
_ for building from source.
See Examples
_ for using the programming interface.
Source code and support are available on
GitHub <https://github.com/cgohlke/imagecodecs>
_.
Requirements
This revision was tested with the following requirements and dependencies
(other versions may work):
CPython <https://www.python.org>
_ 3.10.11, 3.11.9, 3.12.8, 3.13.1 64-bit
Numpy <https://pypi.org/project/numpy>
_ 2.1.3
numcodecs <https://pypi.org/project/numcodecs/>
_ 0.14.1
(optional, for Zarr 2 compatible codecs)
Build requirements:
Cython <https://github.com/cython/cython>
_ 3.0.11
brotli <https://github.com/google/brotli>
_ 1.1.0
brunsli <https://github.com/google/brunsli>
_ 0.1
bzip2 <https://gitlab.com/bzip2/bzip2>
_ 1.0.8
c-blosc <https://github.com/Blosc/c-blosc>
_ 1.21.6
c-blosc2 <https://github.com/Blosc/c-blosc2>
_ 2.15.2
charls <https://github.com/team-charls/charls>
_ 2.4.2
giflib <https://sourceforge.net/projects/giflib/>
_ 5.2.2
jetraw <https://github.com/Jetraw/Jetraw>
_ 23.03.16.4
jxrlib <https://github.com/cgohlke/jxrlib>
_ 1.2
lcms2 <https://github.com/mm2/Little-CMS>
_ 2.16
lerc <https://github.com/Esri/lerc>
_ 4.0.4
libaec <https://gitlab.dkrz.de/k202009/libaec>
_ 1.1.3
libavif <https://github.com/AOMediaCodec/libavif>
_ 1.1.1
(aom <https://aomedia.googlesource.com/aom>
_ 3.11.0,
dav1d <https://github.com/videolan/dav1d>
_ 1.5.0,
rav1e <https://github.com/xiph/rav1e>
_ 0.7.1,
svt-av1 <https://gitlab.com/AOMediaCodec/SVT-AV1>
_ 2.3.0
libyuv <https://chromium.googlesource.com/libyuv/libyuv>
_ main)
libdeflate <https://github.com/ebiggers/libdeflate>
_ 1.23
libheif <https://github.com/strukturag/libheif>
_ 1.19.5
(libde265 <https://github.com/strukturag/libde265>
_ 1.0.15,
x265 <https://bitbucket.org/multicoreware/x265_git/src/master/>
_ 3.6)
libjpeg-turbo <https://github.com/libjpeg-turbo/libjpeg-turbo>
_ 3.1.0
libjxl <https://github.com/libjxl/libjxl>
_ 0.11.1
libjxs <https://jpeg.org/jpegxs/software.html>
_ 2.0.2
liblzma <https://github.com/tukaani-project/xz>
_ 5.6.3
libpng <https://github.com/glennrp/libpng>
_ 1.6.44
libpng-apng <https://sourceforge.net/projects/libpng-apng/>
_ 1.6.44
libtiff <https://gitlab.com/libtiff/libtiff>
_ 4.7.0
libultrahdr <https://github.com/google/libultrahdr>
_ 1.3.0
libwebp <https://github.com/webmproject/libwebp>
_ 1.5.0
lz4 <https://github.com/lz4/lz4>
_ 1.10.0
lzfse <https://github.com/lzfse/lzfse/>
_ 1.0
lzham_codec <https://github.com/richgel999/lzham_codec/>
_ 1.0
lzokay <https://github.com/AxioDL/lzokay>
_ db2df1f
mozjpeg <https://github.com/mozilla/mozjpeg>
_ 4.1.5
openjpeg <https://github.com/uclouvain/openjpeg>
_ 2.5.3
pcodec <https://github.com/mwlon/pcodec>
_ 0.3.1 (0.4.0 crashes)
snappy <https://github.com/google/snappy>
_ 1.2.1
sperr <https://github.com/NCAR/SPERR>
_ 0.8.2
sz3 <https://github.com/szcompressor/SZ3>
_ 3.1.8 (3.2.x crashes)
zfp <https://github.com/LLNL/zfp>
_ 1.0.1
zlib <https://github.com/madler/zlib>
_ 1.3.1
zlib-ng <https://github.com/zlib-ng/zlib-ng>
_ 2.2.2
zopfli <https://github.com/google/zopfli>
_ 1.0.3
zstd <https://github.com/facebook/zstd>
_ 1.5.6
Vendored requirements:
bcdec.h <https://github.com/iOrange/bcdec>
_ 963c5e5
bitshuffle <https://github.com/kiyo-masui/bitshuffle>
_ 0.5.2
cfitsio ricecomp.c <https://heasarc.gsfc.nasa.gov/fitsio/>
_ modified
h5checksum.c <https://github.com/HDFGroup/hdf5/>
_ modified
jpg_0XC3.cpp <https://github.com/rordenlab/dcm2niix/blob/master/console/jpg_0XC3.cpp>
_
modified
liblj92 <https://bitbucket.org/baldand/mlrawviewer/src/master/liblj92/>
_ modified
liblzf <http://oldhome.schmorp.de/marc/liblzf.html>
_ 3.6
libspng <https://github.com/randy408/libspng>
_ 0.7.4
nc4var.c <https://github.com/Unidata/netcdf-c/blob/main/libsrc4/nc4var.c>
_
modified
pg_lzcompress.c <https://github.com/postgres/postgres>
_ modified
qoi.h <https://github.com/phoboslab/qoi/>
_ 36190eb
rgbe.c <https://www.graphics.cornell.edu/~bjw/rgbe/rgbe.c>
_ modified
Test requirements:
tifffile <https://github.com/cgohlke/tifffile>
_ 2024.12.12
czifile <https://github.com/cgohlke/czifile>
_ 2019.7.2
zarr <https://github.com/zarr-developers/zarr-python>
_ 2.18.4
python-blosc <https://github.com/Blosc/python-blosc>
_ 1.11.2
python-blosc2 <https://github.com/Blosc/python-blosc2>
_ 2.7.1
python-brotli <https://github.com/google/brotli/tree/master/python>
_ 1.0.9
python-lz4 <https://github.com/python-lz4/python-lz4>
_ 4.3.3
python-lzf <https://github.com/teepark/python-lzf>
_ 0.2.6
python-snappy <https://github.com/andrix/python-snappy>
_ 0.7.2
python-zstd <https://github.com/sergey-dryabzhinsky/python-zstd>
_ 1.5.5.1
pyliblzfse <https://github.com/ydkhatri/pyliblzfse>
_ 0.4.1
zopflipy <https://github.com/hattya/zopflipy>
_ 1.10
Revisions
2024.12.30
- Pass 7655 tests.
- Fix out parameter array not zeroed in some cases.
- Fix ultrahdr_encode with linear rgbaf16 input (#108).
- Fix jpegls_encode with level greater than 9 (#119).
- Fix jpeg8_encode with bitspersample and lossless=False (#116).
- Fix excessive buffer allocation in lz4h5_encode (#112).
- Fix build error with libjpeg (#111).
2024.9.22
- Use libjpeg-turbo for all Lossless JPEG bit-depths if possible (#105).
- Fix PackBits encoder fails to skip short replication blocks (#107).
- Fix JPEG2K encoder leaving trailing random bytes (#104).
- Fix encoding and decoding JPEG XL with custom bitspersample (#102).
- Improve error handling in lzf_decode (#103).
- Add Ultra HDR (JPEG_R) codec based on libultrahdr library (#108).
- Add JPEGXS codec based on libjxs library (source only).
- Add SZ3 codec based on SZ3 library.
- Deprecate Python 3.9, support Python 3.13.
2024.6.1
- Fix segfault in sperr_decode.
- Fix segfault when strided-decoding into buffers with unexpected shapes (#98).
- Fix jpeg2k_encoder output buffer too small (#101).
- Add PCODEC codec based on pcodec library.
- Support NumPy 2.
2024.1.1
- Add 8/24-bit BMP codec.
- Add SPERR codec based on SPERR library.
- Add LZO decoder based on lzokay library.
- Add DICOMRLE decoder.
- Enable float16 in CMS codec.
- Enable MCT for lossless JPEG2K encoder (#88).
- Ignore pad-byte in PackBits decoder (#86).
- Fix heif_write_callback error message not set.
- Require lcms2 2.16 with issue-420 fixes.
- Require libjxl 0.9, libaec 1.1, Cython 3.
2023.9.18
Refer to the CHANGES file for older revisions.
Objectives
Many scientific image storage formats like TIFF, CZI, DICOM, HDF, and Zarr
are containers that hold large numbers of small data segments (chunks, tiles,
stripes), which are encoded using a variety of compression and pre-filtering
methods. Metadata common to all data segments are typically stored separate
from the segments.
The purpose of the Imagecodecs library is to support Python modules in
encoding and decoding such data segments. The specific aims are:
- Provide functions for encoding and decoding small image data segments
in-memory (not in-file) from and to bytes or numpy arrays for many
compression and filtering methods.
- Support image formats and compression methods not available elsewhere in
the Python ecosystem.
- Reduce the runtime dependency on numerous, large, inapt, or unmaintained
Python packages. The imagecodecs package only depends on numpy.
- Implement codecs as Cython wrappers of 3rd party libraries with a C API
and permissive license if exists, else use own C library.
Provide Cython definition files for the wrapped C libraries.
- Release the Python global interpreter lock (GIL) during extended native/C
function calls for multi-threaded use.
Accessing parts of large data segments and reading metadata from segments
are out of the scope of this library.
Notes
This library is largely a work in progress.
The API is not stable yet and might change between revisions.
Python <= 3.8 is no longer supported. 32-bit versions are deprecated.
Works on little-endian platforms only.
Supported platforms are win_amd64
, win_arm64
, win32
,
macosx_x86_64
, macosx_arm64
, manylinux_x86_64
, and
manylinux_aarch64
.
Wheels may not be available for all platforms and all releases.
Only the win_amd64
wheels include all features.
The tiff
, bcn
, dds
, dicomrle
, eer
, lzo
, packints
,
and jpegsof3
codecs are currently decode-only.
The heif
, jetraw
, and jpegxs
codecs are distributed as source
code only due to license and possible patent usage issues.
The latest Microsoft Visual C++ Redistributable for Visual Studio 2015-2022 <https://docs.microsoft.com/en-US/cpp/windows/latest-supported-vc-redist>
_
is required on Windows.
Refer to the imagecodecs/licenses folder for 3rd-party library licenses.
This software is based in part on the work of the Independent JPEG Group.
Update pip and setuptools to the latest version before installing imagecodecs::
python -m pip install -U pip setuptools wheel Cython
Before building imagecodecs from source code, install required tools and
libraries. For example, on latest Ubuntu Linux distributions:
``sudo apt-get install build-essential python3-dev cython3 python3-pip
python3-setuptools python3-wheel python3-numpy libdeflate-dev libjpeg-dev
libjxr-dev liblcms2-dev liblz4-dev liblerc-dev liblzma-dev libopenjp2-7-dev
libpng-dev libtiff-dev libwebp-dev libz-dev libzstd-dev``
To build and install imagecodecs from source code, run::
python -m pip install .
Many extensions are disabled by default when building from source.
To define which extensions are built, or to modify build settings such as
library names and compiler arguments, provide a
imagecodecs_distributor_setup.customize_build
function, which is
imported and executed during setup.
See setup.py
for pre-defined customize_build
functions.
Other projects providing imaging or compression codecs:
Python zlib <https://docs.python.org/3/library/zlib.html>
,
Python bz2 <https://docs.python.org/3/library/bz2.html>
,
Python lzma <https://docs.python.org/3/library/lzma.html>
,
backports.lzma <https://github.com/peterjc/backports.lzma>
,
python-lzo <https://bitbucket.org/james_taylor/python-lzo-static>
,
python-lzw <https://github.com/joeatwork/python-lzw>
,
python-lerc <https://pypi.org/project/lerc/>
,
wavpack-numcodecs <https://github.com/AllenNeuralDynamics/wavpack-numcodecs>
,
packbits <https://github.com/psd-tools/packbits>
,
isa-l.igzip <https://github.com/intel/isa-l>
,
fpzip <https://github.com/seung-lab/fpzip>
,
libmng <https://sourceforge.net/projects/libmng/>
,
OpenEXR <https://github.com/AcademySoftwareFoundation/openexr>
_
(EXR, PIZ, PXR24, B44, DWA),
pyJetraw <https://github.com/Jetraw/pyJetraw>
,
tinyexr <https://github.com/syoyo/tinyexr>
,
pytinyexr <https://github.com/syoyo/pytinyexr>
,
pyroexr <https://github.com/dragly/pyroexr>
,
JasPer <https://github.com/jasper-software/jasper>
,
libjpeg <https://github.com/thorfdbg/libjpeg>
(GPL),
pylibjpeg <https://github.com/pydicom/pylibjpeg>
,
pylibjpeg-libjpeg <https://github.com/pydicom/pylibjpeg-libjpeg>
(GPL),
pylibjpeg-openjpeg <https://github.com/pydicom/pylibjpeg-openjpeg>
,
pylibjpeg-rle <https://github.com/pydicom/pylibjpeg-rle>
,
glymur <https://github.com/quintusdias/glymur>
,
pyheif <https://github.com/carsales/pyheif>
,
pyrus-cramjam <https://github.com/milesgranger/pyrus-cramjam>
,
PyLZHAM <https://github.com/Galaxy1036/pylzham>
,
BriefLZ <https://github.com/jibsen/brieflz>
,
QuickLZ <http://www.quicklz.com/>
(GPL),
LZO <http://www.oberhumer.com/opensource/lzo/>
_ (GPL),
nvJPEG <https://developer.nvidia.com/nvjpeg>
,
nvJPEG2K <https://developer.nvidia.com/nvjpeg>
,
PyTurboJPEG <https://github.com/lilohuang/PyTurboJPEG>
,
CCSDS123 <https://github.com/drowzie/CCSDS123-Issue-2>
,
LPC-Rice <https://sourceforge.net/projects/lpcrice/>
,
CompressionAlgorithms <https://github.com/glampert/compression-algorithms>
,
Compressonator <https://github.com/GPUOpen-Tools/Compressonator>
,
Wuffs <https://github.com/google/wuffs>
,
TinyDNG <https://github.com/syoyo/tinydng>
,
OpenJPH <https://github.com/aous72/OpenJPH>
,
Grok <https://github.com/GrokImageCompression/grok>
_ (AGPL),
MAFISC <https://wr.informatik.uni-hamburg.de/research/projects/icomex/mafisc>
,
B3D <https://github.com/balintbalazs/B3D>
,
fo-dicom.Codecs <https://github.com/Efferent-Health/fo-dicom.Codecs>
,
jpegli <https://github.com/google/jpegli>
,
hdf5plugin <https://github.com/silx-kit/hdf5plugin>
_.
Examples
Import the JPEG2K codec:
from imagecodecs import (
... jpeg2k_encode,
... jpeg2k_decode,
... jpeg2k_check,
... jpeg2k_version,
... JPEG2K,
... )
Check that the JPEG2K codec is available in the imagecodecs build:
JPEG2K.available
True
Print the version of the JPEG2K codec's underlying OpenJPEG library:
jpeg2k_version()
'openjpeg 2.5.3'
Encode a numpy array in lossless JP2 format:
array = numpy.random.randint(100, 200, (256, 256, 3), numpy.uint8)
encoded = jpeg2k_encode(array, level=0)
bytes(encoded[:12])
b'\x00\x00\x00\x0cjP \r\n\x87\n'
Check that the encoded bytes likely contain a JPEG 2000 stream:
jpeg2k_check(encoded)
True
Decode the JP2 encoded bytes to a numpy array:
decoded = jpeg2k_decode(encoded)
numpy.array_equal(decoded, array)
True
Decode the JP2 encoded bytes to an existing numpy array:
out = numpy.empty_like(array)
_ = jpeg2k_decode(encoded, out=out)
numpy.array_equal(out, array)
True
Not all codecs are fully implemented, raising exceptions at runtime:
from imagecodecs import tiff_encode
tiff_encode(array)
Traceback (most recent call last):
...
NotImplementedError: tiff_encode
Write the numpy array to a JP2 file:
from imagecodecs import imwrite, imread
imwrite('_test.jp2', array)
Read the image from the JP2 file as numpy array:
image = imread('_test.jp2')
numpy.array_equal(image, array)
True
Create a JPEG 2000 compressed Zarr 2 array:
import zarr
import numcodecs
from imagecodecs.numcodecs import Jpeg2k
numcodecs.register_codec(Jpeg2k)
zarr.zeros(
... (4, 5, 512, 512, 3),
... chunks=(1, 1, 256, 256, 3),
... dtype='u1',
... compressor=Jpeg2k(),
... )
<zarr.core.Array (4, 5, 512, 512, 3) uint8>
Access image data in a sequence of JP2 files via tifffile.FileSequence and
dask.array:
import tifffile
import dask.array
def jp2_read(filename):
... with open(filename, 'rb') as fh:
... data = fh.read()
... return jpeg2k_decode(data)
...
with tifffile.FileSequence(jp2_read, '*.jp2') as ims:
... with ims.aszarr() as store:
... dask.array.from_zarr(store)
...
dask.array<from-zarr, shape=(1, 256, 256, 3)...chunksize=(1, 256, 256, 3)...
Write the Zarr 2 store to a fsspec ReferenceFileSystem in JSON format
and open it as a Zarr array:
store.write_fsspec(
... 'temp.json', url='file://', codec_id='imagecodecs_jpeg2k'
... )
import fsspec
mapper = fsspec.get_mapper(
... 'reference://', fo='temp.json', target_protocol='file'
... )
zarr.open(mapper, mode='r')
<zarr.core.Array (1, 256, 256, 3) uint8 read-only>
View the image in the JP2 file from the command line::
python -m imagecodecs _test.jp2