JebP - Single header WebP decoder

Don't let all the files scare you away, infact only one header file is required to use this project.

Currently this project only supports lossless (VP8L) images. This project:

• Does not support decoding lossy files with VP8 (Draft PR).
• Does not support extended file-formats with VP8X.
• Does not support VP8L lossless images with the color-indexing transform (palleted images).
• Does not support VP8L images with more than 256 huffman groups. This is an arbitrary limit to prevent bad images from using too much memory. In theory, images requiring more groups should be very rare. This limit may be increased in the future.

This project is still very new so there is very likely bugs in it. Be kind and report any issues you find.

For usage and documentation, see the header file.

Why?

I genuinely think WebP is a really cool format. Both PNG and JPEG (that are still in wide use) still use ancient technologies. Such technologies have improved alot since when they were released, and while there have been many attempts to invent the "new PNG" or the "new JPEG" most of them fall flat. WebP seems to be the only one that has made a name for itself and has gotten a following, especially in the web. But, despite the name, I do believe WebP could be used in so many more scenarios, not just the web.

However, not everyone might want to import the entire libwebp library, especially if they're used to something like stb_image.h (which doesn't support WebP). And no one else seemed to be doing it, which is understandable being how large the WebP specification is using two different codecs for lossless and lossy. So I decided to try and put one together myself. It may never get used but it was fun making anyway, and I learnt alot along the way :)

What are all these files?

Do not worry, these are all just files to help with development, none (except jebp.h) are needed to use the library.

• jebp.h is the single-header library you're probably looking for.
• jebp.c is a "source file" you can use. All it does is define JEBP_IMPLEMENTATION and then include jebp.h.
• jebpview.c is a demo program using SDL2 to show a WebP image. Use it with jebpview <WebP image>.
• CMakeLists.txt and dev are build and development files to help with development and CI. They build jebpview, E2E tests and the fuzz test, along with making it easier to run tests and format code. The cross files are designed to run in the CI.
• .gitignore, .gitattributes and .github are you standard git and GitHub information files. Notably, included inside of .github is a CI to test JebP on various supported platforms (see below).

What platforms are supported?

Any compiler that is configured to support at-least C99 (VLA support is not required) is supported on any architecture, operating-system or endianness (including PDP-endian technically, see below). If you find a compiler issue or bug with any compiler that 100% supports C99 (without VLA) including support for the required system headers documented in the source, then I will be very happy to fix it, no matter how obscure the compiler is.

However, certain operating-systems, architectures and compilers are explicitly detected by the code to enable better support, extended features or optimizations. Some of these supported platforms also are tested by the CI for every change. The full list of macros used to detect the platform is documented in the source file. The detected platforms are:

• The compilers GCC, Clang and MSVC. Only GCC currently has version detection, the other two assume everything is supported.
• The architectures x86-32 (x86, IA-32, i386), x86-64 (AMD64), AArch32 (arm32, armhf) and AArch64 (arm64).
• The SIMD variants SSE2 (x86) and Neon (AArch). Currently unused.
• Any little-endian architecture. Any other form of endianness, including big-endian, are not detected and do not have optimized functions. Instead, they use naive approaches.

As a subset of these, the following platforms are tested by the CI:

• GCC on Ubuntu.
• Clang on Ubuntu.
• MSVC on Windows.
• Clang on macOS.
• MinGW on Ubuntu.
• Cross-compile GCC x86-32, AArch64, AArch32 (soft and hard float) on Ubuntu.

Finally, the following is also supported:

• Transgender guys, gals, and non-binary pals 🏳️‍⚧️ because everyone needs a bit of support in their life ❤️