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 # dav1d **dav1d** is a new **AV1** cross-platform **d**ecoder, open-source, and focused on speed and correctness. The canonical repository URL for this repo is https://code.videolan.org/videolan/dav1d This project is partially funded by the *Alliance for Open Media*/**AOM**. ## Goal and Features The goal of this project is to provide a decoder for **most platforms**, and achieve the **highest speed** possible to overcome the temporary lack of AV1 hardware decoder. It supports all features from AV1, including all subsampling and bit-depth parameters. In the future, this project will host simple tools or simple wrappings *(like, for example, an MFT transform)*. ## License **dav1d** is released under a very liberal license, a contrario from the other VideoLAN projects, so that it can be embedded anywhere, including non-open-source software; or even drivers, to allow the creation of hybrid decoders. The reasoning behind this decision is the same as for libvorbis, see [RMS on vorbis](https://lwn.net/2001/0301/a/rms-ov-license.php3). # Roadmap The plan is the following: ### Reached 1. Complete C implementation of the decoder, 2. Provide a usable API, 3. Port to most platforms, 4. Make it fast on desktop, by writing asm for AVX-2 chips. 5. Make it fast on mobile, by writing asm for ARMv8 chips, 6. Make it fast on older desktop, by writing asm for SSSE3+ chips. ### On-going 7. Make it fast on older mobiles, by writing asm for ARMv7 chips, 8. Improve C code base with [various tweaks](https://code.videolan.org/videolan/dav1d/wikis/task-list), 9. Accelerate for less common architectures, like PPC, SSE2 or AVX-512. ### After 10. Use more GPU, when possible. # Contribute Currently, we are looking for help from: - C developers, - asm developers, - platform-specific developers, - GPGPU developers, - testers. Our contributions guidelines are quite strict. We want to build a coherent codebase to simplify maintenance and achieve the highest possible speed. Notably, the codebase is in pure C and asm. We are on IRC, on the **#dav1d** channel on *Freenode*. See the [contributions document](CONTRIBUTING.md). ## CLA There is no CLA. People will keep their copyright and their authorship rights, while adhering to the BSD 2-clause license. VideoLAN will only have the collective work rights. ## CoC The [VideoLAN Code of Conduct](https://wiki.videolan.org/CoC) applies to this project. # Compile 1. Install [Meson](https://mesonbuild.com/) (0.47 or higher), [Ninja](https://ninja-build.org/), and, for x86\* targets, [nasm](https://nasm.us/) (2.14 or higher) 2. Run `mkdir build && cd build` to create a build directory and enter it 3. Run `meson ..` to configure meson, add `--default-library=static` if static linking is desired 4. Run `ninja` to compile ## Cross-Compilation for 32- or 64-bit Windows, 32-bit Linux If you're on a linux build machine trying to compile .exe for a Windows target/host machine, run ``` meson build --cross-file=package/crossfiles/x86_64-w64-mingw32.meson ``` or, for 32-bit: ``` meson build --cross-file=package/crossfiles/i686-w64-mingw32.meson ``` `mingw-w64` is a pre-requisite and should be installed on your linux machine via your preferred method or package manager. Note the binary name formats may differ between distributions. Verify the names, and use `alias` if certain binaries cannot be found. For 32-bit linux, run ``` meson build --cross-file=package/crossfiles/i686-linux32.meson ``` # Run tests 1. In the root directory, run `git clone https://code.videolan.org/videolan/dav1d-test-data.git tests/dav1d-test-data` to fetch the test data repository 2. During meson configuration, specify `-Dtestdata_tests=true` 3. Run `meson test -v` after compiling # Support This project is partially funded by the *Alliance for Open Media*/**AOM** and is supported by TwoOrioles and VideoLabs. These companies can provide support and integration help, should you need it. # FAQ ## Why do you not improve libaom rather than starting a new project? - We believe that libaom is a very good library. It was however developed for research purposes during AV1 design. We think that an implementation written from scratch can achieve faster decoding, in the same way that *ffvp9* was faster than *libvpx*. ## Is dav1d a recursive acronym? - Yes. ## Can I help? - Yes. See the [contributions document](CONTRIBUTING.md). ## I am not a developer. Can I help? - Yes. We need testers, bug reporters, and documentation writers. ## What about the AV1 patent license? - This project is an implementation of a decoder. It gives you no special rights on the AV1 patents. Please read the [AV1 patent license](doc/PATENTS) that applies to the AV1 specification and codec. ## Will you care about <my_arch>? <my_os>? - We do, but we don't have either the time or the knowledge. Therefore, patches and contributions welcome.