2.0.2

Significant changes relative to 2.0.1:

  1. Fixed a regression introduced by 2.0.1[5] that prevented a runtime search
    path (rpath) from being embedded in the libjpeg-turbo shared libraries and
    executables for macOS and iOS. This caused a fatal error of the form
    "dyld: Library not loaded" when attempting to use one of the executables,
    unless DYLD_LIBRARY_PATH was explicitly set to the location of the
    libjpeg-turbo shared libraries.

  2. Fixed an integer overflow and subsequent segfault (CVE-2018-20330) that
    occurred when attempting to load a BMP file with more than 1 billion pixels
    using the tjLoadImage() function.

  3. Fixed a buffer overrun (CVE-2018-19664) that occurred when attempting to
    decompress a specially-crafted malformed JPEG image to a 256-color BMP using
    djpeg.

  4. Fixed a floating point exception that occurred when attempting to
    decompress a specially-crafted malformed JPEG image with a specified image
    width or height of 0 using the C version of TJBench.

  5. The TurboJPEG API will now decompress 4:4:4 JPEG images with 2x1, 1x2, 3x1,
    or 1x3 luminance and chrominance sampling factors. This is a non-standard way
    of specifying 1x subsampling (normally 4:4:4 JPEGs have 1x1 luminance and
    chrominance sampling factors), but the JPEG format and the libjpeg API both
    allow it.

  6. Fixed a regression introduced by 2.0 beta1[7] that caused djpeg to generate
    incorrect PPM images when used with the -colors option.

  7. Fixed an issue whereby a static build of libjpeg-turbo (a build in which
    ENABLE_SHARED is 0) could not be installed using the Visual Studio IDE.

  8. Fixed a severe performance issue in the Loongson MMI SIMD extensions that
    occurred when compressing RGB images whose image rows were not 64-bit-aligned.

2.0.1

Significant changes relative to 2.0.0:

  1. Fixed a regression introduced with the new CMake-based Un*x build system,
    whereby jconfig.h could cause compiler warnings of the form
    "HAVE_*_H" redefined if it was included by downstream Autotools-based
    projects that used AC_CHECK_HEADERS() to check for the existence of locale.h,
    stddef.h, or stdlib.h.

  2. The jsimd_quantize_float_dspr2() and jsimd_convsamp_float_dspr2()
    functions in the MIPS DSPr2 SIMD extensions are now disabled at compile time
    if the soft float ABI is enabled. Those functions use instructions that are
    incompatible with the soft float ABI.

  3. Fixed a regression in the SIMD feature detection code, introduced by
    the AVX2 SIMD extensions (2.0 beta1[1]), that caused libjpeg-turbo to crash on
    Windows 7 if Service Pack 1 was not installed.

  4. Fixed out-of-bounds read in cjpeg that occurred when attempting to compress
    a specially-crafted malformed color-index (8-bit-per-sample) Targa file in
    which some of the samples (color indices) exceeded the bounds of the Targa
    file's color table.

  5. Fixed an issue whereby installing a fully static build of libjpeg-turbo
    (a build in which CFLAGS contains -static and ENABLE_SHARED is 0) would
    fail with "No valid ELF RPATH or RUNPATH entry exists in the file."

2.0.0

Significant changes relative to 2.0 beta1:

  1. The TurboJPEG API can now decompress CMYK JPEG images that have subsampled M
    and Y components (not to be confused with YCCK JPEG images, in which the C/M/Y
    components have been transformed into luma and chroma.) Previously, an error
    was generated ("Could not determine subsampling type for JPEG image") when such
    an image was passed to tjDecompressHeader3(), tjTransform(),
    tjDecompressToYUVPlanes(), tjDecompressToYUV2(), or the equivalent Java
    methods.

  2. Fixed an issue (CVE-2018-11813) whereby a specially-crafted malformed input
    file (specifically, a file with a valid Targa header but incomplete pixel data)
    would cause cjpeg to generate a JPEG file that was potentially thousands of
    times larger than the input file. The Targa reader in cjpeg was not properly
    detecting that the end of the input file had been reached prematurely, so after
    all valid pixels had been read from the input, the reader injected dummy pixels
    with values of 255 into the JPEG compressor until the number of pixels
    specified in the Targa header had been compressed. The Targa reader in cjpeg
    now behaves like the PPM reader and aborts compression if the end of the input
    file is reached prematurely. Because this issue only affected cjpeg and not
    the underlying library, and because it did not involve any out-of-bounds reads
    or other exploitable behaviors, it was not believed to represent a security
    threat.

  3. Fixed an issue whereby the tjLoadImage() and tjSaveImage() functions
    would produce a "Bogus message code" error message if the underlying bitmap and
    PPM readers/writers threw an error that was specific to the readers/writers
    (as opposed to a general libjpeg API error.)

  4. Fixed an issue whereby a specially-crafted malformed BMP file, one in which
    the header specified an image width of 1073741824 pixels, would trigger a
    floating point exception (division by zero) in the tjLoadImage() function
    when attempting to load the BMP file into a 4-component image buffer.

  5. Fixed an issue whereby certain combinations of calls to
    jpeg_skip_scanlines() and jpeg_read_scanlines() could trigger an infinite
    loop when decompressing progressive JPEG images that use vertical chroma
    subsampling (for instance, 4:2:0 or 4:4:0.)

  6. Fixed a segfault in jpeg_skip_scanlines() that occurred when decompressing
    a 4:2:2 or 4:2:0 JPEG image using the merged (non-fancy) upsampling algorithms
    (that is, when setting cinfo.do_fancy_upsampling to FALSE.)

  7. The new CMake-based build system will now disable the MIPS DSPr2 SIMD
    extensions if it detects that the compiler does not support DSPr2 instructions.

  8. Fixed out-of-bounds read in cjpeg that occurred when attempting to compress
    a specially-crafted malformed color-index (8-bit-per-sample) BMP file in which
    some of the samples (color indices) exceeded the bounds of the BMP file's color
    table.

  9. Fixed a signed integer overflow in the progressive Huffman decoder, detected
    by the Clang and GCC undefined behavior sanitizers, that could be triggered by
    attempting to decompress a specially-crafted malformed JPEG image. This issue
    did not pose a security threat, but removing the warning made it easier to
    detect actual security issues, should they arise in the future.

1.5.90 (2.0 beta1)

Significant changes relative to 1.5.3:

  1. Added AVX2 SIMD implementations of the colorspace conversion, chroma
    downsampling and upsampling, integer quantization and sample conversion, and
    slow integer DCT/IDCT algorithms. When using the slow integer DCT/IDCT
    algorithms on AVX2-equipped CPUs, the compression of RGB images is
    approximately 13-36% (avg. 22%) faster (relative to libjpeg-turbo 1.5.x) with
    64-bit code and 11-21% (avg. 17%) faster with 32-bit code, and the
    decompression of RGB images is approximately 9-35% (avg. 17%) faster with
    64-bit code and 7-17% (avg. 12%) faster with 32-bit code. (As tested on a
    3 GHz Intel Core i7. Actual mileage may vary.)

  2. Overhauled the build system to use CMake on all platforms, and removed the
    autotools-based build system. This decision resulted from extensive
    discussions within the libjpeg-turbo community. libjpeg-turbo traditionally
    used CMake only for Windows builds, but there was an increasing amount of
    demand to extend CMake support to other platforms. However, because of the
    unique nature of our code base (the need to support different assemblers on
    each platform, the need for Java support, etc.), providing dual build systems
    as other OSS imaging libraries do (including libpng and libtiff) would have
    created a maintenance burden. The use of CMake greatly simplifies some aspects
    of our build system, owing to CMake's built-in support for various assemblers,
    Java, and unit testing, as well as generally fewer quirks that have to be
    worked around in order to implement our packaging system. Eliminating
    autotools puts our project slightly at odds with the traditional practices of
    the OSS community, since most "system libraries" tend to be built with
    autotools, but it is believed that the benefits of this move outweigh the
    risks. In addition to providing a unified build environment, switching to
    CMake allows for the use of various build tools and IDEs that aren't supported
    under autotools, including XCode, Ninja, and Eclipse. It also eliminates the
    need to install autotools via MacPorts/Homebrew on OS X and allows
    libjpeg-turbo to be configured without the use of a terminal/command prompt.
    Extensive testing was conducted to ensure that all features provided by the
    autotools-based build system are provided by the new build system.

  3. The libjpeg API in this version of libjpeg-turbo now includes two additional
    functions, jpeg_read_icc_profile() and jpeg_write_icc_profile(), that can
    be used to extract ICC profile data from a JPEG file while decompressing or to
    embed ICC profile data in a JPEG file while compressing or transforming. This
    eliminates the need for downstream projects, such as color management libraries
    and browsers, to include their own glueware for accomplishing this.

  4. Improved error handling in the TurboJPEG API library:

    • Introduced a new function (tjGetErrorStr2()) in the TurboJPEG C API
      that allows compression/decompression/transform error messages to be retrieved
      in a thread-safe manner. Retrieving error messages from global functions, such
      as tjInitCompress() or tjBufSize(), is still thread-unsafe, but since those
      functions will only throw errors if passed an invalid argument or if a memory
      allocation failure occurs, thread safety is not as much of a concern.
    • Introduced a new function (tjGetErrorCode()) in the TurboJPEG C API
      and a new method (TJException.getErrorCode()) in the TurboJPEG Java API that
      can be used to determine the severity of the last
      compression/decompression/transform error. This allows applications to
      choose whether to ignore warnings (non-fatal errors) from the underlying
      libjpeg API or to treat them as fatal.
    • Introduced a new flag (TJFLAG_STOPONWARNING in the TurboJPEG C API and
      TJ.FLAG_STOPONWARNING in the TurboJPEG Java API) that causes the library to
      immediately halt a compression/decompression/transform operation if it
      encounters a warning from the underlying libjpeg API (the default behavior is
      to allow the operation to complete unless a fatal error is encountered.)
  5. Introduced a new flag in the TurboJPEG C and Java APIs (TJFLAG_PROGRESSIVE
    and TJ.FLAG_PROGRESSIVE, respectively) that causes the library to use
    progressive entropy coding in JPEG images generated by compression and
    transform operations. Additionally, a new transform option
    (TJXOPT_PROGRESSIVE in the C API and TJTransform.OPT_PROGRESSIVE in the
    Java API) has been introduced, allowing progressive entropy coding to be
    enabled for selected transforms in a multi-transform operation.

  6. Introduced a new transform option in the TurboJPEG API (TJXOPT_COPYNONE in
    the C API and TJTransform.OPT_COPYNONE in the Java API) that allows the
    copying of markers (including EXIF and ICC profile data) to be disabled for a
    particular transform.

  7. Added two functions to the TurboJPEG C API (tjLoadImage() and
    tjSaveImage()) that can be used to load/save a BMP or PPM/PGM image to/from a
    memory buffer with a specified pixel format and layout. These functions
    replace the project-private (and slow) bmp API, which was previously used by
    TJBench, and they also provide a convenient way for first-time users of
    libjpeg-turbo to quickly develop a complete JPEG compression/decompression
    program.

  8. The TurboJPEG C API now includes a new convenience array (tjAlphaOffset[])
    that contains the alpha component index for each pixel format (or -1 if the
    pixel format lacks an alpha component.) The TurboJPEG Java API now includes a
    new method (TJ.getAlphaOffset()) that returns the same value. In addition,
    the tjRedOffset[], tjGreenOffset[], and tjBlueOffset[] arrays-- and the
    corresponding TJ.getRedOffset(), TJ.getGreenOffset(), and
    TJ.getBlueOffset() methods-- now return -1 for TJPF_GRAY/TJ.PF_GRAY
    rather than 0. This allows programs to easily determine whether a pixel format
    has red, green, blue, and alpha components.

  9. Added a new example (tjexample.c) that demonstrates the basic usage of the
    TurboJPEG C API. This example mirrors the functionality of TJExample.java.
    Both files are now included in the libjpeg-turbo documentation.

  10. Fixed two signed integer overflows in the arithmetic decoder, detected by
    the Clang undefined behavior sanitizer, that could be triggered by attempting
    to decompress a specially-crafted malformed JPEG image. These issues did not
    pose a security threat, but removing the warnings makes it easier to detect
    actual security issues, should they arise in the future.

  11. Fixed a bug in the merged 4:2:0 upsampling/dithered RGB565 color conversion
    algorithm that caused incorrect dithering in the output image. This algorithm
    now produces bitwise-identical results to the unmerged algorithms.

  12. The SIMD function symbols for x86[-64]/ELF, MIPS/ELF, macOS/x86[-64] (if
    libjpeg-turbo is built with YASM), and iOS/ARM[64] builds are now private.
    This prevents those symbols from being exposed in applications or shared
    libraries that link statically with libjpeg-turbo.

  13. Added Loongson MMI SIMD implementations of the RGB-to-YCbCr and
    YCbCr-to-RGB colorspace conversion, 4:2:0 chroma downsampling, 4:2:0 fancy
    chroma upsampling, integer quantization, and slow integer DCT/IDCT algorithms.
    When using the slow integer DCT/IDCT, this speeds up the compression of RGB
    images by approximately 70-100% and the decompression of RGB images by
    approximately 2-3.5x.

  14. Fixed a build error when building with older MinGW releases (regression
    caused by 1.5.1[7].)

  15. Added SIMD acceleration for progressive Huffman encoding on SSE2-capable
    x86 and x86-64 platforms. This speeds up the compression of full-color
    progressive JPEGs by about 85-90% on average (relative to libjpeg-turbo 1.5.x)
    when using modern Intel and AMD CPUs.

1.5.3

Significant changes relative to 1.5.2:

  1. Fixed a NullPointerException in the TurboJPEG Java wrapper that occurred
    when using the YUVImage constructor that creates an instance backed by separate
    image planes and allocates memory for the image planes.

  2. Fixed an issue whereby the Java version of TJUnitTest would fail when
    testing BufferedImage encoding/decoding on big endian systems.

  3. Fixed a segfault in djpeg that would occur if an output format other than
    PPM/PGM was selected along with the -crop option. The -crop option now
    works with the GIF and Targa formats as well (unfortunately, it cannot be made
    to work with the BMP and RLE formats due to the fact that those output engines
    write scanlines in bottom-up order.) djpeg will now exit gracefully if an
    output format other than PPM/PGM, GIF, or Targa is selected along with the
    -crop option.

  4. Fixed an issue whereby jpeg_skip_scanlines() would segfault if color
    quantization was enabled.

  5. TJBench (both C and Java versions) will now display usage information if any
    command-line argument is unrecognized. This prevents the program from silently
    ignoring typos.

  6. Fixed an access violation in tjbench.exe (Windows) that occurred when the
    program was used to decompress an existing JPEG image.

  7. Fixed an ArrayIndexOutOfBoundsException in the TJExample Java program that
    occurred when attempting to decompress a JPEG image that had been compressed
    with 4:1:1 chrominance subsampling.

  8. Fixed an issue whereby, when using jpeg_skip_scanlines() to skip to the
    end of a single-scan (non-progressive) image, subsequent calls to
    jpeg_consume_input() would return JPEG_SUSPENDED rather than
    JPEG_REACHED_EOI.

  9. jpeg_crop_scanlines() now works correctly when decompressing grayscale
    JPEG images that were compressed with a sampling factor other than 1 (for
    instance, with cjpeg -grayscale -sample 2x2).

1.5.2

Significant changes relative to 1.5.1:

  1. Fixed a regression introduced by 1.5.1[7] that prevented libjpeg-turbo from
    building with Android NDK platforms prior to android-21 (5.0).

  2. Fixed a regression introduced by 1.5.1[1] that prevented the MIPS DSPR2 SIMD
    code in libjpeg-turbo from building.

  3. Fixed a regression introduced by 1.5 beta1[11] that prevented the Java
    version of TJBench from outputting any reference images (the -nowrite switch
    was accidentally enabled by default.)

  4. libjpeg-turbo should now build and run with full AltiVec SIMD acceleration
    on PowerPC-based AmigaOS 4 and OpenBSD systems.

  5. Fixed build and runtime errors on Windows that occurred when building
    libjpeg-turbo with libjpeg v7 API/ABI emulation and the in-memory
    source/destination managers. Due to an oversight, the jpeg_skip_scanlines()
    and jpeg_crop_scanlines() functions were not being included in jpeg7.dll when
    libjpeg-turbo was built with -DWITH_JPEG7=1 and -DWITH_MEMSRCDST=1.

  6. Fixed "Bogus virtual array access" error that occurred when using the
    lossless crop feature in jpegtran or the TurboJPEG API, if libjpeg-turbo was
    built with libjpeg v7 API/ABI emulation. This was apparently a long-standing
    bug that has existed since the introduction of libjpeg v7/v8 API/ABI emulation
    in libjpeg-turbo v1.1.

  7. The lossless transform features in jpegtran and the TurboJPEG API will now
    always attempt to adjust the EXIF image width and height tags if the image size
    changed as a result of the transform. This behavior has always existed when
    using libjpeg v8 API/ABI emulation. It was supposed to be available with
    libjpeg v7 API/ABI emulation as well but did not work properly due to a bug.
    Furthermore, there was never any good reason not to enable it with libjpeg v6b
    API/ABI emulation, since the behavior is entirely internal. Note that
    -copy all must be passed to jpegtran in order to transfer the EXIF tags from
    the source image to the destination image.

  8. Fixed several memory leaks in the TurboJPEG API library that could occur
    if the library was built with certain compilers and optimization levels
    (known to occur with GCC 4.x and clang with -O1 and higher but not with
    GCC 5.x or 6.x) and one of the underlying libjpeg API functions threw an error
    after a TurboJPEG API function allocated a local buffer.

  9. The libjpeg-turbo memory manager will now honor the max_memory_to_use
    structure member in jpeg_memory_mgr, which can be set to the maximum amount
    of memory (in bytes) that libjpeg-turbo should use during decompression or
    multi-pass (including progressive) compression. This limit can also be set
    using the JPEGMEM environment variable or using the -maxmemory switch in
    cjpeg/djpeg/jpegtran (refer to the respective man pages for more details.)
    This has been a documented feature of libjpeg since v5, but the
    malloc()/free() implementation of the memory manager (jmemnobs.c) never
    implemented the feature. Restricting libjpeg-turbo's memory usage is useful
    for two reasons: it allows testers to more easily work around the 2 GB limit
    in libFuzzer, and it allows developers of security-sensitive applications to
    more easily defend against one of the progressive JPEG exploits (LJT-01-004)
    identified in
    this report.

  10. TJBench will now run each benchmark for 1 second prior to starting the
    timer, in order to improve the consistency of the results. Furthermore, the
    -warmup option is now used to specify the amount of warmup time rather than
    the number of warmup iterations.

  11. Fixed an error (short jump is out of range) that occurred when assembling
    the 32-bit x86 SIMD extensions with NASM versions prior to 2.04. This was a
    regression introduced by 1.5 beta1[12].

1.5.1

Significant changes relative to 1.5.0:

  1. Previously, the undocumented JSIMD_FORCE* environment variables could be
    used to force-enable a particular SIMD instruction set if multiple instruction
    sets were available on a particular platform. On x86 platforms, where CPU
    feature detection is bulletproof and multiple SIMD instruction sets are
    available, it makes sense for those environment variables to allow forcing the
    use of an instruction set only if that instruction set is available. However,
    since the ARM implementations of libjpeg-turbo can only use one SIMD
    instruction set, and since their feature detection code is less bulletproof
    (parsing /proc/cpuinfo), it makes sense for the JSIMD_FORCENEON environment
    variable to bypass the feature detection code and really force the use of NEON
    instructions. A new environment variable (JSIMD_FORCEDSPR2) was introduced
    in the MIPS implementation for the same reasons, and the existing
    JSIMD_FORCENONE environment variable was extended to that implementation.
    These environment variables provide a workaround for those attempting to test
    ARM and MIPS builds of libjpeg-turbo in QEMU, which passes through
    /proc/cpuinfo from the host system.

  2. libjpeg-turbo previously assumed that AltiVec instructions were always
    available on PowerPC platforms, which led to "illegal instruction" errors when
    running on PowerPC chips that lack AltiVec support (such as the older 7xx/G3
    and newer e5500 series.) libjpeg-turbo now examines /proc/cpuinfo on
    Linux/Android systems and enables AltiVec instructions only if the CPU supports
    them. It also now provides two environment variables, JSIMD_FORCEALTIVEC and
    JSIMD_FORCENONE, to force-enable and force-disable AltiVec instructions in
    environments where /proc/cpuinfo is an unreliable means of CPU feature
    detection (such as when running in QEMU.) On OS X, libjpeg-turbo continues to
    assume that AltiVec support is always available, which means that libjpeg-turbo
    cannot be used with G3 Macs unless you set the environment variable
    JSIMD_FORCENONE to 1.

  3. Fixed an issue whereby 64-bit ARM (AArch64) builds of libjpeg-turbo would
    crash when built with recent releases of the Clang/LLVM compiler. This was
    caused by an ABI conformance issue in some of libjpeg-turbo's 64-bit NEON SIMD
    routines. Those routines were incorrectly using 64-bit instructions to
    transfer a 32-bit JDIMENSION argument, whereas the ABI allows the upper
    (unused) 32 bits of a 32-bit argument's register to be undefined. The new
    Clang/LLVM optimizer uses load combining to transfer multiple adjacent 32-bit
    structure members into a single 64-bit register, and this exposed the ABI
    conformance issue.

  4. Fancy upsampling is now supported when decompressing JPEG images that use
    4:4:0 (h1v2) chroma subsampling. These images are generated when losslessly
    rotating or transposing JPEG images that use 4:2:2 (h2v1) chroma subsampling.
    The h1v2 fancy upsampling algorithm is not currently SIMD-accelerated.

  5. If merged upsampling isn't SIMD-accelerated but YCbCr-to-RGB conversion is,
    then libjpeg-turbo will now disable merged upsampling when decompressing YCbCr
    JPEG images into RGB or extended RGB output images. This significantly speeds
    up the decompression of 4:2:0 and 4:2:2 JPEGs on ARM platforms if fancy
    upsampling is not used (for example, if the -nosmooth option to djpeg is
    specified.)

  6. The TurboJPEG API will now decompress 4:2:2 and 4:4:0 JPEG images with
    2x2 luminance sampling factors and 2x1 or 1x2 chrominance sampling factors.
    This is a non-standard way of specifying 2x subsampling (normally 4:2:2 JPEGs
    have 2x1 luminance and 1x1 chrominance sampling factors, and 4:4:0 JPEGs have
    1x2 luminance and 1x1 chrominance sampling factors), but the JPEG format and
    the libjpeg API both allow it.

  7. Fixed an unsigned integer overflow in the libjpeg memory manager, detected
    by the Clang undefined behavior sanitizer, that could be triggered by
    attempting to decompress a specially-crafted malformed JPEG image. This issue
    affected only 32-bit code and did not pose a security threat, but removing the
    warning makes it easier to detect actual security issues, should they arise in
    the future.

  8. Fixed additional negative left shifts and other issues reported by the GCC
    and Clang undefined behavior sanitizers when attempting to decompress
    specially-crafted malformed JPEG images. None of these issues posed a security
    threat, but removing the warnings makes it easier to detect actual security
    issues, should they arise in the future.

  9. Fixed an out-of-bounds array reference, introduced by 1.4.90[2] (partial
    image decompression) and detected by the Clang undefined behavior sanitizer,
    that could be triggered by a specially-crafted malformed JPEG image with more
    than four components. Because the out-of-bounds reference was still within the
    same structure, it was not known to pose a security threat, but removing the
    warning makes it easier to detect actual security issues, should they arise in
    the future.

  10. Fixed another ABI conformance issue in the 64-bit ARM (AArch64) NEON SIMD
    code. Some of the routines were incorrectly reading and storing data below the
    stack pointer, which caused segfaults in certain applications under specific
    circumstances.

1.5.0

Significant changes relative to 1.5 beta1:

  1. Fixed an issue whereby a malformed motion-JPEG frame could cause the "fast
    path" of libjpeg-turbo's Huffman decoder to read from uninitialized memory.

  2. Added libjpeg-turbo version and build information to the global string table
    of the libjpeg and TurboJPEG API libraries. This is a common practice in other
    infrastructure libraries, such as OpenSSL and libpng, because it makes it easy
    to examine an application binary and determine which version of the library the
    application was linked against.

  3. Fixed a couple of issues in the PPM reader that would cause buffer overruns
    in cjpeg if one of the values in a binary PPM/PGM input file exceeded the
    maximum value defined in the file's header. libjpeg-turbo 1.4.2 already
    included a similar fix for ASCII PPM/PGM files. Note that these issues were
    not security bugs, since they were confined to the cjpeg program and did not
    affect any of the libjpeg-turbo libraries.

  4. Fixed an issue whereby attempting to decompress a JPEG file with a corrupt
    header using the tjDecompressToYUV2() function would cause the function to
    abort without returning an error and, under certain circumstances, corrupt the
    stack. This only occurred if tjDecompressToYUV2() was called prior to
    calling tjDecompressHeader3(), or if the return value from
    tjDecompressHeader3() was ignored (both cases represent incorrect usage of
    the TurboJPEG API.)

  5. Fixed an issue in the ARM 32-bit SIMD-accelerated Huffman encoder that
    prevented the code from assembling properly with clang.

  6. The jpeg_stdio_src(), jpeg_mem_src(), jpeg_stdio_dest(), and
    jpeg_mem_dest() functions in the libjpeg API will now throw an error if a
    source/destination manager has already been assigned to the compress or
    decompress object by a different function or by the calling program. This
    prevents these functions from attempting to reuse a source/destination manager
    structure that was allocated elsewhere, because there is no way to ensure that
    it would be big enough to accommodate the new source/destination manager.

1.4.90 (1.5 beta1)

Significant changes relative to 1.4.2:

  1. Added full SIMD acceleration for PowerPC platforms using AltiVec VMX
    (128-bit SIMD) instructions. Although the performance of libjpeg-turbo on
    PowerPC was already good, due to the increased number of registers available
    to the compiler vs. x86, it was still possible to speed up compression by about
    3-4x and decompression by about 2-2.5x (relative to libjpeg v6b) through the
    use of AltiVec instructions.

  2. Added two new libjpeg API functions (jpeg_skip_scanlines() and
    jpeg_crop_scanline()) that can be used to partially decode a JPEG image. See
    libjpeg.txt for more details.

  3. The TJCompressor and TJDecompressor classes in the TurboJPEG Java API now
    implement the Closeable interface, so those classes can be used with a
    try-with-resources statement.

  4. The TurboJPEG Java classes now throw unchecked idiomatic exceptions
    (IllegalArgumentException, IllegalStateException) for unrecoverable errors
    caused by incorrect API usage, and those classes throw a new checked exception
    type (TJException) for errors that are passed through from the C library.

  5. Source buffers for the TurboJPEG C API functions, as well as the
    jpeg_mem_src() function in the libjpeg API, are now declared as const
    pointers. This facilitates passing read-only buffers to those functions and
    ensures the caller that the source buffer will not be modified. This should
    not create any backward API or ABI incompatibilities with prior libjpeg-turbo
    releases.

  6. The MIPS DSPr2 SIMD code can now be compiled to support either FR=0 or FR=1
    FPUs.

  7. Fixed additional negative left shifts and other issues reported by the GCC
    and Clang undefined behavior sanitizers. Most of these issues affected only
    32-bit code, and none of them was known to pose a security threat, but removing
    the warnings makes it easier to detect actual security issues, should they
    arise in the future.

  8. Removed the unnecessary .arch directive from the ARM64 NEON SIMD code.
    This directive was preventing the code from assembling using the clang
    integrated assembler.

  9. Fixed a regression caused by 1.4.1[6] that prevented 32-bit and 64-bit
    libjpeg-turbo RPMs from being installed simultaneously on recent Red Hat/Fedora
    distributions. This was due to the addition of a macro in jconfig.h that
    allows the Huffman codec to determine the word size at compile time. Since
    that macro differs between 32-bit and 64-bit builds, this caused a conflict
    between the i386 and x86_64 RPMs (any differing files, other than executables,
    are not allowed when 32-bit and 64-bit RPMs are installed simultaneously.)
    Since the macro is used only internally, it has been moved into jconfigint.h.

  10. The x86-64 SIMD code can now be disabled at run time by setting the
    JSIMD_FORCENONE environment variable to 1 (the other SIMD implementations
    already had this capability.)

  11. Added a new command-line argument to TJBench (-nowrite) that prevents the
    benchmark from outputting any images. This removes any potential operating
    system overhead that might be caused by lazy writes to disk and thus improves
    the consistency of the performance measurements.

  12. Added SIMD acceleration for Huffman encoding on SSE2-capable x86 and x86-64
    platforms. This speeds up the compression of full-color JPEGs by about 10-15%
    on average (relative to libjpeg-turbo 1.4.x) when using modern Intel and AMD
    CPUs. Additionally, this works around an issue in the clang optimizer that
    prevents it (as of this writing) from achieving the same performance as GCC
    when compiling the C version of the Huffman encoder
    (https://llvm.org/bugs/show_bug.cgi?id=16035). For the purposes of
    benchmarking or regression testing, SIMD-accelerated Huffman encoding can be
    disabled by setting the JSIMD_NOHUFFENC environment variable to 1.

  13. Added ARM 64-bit (ARMv8) NEON SIMD implementations of the commonly-used
    compression algorithms (including the slow integer forward DCT and h2v2 & h2v1
    downsampling algorithms, which are not accelerated in the 32-bit NEON
    implementation.) This speeds up the compression of full-color JPEGs by about
    75% on average on a Cavium ThunderX processor and by about 2-2.5x on average on
    Cortex-A53 and Cortex-A57 cores.

  14. Added SIMD acceleration for Huffman encoding on NEON-capable ARM 32-bit
    and 64-bit platforms.

    For 32-bit code, this speeds up the compression of full-color JPEGs by
    about 30% on average on a typical iOS device (iPhone 4S, Cortex-A9) and by
    about 6-7% on average on a typical Android device (Nexus 5X, Cortex-A53 and
    Cortex-A57), relative to libjpeg-turbo 1.4.x. Note that the larger speedup
    under iOS is due to the fact that iOS builds use LLVM, which does not optimize
    the C Huffman encoder as well as GCC does.

    For 64-bit code, NEON-accelerated Huffman encoding speeds up the
    compression of full-color JPEGs by about 40% on average on a typical iOS device
    (iPhone 5S, Apple A7) and by about 7-8% on average on a typical Android device
    (Nexus 5X, Cortex-A53 and Cortex-A57), in addition to the speedup described in
    [13] above.

    For the purposes of benchmarking or regression testing, SIMD-accelerated
    Huffman encoding can be disabled by setting the JSIMD_NOHUFFENC environment
    variable to 1.

  15. pkg-config (.pc) scripts are now included for both the libjpeg and
    TurboJPEG API libraries on Un*x systems. Note that if a project's build system
    relies on these scripts, then it will not be possible to build that project
    with libjpeg or with a prior version of libjpeg-turbo.

  16. Optimized the ARM 64-bit (ARMv8) NEON SIMD decompression routines to
    improve performance on CPUs with in-order pipelines. This speeds up the
    decompression of full-color JPEGs by nearly 2x on average on a Cavium ThunderX
    processor and by about 15% on average on a Cortex-A53 core.

  17. Fixed an issue in the accelerated Huffman decoder that could have caused
    the decoder to read past the end of the input buffer when a malformed,
    specially-crafted JPEG image was being decompressed. In prior versions of
    libjpeg-turbo, the accelerated Huffman decoder was invoked (in most cases) only
    if there were > 128 bytes of data in the input buffer. However, it is possible
    to construct a JPEG image in which a single Huffman block is over 430 bytes
    long, so this version of libjpeg-turbo activates the accelerated Huffman
    decoder only if there are > 512 bytes of data in the input buffer.

  18. Fixed a memory leak in tjunittest encountered when running the program
    with the -yuv option.

1.4.2

Significant changes relative to 1.4.1:

  1. Fixed an issue whereby cjpeg would segfault if a Windows bitmap with a
    negative width or height was used as an input image (Windows bitmaps can have
    a negative height if they are stored in top-down order, but such files are
    rare and not supported by libjpeg-turbo.)

  2. Fixed an issue whereby, under certain circumstances, libjpeg-turbo would
    incorrectly encode certain JPEG images when quality=100 and the fast integer
    forward DCT were used. This was known to cause make test to fail when the
    library was built with -march=haswell on x86 systems.

  3. Fixed an issue whereby libjpeg-turbo would crash when built with the latest
    & greatest development version of the Clang/LLVM compiler. This was caused by
    an x86-64 ABI conformance issue in some of libjpeg-turbo's 64-bit SSE2 SIMD
    routines. Those routines were incorrectly using a 64-bit mov instruction to
    transfer a 32-bit JDIMENSION argument, whereas the x86-64 ABI allows the upper
    (unused) 32 bits of a 32-bit argument's register to be undefined. The new
    Clang/LLVM optimizer uses load combining to transfer multiple adjacent 32-bit
    structure members into a single 64-bit register, and this exposed the ABI
    conformance issue.

  4. Fixed a bug in the MIPS DSPr2 4:2:0 "plain" (non-fancy and non-merged)
    upsampling routine that caused a buffer overflow (and subsequent segfault) when
    decompressing a 4:2:0 JPEG image whose scaled output width was less than 16
    pixels. The "plain" upsampling routines are normally only used when
    decompressing a non-YCbCr JPEG image, but they are also used when decompressing
    a JPEG image whose scaled output height is 1.

  5. Fixed various negative left shifts and other issues reported by the GCC and
    Clang undefined behavior sanitizers. None of these was known to pose a
    security threat, but removing the warnings makes it easier to detect actual
    security issues, should they arise in the future.

1.4.1

Significant changes relative to 1.4.0:

  1. tjbench now properly handles CMYK/YCCK JPEG files. Passing an argument of
    -cmyk (instead of, for instance, -rgb) will cause tjbench to internally
    convert the source bitmap to CMYK prior to compression, to generate YCCK JPEG
    files, and to internally convert the decompressed CMYK pixels back to RGB after
    decompression (the latter is done automatically if a CMYK or YCCK JPEG is
    passed to tjbench as a source image.) The CMYK<->RGB conversion operation is
    not benchmarked. NOTE: The quick & dirty CMYK<->RGB conversions that tjbench
    uses are suitable for testing only. Proper conversion between CMYK and RGB
    requires a color management system.

  2. make test now performs additional bitwise regression tests using tjbench,
    mainly for the purpose of testing compression from/decompression to a subregion
    of a larger image buffer.

  3. make test no longer tests the regression of the floating point DCT/IDCT
    by default, since the results of those tests can vary if the algorithms in
    question are not implemented using SIMD instructions on a particular platform.
    See the comments in Makefile.am for information on how to
    re-enable the tests and to specify an expected result for them based on the
    particulars of your platform.

  4. The NULL color conversion routines have been significantly optimized,
    which speeds up the compression of RGB and CMYK JPEGs by 5-20% when using
    64-bit code and 0-3% when using 32-bit code, and the decompression of those
    images by 10-30% when using 64-bit code and 3-12% when using 32-bit code.

  5. Fixed an "illegal instruction" error that occurred when djpeg from a
    SIMD-enabled libjpeg-turbo MIPS build was executed with the -nosmooth option
    on a MIPS machine that lacked DSPr2 support. The MIPS SIMD routines for h2v1
    and h2v2 merged upsampling were not properly checking for the existence of
    DSPr2.

  6. Performance has been improved significantly on 64-bit non-Linux and
    non-Windows platforms (generally 10-20% faster compression and 5-10% faster
    decompression.) Due to an oversight, the 64-bit version of the accelerated
    Huffman codec was not being compiled in when libjpeg-turbo was built on
    platforms other than Windows or Linux. Oops.

  7. Fixed an extremely rare bug in the Huffman encoder that caused 64-bit
    builds of libjpeg-turbo to incorrectly encode a few specific test images when
    quality=98, an optimized Huffman table, and the slow integer forward DCT were
    used.

  8. The Windows (CMake) build system now supports building only static or only
    shared libraries. This is accomplished by adding either -DENABLE_STATIC=0 or
    -DENABLE_SHARED=0 to the CMake command line.

  9. TurboJPEG API functions will now return an error code if a warning is
    triggered in the underlying libjpeg API. For instance, if a JPEG file is
    corrupt, the TurboJPEG decompression functions will attempt to decompress
    as much of the image as possible, but those functions will now return -1 to
    indicate that the decompression was not entirely successful.

  10. Fixed a bug in the MIPS DSPr2 4:2:2 fancy upsampling routine that caused a
    buffer overflow (and subsequent segfault) when decompressing a 4:2:2 JPEG image
    in which the right-most MCU was 5 or 6 pixels wide.

1.4.0

Significant changes relative to 1.4 beta1:

  1. Fixed a build issue on OS X PowerPC platforms (md5cmp failed to build
    because OS X does not provide the le32toh() and htole32() functions.)

  2. The non-SIMD RGB565 color conversion code did not work correctly on big
    endian machines. This has been fixed.

  3. Fixed an issue in tjPlaneSizeYUV() whereby it would erroneously return 1
    instead of -1 if componentID was > 0 and subsamp was TJSAMP_GRAY.

  4. Fixed an issue in tjBufSizeYUV2() whereby it would erroneously return 0
    instead of -1 if width was < 1.

  5. The Huffman encoder now uses clz and bsr instructions for bit counting
    on ARM64 platforms (see 1.4 beta1[5].)

  6. The close() method in the TJCompressor and TJDecompressor Java classes is
    now idempotent. Previously, that method would call the native tjDestroy()
    function even if the TurboJPEG instance had already been destroyed. This
    caused an exception to be thrown during finalization, if the close() method
    had already been called. The exception was caught, but it was still an
    expensive operation.

  7. The TurboJPEG API previously generated an error (Could not determine subsampling type for JPEG image) when attempting to decompress grayscale JPEG
    images that were compressed with a sampling factor other than 1 (for instance,
    with cjpeg -grayscale -sample 2x2). Subsampling technically has no meaning
    with grayscale JPEGs, and thus the horizontal and vertical sampling factors
    for such images are ignored by the decompressor. However, the TurboJPEG API
    was being too rigid and was expecting the sampling factors to be equal to 1
    before it treated the image as a grayscale JPEG.

  8. cjpeg, djpeg, and jpegtran now accept an argument of -version, which will
    print the library version and exit.

  9. Referring to 1.4 beta1[15], another extremely rare circumstance was
    discovered under which the Huffman encoder's local buffer can be overrun
    when a buffered destination manager is being used and an
    extremely-high-frequency block (basically junk image data) is being encoded.
    Even though the Huffman local buffer was increased from 128 bytes to 136 bytes
    to address the previous issue, the new issue caused even the larger buffer to
    be overrun. Further analysis reveals that, in the absolute worst case (such as
    setting alternating AC coefficients to 32767 and -32768 in the JPEG scanning
    order), the Huffman encoder can produce encoded blocks that approach double the
    size of the unencoded blocks. Thus, the Huffman local buffer was increased to
    256 bytes, which should prevent any such issue from re-occurring in the future.

  10. The new tjPlaneSizeYUV(), tjPlaneWidth(), and tjPlaneHeight()
    functions were not actually usable on any platform except OS X and Windows,
    because those functions were not included in the libturbojpeg mapfile. This
    has been fixed.

  11. Restored the JPP(), JMETHOD(), and FAR macros in the libjpeg-turbo
    header files. The JPP() and JMETHOD() macros were originally implemented
    in libjpeg as a way of supporting non-ANSI compilers that lacked support for
    prototype parameters. libjpeg-turbo has never supported such compilers, but
    some software packages still use the macros to define their own prototypes.
    Similarly, libjpeg-turbo has never supported MS-DOS and other platforms that
    have far symbols, but some software packages still use the FAR macro. A
    pretty good argument can be made that this is a bad practice on the part of the
    software in question, but since this affects more than one package, it's just
    easier to fix it here.

  12. Fixed issues that were preventing the ARM 64-bit SIMD code from compiling
    for iOS, and included an ARMv8 architecture in all of the binaries installed by
    the "official" libjpeg-turbo SDK for OS X.

1.3.90 (1.4 beta1)

Significant changes relative to 1.3.1:

  1. New features in the TurboJPEG API:

    • YUV planar images can now be generated with an arbitrary line padding
      (previously only 4-byte padding, which was compatible with X Video, was
      supported.)
    • The decompress-to-YUV function has been extended to support image
      scaling.
    • JPEG images can now be compressed from YUV planar source images.
    • YUV planar images can now be decoded into RGB or grayscale images.
    • 4:1:1 subsampling is now supported. This is mainly included for
      compatibility, since 4:1:1 is not fully accelerated in libjpeg-turbo and has no
      significant advantages relative to 4:2:0.
    • CMYK images are now supported. This feature allows CMYK source images
      to be compressed to YCCK JPEGs and YCCK or CMYK JPEGs to be decompressed to
      CMYK destination images. Conversion between CMYK/YCCK and RGB or YUV images is
      not supported. Such conversion requires a color management system and is thus
      out of scope for a codec library.
    • The handling of YUV images in the Java API has been significantly
      refactored and should now be much more intuitive.
    • The Java API now supports encoding a YUV image from an arbitrary
      position in a large image buffer.
    • All of the YUV functions now have a corresponding function that operates
      on separate image planes instead of a unified image buffer. This allows for
      compressing/decoding from or decompressing/encoding to a subregion of a larger
      YUV image. It also allows for handling YUV formats that swap the order of the
      U and V planes.
  2. Added SIMD acceleration for DSPr2-capable MIPS platforms. This speeds up
    the compression of full-color JPEGs by 70-80% on such platforms and
    decompression by 25-35%.

  3. If an application attempts to decompress a Huffman-coded JPEG image whose
    header does not contain Huffman tables, libjpeg-turbo will now insert the
    default Huffman tables. In order to save space, many motion JPEG video frames
    are encoded without the default Huffman tables, so these frames can now be
    successfully decompressed by libjpeg-turbo without additional work on the part
    of the application. An application can still override the Huffman tables, for
    instance to re-use tables from a previous frame of the same video.

  4. The Mac packaging system now uses pkgbuild and productbuild rather than
    PackageMaker (which is obsolete and no longer supported.) This means that
    OS X 10.6 "Snow Leopard" or later must be used when packaging libjpeg-turbo,
    although the packages produced can be installed on OS X 10.5 "Leopard" or
    later. OS X 10.4 "Tiger" is no longer supported.

  5. The Huffman encoder now uses clz and bsr instructions for bit counting
    on ARM platforms rather than a lookup table. This reduces the memory footprint
    by 64k, which may be important for some mobile applications. Out of four
    Android devices that were tested, two demonstrated a small overall performance
    loss (~3-4% on average) with ARMv6 code and a small gain (also ~3-4%) with
    ARMv7 code when enabling this new feature, but the other two devices
    demonstrated a significant overall performance gain with both ARMv6 and ARMv7
    code (~10-20%) when enabling the feature. Actual mileage may vary.

  6. Worked around an issue with Visual C++ 2010 and later that caused incorrect
    pixels to be generated when decompressing a JPEG image to a 256-color bitmap,
    if compiler optimization was enabled when libjpeg-turbo was built. This caused
    the regression tests to fail when doing a release build under Visual C++ 2010
    and later.

  7. Improved the accuracy and performance of the non-SIMD implementation of the
    floating point inverse DCT (using code borrowed from libjpeg v8a and later.)
    The accuracy of this implementation now matches the accuracy of the SSE/SSE2
    implementation. Note, however, that the floating point DCT/IDCT algorithms are
    mainly a legacy feature. They generally do not produce significantly better
    accuracy than the slow integer DCT/IDCT algorithms, and they are quite a bit
    slower.

  8. Added a new output colorspace (JCS_RGB565) to the libjpeg API that allows
    for decompressing JPEG images into RGB565 (16-bit) pixels. If dithering is not
    used, then this code path is SIMD-accelerated on ARM platforms.

  9. Numerous obsolete features, such as support for non-ANSI compilers and
    support for the MS-DOS memory model, were removed from the libjpeg code,
    greatly improving its readability and making it easier to maintain and extend.

  10. Fixed a segfault that occurred when calling output_message() with
    msg_code set to JMSG_COPYRIGHT.

  11. Fixed an issue whereby wrjpgcom was allowing comments longer than 65k
    characters to be passed on the command line, which was causing it to generate
    incorrect JPEG files.

  12. Fixed a bug in the build system that was causing the Windows version of
    wrjpgcom to be built using the rdjpgcom source code.

  13. Restored 12-bit-per-component JPEG support. A 12-bit version of
    libjpeg-turbo can now be built by passing an argument of --with-12bit to
    configure (Unix) or -DWITH_12BIT=1 to cmake (Windows.) 12-bit JPEG support
    is included only for convenience. Enabling this feature disables all of the
    performance features in libjpeg-turbo, as well as arithmetic coding and the
    TurboJPEG API. The resulting library still contains the other libjpeg-turbo
    features (such as the colorspace extensions), but in general, it performs no
    faster than libjpeg v6b.

  14. Added ARM 64-bit SIMD acceleration for the YCC-to-RGB color conversion
    and IDCT algorithms (both are used during JPEG decompression.) For unknown
    reasons (probably related to clang), this code cannot currently be compiled for
    iOS.

  15. Fixed an extremely rare bug that could cause the Huffman encoder's local
    buffer to overrun when a very high-frequency MCU is compressed using quality
    100 and no subsampling, and when the JPEG output buffer is being dynamically
    resized by the destination manager. This issue was so rare that, even with a
    test program specifically designed to make the bug occur (by injecting random
    high-frequency YUV data into the compressor), it was reproducible only once in
    about every 25 million iterations.

  16. Fixed an oversight in the TurboJPEG C wrapper: if any of the JPEG
    compression functions was called repeatedly with the same
    automatically-allocated destination buffer, then TurboJPEG would erroneously
    assume that the jpegSize parameter was equal to the size of the buffer, when
    in fact that parameter was probably equal to the size of the most recently
    compressed JPEG image. If the size of the previous JPEG image was not as large
    as the current JPEG image, then TurboJPEG would unnecessarily reallocate the
    destination buffer.

1.3.1

Significant changes relative to 1.3.0:

  1. On Un*x systems, make install now installs the libjpeg-turbo libraries
    into /opt/libjpeg-turbo/lib32 by default on any 32-bit system, not just x86,
    and into /opt/libjpeg-turbo/lib64 by default on any 64-bit system, not just
    x86-64. You can override this by overriding either the prefix or libdir
    configure variables.

  2. The Windows installer now places a copy of the TurboJPEG DLLs in the same
    directory as the rest of the libjpeg-turbo binaries. This was mainly done
    to support TurboVNC 1.3, which bundles the DLLs in its Windows installation.
    When using a 32-bit version of CMake on 64-bit Windows, it is impossible to
    access the c:\WINDOWS\system32 directory, which made it impossible for the
    TurboVNC build scripts to bundle the 64-bit TurboJPEG DLL.

  3. Fixed a bug whereby attempting to encode a progressive JPEG with arithmetic
    entropy coding (by passing arguments of -progressive -arithmetic to cjpeg or
    jpegtran, for instance) would result in an error, Requested feature was omitted at compile time.

  4. Fixed a couple of issues whereby malformed JPEG images would cause
    libjpeg-turbo to use uninitialized memory during decompression.

  5. Fixed an error (Buffer passed to JPEG library is too small) that occurred
    when calling the TurboJPEG YUV encoding function with a very small (< 5x5)
    source image, and added a unit test to check for this error.

  6. The Java classes should now build properly under Visual Studio 2010 and
    later.

  7. Fixed an issue that prevented SRPMs generated using the in-tree packaging
    tools from being rebuilt on certain newer Linux distributions.

  8. Numerous minor fixes to eliminate compilation and build/packaging system
    warnings, fix cosmetic issues, improve documentation clarity, and other general
    source cleanup.

1.3.0

Significant changes relative to 1.3 beta1:

  1. make test now works properly on FreeBSD, and it no longer requires the
    md5sum executable to be present on other Un*x platforms.

  2. Overhauled the packaging system:

    • To avoid conflict with vendor-supplied libjpeg-turbo packages, the
      official RPMs and DEBs for libjpeg-turbo have been renamed to
      "libjpeg-turbo-official".
    • The TurboJPEG libraries are now located under /opt/libjpeg-turbo in the
      official Linux and Mac packages, to avoid conflict with vendor-supplied
      packages and also to streamline the packaging system.
    • Release packages are now created with the directory structure defined
      by the configure variables prefix, bindir, libdir, etc. (Un*x) or by the
      CMAKE_INSTALL_PREFIX variable (Windows.) The exception is that the docs are
      always located under the system default documentation directory on Un*x and
      Mac systems, and on Windows, the TurboJPEG DLL is always located in the Windows
      system directory.
    • To avoid confusion, official libjpeg-turbo packages on Linux/Unix
      platforms (except for Mac) will always install the 32-bit libraries in
      /opt/libjpeg-turbo/lib32 and the 64-bit libraries in /opt/libjpeg-turbo/lib64.
    • Fixed an issue whereby, in some cases, the libjpeg-turbo executables on
      Un*x systems were not properly linking with the shared libraries installed by
      the same package.
    • Fixed an issue whereby building the "installer" target on Windows when
      WITH_JAVA=1 would fail if the TurboJPEG JAR had not been previously built.
    • Building the "install" target on Windows now installs files into the
      same places that the installer does.
  3. Fixed a Huffman encoder bug that prevented I/O suspension from working
    properly.

1.2.90 (1.3 beta1)

Significant changes relative to 1.2.1:

  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. 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 have a policy against accepting any library that isn't
    versioned.

  3. Extended the TurboJPEG Java API so that it can be used to compress a JPEG
    image from and decompress a JPEG image to an arbitrary position in a large
    image buffer.

  4. The tjDecompressToYUV() function now supports the TJFLAG_FASTDCT flag.

  5. The 32-bit supplementary package for amd64 Debian systems now provides
    symlinks in /usr/lib/i386-linux-gnu for the TurboJPEG libraries in /usr/lib32.
    This allows those libraries to be used on MultiArch-compatible systems (such as
    Ubuntu 11 and later) without setting the linker path.

  6. The TurboJPEG Java wrapper should now find the JNI library on Mac systems
    without having to pass -Djava.library.path=/usr/lib to java.

  7. TJBench has been ported to Java to provide a convenient way of validating
    the performance of the TurboJPEG Java API. It can be run with
    java -cp turbojpeg.jar TJBench.

  8. cjpeg can now be used to generate JPEG files with the RGB colorspace
    (feature ported from jpeg-8d.)

  9. The width and height in the -crop argument passed to jpegtran can now be
    suffixed with f to indicate that, when the upper left corner of the cropping
    region is automatically moved to the nearest iMCU boundary, the bottom right
    corner should be moved by the same amount. In other words, this feature causes
    jpegtran to strictly honor the specified width/height rather than the specified
    bottom right corner (feature ported from jpeg-8d.)

  10. JPEG files using the RGB colorspace can now be decompressed into grayscale
    images (feature ported from jpeg-8d.)

  11. Fixed a regression caused by 1.2.1[7] whereby the build would fail with
    multiple "Mismatch in operand sizes" errors when attempting to build the x86
    SIMD code with NASM 0.98.

  12. The in-memory source/destination managers (jpeg_mem_src() and
    jpeg_mem_dest()) are now included by default when building libjpeg-turbo with
    libjpeg v6b or v7 emulation, so that programs can take advantage of these
    functions without requiring the use of the backward-incompatible libjpeg v8
    ABI. The "age number" of the libjpeg-turbo library on Un*x systems has been
    incremented by 1 to reflect this. You can disable this feature with a
    configure/CMake switch in order to retain strict API/ABI compatibility with the
    libjpeg v6b or v7 API/ABI (or with previous versions of libjpeg-turbo.) See
    README.md for more details.

  13. Added ARMv7s architecture to libjpeg.a and libturbojpeg.a in the official
    libjpeg-turbo binary package for OS X, so that those libraries can be used to
    build applications that leverage the faster CPUs in the iPhone 5 and iPad 4.

1.2.1

Significant changes relative to 1.2.0:

  1. 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.

  2. 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.

  3. 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.

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

  5. Worked around a severe performance issue with "Bobcat" (AMD Embedded APU)
    processors. The MASKMOVDQU instruction, which was used by the libjpeg-turbo
    SSE2 SIMD code, is apparently implemented in microcode on AMD processors, and
    it is painfully slow on Bobcat processors in particular. Eliminating the use
    of this instruction improved performance by an order of magnitude on Bobcat
    processors and by a small amount (typically 5%) on AMD desktop processors.

  6. 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.

  7. Fixed a regression caused by 1.2.0[2] whereby, on Linux/x86 platforms
    running the 32-bit SSE2 SIMD code in libjpeg-turbo, decompressing a 4:2:0 or
    4:2:2 JPEG image into a 32-bit (RGBX, BGRX, etc.) buffer without using fancy
    upsampling would produce several incorrect columns of pixels at the right-hand
    side of the output image if each row in the output image was not evenly
    divisible by 16 bytes.

  8. Fixed an issue whereby attempting to build the SIMD extensions with Xcode
    4.3 on OS X platforms would cause NASM to return numerous errors of the form
    "'%define' expects a macro identifier".

  9. Added flags to the TurboJPEG API that allow the caller to force the use of
    either the fast or the accurate DCT/IDCT algorithms in the underlying codec.

1.2.0

Significant changes relative to 1.2 beta1:

  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 ARMv6 and ARMv7 architectures to libjpeg.a and libturbojpeg.a in
    the official libjpeg-turbo binary package for OS X, so that those libraries can
    be used to build both OS X and iOS applications.

1.1.90 (1.2 beta1)

Significant changes relative to 1.1.1:

  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 the
    TurboJPEG API 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

Significant changes relative to 1.1.0:

  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

Significant changes relative to 1.1 beta1:

  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 the TurboJPEG wrapper 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)

Significant changes relative to 1.0.1:

  1. Added emulation of the libjpeg v7 and v8 APIs and ABIs. See
    README.md 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

Significant changes relative to 1.0.0:

  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. The configure script will now automatically determine whether the
    INCOMPLETE_TYPES_BROKEN macro should be defined.

1.0.0

Significant changes relative to 0.0.93:

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

  2. Created symlinks 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

Significant changes since 0.0.91:

  1. 2982659: Fixed x86-64 build on FreeBSD systems

  2. 2988188: Added support for Windows 64-bit systems

0.0.91

Significant changes relative to 0.0.90:

  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