README.md - libavif - Git at Google

 # libavif

 This library aims to be a friendly, portable C implementation of the AV1 Image
 File Format, as described here:

 <https://aomediacodec.github.io/av1-avif/>

 It can encode and decode all AV1 supported YUV formats and bit depths (with
 alpha).

 It is recommended that you check out/use
 [tagged releases](https://github.com/AOMediaCodec/libavif/releases) instead of
 just using the main branch. We will regularly create new versions as bug fixes
 and features are added.

 ## Usage

 Please see the examples in the "examples" directory. If you're already building
 `libavif`, enable the CMake option `AVIF_BUILD_EXAMPLES` in order to build and
 run the examples too.

 ## Installation

 `libavif` is a package in most major OSs.

 ### Windows

 ```sh
 vcpkg install libavif
 ```
 You can also download the official windows binaries on the
 [release](https://github.com/AOMediaCodec/libavif/releases) page.

 ### macOS

 Homebrew:
 ```sh
 brew install libavif
 ```
 MacPorts:
 ```sh
 sudo port install libavif
 ```

 ### Linux

 Debian-based distributions:
 ```sh
 sudo apt install libavif-dev
 ```
 Red Hat-based distributions:
 ```sh
 sudo yum -y install libavif
 ```

 ### MinGW

 For the "default" MSYS2 UCRT64 environment:
 ```sh
 pacman -S mingw-w64-ucrt-x86_64-libavif
 ```

 ## Build Notes

 Building libavif requires [CMake](https://cmake.org/).

 No AV1 codecs are enabled by default. Enable them by setting any of the
 following CMake options to `LOCAL` or `SYSTEM` whether you want to use a
 locally built or a system installed version (e.g. `-DAVIF_CODEC_AOM=LOCAL`):

 * `AVIF_CODEC_AOM` for [libaom](https://aomedia.googlesource.com/aom/) (encoder
   and decoder)
 * `AVIF_CODEC_DAV1D` for [dav1d](https://code.videolan.org/videolan/dav1d)
   (decoder)
 * `AVIF_CODEC_LIBGAV1` for
   [libgav1](https://chromium.googlesource.com/codecs/libgav1/) (decoder)
 * `AVIF_CODEC_RAV1E` for [rav1e](https://github.com/xiph/rav1e) (encoder)
 * `AVIF_CODEC_SVT` for [SVT-AV1](https://gitlab.com/AOMediaCodec/SVT-AV1)
   (encoder)

 When set to `SYSTEM`, these libraries (in their C API form) must be externally
 available (discoverable via CMake's `FIND_LIBRARY`) to use them, or if libavif
 is a child CMake project, the appropriate CMake target must already exist
 by the time libavif's CMake scripts are executed.

 ### Static Builds

 When set to `LOCAL`, these libraries and the other dependencies will be pulled
 locally by CMake to known-good versions.

 To override a local dependency version or to use a custom build of a dependency,
 first run the associated script in the `ext/` subdirectory.

 ### Tests

 A few tests written in C can be built by enabling the `AVIF_BUILD_TESTS` CMake
 option.

 The remaining tests can be built by enabling the `AVIF_BUILD_TESTS` and
 `AVIF_ENABLE_GTEST` CMake options. They require GoogleTest
 (`-DAVIF_GTEST=SYSTEM` or `-DAVIF_GTEST=LOCAL`).

 ### Command Lines

 The following instructions can be used to build the libavif library and the
 `avifenc` and `avifdec` tools.

 #### Build using installed dependencies

 To link against the already installed `aom`, `libjpeg` and `libpng` dependency
 libraries (recommended):

 ```sh
 git clone -b v1.1.1 https://github.com/AOMediaCodec/libavif.git
 cmake -S libavif -B libavif/build -DAVIF_CODEC_AOM=SYSTEM -DAVIF_BUILD_APPS=ON
 cmake --build libavif/build --parallel
 ```

 #### Build everything from scratch

 For development and debugging purposes, or to generate fully static binaries:

 ```sh
 git clone -b v1.1.1 https://github.com/AOMediaCodec/libavif.git
 cmake -S libavif -B libavif/build -DBUILD_SHARED_LIBS=OFF -DAVIF_CODEC_AOM=LOCAL -DAVIF_LIBYUV=LOCAL -DAVIF_LIBSHARPYUV=LOCAL -DAVIF_JPEG=LOCAL -DAVIF_ZLIBPNG=LOCAL -DAVIF_BUILD_APPS=ON -DCMAKE_C_FLAGS_RELEASE="-static" -DCMAKE_EXE_LINKER_FLAGS="-static"
 cmake --build libavif/build --parallel
 ```

 ## Prebuilt Binaries (Windows)

 Statically-linked `avifenc.exe` and `avifdec.exe` can be downloaded from the
 [Releases](https://github.com/AOMediaCodec/libavif/releases) page.

 ## Development Notes

 Please check the [wiki](https://github.com/AOMediaCodec/libavif/wiki) for extra
 resources on libavif, such as the Release Checklist.

 The libavif library is written in C99. Most of the tests are written in C++14.

 ### Formatting

 Use [clang-format](https://clang.llvm.org/docs/ClangFormat.html) to format the
 sources from the top-level folder (`clang-format-16` preferred):

 ```sh
 clang-format -style=file -i \
   apps/*.c apps/*/*.c apps/*/*.cc apps/*/*.h examples/*.c \
   include/avif/*.h src/*.c src/*.cc \
   tests/*.c tests/*/*.cc tests/*/*.h
 ```

 Use [cmake-format](https://github.com/cheshirekow/cmake_format) to format the
 CMakeLists.txt files from the top-level folder:

 ```sh
 cmake-format -i \
   CMakeLists.txt \
   tests/CMakeLists.txt \
   cmake/Modules/*.cmake \
   contrib/CMakeLists.txt \
   contrib/gdk-pixbuf/CMakeLists.txt \
   android_jni/avifandroidjni/src/main/jni/CMakeLists.txt
 ```

 ---

 ## License

 Released under the BSD License.

 ```markdown
 Copyright 2019 Joe Drago. All rights reserved.

 Redistribution and use in source and binary forms, with or without
 modification, are permitted provided that the following conditions are met:

 1. Redistributions of source code must retain the above copyright notice, this
 list of conditions and the following disclaimer.

 2. Redistributions in binary form must reproduce the above copyright notice,
 this list of conditions and the following disclaimer in the documentation
 and/or other materials provided with the distribution.

 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
 FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
 CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 ```
	# libavif

	This library aims to be a friendly, portable C implementation of the AV1 Image
	File Format, as described here:

	<https://aomediacodec.github.io/av1-avif/>

	It can encode and decode all AV1 supported YUV formats and bit depths (with
	alpha).

	It is recommended that you check out/use
	[tagged releases](https://github.com/AOMediaCodec/libavif/releases) instead of
	just using the main branch. We will regularly create new versions as bug fixes
	and features are added.

	## Usage

	Please see the examples in the "examples" directory. If you're already building
	`libavif`, enable the CMake option `AVIF_BUILD_EXAMPLES` in order to build and
	run the examples too.

	## Installation

	`libavif` is a package in most major OSs.

	### Windows

	```sh
	vcpkg install libavif
	```
	You can also download the official windows binaries on the
	[release](https://github.com/AOMediaCodec/libavif/releases) page.

	### macOS

	Homebrew:
	```sh
	brew install libavif
	```
	MacPorts:
	```sh
	sudo port install libavif
	```

	### Linux

	Debian-based distributions:
	```sh
	sudo apt install libavif-dev
	```
	Red Hat-based distributions:
	```sh
	sudo yum -y install libavif
	```

	### MinGW

	For the "default" MSYS2 UCRT64 environment:
	```sh
	pacman -S mingw-w64-ucrt-x86_64-libavif
	```

	## Build Notes

	Building libavif requires [CMake](https://cmake.org/).

	No AV1 codecs are enabled by default. Enable them by setting any of the
	following CMake options to `LOCAL` or `SYSTEM` whether you want to use a
	locally built or a system installed version (e.g. `-DAVIF_CODEC_AOM=LOCAL`):

	* `AVIF_CODEC_AOM` for [libaom](https://aomedia.googlesource.com/aom/) (encoder
	and decoder)
	* `AVIF_CODEC_DAV1D` for [dav1d](https://code.videolan.org/videolan/dav1d)
	(decoder)
	* `AVIF_CODEC_LIBGAV1` for
	[libgav1](https://chromium.googlesource.com/codecs/libgav1/) (decoder)
	* `AVIF_CODEC_RAV1E` for [rav1e](https://github.com/xiph/rav1e) (encoder)
	* `AVIF_CODEC_SVT` for [SVT-AV1](https://gitlab.com/AOMediaCodec/SVT-AV1)
	(encoder)

	When set to `SYSTEM`, these libraries (in their C API form) must be externally
	available (discoverable via CMake's `FIND_LIBRARY`) to use them, or if libavif
	is a child CMake project, the appropriate CMake target must already exist
	by the time libavif's CMake scripts are executed.

	### Static Builds

	When set to `LOCAL`, these libraries and the other dependencies will be pulled
	locally by CMake to known-good versions.

	To override a local dependency version or to use a custom build of a dependency,
	first run the associated script in the `ext/` subdirectory.

	### Tests

	A few tests written in C can be built by enabling the `AVIF_BUILD_TESTS` CMake
	option.

	The remaining tests can be built by enabling the `AVIF_BUILD_TESTS` and
	`AVIF_ENABLE_GTEST` CMake options. They require GoogleTest
	(`-DAVIF_GTEST=SYSTEM` or `-DAVIF_GTEST=LOCAL`).

	### Command Lines

	The following instructions can be used to build the libavif library and the
	`avifenc` and `avifdec` tools.

	#### Build using installed dependencies

	To link against the already installed `aom`, `libjpeg` and `libpng` dependency
	libraries (recommended):

	```sh
	git clone -b v1.1.1 https://github.com/AOMediaCodec/libavif.git
	cmake -S libavif -B libavif/build -DAVIF_CODEC_AOM=SYSTEM -DAVIF_BUILD_APPS=ON
	cmake --build libavif/build --parallel
	```

	#### Build everything from scratch

	For development and debugging purposes, or to generate fully static binaries:

	```sh
	git clone -b v1.1.1 https://github.com/AOMediaCodec/libavif.git
	cmake -S libavif -B libavif/build -DBUILD_SHARED_LIBS=OFF -DAVIF_CODEC_AOM=LOCAL -DAVIF_LIBYUV=LOCAL -DAVIF_LIBSHARPYUV=LOCAL -DAVIF_JPEG=LOCAL -DAVIF_ZLIBPNG=LOCAL -DAVIF_BUILD_APPS=ON -DCMAKE_C_FLAGS_RELEASE="-static" -DCMAKE_EXE_LINKER_FLAGS="-static"
	cmake --build libavif/build --parallel
	```

	## Prebuilt Binaries (Windows)

	Statically-linked `avifenc.exe` and `avifdec.exe` can be downloaded from the
	[Releases](https://github.com/AOMediaCodec/libavif/releases) page.

	## Development Notes

	Please check the [wiki](https://github.com/AOMediaCodec/libavif/wiki) for extra
	resources on libavif, such as the Release Checklist.

	The libavif library is written in C99. Most of the tests are written in C++14.

	### Formatting

	Use [clang-format](https://clang.llvm.org/docs/ClangFormat.html) to format the
	sources from the top-level folder (`clang-format-16` preferred):

	```sh
	clang-format -style=file -i \
	apps/.c apps//.c apps//.cc apps//.h examples/.c \
	include/avif/.h src/.c src/*.cc \
	tests/.c tests//.cc tests//*.h
	```

	Use [cmake-format](https://github.com/cheshirekow/cmake_format) to format the
	CMakeLists.txt files from the top-level folder:

	```sh
	cmake-format -i \
	CMakeLists.txt \
	tests/CMakeLists.txt \
	cmake/Modules/*.cmake \
	contrib/CMakeLists.txt \
	contrib/gdk-pixbuf/CMakeLists.txt \
	android_jni/avifandroidjni/src/main/jni/CMakeLists.txt
	```

	---

	## License

	Released under the BSD License.

	```markdown
	Copyright 2019 Joe Drago. All rights reserved.

	Redistribution and use in source and binary forms, with or without
	modification, are permitted provided that the following conditions are met:

	1. Redistributions of source code must retain the above copyright notice, this
	list of conditions and the following disclaimer.

	2. Redistributions in binary form must reproduce the above copyright notice,
	this list of conditions and the following disclaimer in the documentation
	and/or other materials provided with the distribution.

	THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
	AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
	DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
	FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
	SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
	CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
	OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
	OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	```