Astc-encoder-py

**Status:** June 2023

The 4.5.0 release is a minor release with minor image quality improvements, and multiple build system quality-of-life improvements.

* **General:**
* **Bug-fix:** Improved handling compiler arguments in CMake, including consistent use of MSVC-style command line arguments for ClangCL.
* **Bug-fix:** Invariant Clang builds now use `-ffp-model=precise` with `-ffp-contract=off` which is needed to restore invariance due to recent changes in compiler defaults.
* **Change:** macOS binary releases are now distributed as a single universal binary for all platforms.
* **Change:** Windows binary releases are now compiled with VS2022.
* **Change:** Invariant MSVC builds for VS2022 now use `/fp:precise` instead of `/fp:strict`, which is is now possible because precise no longer implies contraction. This should improve performance for MSVC builds.
* **Change:** Non-invariant Clang builds now use `-ffp-model=precise` with `-ffp-contract=on`. This should improve performance on older Clang versions which defaulted to no contraction.
* **Change:** Non-invariant MSVC builds for VS2022 now use `/fp:precise` with `/fp:contract`. This should improve performance for MSVC builds.
* **Change:** CMake config variables now use an `ASTCENC_` prefix to add a namespace and group options when the library is used in a larger project.
* **Change:** CMake config `ASTCENC_UNIVERSAL_BUILD` for building macOS universal binaries has been improved to include the `x86_64h` slice for AVX2 builds. Universal builds are now on by default for macOS, and always include NEON (arm64), SSE4.1 (x86_64), and AVX2 (x86_64h) variants.
* **Change:** CMake config `ASTCENC_NO_INVARIANCE` has been inverted to remove the negated option, and is now `ASTCENC_INVARIANCE` with a default of `ON`. Disabling this option can substantially improve performance, but images can different across platforms and compilers.
* **Optimization:** Color quantization and packing for LDR RGB and RGBA has been vectorized to improve performance.
* **Change:** Color quantization for LDR RGB and RGBA endpoints will now try multiple quantization packing methods, and pick the one with the lowest endpoint encoding error. This gives a minor image quality improvement, for no significant performance impact when combined with the vectorization optimizations.

Binary release sha256 checksums


fe2a1e5c8e57fc77175c6e9d0e1a10e583816507c82c748c568694bf39ae9f57 astcenc-4.5.0-linux-x64.zip
bc8895222820106135575b7dd1bef4d9f184be7ef7de6e684ab563b64c22d163 astcenc-4.5.0-macos-universal.zip
7c63f167558c65e607f72a4dc30b86d631ae3b561cffaee9d2afb5d5149d72e0 astcenc-4.5.0-windows-x64.zip

**Status:** March 2023

The 4.4.0 release is a minor release with image quality improvements, a small performance boost, a few new quality-of-life features, and a few minor fixes for uncommon build configurations.

* **General:**
* **Change:** Core library no longer checks availability of required instruction set extensions, such as SSE4.1 or AVX2. Checking compatibility is now the responsibility of the caller. See `astcenccli_entry.cpp` for an example of code performing this check.
* **Change:** Core library can be built as a shared object by setting the `-DSHAREDLIB=ON` CMake option, resulting in e.g. `libastcenc-avx2-shared.so`. Note that the command line tool is always statically linked.
* **Change:** Decompressed 3D images will now write one output file per slice, if the target format is a 2D image format, rather than just writing slice zero.
* **Change:** Command line tool errors print to `stderr` instead of `stdout`.
* **Change:** Color encoding uses new quantization tables, that now factor in floating-point rounding if a distance tie is found when using the integer quant256 value. This improves image quality for 4x4 and 5x5 block sizes.
* **Optimization:** Partition selection uses a simplified line calculation with a faster approximation. This improves performance for all block sizes.
* **Bug-fix:** Fixed missing symbol error in dead code for decompressor-only builds.
* **Bug-fix:** Fixed infinity handling in debug trace JSON files.

Binary release sha256 checksums


98267b6e23f188658de1e275816bad6bf1e9fe3ae113a1bac4109bf7ee75d579 astcenc-4.4.0-linux-x64.zip
d88c90c82f0e5cf15b9fae7582da394e5855a7cdeee776887351b07f5b6d21ea astcenc-4.4.0-macos-aarch64.zip
8f97f78dd9bedc8a21cfdafdd712ee1f8ec29414804c4e38bd630f4c8894517f astcenc-4.4.0-macos-x64.zip
e5407a8d7c4a0355aa1f0614aee21f3407c7f10cac2349bf3e57e8aaa4a21d53 astcenc-4.4.0-windows-x64.zip

**Status:** January 2023

The 4.3.1 release is a minor maintenance release. No performance or image quality changes are expected.

* **General:**
* **Bug-fix:** Fixed typo in -2/3/4partitioncandidatelimit CLI options.
* **Bug-fix:** Fixed handling for -3/4partitionindexlimit CLI options.
* **Bug-fix:** Updated to stb_image.h v2.28, which includes multiple fixes for image loading.

Binary release sha256 checksums


93ccb1c96493a9066487f641c2bc5eca87c7ec58b2270f7645af95db795dda7f astcenc-4.3.1-linux-x64.zip
ddd548181b5beda535171c6eda6280ff99e175868cc75e22efc65bbcccd37fa9 astcenc-4.3.1-macos-aarch64.zip
eaa425ad34a0455960bb660271fe853ba374543adf6c22823dbaa96d8aff7593 astcenc-4.3.1-macos-x64.zip
95bbd32112fcf21ef17927dcc4d446b24bfc5838efd9c4d8bb34edbfb85849e8 astcenc-4.3.1-windows-x64.zip

**Status:** January 2023

The 4.3.0 release is an optimization release. There are minor performance improvements, minor image quality improvements, significant memory footprint improvements, and library interface changes in this release.

Reminder - the codec library API is not designed to be binary compatible across versions. We always recommend rebuilding your client-side code using the updated `astcenc.h` header.

* **General:**
* **Bug-fix:** Use lower case `windows.h` include for MinGW compatibility.
* **Change:** The `-mask` command line option, `ASTCENC_FLG_MAP_MASK` in the library API, has been removed.
* **Optimization:** Always skip blue-contraction for `QUANT_256` encodings. This gives a small image quality improvement for images using the 4x4 block size.
* **Optimization:** Always skip RGBO vector calculation for LDR encodings.
* **Optimization:** Defer color packing and scrambling to physical layer.
* **Optimization:** Remove folded `decimation_info` lookup tables. This significantly reduces compressor memory footprint and improves context creation time. Impact increases with block size.
* **Optimization:** Increased trial and refinement pruning by using stricter target errors when determining whether to skip iterations.

Binary release sha256 checksums


7d74df06ec5e186f1ae2c3718df4eac649f80b0d3e38bcd1378a8803574e5459 astcenc-4.3.0-linux-x64.zip
1e3ad1c07f234c97d2668639910fc032677b5a7716425e478cba219708cc6a65 astcenc-4.3.0-macos-aarch64.zip
fa6d1322c59c8b1cdbfbf607bdfe546d6325c6fe067c740f704e026efdacbe43 astcenc-4.3.0-macos-x64.zip
e3b648bcbbc016f67091aef5563983cafeffc8c3feb3ef6a8d4e988fabce152a astcenc-4.3.0-windows-x64.zip

**Status:** November 2022


The 4.2.0 release is an optimization release. There are significant performance improvements, minor image quality improvements, and library interface changes in this release.

Reminder - the codec library API is not designed to be binary compatible across versions. We always recommend rebuilding your client-side code using the updated `astcenc.h` header.

* **General:**
* **Bug-fix:** Compression for RGB and RGBA base+offset encodings no longer generate endpoints with the incorrect blue-contract behavior.
* **Bug-fix:** Lowest channel correlation calculation now correctly ignores constant color channels for the purposes of filtering 2 plane encodings.
* **Bug-fix:** ISA compatibility now checked in `config_init()` as well as in `context_alloc()`.
* **Change:** Removed the low-weight count optimization, as more recent changes had significantly reduced its performance benefit. Option removed from both command line and configuration structure.
* **Feature:** The `-exhaustive` mode now runs full trials on more partitioning candidates and block candidates. This improves image quality by 0.1 to 0.25 dB, but slows down compression by 3x. The `-verythorough` and `-thorough` modes also test more candidates.
* **Feature:** A new preset, `-verythorough`, has been introduced to provide a standard performance point between `-thorough` and the re-tuned `-exhaustive` mode. This new mode is faster and higher quality than the `-exhaustive` preset in the 4.1 release.
* **Feature:** The compressor can now independently vary the number of partitionings considered for error estimation for 2/3/4 partitions. This allows heuristics to put more effort into 2 partitions, and less in to 3 and 4 partitions.
* **Feature:** The compressor can now run trials on a variable number of candidate partitionings, allowing high quality modes to explore more of the search space at the expense of slower compression. The number of trials is independently configurable for 2/3/4 partition cases.
* **Optimization:** Introduce early-out threshold for 2/3/4 partition searches based on the results after 1 of 2 trials. This significantly
improves performance for `-medium` and `-thorough` searches, for a minor loss in image quality.
* **Optimization:** Reduce early-out threshold for 3/4 partition searches based on 2/3 partition results. This significantly improves performance, especially for `-thorough` searches, for a minor loss in image quality.
* **Optimization:** Use direct vector compare to create a SIMD mask instead of a scalar compare that is broadcast to a vector mask.
* **Optimization:** Remove obsolete partition validity masks from the partition selection algorithm.
* **Optimization:** Removed obsolete channel scaling from partition `avgs_and_dirs()` calculations.

Binary release sha256 checksums


1987a3d80dac1f3022216f60234c606bd1862e4d87529651dabc1cda240cbf57 astcenc-4.2.0-linux-x64.zip
21b95c9061a5be1554b346c5b105aa0d9b26415b0d47176c3ec4ecbe5fd6d9cf astcenc-4.2.0-macos-aarch64.zip
9049f7826074e1a793d2ff0c57e20f361e5ce3256ff3c2579bf39ca42af324fc astcenc-4.2.0-macos-x64.zip
aa767ab52db3f6a3316386f4a95d98d236aca1872cda53b6b28dabe48decb21f astcenc-4.2.0-windows-x64.zip

**Status:** August 2022

The 4.1.0 release is a maintenance release. There is no performance or image quality change in this release.

* **General:**
* **Change:** Command line decompressor no longer uses the legacy `GL_LUMINANCE` or `GL_LUMINANCE_ALPHA` format enums when writing KTX output files. Luminance textures now use the `GL_RED` format and luminance_alpha textures now use the `GL_RG` format.
* **Change:** Command line tool gains a new `-dimage` option to generate diagnostic images showing aspects of the compression encoding. The output file name with its extension stripped is used as the stem of the diagnostic image file names.
* **Bug-fix:** Library decompressor builds for SSE no longer use masked store `maskmovdqu`, as they can generate faults on masked lanes.
* **Bug-fix:** Command line decompressor now correctly uses sized type enums for the internal format when writing output KTX files.
* **Bug-fix:** Command line compressor now correctly loads 16 and 32-bit per component input KTX files.
* **Bug-fix:** Fixed GCC9 compiler warnings on Arm aarch64.

Binary release sha256 checksums


31ffdd64c9a8fc21313bc039e5a7a3c29350ce6e24004f3649dcd1b128d2d6a2 astcenc-4.1.0-linux-x64.zip
8ed8bea302542d28b37a1026f80e54afeada30b1876b00cdf9034eaf384b491c astcenc-4.1.0-macos-aarch64.zip
99c174c7f8f7660fc265d13ce6fe97379130ada05f1fbbcf5a82da646439ba97 astcenc-4.1.0-macos-x64.zip
3dbc32f146e00999e48c9dc29be483ec70ec7adf13dc879775f99bebaf8a2627 astcenc-4.1.0-windows-x64.zip