| commit | 938c4aaa6901adf695c84d023e5bf9b9e7483d02 | [log] [tgz] |
|---|---|---|
| author | Wan-Teh Chang <wtc@google.com> | Wed Nov 18 15:28:42 2020 -0800 |
| committer | Joe Drago <joedrago@gmail.com> | Thu Nov 19 16:48:35 2020 -0800 |
| tree | fac14abda8783cbf9c89466a0b64335522354167 | |
| parent | bb4918dac00168df371cac64af5e4fdf2e437289 [diff] |
Add AVIF_MATRIX_COEFFICIENTS_YCGCO (YCgCo) support Add AVIF_MATRIX_COEFFICIENTS_YCGCO=8 (YCgCo) support to src/reformat.c. Only full range is supported. Limited range is not supported. The YCgCo color space has the following two differences: 1. The limited-full range adjustment is applied to R,G,B as opposed to Y,Cb,Cr. In this aspect, it is the same as Identity. 2. For the RGB-to-YUV conversion, it is similar to normal YUV conversion but uses different equations (its equations do not use the Kb and Kr coefficients). To reuse the current implementation for normal YUV conversion, YCgCo is only supported with full range so that we don't need to deal with the different limited-full range adjustment. Note: Although R,G,B limited-full range adjustment is also used with Identity, it is easier to handle because Identity's matrix is a no-op and therefore it does not matter whether range adjustment is performed before or after a no-op. Fix https://github.com/AOMediaCodec/libavif/issues/418
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 is a work-in-progress, but can already encode and decode all AOM supported YUV formats and bit depths (with alpha).
For now, it is recommended that you checkout/use tagged releases instead of just using the master branch. I will regularly create new versions as bugfixes and features are added.
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.
Building libavif requires CMake.
No AV1 codecs are enabled by default. Enable them by enabling any of the following CMake options:
AVIF_CODEC_AOM - requires CMake, NASMAVIF_CODEC_DAV1D - requires Meson, Ninja, NASMAVIF_CODEC_LIBGAV1 - requires CMake, NinjaAVIF_CODEC_RAV1E - requires cargo (Rust), NASMThese 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.
The ext/ subdirectory contains a handful of basic scripts which each pull down a known-good copy of an AV1 codec and make a local static library build. If you want to statically link any codec into your local (static) build of libavif, building using one of these scripts and then enabling the associated AVIF_LOCAL_* is a convenient method, but you must make sure to disable BUILD_SHARED_LIBS in CMake to instruct it to make a static libavif library.
If you want to build/install shared libraries for AV1 codecs, you can still peek inside of each script to see where the current known-good SHA is for each codec.
If you're building on Windows with Visual Studio 2019 and want to try out libavif without going through the build process, static library builds for both Debug and Release are available on AppVeyor.
Released under the BSD License.
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.