ChangeLog.txt

1.3 pre-beta
============

[1] Added support for additional scaling factors (3/8, 5/8, 3/4, 7/8, 9/8, 5/4,
11/8, 3/2, 13/8, 7/4, 15/8, and 2) when decompressing.  Note that the IDCT will
not be SIMD-accelerated when using any of these new scaling factors.

[2] Added SIMD acceleration for performing 4:2:2 upsampling on NEON-capable ARM
platforms.  This speeds up the decompression of 4:2:2 JPEGs by 20-25% on such
platforms.

[3] Creating or decoding a JPEG file that uses the RGB colorspace should now
properly work when the input or output colorspace is one of the libjpeg-turbo
colorspace extensions.

[4] When libjpeg-turbo was built without SIMD support and merged (non-fancy)
upsampling was used along with an alpha-enabled colorspace during
decompression, the unused byte of the decompressed pixels was not being set to
0xFF.  This has been fixed.  TJUnitTest has also been extended to test for the
correct behavior of the colorspace extensions when merged upsampling is used.

[5] The TurboJPEG dynamic library is now versioned.  It was not strictly
necessary to do so, because TurboJPEG uses versioned symbols, and if a function
changes in an ABI-incompatible way, that function is renamed and a legacy
function is provided to maintain backward compatibility.  However, certain
Linux distro maintainers will blindly reject any library that is not versioned,
so this was an attempt to make them happy.

[6] Fixed a bug whereby the libjpeg-turbo SSE2 SIMD code would not preserve the
upper 64 bits of xmm6 and xmm7 on Win64 platforms, which violated the Win64
calling conventions.

[7] Fixed a regression caused by 1.2.0[6] in which decompressing corrupt JPEG
images (specifically, images in which the component count was erroneously set
to a large value) would cause libjpeg-turbo to segfault.


1.2.0
=====

[1] Fixed build issue with YASM on Unix systems (the libjpeg-turbo build system
was not adding the current directory to the assembler include path, so YASM
was not able to find jsimdcfg.inc.)

[2] Fixed out-of-bounds read in SSE2 SIMD code that occurred when decompressing
a JPEG image to a bitmap buffer whose size was not a multiple of 16 bytes.
This was more of an annoyance than an actual bug, since it did not cause any
actual run-time problems, but the issue showed up when running libjpeg-turbo in
valgrind.  See http://crbug.com/72399 for more information.

[3] Added a compile-time macro (LIBJPEG_TURBO_VERSION) that can be used to
check the version of libjpeg-turbo against which an application was compiled.

[4] Added new RGBA/BGRA/ABGR/ARGB colorspace extension constants (libjpeg API)
and pixel formats (TurboJPEG API), which allow applications to specify that,
when decompressing to a 4-component RGB buffer, the unused byte should be set
to 0xFF so that it can be interpreted as an opaque alpha channel.

[5] Fixed regression issue whereby DevIL failed to build against libjpeg-turbo
because libjpeg-turbo's distributed version of jconfig.h contained an INLINE
macro, which conflicted with a similar macro in DevIL.  This macro is used only
internally when building libjpeg-turbo, so it was moved into config.h.

[6] libjpeg-turbo will now correctly decompress erroneous CMYK/YCCK JPEGs whose
K component is assigned a component ID of 1 instead of 4.  Although these files
are in violation of the spec, other JPEG implementations handle them
correctly.

[7] Added ARM v6 and ARM v7 architectures to libjpeg.a and libturbojpeg.a in
the official OS X distribution package, so that those libraries can be used to
build both OS X and iOS applications.


1.1.90 (1.2 beta1)
==================

[1] Added a Java wrapper for the TurboJPEG API.  See java/README for more
details.

[2] The TurboJPEG API can now be used to scale down images during
decompression.

[3] Added SIMD routines for RGB-to-grayscale color conversion, which
significantly improves the performance of grayscale JPEG compression from an
RGB source image.

[4] Improved the performance of the C color conversion routines, which are used
on platforms for which SIMD acceleration is not available.

[5] Added a function to the TurboJPEG API that performs lossless transforms.
This function is implemented using the same back end as jpegtran, but it
performs transcoding entirely in memory and allows multiple transforms and/or
crop operations to be batched together, so the source coefficients only need to
be read once.  This is useful when generating image tiles from a single source
JPEG.

[6] Added tests for the new TurboJPEG scaled decompression and lossless
transform features to tjbench (the TurboJPEG benchmark, formerly called
"jpgtest".)

[7] Added support for 4:4:0 (transposed 4:2:2) subsampling in TurboJPEG, which
was necessary in order for it to read 4:2:2 JPEG files that had been losslessly
transposed or rotated 90 degrees.

[8] All legacy VirtualGL code has been re-factored, and this has allowed
libjpeg-turbo, in its entirety, to be re-licensed under a BSD-style license.

[9] libjpeg-turbo can now be built with YASM.

[10] Added SIMD acceleration for ARM Linux and iOS platforms that support
NEON instructions.

[11] Refactored the TurboJPEG C API and documented it using Doxygen.  The
TurboJPEG 1.2 API uses pixel formats to define the size and component order of
the uncompressed source/destination images, and it includes a more efficient
version of TJBUFSIZE() that computes a worst-case JPEG size based on the level
of chrominance subsampling.  The refactored implementation of TurboJPEG/OSS
now uses the libjpeg memory source and destination managers, which allows the
TurboJPEG compressor to grow the JPEG buffer as necessary.

[12] Eliminated errors in the output of jpegtran on Windows that occurred when
the application was invoked using I/O redirection
(jpegtran <input.jpg >output.jpg).

[13] The inclusion of libjpeg v7 and v8 emulation as well as arithmetic coding
support in libjpeg-turbo v1.1.0 introduced several new error constants in
jerror.h, and these were mistakenly enabled for all emulation modes, causing
the error enum in libjpeg-turbo to sometimes have different values than the
same enum in libjpeg.  This represents an ABI incompatibility, and it caused
problems with rare applications that took specific action based on a particular
error value.  The fix was to include the new error constants conditionally
based on whether libjpeg v7 or v8 emulation was enabled.

[14] Fixed an issue whereby Windows applications that used libjpeg-turbo would
fail to compile if the Windows system headers were included before jpeglib.h.
This issue was caused by a conflict in the definition of the INT32 type.

[15] Fixed 32-bit supplementary package for amd64 Debian systems, which was
broken by enhancements to the packaging system in 1.1.

[16] When decompressing a JPEG image using an output colorspace of
JCS_EXT_RGBX, JCS_EXT_BGRX, JCS_EXT_XBGR, or JCS_EXT_XRGB, libjpeg-turbo will
now set the unused byte to 0xFF, which allows applications to interpret that
byte as an alpha channel (0xFF = opaque).


1.1.1
=====

[1] Fixed a 1-pixel error in row 0, column 21 of the luminance plane generated
by tjEncodeYUV().

[2] libjpeg-turbo's accelerated Huffman decoder previously ignored unexpected
markers found in the middle of the JPEG data stream during decompression.  It
will now hand off decoding of a particular block to the unaccelerated Huffman
decoder if an unexpected marker is found, so that the unaccelerated Huffman
decoder can generate an appropriate warning.

[3] Older versions of MinGW64 prefixed symbol names with underscores by
default, which differed from the behavior of 64-bit Visual C++.  MinGW64 1.0
has adopted the behavior of 64-bit Visual C++ as the default, so to accommodate
this, the libjpeg-turbo SIMD function names are no longer prefixed with an
underscore when building with MinGW64.  This means that, when building
libjpeg-turbo with older versions of MinGW64, you will now have to add
-fno-leading-underscore to the CFLAGS.

[4] Fixed a regression bug in the NSIS script that caused the Windows installer
build to fail when using the Visual Studio IDE.

[5] Fixed a bug in jpeg_read_coefficients() whereby it would not initialize
cinfo->image_width and cinfo->image_height if libjpeg v7 or v8 emulation was
enabled.  This specifically caused the jpegoptim program to fail if it was
linked against a version of libjpeg-turbo that was built with libjpeg v7 or v8
emulation.

[6] Eliminated excessive I/O overhead that occurred when reading BMP files in
cjpeg.

[7] Eliminated errors in the output of cjpeg on Windows that occurred when the
application was invoked using I/O redirection (cjpeg <inputfile >output.jpg).


1.1.0
=====

[1] The algorithm used by the SIMD quantization function cannot produce correct
results when the JPEG quality is >= 98 and the fast integer forward DCT is
used.  Thus, the non-SIMD quantization function is now used for those cases,
and libjpeg-turbo should now produce identical output to libjpeg v6b in all
cases.

[2] Despite the above, the fast integer forward DCT still degrades somewhat for
JPEG qualities greater than 95, so TurboJPEG/OSS will now automatically use the
slow integer forward DCT when generating JPEG images of quality 96 or greater.
This reduces compression performance by as much as 15% for these high-quality
images but is necessary to ensure that the images are perceptually lossless.
It also ensures that the library can avoid the performance pitfall created by
[1].

[3] Ported jpgtest.cxx to pure C to avoid the need for a C++ compiler.

[4] Fixed visual artifacts in grayscale JPEG compression caused by a typo in
the RGB-to-luminance lookup tables.

[5] The Windows distribution packages now include the libjpeg run-time programs
(cjpeg, etc.)

[6] All packages now include jpgtest.

[7] The TurboJPEG dynamic library now uses versioned symbols.

[8] Added two new TurboJPEG API functions, tjEncodeYUV() and
tjDecompressToYUV(), to replace the somewhat hackish TJ_YUV flag.


1.0.90 (1.1 beta1)
==================

[1] Added emulation of the libjpeg v7 and v8 APIs and ABIs.  See
README-turbo.txt for more details.  This feature was sponsored by CamTrace SAS.

[2] Created a new CMake-based build system for the Visual C++ and MinGW builds.

[3] Grayscale bitmaps can now be compressed from/decompressed to using the
TurboJPEG API.

[4] jpgtest can now be used to test decompression performance with existing
JPEG images.

[5] If the default install prefix (/opt/libjpeg-turbo) is used, then
'make install' now creates /opt/libjpeg-turbo/lib32 and
/opt/libjpeg-turbo/lib64 sym links to duplicate the behavior of the binary
packages.

[6] All symbols in the libjpeg-turbo dynamic library are now versioned, even
when the library is built with libjpeg v6b emulation.

[7] Added arithmetic encoding and decoding support (can be disabled with
configure or CMake options)

[8] Added a TJ_YUV flag to the TurboJPEG API, which causes both the compressor
and decompressor to output planar YUV images.

[9] Added an extended version of tjDecompressHeader() to the TurboJPEG API,
which allows the caller to determine the type of subsampling used in a JPEG
image.

[10] Added further protections against invalid Huffman codes.


1.0.1
=====

[1] The Huffman decoder will now handle erroneous Huffman codes (for instance,
from a corrupt JPEG image.)  Previously, these would cause libjpeg-turbo to
crash under certain circumstances.

[2] Fixed typo in SIMD dispatch routines that was causing 4:2:2 upsampling to
be used instead of 4:2:0 when decompressing JPEG images using SSE2 code.

[3] configure script will now automatically determine whether the
INCOMPLETE_TYPES_BROKEN macro should be defined.


1.0.0
=====

[1] 2983700: Further FreeBSD build tweaks (no longer necessary to specify
--host when configuring on a 64-bit system)

[2] Created sym. links in the Unix/Linux packages so that the TurboJPEG
include file can always be found in /opt/libjpeg-turbo/include, the 32-bit
static libraries can always be found in /opt/libjpeg-turbo/lib32, and the
64-bit static libraries can always be found in /opt/libjpeg-turbo/lib64.

[3] The Unix/Linux distribution packages now include the libjpeg run-time
programs (cjpeg, etc.) and man pages.

[4] Created a 32-bit supplementary package for amd64 Debian systems, which
contains just the 32-bit libjpeg-turbo libraries.

[5] Moved the libraries from */lib32 to */lib in the i386 Debian package.

[6] Include distribution package for Cygwin

[7] No longer necessary to specify --without-simd on non-x86 architectures, and
unit tests now work on those architectures.


0.0.93
======

[1] 2982659, Fixed x86-64 build on FreeBSD systems

[2] 2988188: Added support for Windows 64-bit systems


0.0.91
======

[1] Added documentation to .deb packages

[2] 2968313: Fixed data corruption issues when decompressing large JPEG images
and/or using buffered I/O with the libjpeg-turbo decompressor


0.0.90
======

Initial release