-- automake 1.7 or later
-- libtool 1.4 or later
--- NASM
+-- NASM (if building x86 or x86-64 SIMD extensions)
* 0.98, or 2.01 or later is required for a 32-bit build
* NASM 2.00 or later is required for a 64-bit build
* NASM 2.07 or later is required for a 64-bit build on OS X. This can be
make udmg [BUILDDIR32={32-bit build directory}]
On 64-bit OS X systems, this creates a version of the Macintosh package and
- disk image which contains universal i386/x86-64 binaries. You should first
+ disk image that contains universal i386/x86-64 binaries. You should first
configure a 32-bit out-of-tree build of libjpeg-turbo, then configure a
64-bit out-of-tree build, then run 'make udmg' from the 64-bit build
directory. The build system will look for the 32-bit build under
make csunpkg [BUILDDIR32={32-bit build directory}]
- On 64-bit Solaris systems, this creates a combined package which contains
+ On 64-bit Solaris systems, this creates a combined package that contains
both 32-bit and 64-bit libraries. You should first configure a 32-bit
out-of-tree build of libjpeg-turbo, then configure a 64-bit out-of-tree
build, then run 'make csunpkg' from the 64-bit build directory. The build
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.
-[4] Fixed 32-bit supplementary package for amd64 Debian systems which was
+[4] Fixed 32-bit supplementary package for amd64 Debian systems, which was
broken by enhancements to the packaging system in 1.1.
[5] Fixed out-of-bounds read in SSE2 SIMD code that occurred when decompressing
[2] Created a new CMake-based build system for the Visual C++ and MinGW builds.
-[3] TurboJPEG/OSS can now compress from/decompress to grayscale bitmaps.
+[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.
[7] Added arithmetic encoding and decoding support (can be disabled with
configure or CMake options)
-[8] Added a TJ_YUV flag to TurboJPEG/OSS which causes both the compressor and
-decompressor to output planar YUV images.
+[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 TurboJPEG/OSS which
-allows the caller to determine the type of subsampling used in a JPEG image.
+[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.
from a corrupt JPEG image.) Previously, these would cause libjpeg-turbo to
crash under certain circumstances.
-[2] Fixed typo in SIMD dispatch routines which was causing 4:2:2 upsampling to
+[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
[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
+[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.
** Background
*******************************************************************************
-libjpeg-turbo is a derivative of libjpeg which uses SIMD instructions (MMX,
+libjpeg-turbo is a derivative of libjpeg that uses SIMD instructions (MMX,
SSE2, etc.) to accelerate baseline JPEG compression and decompression on x86
and x86-64 systems. On such systems, libjpeg-turbo is generally 2-4x as fast
as the unmodified version of libjpeg, all else being equal.
The TurboJPEG/OSS wrapper, as well as some of the optimizations to the Huffman
encoder (jchuff.c) and decoder (jdhuff.c), were borrowed from VirtualGL, and
-thus any distribution of libjpeg-turbo which includes those files must, as a
+thus any distribution of libjpeg-turbo that includes those files must, as a
whole, be subject to the terms of the wxWindows Library Licence, Version 3.1.
A copy of this license can be found in this directory under LICENSE.txt. The
-wxWindows Library License is based on the LGPL but includes provisions which
+wxWindows Library License is based on the LGPL but includes provisions that
allow the Library to be statically linked into proprietary libraries and
applications without requiring the resulting binaries to be distributed under
the terms of the LGPL.
Windows releases can obtain it from the Visual C++ 2008 Redistributable
Package, which is available as a free download from Microsoft's web site.
-NOTE: Features of libjpeg which require passing a C run time structure, such
+NOTE: Features of libjpeg that require passing a C run time structure, such
as a file handle, from an application to libjpeg will probably not work with
the version of the libjpeg-turbo DLL distributed in the libjpeg-turbo SDK for
Visual C++, unless the application is also built to use the Visual C++ 2008 C
Colorspace Extensions
=====================
-libjpeg-turbo includes extensions which allow JPEG images to be compressed
-directly from (and decompressed directly to) buffers which use BGR, BGRX,
+libjpeg-turbo includes extensions that allow JPEG images to be compressed
+directly from (and decompressed directly to) buffers that use BGR, BGRX,
RGBX, XBGR, and XRGB pixel ordering. This is implemented with six new
colorspace constants:
Setting cinfo.in_color_space (compression) or cinfo.out_color_space
(decompression) to one of these values will cause libjpeg-turbo to read the
red, green, and blue values from (or write them to) the appropriate position in
-the pixel when YUV conversion is performed.
+the pixel when compressing from/decompressing to an RGB buffer.
Your application can check for the existence of these extensions at compile
time with:
libjpeg v7 and v8 added new features to the API/ABI, and, unfortunately, the
compression and decompression structures were extended in a backward-
-incompatible manner to accommodate these features. Thus, programs which are
+incompatible manner to accommodate these features. Thus, programs that are
built to use libjpeg v7 or v8 did not work with libjpeg-turbo, since it is
based on the libjpeg v6b code base. Although libjpeg v7 and v8 are still not
as widely used as v6b, enough programs (including a few Linux distros) have
API/ABI in libjpeg-turbo.
Some of the libjpeg v7 and v8 features -- DCT scaling, to name one -- involve
-deep modifications to the code which cannot be accommodated by libjpeg-turbo
+deep modifications to the code that cannot be accommodated by libjpeg-turbo
without either breaking compatibility with libjpeg v6b or producing an
unsupportable mess. In order to fully support libjpeg v8 with all of its
features, we would have to essentially port the SIMD extensions to the libjpeg
By passing an argument of --with-jpeg7 or --with-jpeg8 to configure, or an
argument of -DWITH_JPEG7=1 or -DWITH_JPEG8=1 to cmake, you can build a version
-of libjpeg-turbo which emulates the libjpeg v7 or v8 API/ABI, so that programs
-which are built against libjpeg v7 or v8 can be run with libjpeg-turbo. The
+of libjpeg-turbo that emulates the libjpeg v7 or v8 API/ABI, so that programs
+that are built against libjpeg v7 or v8 can be run with libjpeg-turbo. The
following section describes which libjpeg v7+ features are supported and which
aren't.
[INPUT] height = height (in pixels) of the source image
[INPUT] pixelsize = size (in bytes) of each pixel in the source image
RGBX/BGRX/XRGB/XBGR: 4, RGB/BGR: 3, Grayscale: 1
- [INPUT] dstbuf = pointer to user-allocated image buffer which will receive
+ [INPUT] dstbuf = pointer to user-allocated image buffer that will receive
the JPEG image. Use the TJBUFSIZE(width, height) function to determine
the appropriate size for this buffer based on the image width and height.
- [OUTPUT] size = pointer to unsigned long which receives the size (in bytes)
+ [OUTPUT] size = pointer to unsigned long that receives the size (in bytes)
of the compressed image
[INPUT] jpegsubsamp = Specifies either 4:2:0, 4:2:2, 4:4:4, or grayscale
subsampling. When the image is converted from the RGB to YCbCr colorspace
/*
unsigned long TJBUFSIZE(int width, int height)
- Convenience function which returns the maximum size of the buffer required to
+ Convenience function that returns the maximum size of the buffer required to
hold a JPEG image with the given width and height
RETURNS: -1 if arguments are out of bounds
/*
unsigned long TJBUFSIZEYUV(int width, int height, int subsamp)
- Convenience function which returns the size of the buffer required to
+ Convenience function that returns the size of the buffer required to
hold a YUV planar image with the given width, height, and level of
chrominance subsampling
[INPUT] height = height (in pixels) of the source image
[INPUT] pixelsize = size (in bytes) of each pixel in the source image
RGBX/BGRX/XRGB/XBGR: 4, RGB/BGR: 3, Grayscale: 1
- [INPUT] dstbuf = pointer to user-allocated image buffer which will receive
+ [INPUT] dstbuf = pointer to user-allocated image buffer that will receive
the YUV image. Use the TJBUFSIZEYUV(width, height, subsamp) function to
determine the appropriate size for this buffer based on the image width,
height, and level of subsampling.
[INPUT] srcbuf = pointer to a user-allocated buffer containing the JPEG image
to decompress
[INPUT] size = size of the JPEG image buffer (in bytes)
- [INPUT] dstbuf = pointer to user-allocated image buffer which will receive
+ [INPUT] dstbuf = pointer to user-allocated image buffer that will receive
the bitmap image. This buffer should normally be pitch*height
bytes in size, although this pointer may also be used to decompress into
a specific region of a larger buffer.
[INPUT] srcbuf = pointer to a user-allocated buffer containing the JPEG image
to decompress
[INPUT] size = size of the JPEG image buffer (in bytes)
- [INPUT] dstbuf = pointer to user-allocated image buffer which will receive
+ [INPUT] dstbuf = pointer to user-allocated image buffer that will receive
the YUV image. Use the TJBUFSIZEYUV(width, height, subsamp) function to
determine the appropriate size for this buffer based on the image width,
height, and level of subsampling.
projects / libjpeg-turbo / commitdiff