| ChangeLog.md |
|
113896 |
| jaricom.c |
jaricom.c
This file was part of the Independent JPEG Group's software:
Developed 1997-2009 by Guido Vollbeding.
libjpeg-turbo Modifications:
Copyright (C) 2015, 2018, D. R. Commander.
For conditions of distribution and use, see the accompanying README.ijg
file.
This file contains probability estimation tables for common use in
arithmetic entropy encoding and decoding routines.
This data represents Table D.2 in
Recommendation ITU-T T.81 (1992) | ISO/IEC 10918-1:1994 and Table 24 in
Recommendation ITU-T T.82 (1993) | ISO/IEC 11544:1993.
|
5132 |
| jcapimin.c |
jcapimin.c
This file was part of the Independent JPEG Group's software:
Copyright (C) 1994-1998, Thomas G. Lane.
Modified 2003-2010 by Guido Vollbeding.
libjpeg-turbo Modifications:
Copyright (C) 2022, D. R. Commander.
For conditions of distribution and use, see the accompanying README.ijg
file.
This file contains application interface code for the compression half
of the JPEG library. These are the "minimum" API routines that may be
needed in either the normal full-compression case or the transcoding-only
case.
Most of the routines intended to be called directly by an application
are in this file or in jcapistd.c. But also see jcparam.c for
parameter-setup helper routines, jcomapi.c for routines shared by
compression and decompression, and jctrans.c for the transcoding case.
|
10517 |
| jcapistd.c |
jcapistd.c
This file was part of the Independent JPEG Group's software:
Copyright (C) 1994-1996, Thomas G. Lane.
libjpeg-turbo Modifications:
Copyright (C) 2022, D. R. Commander.
For conditions of distribution and use, see the accompanying README.ijg
file.
This file contains application interface code for the compression half
of the JPEG library. These are the "standard" API routines that are
used in the normal full-compression case. They are not used by a
transcoding-only application. Note that if an application links in
jpeg_start_compress, it will end up linking in the entire compressor.
We thus must separate this file from jcapimin.c to avoid linking the
whole compression library into a transcoder.
|
6551 |
| jcarith.c |
jcarith.c
This file was part of the Independent JPEG Group's software:
Developed 1997-2009 by Guido Vollbeding.
libjpeg-turbo Modifications:
Copyright (C) 2015, 2018, 2021-2022, D. R. Commander.
For conditions of distribution and use, see the accompanying README.ijg
file.
This file contains portable arithmetic entropy encoding routines for JPEG
(implementing Recommendation ITU-T T.81 | ISO/IEC 10918-1).
Both sequential and progressive modes are supported in this single module.
Suspension is not currently supported in this module.
NOTE: All referenced figures are from
Recommendation ITU-T T.81 (1992) | ISO/IEC 10918-1:1994.
|
29668 |
| jccoefct.c |
jccoefct.c
This file was part of the Independent JPEG Group's software:
Copyright (C) 1994-1997, Thomas G. Lane.
libjpeg-turbo Modifications:
Copyright (C) 2022, D. R. Commander.
For conditions of distribution and use, see the accompanying README.ijg
file.
This file contains the coefficient buffer controller for compression.
This controller is the top level of the lossy JPEG compressor proper.
The coefficient buffer lies between forward-DCT and entropy encoding steps.
|
17425 |
| jccolext.c |
jccolext.c
This file was part of the Independent JPEG Group's software:
Copyright (C) 1991-1996, Thomas G. Lane.
libjpeg-turbo Modifications:
Copyright (C) 2009-2012, 2015, 2022, D. R. Commander.
For conditions of distribution and use, see the accompanying README.ijg
file.
This file contains input colorspace conversion routines.
|
4790 |
| jccolor.c |
jccolor.c
This file was part of the Independent JPEG Group's software:
Copyright (C) 1991-1996, Thomas G. Lane.
libjpeg-turbo Modifications:
Copyright 2009 Pierre Ossman <ossman@cendio.se> for Cendio AB
Copyright (C) 2009-2012, 2015, 2022, D. R. Commander.
Copyright (C) 2014, MIPS Technologies, Inc., California.
For conditions of distribution and use, see the accompanying README.ijg
file.
This file contains input colorspace conversion routines.
|
23875 |
| jcdctmgr.c |
jcdctmgr.c
This file was part of the Independent JPEG Group's software:
Copyright (C) 1994-1996, Thomas G. Lane.
libjpeg-turbo Modifications:
Copyright (C) 1999-2006, MIYASAKA Masaru.
Copyright 2009 Pierre Ossman <ossman@cendio.se> for Cendio AB
Copyright (C) 2011, 2014-2015, 2022, 2024, D. R. Commander.
For conditions of distribution and use, see the accompanying README.ijg
file.
This file contains the forward-DCT management logic.
This code selects a particular DCT implementation to be used,
and it performs related housekeeping chores including coefficient
quantization.
|
23029 |
| jcdiffct.c |
jcdiffct.c
This file was part of the Independent JPEG Group's software:
Copyright (C) 1994-1997, Thomas G. Lane.
Lossless JPEG Modifications:
Copyright (C) 1999, Ken Murchison.
libjpeg-turbo Modifications:
Copyright (C) 2022, D. R. Commander.
For conditions of distribution and use, see the accompanying README.ijg
file.
This file contains the difference buffer controller for compression.
This controller is the top level of the lossless JPEG compressor proper.
The difference buffer lies between the prediction/differencing and entropy
encoding steps.
|
14840 |
| jchuff.c |
jchuff.c
This file was part of the Independent JPEG Group's software:
Copyright (C) 1991-1997, Thomas G. Lane.
Lossless JPEG Modifications:
Copyright (C) 1999, Ken Murchison.
libjpeg-turbo Modifications:
Copyright (C) 2009-2011, 2014-2016, 2018-2024, D. R. Commander.
Copyright (C) 2015, Matthieu Darbois.
Copyright (C) 2018, Matthias Räncker.
Copyright (C) 2020, Arm Limited.
Copyright (C) 2022, Felix Hanau.
For conditions of distribution and use, see the accompanying README.ijg
file.
This file contains Huffman entropy encoding routines.
Much of the complexity here has to do with supporting output suspension.
If the data destination module demands suspension, we want to be able to
back up to the start of the current MCU. To do this, we copy state
variables into local working storage, and update them back to the
permanent JPEG objects only upon successful completion of an MCU.
NOTE: All referenced figures are from
Recommendation ITU-T T.81 (1992) | ISO/IEC 10918-1:1994.
|
37246 |
| jchuff.h |
jchuff.h
This file was part of the Independent JPEG Group's software:
Copyright (C) 1991-1997, Thomas G. Lane.
libjpeg-turbo Modifications:
Copyright (C) 2022, D. R. Commander.
For conditions of distribution and use, see the accompanying README.ijg
file.
This file contains declarations for Huffman entropy encoding routines
that are shared between the sequential encoder (jchuff.c) and the
progressive encoder (jcphuff.c). No other modules need to see these.
|
1766 |
| jcicc.c |
jcicc.c
Copyright (C) 1997-1998, Thomas G. Lane, Todd Newman.
Copyright (C) 2017, D. R. Commander.
For conditions of distribution and use, see the accompanying README.ijg
file.
This file provides code to write International Color Consortium (ICC) device
profiles embedded in JFIF JPEG image files. The ICC has defined a standard
for including such data in JPEG "APP2" markers. The code given here does
not know anything about the internal structure of the ICC profile data; it
just knows how to embed the profile data in a JPEG file while writing it.
|
4072 |
| jcinit.c |
jcinit.c
This file was part of the Independent JPEG Group's software:
Copyright (C) 1991-1997, Thomas G. Lane.
Lossless JPEG Modifications:
Copyright (C) 1999, Ken Murchison.
libjpeg-turbo Modifications:
Copyright (C) 2020, 2022, D. R. Commander.
For conditions of distribution and use, see the accompanying README.ijg
file.
This file contains initialization logic for the JPEG compressor.
This routine is in charge of selecting the modules to be executed and
making an initialization call to each one.
Logically, this code belongs in jcmaster.c. It's split out because
linking this routine implies linking the entire compression library.
For a transcoding-only application, we want to be able to use jcmaster.c
without linking in the whole library.
|
5186 |
| jclhuff.c |
jclhuff.c
This file was part of the Independent JPEG Group's software:
Copyright (C) 1991-1997, Thomas G. Lane.
Lossless JPEG Modifications:
Copyright (C) 1999, Ken Murchison.
libjpeg-turbo Modifications:
Copyright (C) 2022, D. R. Commander.
For conditions of distribution and use, see the accompanying README.ijg
file.
This file contains Huffman entropy encoding routines for lossless JPEG.
Much of the complexity here has to do with supporting output suspension.
If the data destination module demands suspension, we want to be able to
back up to the start of the current MCU. To do this, we copy state
variables into local working storage, and update them back to the
permanent JPEG objects only upon successful completion of an MCU.
|
18635 |
| jclossls.c |
jclossls.c
This file was part of the Independent JPEG Group's software:
Copyright (C) 1998, Thomas G. Lane.
Lossless JPEG Modifications:
Copyright (C) 1999, Ken Murchison.
libjpeg-turbo Modifications:
Copyright (C) 2022, D. R. Commander.
For conditions of distribution and use, see the accompanying README.ijg
file.
This file contains prediction, sample differencing, and point transform
routines for the lossless JPEG compressor.
|
8895 |
| jcmainct.c |
jcmainct.c
This file was part of the Independent JPEG Group's software:
Copyright (C) 1994-1996, Thomas G. Lane.
Lossless JPEG Modifications:
Copyright (C) 1999, Ken Murchison.
libjpeg-turbo Modifications:
Copyright (C) 2022, D. R. Commander.
For conditions of distribution and use, see the accompanying README.ijg
file.
This file contains the main buffer controller for compression.
The main buffer lies between the pre-processor and the JPEG
compressor proper; it holds downsampled data in the JPEG colorspace.
|
5632 |
| jcmarker.c |
jcmarker.c
This file was part of the Independent JPEG Group's software:
Copyright (C) 1991-1998, Thomas G. Lane.
Modified 2003-2010 by Guido Vollbeding.
Lossless JPEG Modifications:
Copyright (C) 1999, Ken Murchison.
libjpeg-turbo Modifications:
Copyright (C) 2010, 2022, D. R. Commander.
For conditions of distribution and use, see the accompanying README.ijg
file.
This file contains routines to write JPEG datastream markers.
|
17896 |
| jcmaster.c |
jcmaster.c
This file was part of the Independent JPEG Group's software:
Copyright (C) 1991-1997, Thomas G. Lane.
Modified 2003-2010 by Guido Vollbeding.
Lossless JPEG Modifications:
Copyright (C) 1999, Ken Murchison.
libjpeg-turbo Modifications:
Copyright (C) 2010, 2016, 2018, 2022-2024, D. R. Commander.
For conditions of distribution and use, see the accompanying README.ijg
file.
This file contains master control logic for the JPEG compressor.
These routines are concerned with parameter validation, initial setup,
and inter-pass control (determining the number of passes and the work
to be done in each pass).
|
28025 |
| jcmaster.h |
jcmaster.h
This file was part of the Independent JPEG Group's software:
Copyright (C) 1991-1995, Thomas G. Lane.
libjpeg-turbo Modifications:
Copyright (C) 2016, D. R. Commander.
For conditions of distribution and use, see the accompanying README.ijg
file.
This file contains master control structure for the JPEG compressor.
|
1376 |
| jcomapi.c |
jcomapi.c
This file was part of the Independent JPEG Group's software:
Copyright (C) 1994-1997, Thomas G. Lane.
libjpeg-turbo Modifications:
Copyright (C) 2024, D. R. Commander.
For conditions of distribution and use, see the accompanying README.ijg
file.
This file contains application interface routines that are used for both
compression and decompression.
|
3275 |
| jconfig.h |
Version ID for the JPEG library.
Might be useful for tests like "#if JPEG_LIB_VERSION >= 60".
|
1485 |
| jconfigint.h |
libjpeg-turbo build number |
2030 |
| jcparam.c |
jcparam.c
This file was part of the Independent JPEG Group's software:
Copyright (C) 1991-1998, Thomas G. Lane.
Modified 2003-2008 by Guido Vollbeding.
Lossless JPEG Modifications:
Copyright (C) 1999, Ken Murchison.
libjpeg-turbo Modifications:
Copyright (C) 2009-2011, 2018, 2023, D. R. Commander.
For conditions of distribution and use, see the accompanying README.ijg
file.
This file contains optional default-setting code for the JPEG compressor.
Applications do not have to use this file, but those that don't use it
must know a lot more about the innards of the JPEG code.
|
19497 |
| jcphuff.c |
jcphuff.c
This file was part of the Independent JPEG Group's software:
Copyright (C) 1995-1997, Thomas G. Lane.
Lossless JPEG Modifications:
Copyright (C) 1999, Ken Murchison.
libjpeg-turbo Modifications:
Copyright (C) 2011, 2015, 2018, 2021-2022, 2024, D. R. Commander.
Copyright (C) 2016, 2018, 2022, Matthieu Darbois.
Copyright (C) 2020, Arm Limited.
Copyright (C) 2021, Alex Richardson.
For conditions of distribution and use, see the accompanying README.ijg
file.
This file contains Huffman entropy encoding routines for progressive JPEG.
We do not support output suspension in this module, since the library
currently does not allow multiple-scan files to be written with output
suspension.
|
32790 |
| jcprepct.c |
jcprepct.c
This file was part of the Independent JPEG Group's software:
Copyright (C) 1994-1996, Thomas G. Lane.
Lossless JPEG Modifications:
Copyright (C) 1999, Ken Murchison.
libjpeg-turbo Modifications:
Copyright (C) 2022, D. R. Commander.
For conditions of distribution and use, see the accompanying README.ijg
file.
This file contains the compression preprocessing controller.
This controller manages the color conversion, downsampling,
and edge expansion steps.
Most of the complexity here is associated with buffering input rows
as required by the downsampler. See the comments at the head of
jcsample.c for the downsampler's needs.
|
13564 |
| jcsample.c |
jcsample.c
This file was part of the Independent JPEG Group's software:
Copyright (C) 1991-1996, Thomas G. Lane.
Lossless JPEG Modifications:
Copyright (C) 1999, Ken Murchison.
libjpeg-turbo Modifications:
Copyright 2009 Pierre Ossman <ossman@cendio.se> for Cendio AB
Copyright (C) 2014, MIPS Technologies, Inc., California.
Copyright (C) 2015, 2019, 2022, D. R. Commander.
For conditions of distribution and use, see the accompanying README.ijg
file.
This file contains downsampling routines.
Downsampling input data is counted in "row groups". A row group
is defined to be max_v_samp_factor pixel rows of each component,
from which the downsampler produces v_samp_factor sample rows.
A single row group is processed in each call to the downsampler module.
The downsampler is responsible for edge-expansion of its output data
to fill an integral number of DCT blocks horizontally. The source buffer
may be modified if it is helpful for this purpose (the source buffer is
allocated wide enough to correspond to the desired output width).
The caller (the prep controller) is responsible for vertical padding.
The downsampler may request "context rows" by setting need_context_rows
during startup. In this case, the input arrays will contain at least
one row group's worth of pixels above and below the passed-in data;
the caller will create dummy rows at image top and bottom by replicating
the first or last real pixel row.
An excellent reference for image resampling is
Digital Image Warping, George Wolberg, 1990.
Pub. by IEEE Computer Society Press, Los Alamitos, CA. ISBN 0-8186-8944-7.
The downsampling algorithm used here is a simple average of the source
pixels covered by the output pixel. The hi-falutin sampling literature
refers to this as a "box filter". In general the characteristics of a box
filter are not very good, but for the specific cases we normally use (1:1
and 2:1 ratios) the box is equivalent to a "triangle filter" which is not
nearly so bad. If you intend to use other sampling ratios, you'd be well
advised to improve this code.
A simple input-smoothing capability is provided. This is mainly intended
for cleaning up color-dithered GIF input files (if you find it inadequate,
we suggest using an external filtering program such as pnmconvol). When
enabled, each input pixel P is replaced by a weighted sum of itself and its
eight neighbors. P's weight is 1-8*SF and each neighbor's weight is SF,
where SF = (smoothing_factor / 1024).
Currently, smoothing is only supported for 2h2v sampling factors.
|
19963 |
| jctrans.c |
jctrans.c
This file was part of the Independent JPEG Group's software:
Copyright (C) 1995-1998, Thomas G. Lane.
Modified 2000-2009 by Guido Vollbeding.
libjpeg-turbo Modifications:
Copyright (C) 2020, 2022, D. R. Commander.
For conditions of distribution and use, see the accompanying README.ijg
file.
This file contains library routines for transcoding compression,
that is, writing raw DCT coefficient arrays to an output JPEG file.
The routines in jcapimin.c will also be needed by a transcoder.
|
15276 |
| jdapimin.c |
jdapimin.c
This file was part of the Independent JPEG Group's software:
Copyright (C) 1994-1998, Thomas G. Lane.
Lossless JPEG Modifications:
Copyright (C) 1999, Ken Murchison.
libjpeg-turbo Modifications:
Copyright (C) 2016, 2022, 2024, D. R. Commander.
For conditions of distribution and use, see the accompanying README.ijg
file.
This file contains application interface code for the decompression half
of the JPEG library. These are the "minimum" API routines that may be
needed in either the normal full-decompression case or the
transcoding-only case.
Most of the routines intended to be called directly by an application
are in this file or in jdapistd.c. But also see jcomapi.c for routines
shared by compression and decompression, and jdtrans.c for the transcoding
case.
|
13610 |
| jdapistd.c |
jdapistd.c
This file was part of the Independent JPEG Group's software:
Copyright (C) 1994-1996, Thomas G. Lane.
libjpeg-turbo Modifications:
Copyright (C) 2010, 2015-2020, 2022-2024, D. R. Commander.
Copyright (C) 2015, Google, Inc.
For conditions of distribution and use, see the accompanying README.ijg
file.
This file contains application interface code for the decompression half
of the JPEG library. These are the "standard" API routines that are
used in the normal full-decompression case. They are not used by a
transcoding-only application. Note that if an application links in
jpeg_start_decompress, it will end up linking in the entire decompressor.
We thus must separate this file from jdapimin.c to avoid linking the
whole decompression library into a transcoder.
|
27436 |
| jdarith.c |
jdarith.c
This file was part of the Independent JPEG Group's software:
Developed 1997-2015 by Guido Vollbeding.
libjpeg-turbo Modifications:
Copyright (C) 2015-2020, 2022, D. R. Commander.
For conditions of distribution and use, see the accompanying README.ijg
file.
This file contains portable arithmetic entropy encoding routines for JPEG
(implementing Recommendation ITU-T T.81 | ISO/IEC 10918-1).
Both sequential and progressive modes are supported in this single module.
Suspension is not currently supported in this module.
NOTE: All referenced figures are from
Recommendation ITU-T T.81 (1992) | ISO/IEC 10918-1:1994.
|
25539 |
| jdatadst.c |
jdatadst.c
This file was part of the Independent JPEG Group's software:
Copyright (C) 1994-1996, Thomas G. Lane.
Modified 2009-2012 by Guido Vollbeding.
libjpeg-turbo Modifications:
Copyright (C) 2013, 2016, 2022, D. R. Commander.
For conditions of distribution and use, see the accompanying README.ijg
file.
This file contains compression data destination routines for the case of
emitting JPEG data to memory or to a file (or any stdio stream).
While these routines are sufficient for most applications,
some will want to use a different destination manager.
IMPORTANT: we assume that fwrite() will correctly transcribe an array of
JOCTETs into 8-bit-wide elements on external storage. If char is wider
than 8 bits on your machine, you may need to do some tweaking.
|
9222 |
| jdatasrc.c |
jdatasrc.c
This file was part of the Independent JPEG Group's software:
Copyright (C) 1994-1996, Thomas G. Lane.
Modified 2009-2011 by Guido Vollbeding.
libjpeg-turbo Modifications:
Copyright (C) 2013, 2016, 2022, D. R. Commander.
For conditions of distribution and use, see the accompanying README.ijg
file.
This file contains decompression data source routines for the case of
reading JPEG data from memory or from a file (or any stdio stream).
While these routines are sufficient for most applications,
some will want to use a different source manager.
IMPORTANT: we assume that fread() will correctly transcribe an array of
JOCTETs from 8-bit-wide elements on external storage. If char is wider
than 8 bits on your machine, you may need to do some tweaking.
|
10087 |
| jdcoefct.c |
jdcoefct.c
This file was part of the Independent JPEG Group's software:
Copyright (C) 1994-1997, Thomas G. Lane.
libjpeg-turbo Modifications:
Copyright 2009 Pierre Ossman <ossman@cendio.se> for Cendio AB
Copyright (C) 2010, 2015-2016, 2019-2020, 2022-2023, D. R. Commander.
Copyright (C) 2015, 2020, Google, Inc.
For conditions of distribution and use, see the accompanying README.ijg
file.
This file contains the coefficient buffer controller for decompression.
This controller is the top level of the lossy JPEG decompressor proper.
The coefficient buffer lies between entropy decoding and inverse-DCT steps.
In buffered-image mode, this controller is the interface between
input-oriented processing and output-oriented processing.
Also, the input side (only) is used when reading a file for transcoding.
|
34360 |
| jdcoefct.h |
jdcoefct.h
This file was part of the Independent JPEG Group's software:
Copyright (C) 1994-1997, Thomas G. Lane.
libjpeg-turbo Modifications:
Copyright 2009 Pierre Ossman <ossman@cendio.se> for Cendio AB
Copyright (C) 2020, Google, Inc.
Copyright (C) 2022, D. R. Commander.
For conditions of distribution and use, see the accompanying README.ijg
file.
|
2873 |
| jdcol565.c |
jdcol565.c
This file was part of the Independent JPEG Group's software:
Copyright (C) 1991-1997, Thomas G. Lane.
Modifications:
Copyright (C) 2013, Linaro Limited.
Copyright (C) 2014-2015, 2022, D. R. Commander.
For conditions of distribution and use, see the accompanying README.ijg
file.
This file contains output colorspace conversion routines.
|
11909 |
| jdcolext.c |
jdcolext.c
This file was part of the Independent JPEG Group's software:
Copyright (C) 1991-1997, Thomas G. Lane.
libjpeg-turbo Modifications:
Copyright (C) 2009, 2011, 2015, 2022-2023, D. R. Commander.
For conditions of distribution and use, see the accompanying README.ijg
file.
This file contains output colorspace conversion routines.
|
4514 |
| jdcolor.c |
jdcolor.c
This file was part of the Independent JPEG Group's software:
Copyright (C) 1991-1997, Thomas G. Lane.
Modified 2011 by Guido Vollbeding.
libjpeg-turbo Modifications:
Copyright 2009 Pierre Ossman <ossman@cendio.se> for Cendio AB
Copyright (C) 2009, 2011-2012, 2014-2015, 2022, D. R. Commander.
Copyright (C) 2013, Linaro Limited.
For conditions of distribution and use, see the accompanying README.ijg
file.
This file contains output colorspace conversion routines.
|
29866 |
| jdct.h |
jdct.h
This file was part of the Independent JPEG Group's software:
Copyright (C) 1994-1996, Thomas G. Lane.
libjpeg-turbo Modifications:
Copyright (C) 2015, 2022, D. R. Commander.
For conditions of distribution and use, see the accompanying README.ijg
file.
This include file contains common declarations for the forward and
inverse DCT modules. These declarations are private to the DCT managers
(jcdctmgr.c, jddctmgr.c) and the individual DCT algorithms.
The individual DCT algorithms are kept in separate files to ease
machine-dependent tuning (e.g., assembly coding).
|
10135 |
| jddctmgr.c |
jddctmgr.c
This file was part of the Independent JPEG Group's software:
Copyright (C) 1994-1996, Thomas G. Lane.
Modified 2002-2010 by Guido Vollbeding.
libjpeg-turbo Modifications:
Copyright 2009 Pierre Ossman <ossman@cendio.se> for Cendio AB
Copyright (C) 2010, 2015, 2022, D. R. Commander.
Copyright (C) 2013, MIPS Technologies, Inc., California.
For conditions of distribution and use, see the accompanying README.ijg
file.
This file contains the inverse-DCT management logic.
This code selects a particular IDCT implementation to be used,
and it performs related housekeeping chores. No code in this file
is executed per IDCT step, only during output pass setup.
Note that the IDCT routines are responsible for performing coefficient
dequantization as well as the IDCT proper. This module sets up the
dequantization multiplier table needed by the IDCT routine.
|
11724 |
| jddiffct.c |
jddiffct.c
This file was part of the Independent JPEG Group's software:
Copyright (C) 1994-1997, Thomas G. Lane.
Lossless JPEG Modifications:
Copyright (C) 1999, Ken Murchison.
libjpeg-turbo Modifications:
Copyright (C) 2022, D. R. Commander.
For conditions of distribution and use, see the accompanying README.ijg
file.
This file contains the [un]difference buffer controller for decompression.
This controller is the top level of the lossless JPEG decompressor proper.
The difference buffer lies between the entropy decoding and
prediction/undifferencing steps. The undifference buffer lies between the
prediction/undifferencing and scaling steps.
In buffered-image mode, this controller is the interface between
input-oriented processing and output-oriented processing.
|
13396 |
| jdhuff.c |
jdhuff.c
This file was part of the Independent JPEG Group's software:
Copyright (C) 1991-1997, Thomas G. Lane.
Lossless JPEG Modifications:
Copyright (C) 1999, Ken Murchison.
libjpeg-turbo Modifications:
Copyright (C) 2009-2011, 2016, 2018-2019, 2022, D. R. Commander.
Copyright (C) 2018, Matthias Räncker.
For conditions of distribution and use, see the accompanying README.ijg
file.
This file contains Huffman entropy decoding routines.
Much of the complexity here has to do with supporting input suspension.
If the data source module demands suspension, we want to be able to back
up to the start of the current MCU. To do this, we copy state variables
into local working storage, and update them back to the permanent
storage only upon successful completion of an MCU.
NOTE: All referenced figures are from
Recommendation ITU-T T.81 (1992) | ISO/IEC 10918-1:1994.
|
26826 |
| jdhuff.h |
jdhuff.h
This file was part of the Independent JPEG Group's software:
Copyright (C) 1991-1997, Thomas G. Lane.
Lossless JPEG Modifications:
Copyright (C) 1999, Ken Murchison.
libjpeg-turbo Modifications:
Copyright (C) 2010-2011, 2015-2016, 2021, D. R. Commander.
Copyright (C) 2018, Matthias Räncker.
For conditions of distribution and use, see the accompanying README.ijg
file.
This file contains declarations for Huffman entropy decoding routines
that are shared between the sequential decoder (jdhuff.c), the progressive
decoder (jdphuff.c), and the lossless decoder (jdlhuff.c). No other modules
need to see these.
|
9903 |
| jdicc.c |
jdicc.c
Copyright (C) 1997-1998, Thomas G. Lane, Todd Newman.
Copyright (C) 2017, D. R. Commander.
For conditions of distribution and use, see the accompanying README.ijg
file.
This file provides code to read International Color Consortium (ICC) device
profiles embedded in JFIF JPEG image files. The ICC has defined a standard
for including such data in JPEG "APP2" markers. The code given here does
not know anything about the internal structure of the ICC profile data; it
just knows how to get the profile data from a JPEG file while reading it.
|
5409 |
| jdinput.c |
jdinput.c
This file was part of the Independent JPEG Group's software:
Copyright (C) 1991-1997, Thomas G. Lane.
Lossless JPEG Modifications:
Copyright (C) 1999, Ken Murchison.
libjpeg-turbo Modifications:
Copyright (C) 2010, 2016, 2018, 2022, D. R. Commander.
Copyright (C) 2015, Google, Inc.
For conditions of distribution and use, see the accompanying README.ijg
file.
This file contains input control logic for the JPEG decompressor.
These routines are concerned with controlling the decompressor's input
processing (marker reading and coefficient/difference decoding).
The actual input reading is done in jdmarker.c, jdhuff.c, jdphuff.c,
and jdlhuff.c.
|
15069 |
| jdlhuff.c |
jdlhuff.c
This file was part of the Independent JPEG Group's software:
Copyright (C) 1991-1997, Thomas G. Lane.
Lossless JPEG Modifications:
Copyright (C) 1999, Ken Murchison.
libjpeg-turbo Modifications:
Copyright (C) 2022, D. R. Commander.
For conditions of distribution and use, see the accompanying README.ijg
file.
This file contains Huffman entropy decoding routines for lossless JPEG.
Much of the complexity here has to do with supporting input suspension.
If the data source module demands suspension, we want to be able to back
up to the start of the current MCU. To do this, we copy state variables
into local working storage, and update them back to the permanent
storage only upon successful completion of an MCU.
|
10030 |
| jdlossls.c |
jdlossls.c
This file was part of the Independent JPEG Group's software:
Copyright (C) 1998, Thomas G. Lane.
Lossless JPEG Modifications:
Copyright (C) 1999, Ken Murchison.
libjpeg-turbo Modifications:
Copyright (C) 2022, D. R. Commander.
For conditions of distribution and use, see the accompanying README.ijg
file.
This file contains prediction, sample undifferencing, point transform, and
sample scaling routines for the lossless JPEG decompressor.
|
8522 |
| jdmainct.c |
jdmainct.c
This file was part of the Independent JPEG Group's software:
Copyright (C) 1994-1996, Thomas G. Lane.
libjpeg-turbo Modifications:
Copyright (C) 2010, 2016, 2022, D. R. Commander.
For conditions of distribution and use, see the accompanying README.ijg
file.
This file contains the main buffer controller for decompression.
The main buffer lies between the JPEG decompressor proper and the
post-processor; it holds downsampled data in the JPEG colorspace.
Note that this code is bypassed in raw-data mode, since the application
supplies the equivalent of the main buffer in that case.
|
20170 |
| jdmainct.h |
jdmainct.h
This file was part of the Independent JPEG Group's software:
Copyright (C) 1994-1996, Thomas G. Lane.
libjpeg-turbo Modifications:
Copyright (C) 2022, D. R. Commander.
For conditions of distribution and use, see the accompanying README.ijg
file.
|
2679 |
| jdmarker.c |
jdmarker.c
This file was part of the Independent JPEG Group's software:
Copyright (C) 1991-1998, Thomas G. Lane.
Lossless JPEG Modifications:
Copyright (C) 1999, Ken Murchison.
libjpeg-turbo Modifications:
Copyright (C) 2012, 2015, 2022, 2024, D. R. Commander.
For conditions of distribution and use, see the accompanying README.ijg
file.
This file contains routines to decode JPEG datastream markers.
Most of the complexity arises from our desire to support input
suspension: if not all of the data for a marker is available,
we must exit back to the application. On resumption, we reprocess
the marker.
|
42610 |
| jdmaster.c |
jdmaster.c
This file was part of the Independent JPEG Group's software:
Copyright (C) 1991-1997, Thomas G. Lane.
Modified 2002-2009 by Guido Vollbeding.
Lossless JPEG Modifications:
Copyright (C) 1999, Ken Murchison.
libjpeg-turbo Modifications:
Copyright (C) 2009-2011, 2016, 2019, 2022-2023, D. R. Commander.
Copyright (C) 2013, Linaro Limited.
Copyright (C) 2015, Google, Inc.
For conditions of distribution and use, see the accompanying README.ijg
file.
This file contains master control logic for the JPEG decompressor.
These routines are concerned with selecting the modules to be executed
and with determining the number of passes and the work to be done in each
pass.
|
34487 |
| jdmaster.h |
jdmaster.h
This file was part of the Independent JPEG Group's software:
Copyright (C) 1991-1995, Thomas G. Lane.
For conditions of distribution and use, see the accompanying README.ijg
file.
This file contains the master control structure for the JPEG decompressor.
|
788 |
| jdmerge.c |
jdmerge.c
This file was part of the Independent JPEG Group's software:
Copyright (C) 1994-1996, Thomas G. Lane.
libjpeg-turbo Modifications:
Copyright 2009 Pierre Ossman <ossman@cendio.se> for Cendio AB
Copyright (C) 2009, 2011, 2014-2015, 2020, 2022, D. R. Commander.
Copyright (C) 2013, Linaro Limited.
For conditions of distribution and use, see the accompanying README.ijg
file.
This file contains code for merged upsampling/color conversion.
This file combines functions from jdsample.c and jdcolor.c;
read those files first to understand what's going on.
When the chroma components are to be upsampled by simple replication
(ie, box filtering), we can save some work in color conversion by
calculating all the output pixels corresponding to a pair of chroma
samples at one time. In the conversion equations
R = Y + K1 * Cr
G = Y + K2 * Cb + K3 * Cr
B = Y + K4 * Cb
only the Y term varies among the group of pixels corresponding to a pair
of chroma samples, so the rest of the terms can be calculated just once.
At typical sampling ratios, this eliminates half or three-quarters of the
multiplications needed for color conversion.
This file currently provides implementations for the following cases:
YCbCr => RGB color conversion only.
Sampling ratios of 2h1v or 2h2v.
No scaling needed at upsample time.
Corner-aligned (non-CCIR601) sampling alignment.
Other special cases could be added, but in most applications these are
the only common cases. (For uncommon cases we fall back on the more
general code in jdsample.c and jdcolor.c.)
|
19979 |
| jdmerge.h |
jdmerge.h
This file was part of the Independent JPEG Group's software:
Copyright (C) 1994-1996, Thomas G. Lane.
libjpeg-turbo Modifications:
Copyright (C) 2020, 2022, D. R. Commander.
For conditions of distribution and use, see the accompanying README.ijg
file.
|
1664 |
| jdmrg565.c |
jdmrg565.c
This file was part of the Independent JPEG Group's software:
Copyright (C) 1994-1996, Thomas G. Lane.
libjpeg-turbo Modifications:
Copyright (C) 2013, Linaro Limited.
Copyright (C) 2014-2015, 2018, 2020, 2022, D. R. Commander.
For conditions of distribution and use, see the accompanying README.ijg
file.
This file contains code for merged upsampling/color conversion.
|
11138 |
| jdmrgext.c |
jdmrgext.c
This file was part of the Independent JPEG Group's software:
Copyright (C) 1994-1996, Thomas G. Lane.
libjpeg-turbo Modifications:
Copyright (C) 2011, 2015, 2020, 2022-2023, D. R. Commander.
For conditions of distribution and use, see the accompanying README.ijg
file.
This file contains code for merged upsampling/color conversion.
|
5895 |
| jdphuff.c |
jdphuff.c
This file was part of the Independent JPEG Group's software:
Copyright (C) 1995-1997, Thomas G. Lane.
Lossless JPEG Modifications:
Copyright (C) 1999, Ken Murchison.
libjpeg-turbo Modifications:
Copyright (C) 2015-2016, 2018-2022, D. R. Commander.
For conditions of distribution and use, see the accompanying README.ijg
file.
This file contains Huffman entropy decoding routines for progressive JPEG.
Much of the complexity here has to do with supporting input suspension.
If the data source module demands suspension, we want to be able to back
up to the start of the current MCU. To do this, we copy state variables
into local working storage, and update them back to the permanent
storage only upon successful completion of an MCU.
NOTE: All referenced figures are from
Recommendation ITU-T T.81 (1992) | ISO/IEC 10918-1:1994.
|
22244 |
| jdpostct.c |
jdpostct.c
This file was part of the Independent JPEG Group's software:
Copyright (C) 1994-1996, Thomas G. Lane.
libjpeg-turbo Modifications:
Copyright (C) 2022-2023, D. R. Commander.
For conditions of distribution and use, see the accompanying README.ijg
file.
This file contains the decompression postprocessing controller.
This controller manages the upsampling, color conversion, and color
quantization/reduction steps; specifically, it controls the buffering
between upsample/color conversion and color quantization/reduction.
If no color quantization/reduction is required, then this module has no
work to do, and it just hands off to the upsample/color conversion code.
An integrated upsample/convert/quantize process would replace this module
entirely.
|
11617 |
| jdsample.c |
jdsample.c
This file was part of the Independent JPEG Group's software:
Copyright (C) 1991-1996, Thomas G. Lane.
libjpeg-turbo Modifications:
Copyright 2009 Pierre Ossman <ossman@cendio.se> for Cendio AB
Copyright (C) 2010, 2015-2016, 2022, D. R. Commander.
Copyright (C) 2014, MIPS Technologies, Inc., California.
Copyright (C) 2015, Google, Inc.
Copyright (C) 2019-2020, Arm Limited.
For conditions of distribution and use, see the accompanying README.ijg
file.
This file contains upsampling routines.
Upsampling input data is counted in "row groups". A row group
is defined to be (v_samp_factor * DCT_scaled_size / min_DCT_scaled_size)
sample rows of each component. Upsampling will normally produce
max_v_samp_factor pixel rows from each row group (but this could vary
if the upsampler is applying a scale factor of its own).
An excellent reference for image resampling is
Digital Image Warping, George Wolberg, 1990.
Pub. by IEEE Computer Society Press, Los Alamitos, CA. ISBN 0-8186-8944-7.
|
18583 |
| jdsample.h |
jdsample.h
This file was part of the Independent JPEG Group's software:
Copyright (C) 1991-1996, Thomas G. Lane.
libjpeg-turbo Modifications:
Copyright (C) 2022, D. R. Commander.
For conditions of distribution and use, see the accompanying README.ijg
file.
|
1825 |
| jdtrans.c |
jdtrans.c
This file was part of the Independent JPEG Group's software:
Copyright (C) 1995-1997, Thomas G. Lane.
libjpeg-turbo Modifications:
Copyright (C) 2020, 2022, D. R. Commander.
For conditions of distribution and use, see the accompanying README.ijg
file.
This file contains library routines for transcoding decompression,
that is, reading raw DCT coefficient arrays from an input JPEG file.
The routines in jdapimin.c will also be needed by a transcoder.
|
5624 |
| jerror.c |
jerror.c
This file was part of the Independent JPEG Group's software:
Copyright (C) 1991-1998, Thomas G. Lane.
libjpeg-turbo Modifications:
Copyright (C) 2022, 2024, D. R. Commander.
For conditions of distribution and use, see the accompanying README.ijg
file.
This file contains simple error-reporting and trace-message routines.
These are suitable for Unix-like systems and others where writing to
stderr is the right thing to do. Many applications will want to replace
some or all of these routines.
If you define USE_WINDOWS_MESSAGEBOX in jconfig.h or in the makefile,
you get a Windows-specific hack to display error messages in a dialog box.
It ain't much, but it beats dropping error messages into the bit bucket,
which is what happens to output to stderr under most Windows C compilers.
These routines are used by both the compression and decompression code.
|
7566 |
| jerror.h |
jerror.h
This file was part of the Independent JPEG Group's software:
Copyright (C) 1994-1997, Thomas G. Lane.
Modified 1997-2009 by Guido Vollbeding.
Lossless JPEG Modifications:
Copyright (C) 1999, Ken Murchison.
libjpeg-turbo Modifications:
Copyright (C) 2014, 2017, 2021-2023, D. R. Commander.
For conditions of distribution and use, see the accompanying README.ijg
file.
This file defines the error and message codes for the JPEG library.
Edit this file to add new codes, or to translate the message strings to
some other language.
A set of error-reporting macros are defined too. Some applications using
the JPEG library may wish to include this file to get the error codes
and/or the macros.
|
16159 |
| jfdctflt.c |
jfdctflt.c
Copyright (C) 1994-1996, Thomas G. Lane.
This file is part of the Independent JPEG Group's software.
For conditions of distribution and use, see the accompanying README.ijg
file.
This file contains a floating-point implementation of the
forward DCT (Discrete Cosine Transform).
This implementation should be more accurate than either of the integer
DCT implementations. However, it may not give the same results on all
machines because of differences in roundoff behavior. Speed will depend
on the hardware's floating point capacity.
A 2-D DCT can be done by 1-D DCT on each row followed by 1-D DCT
on each column. Direct algorithms are also available, but they are
much more complex and seem not to be any faster when reduced to code.
This implementation is based on Arai, Agui, and Nakajima's algorithm for
scaled DCT. Their original paper (Trans. IEICE E-71(11):1095) is in
Japanese, but the algorithm is described in the Pennebaker & Mitchell
JPEG textbook (see REFERENCES section in file README.ijg). The following
code is based directly on figure 4-8 in P&M.
While an 8-point DCT cannot be done in less than 11 multiplies, it is
possible to arrange the computation so that many of the multiplies are
simple scalings of the final outputs. These multiplies can then be
folded into the multiplications or divisions by the JPEG quantization
table entries. The AA&N method leaves only 5 multiplies and 29 adds
to be done in the DCT itself.
The primary disadvantage of this method is that with a fixed-point
implementation, accuracy is lost due to imprecise representation of the
scaled quantization values. However, that problem does not arise if
we use floating point arithmetic.
|
5588 |
| jfdctfst.c |
jfdctfst.c
This file was part of the Independent JPEG Group's software:
Copyright (C) 1994-1996, Thomas G. Lane.
libjpeg-turbo Modifications:
Copyright (C) 2015, D. R. Commander.
For conditions of distribution and use, see the accompanying README.ijg
file.
This file contains a fast, not so accurate integer implementation of the
forward DCT (Discrete Cosine Transform).
A 2-D DCT can be done by 1-D DCT on each row followed by 1-D DCT
on each column. Direct algorithms are also available, but they are
much more complex and seem not to be any faster when reduced to code.
This implementation is based on Arai, Agui, and Nakajima's algorithm for
scaled DCT. Their original paper (Trans. IEICE E-71(11):1095) is in
Japanese, but the algorithm is described in the Pennebaker & Mitchell
JPEG textbook (see REFERENCES section in file README.ijg). The following
code is based directly on figure 4-8 in P&M.
While an 8-point DCT cannot be done in less than 11 multiplies, it is
possible to arrange the computation so that many of the multiplies are
simple scalings of the final outputs. These multiplies can then be
folded into the multiplications or divisions by the JPEG quantization
table entries. The AA&N method leaves only 5 multiplies and 29 adds
to be done in the DCT itself.
The primary disadvantage of this method is that with fixed-point math,
accuracy is lost due to imprecise representation of the scaled
quantization values. The smaller the quantization table entry, the less
precise the scaled value, so this implementation does worse with high-
quality-setting files than with low-quality ones.
|
7793 |
| jfdctint.c |
jfdctint.c
This file was part of the Independent JPEG Group's software:
Copyright (C) 1991-1996, Thomas G. Lane.
libjpeg-turbo Modifications:
Copyright (C) 2015, 2020, 2022, D. R. Commander.
For conditions of distribution and use, see the accompanying README.ijg
file.
This file contains a slower but more accurate integer implementation of the
forward DCT (Discrete Cosine Transform).
A 2-D DCT can be done by 1-D DCT on each row followed by 1-D DCT
on each column. Direct algorithms are also available, but they are
much more complex and seem not to be any faster when reduced to code.
This implementation is based on an algorithm described in
C. Loeffler, A. Ligtenberg and G. Moschytz, "Practical Fast 1-D DCT
Algorithms with 11 Multiplications", Proc. Int'l. Conf. on Acoustics,
Speech, and Signal Processing 1989 (ICASSP '89), pp. 988-991.
The primary algorithm described there uses 11 multiplies and 29 adds.
We use their alternate method with 12 multiplies and 32 adds.
The advantage of this method is that no data path contains more than one
multiplication; this allows a very simple and accurate implementation in
scaled fixed-point arithmetic, with a minimal number of shifts.
|
11515 |
| jidctflt.c |
jidctflt.c
This file was part of the Independent JPEG Group's software:
Copyright (C) 1994-1998, Thomas G. Lane.
Modified 2010 by Guido Vollbeding.
libjpeg-turbo Modifications:
Copyright (C) 2014, 2022, D. R. Commander.
For conditions of distribution and use, see the accompanying README.ijg
file.
This file contains a floating-point implementation of the
inverse DCT (Discrete Cosine Transform). In the IJG code, this routine
must also perform dequantization of the input coefficients.
This implementation should be more accurate than either of the integer
IDCT implementations. However, it may not give the same results on all
machines because of differences in roundoff behavior. Speed will depend
on the hardware's floating point capacity.
A 2-D IDCT can be done by 1-D IDCT on each column followed by 1-D IDCT
on each row (or vice versa, but it's more convenient to emit a row at
a time). Direct algorithms are also available, but they are much more
complex and seem not to be any faster when reduced to code.
This implementation is based on Arai, Agui, and Nakajima's algorithm for
scaled DCT. Their original paper (Trans. IEICE E-71(11):1095) is in
Japanese, but the algorithm is described in the Pennebaker & Mitchell
JPEG textbook (see REFERENCES section in file README.ijg). The following
code is based directly on figure 4-8 in P&M.
While an 8-point DCT cannot be done in less than 11 multiplies, it is
possible to arrange the computation so that many of the multiplies are
simple scalings of the final outputs. These multiplies can then be
folded into the multiplications or divisions by the JPEG quantization
table entries. The AA&N method leaves only 5 multiplies and 29 adds
to be done in the DCT itself.
The primary disadvantage of this method is that with a fixed-point
implementation, accuracy is lost due to imprecise representation of the
scaled quantization values. However, that problem does not arise if
we use floating point arithmetic.
|
8754 |
| jidctfst.c |
jidctfst.c
This file was part of the Independent JPEG Group's software:
Copyright (C) 1994-1998, Thomas G. Lane.
libjpeg-turbo Modifications:
Copyright (C) 2015, 2022, D. R. Commander.
For conditions of distribution and use, see the accompanying README.ijg
file.
This file contains a fast, not so accurate integer implementation of the
inverse DCT (Discrete Cosine Transform). In the IJG code, this routine
must also perform dequantization of the input coefficients.
A 2-D IDCT can be done by 1-D IDCT on each column followed by 1-D IDCT
on each row (or vice versa, but it's more convenient to emit a row at
a time). Direct algorithms are also available, but they are much more
complex and seem not to be any faster when reduced to code.
This implementation is based on Arai, Agui, and Nakajima's algorithm for
scaled DCT. Their original paper (Trans. IEICE E-71(11):1095) is in
Japanese, but the algorithm is described in the Pennebaker & Mitchell
JPEG textbook (see REFERENCES section in file README.ijg). The following
code is based directly on figure 4-8 in P&M.
While an 8-point DCT cannot be done in less than 11 multiplies, it is
possible to arrange the computation so that many of the multiplies are
simple scalings of the final outputs. These multiplies can then be
folded into the multiplications or divisions by the JPEG quantization
table entries. The AA&N method leaves only 5 multiplies and 29 adds
to be done in the DCT itself.
The primary disadvantage of this method is that with fixed-point math,
accuracy is lost due to imprecise representation of the scaled
quantization values. The smaller the quantization table entry, the less
precise the scaled value, so this implementation does worse with high-
quality-setting files than with low-quality ones.
|
13565 |
| jidctint.c |
jidctint.c
This file was part of the Independent JPEG Group's software:
Copyright (C) 1991-1998, Thomas G. Lane.
Modification developed 2002-2018 by Guido Vollbeding.
libjpeg-turbo Modifications:
Copyright (C) 2015, 2020, 2022, D. R. Commander.
For conditions of distribution and use, see the accompanying README.ijg
file.
This file contains a slower but more accurate integer implementation of the
inverse DCT (Discrete Cosine Transform). In the IJG code, this routine
must also perform dequantization of the input coefficients.
A 2-D IDCT can be done by 1-D IDCT on each column followed by 1-D IDCT
on each row (or vice versa, but it's more convenient to emit a row at
a time). Direct algorithms are also available, but they are much more
complex and seem not to be any faster when reduced to code.
This implementation is based on an algorithm described in
C. Loeffler, A. Ligtenberg and G. Moschytz, "Practical Fast 1-D DCT
Algorithms with 11 Multiplications", Proc. Int'l. Conf. on Acoustics,
Speech, and Signal Processing 1989 (ICASSP '89), pp. 988-991.
The primary algorithm described there uses 11 multiplies and 29 adds.
We use their alternate method with 12 multiplies and 32 adds.
The advantage of this method is that no data path contains more than one
multiplication; this allows a very simple and accurate implementation in
scaled fixed-point arithmetic, with a minimal number of shifts.
We also provide IDCT routines with various output sample block sizes for
direct resolution reduction or enlargement without additional resampling:
NxN (N=1...16) pixels for one 8x8 input DCT block.
For N<8 we simply take the corresponding low-frequency coefficients of
the 8x8 input DCT block and apply an NxN point IDCT on the sub-block
to yield the downscaled outputs.
This can be seen as direct low-pass downsampling from the DCT domain
point of view rather than the usual spatial domain point of view,
yielding significant computational savings and results at least
as good as common bilinear (averaging) spatial downsampling.
For N>8 we apply a partial NxN IDCT on the 8 input coefficients as
lower frequencies and higher frequencies assumed to be zero.
It turns out that the computational effort is similar to the 8x8 IDCT
regarding the output size.
Furthermore, the scaling and descaling is the same for all IDCT sizes.
CAUTION: We rely on the FIX() macro except for the N=1,2,4,8 cases
since there would be too many additional constants to pre-calculate.
|
106340 |
| jidctred.c |
jidctred.c
This file was part of the Independent JPEG Group's software:
Copyright (C) 1994-1998, Thomas G. Lane.
libjpeg-turbo Modifications:
Copyright (C) 2015, 2022, D. R. Commander.
For conditions of distribution and use, see the accompanying README.ijg
file.
This file contains inverse-DCT routines that produce reduced-size output:
either 4x4, 2x2, or 1x1 pixels from an 8x8 DCT block.
The implementation is based on the Loeffler, Ligtenberg and Moschytz (LL&M)
algorithm used in jidctint.c. We simply replace each 8-to-8 1-D IDCT step
with an 8-to-4 step that produces the four averages of two adjacent outputs
(or an 8-to-2 step producing two averages of four outputs, for 2x2 output).
These steps were derived by computing the corresponding values at the end
of the normal LL&M code, then simplifying as much as possible.
1x1 is trivial: just take the DC coefficient divided by 8.
See jidctint.c for additional comments.
|
14555 |
| jinclude.h |
jinclude.h
This file was part of the Independent JPEG Group's software:
Copyright (C) 1991-1994, Thomas G. Lane.
libjpeg-turbo Modifications:
Copyright (C) 2022-2023, D. R. Commander.
For conditions of distribution and use, see the accompanying README.ijg
file.
This file exists to provide a single place to fix any problems with
including the wrong system include files. (Common problems are taken
care of by the standard jconfig symbols, but on really weird systems
you may have to edit this file.)
NOTE: this file is NOT intended to be included by applications using the
JPEG library. Most applications need only include jpeglib.h.
|
3188 |
| jlossls.h |
jlossls.h
This file was part of the Independent JPEG Group's software:
Copyright (C) 1998, Thomas G. Lane.
Lossless JPEG Modifications:
Copyright (C) 1999, Ken Murchison.
libjpeg-turbo Modifications:
Copyright (C) 2022, D. R. Commander.
For conditions of distribution and use, see the accompanying README.ijg
file.
This include file contains common declarations for the lossless JPEG
codec modules.
|
3235 |
| jmemmgr.c |
jmemmgr.c
This file was part of the Independent JPEG Group's software:
Copyright (C) 1991-1997, Thomas G. Lane.
libjpeg-turbo Modifications:
Copyright (C) 2016, 2021-2022, D. R. Commander.
For conditions of distribution and use, see the accompanying README.ijg
file.
This file contains the JPEG system-independent memory management
routines. This code is usable across a wide variety of machines; most
of the system dependencies have been isolated in a separate file.
The major functions provided here are:
* pool-based allocation and freeing of memory;
* policy decisions about how to divide available memory among the
virtual arrays;
* control logic for swapping virtual arrays between main memory and
backing storage.
The separate system-dependent file provides the actual backing-storage
access code, and it contains the policy decision about how much total
main memory to use.
This file is system-dependent in the sense that some of its functions
are unnecessary in some systems. For example, if there is enough virtual
memory so that backing storage will never be used, much of the virtual
array control logic could be removed. (Of course, if you have that much
memory then you shouldn't care about a little bit of unused code...)
|
50008 |
| jmemnobs.c |
jmemnobs.c
This file was part of the Independent JPEG Group's software:
Copyright (C) 1992-1996, Thomas G. Lane.
libjpeg-turbo Modifications:
Copyright (C) 2017-2018, 2024, D. R. Commander.
For conditions of distribution and use, see the accompanying README.ijg
file.
This file provides a really simple implementation of the system-
dependent portion of the JPEG memory manager. This implementation
assumes that no backing-store files are needed: all required space
can be obtained from malloc().
This is very portable in the sense that it'll compile on almost anything,
but you'd better have lots of main memory (or virtual memory) if you want
to process big images.
|
2680 |
| jmemsys.h |
jmemsys.h
This file was part of the Independent JPEG Group's software:
Copyright (C) 1992-1997, Thomas G. Lane.
It was modified by The libjpeg-turbo Project to include only code and
information relevant to libjpeg-turbo.
For conditions of distribution and use, see the accompanying README.ijg
file.
This include file defines the interface between the system-independent
and system-dependent portions of the JPEG memory manager. No other
modules need include it. (The system-independent portion is jmemmgr.c;
there are several different versions of the system-dependent portion.)
This file works as-is for the system-dependent memory managers supplied
in the IJG distribution. You may need to modify it if you write a
custom memory manager. If system-dependent changes are needed in
this file, the best method is to #ifdef them based on a configuration
symbol supplied in jconfig.h.
|
6692 |
| jmorecfg.h |
jmorecfg.h
This file was part of the Independent JPEG Group's software:
Copyright (C) 1991-1997, Thomas G. Lane.
Modified 1997-2009 by Guido Vollbeding.
Lossless JPEG Modifications:
Copyright (C) 1999, Ken Murchison.
libjpeg-turbo Modifications:
Copyright (C) 2009, 2011, 2014-2015, 2018, 2020, 2022, D. R. Commander.
For conditions of distribution and use, see the accompanying README.ijg
file.
This file contains additional configuration options that customize the
JPEG software for special applications or support machine-dependent
optimizations. Most users will not need to touch this file.
|
14017 |
| jpeg_nbits.c |
Copyright (C) 2024, D. R. Commander.
For conditions of distribution and use, see the accompanying README.ijg
file.
|
271113 |
| jpeg_nbits.h |
Copyright (C) 2014, 2021, 2024, D. R. Commander.
Copyright (C) 2014, Olle Liljenzin.
Copyright (C) 2020, Arm Limited.
For conditions of distribution and use, see the accompanying README.ijg
file.
|
1701 |
| jpeg12 |
|
|
| jpeg16 |
|
|
| jpegapicomp.h |
jpegapicomp.h
Copyright (C) 2010, 2020, D. R. Commander.
For conditions of distribution and use, see the accompanying README.ijg
file.
JPEG compatibility macros
These declarations are considered internal to the JPEG library; most
applications using the library shouldn't need to include this file.
|
1133 |
| jpegint.h |
jpegint.h
This file was part of the Independent JPEG Group's software:
Copyright (C) 1991-1997, Thomas G. Lane.
Modified 1997-2009 by Guido Vollbeding.
Lossless JPEG Modifications:
Copyright (C) 1999, Ken Murchison.
libjpeg-turbo Modifications:
Copyright (C) 2015-2017, 2019, 2021-2022, 2024, D. R. Commander.
Copyright (C) 2015, Google, Inc.
Copyright (C) 2021, Alex Richardson.
For conditions of distribution and use, see the accompanying README.ijg
file.
This file provides common declarations for the various JPEG modules.
These declarations are considered internal to the JPEG library; most
applications using the library shouldn't need to include this file.
|
27226 |
| jpeglib.h |
jpeglib.h
This file was part of the Independent JPEG Group's software:
Copyright (C) 1991-1998, Thomas G. Lane.
Modified 2002-2009 by Guido Vollbeding.
Lossless JPEG Modifications:
Copyright (C) 1999, Ken Murchison.
libjpeg-turbo Modifications:
Copyright (C) 2009-2011, 2013-2014, 2016-2017, 2020, 2022-2024,
D. R. Commander.
Copyright (C) 2015, Google, Inc.
For conditions of distribution and use, see the accompanying README.ijg
file.
This file defines the application interface for the JPEG library.
Most applications using the library need only include this file,
and perhaps jerror.h if they want to know the exact error codes.
|
55479 |
| jquant1.c |
jquant1.c
This file was part of the Independent JPEG Group's software:
Copyright (C) 1991-1996, Thomas G. Lane.
libjpeg-turbo Modifications:
Copyright (C) 2009, 2015, 2022-2023, D. R. Commander.
For conditions of distribution and use, see the accompanying README.ijg
file.
This file contains 1-pass color quantization (color mapping) routines.
These routines provide mapping to a fixed color map using equally spaced
color values. Optional Floyd-Steinberg or ordered dithering is available.
|
32887 |
| jquant2.c |
jquant2.c
This file was part of the Independent JPEG Group's software:
Copyright (C) 1991-1996, Thomas G. Lane.
libjpeg-turbo Modifications:
Copyright (C) 2009, 2014-2015, 2020, 2022-2023, D. R. Commander.
For conditions of distribution and use, see the accompanying README.ijg
file.
This file contains 2-pass color quantization (color mapping) routines.
These routines provide selection of a custom color map for an image,
followed by mapping of the image to that color map, with optional
Floyd-Steinberg dithering.
It is also possible to use just the second pass to map to an arbitrary
externally-given color map.
Note: ordered dithering is not supported, since there isn't any fast
way to compute intercolor distances; it's unclear that ordered dither's
fundamental assumptions even hold with an irregularly spaced color map.
|
49272 |
| jsamplecomp.h |
jsamplecomp.h
Copyright (C) 2022, D. R. Commander.
For conditions of distribution and use, see the accompanying README.ijg
file.
|
12826 |
| jsimd.h |
jsimd.h
Copyright 2009 Pierre Ossman <ossman@cendio.se> for Cendio AB
Copyright (C) 2011, 2014, 2022, D. R. Commander.
Copyright (C) 2015-2016, 2018, 2022, Matthieu Darbois.
Copyright (C) 2020, Arm Limited.
Based on the x86 SIMD extension for IJG JPEG library,
Copyright (C) 1999-2006, MIYASAKA Masaru.
For conditions of distribution and use, see copyright notice in jsimdext.inc
|
5909 |
| jsimddct.h |
jsimddct.h
Copyright 2009 Pierre Ossman <ossman@cendio.se> for Cendio AB
Based on the x86 SIMD extension for IJG JPEG library,
Copyright (C) 1999-2006, MIYASAKA Masaru.
For conditions of distribution and use, see copyright notice in jsimdext.inc
|
3085 |
| jstdhuff.c |
jstdhuff.c
This file was part of the Independent JPEG Group's software:
Copyright (C) 1991-1998, Thomas G. Lane.
libjpeg-turbo Modifications:
Copyright (C) 2013, 2022, D. R. Commander.
For conditions of distribution and use, see the accompanying README.ijg
file.
This file contains routines to set the default Huffman tables, if they are
not already set.
|
5321 |
| jutils.c |
jutils.c
This file was part of the Independent JPEG Group's software:
Copyright (C) 1991-1996, Thomas G. Lane.
libjpeg-turbo Modifications:
Copyright (C) 2022, D. R. Commander.
For conditions of distribution and use, see the accompanying README.ijg
file.
This file contains tables and miscellaneous utility routines needed
for both compression and decompression.
Note we prefix all global names with "j" to minimize conflicts with
a surrounding application.
|
4129 |
| jversion.h |
jversion.h
This file was part of the Independent JPEG Group's software:
Copyright (C) 1991-2020, Thomas G. Lane, Guido Vollbeding.
libjpeg-turbo Modifications:
Copyright (C) 2010, 2012-2024, D. R. Commander.
For conditions of distribution and use, see the accompanying README.ijg
file.
This file contains software version identification.
|
1818 |
| LICENSE.md |
|
5620 |
| moz.build |
|
11281 |
| MOZCHANGES |
|
5525 |
| mozilla.diff |
|
3434 |
| README.ijg |
libjpeg-turbo note: This file has been modified by The libjpeg-turbo Project |
12715 |
| README.md |
Background |
17643 |
| simd |
|
|