libjpeg-turbo/libjpeg-turbo 1.4.90

1.4.90 (1.5 beta1)

on GitHub

Official binaries and source tarball are available at:
https://sourceforge.net/projects/libjpeg-turbo/files/1.4.90%20%281.5%20beta1%29/

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 accurate 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.