1 2 3# dav1d 4 5**dav1d** is an **AV1** cross-platform **d**ecoder, open-source, and focused on speed and correctness. 6 7It is now battle-tested and production-ready and can be used everywhere. 8 9The canonical repository URL for this repo is https://code.videolan.org/videolan/dav1d 10 11This project was partially funded by the *Alliance for Open Media*/**AOM**. 12 13## Goal and Features 14 15The 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. 16 17It supports all features from AV1, including all subsampling and bit-depth parameters. 18 19In the future, this project will host simple tools or simple wrappings *(like, for example, an MFT transform)*. 20 21## License 22 23**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. 24 25The reasoning behind this decision is the same as for libvorbis, see [RMS on vorbis](https://lwn.net/2001/0301/a/rms-ov-license.php3). 26 27# Roadmap 28 29The plan is the following: 30 31### Reached 321. Complete C implementation of the decoder, 332. Provide a usable API, 343. Port to most platforms, 354. Make it fast on desktop, by writing asm for AVX2 chips. 365. Make it fast on mobile, by writing asm for ARMv8 chips, 376. Make it fast on older desktop, by writing asm for SSSE3+ chips, 387. Make high bit-depth fast on mobile, by writing asm for ARMv8 chips. 398. Make it fast on older mobile, by writing asm for ARMv7 chips, 409. Make high bit-depth fast on older mobile, by writing asm for ARMv7 chips, 4110. Make high bit-depth fast on desktop, by writing asm for AVX2 chips, 4211. Make high bit-depth fast on older desktop, by writing asm for SSSE3+ chips, 4312. Improve threading. 44 45### On-going 4613. Improve C code base with [various tweaks](https://code.videolan.org/videolan/dav1d/wikis/task-list), 4714. Accelerate for less common architectures, like PPC, SSE2, RISC-V or AVX-512. 48 49### After 5015. Use more GPU decoding, when possible. 51 52# Contribute 53 54Currently, we are looking for help from: 55- C developers, 56- asm developers, 57- platform-specific developers, 58- GPGPU developers, 59- testers. 60 61Our contributions guidelines are quite strict. We want to build a coherent codebase to simplify maintenance and achieve the highest possible speed. 62 63Notably, the codebase is in pure C and asm. 64 65We are on IRC, on the **#dav1d** channel on [*Libera.chat*](http://libera.chat/). If you do not have an IRC Client at hand, use [IRC Web Interface](https://web.libera.chat/#dav1d). 66 67See the [contributions document](CONTRIBUTING.md). 68 69## CLA 70 71There is no CLA. 72 73People will keep their copyright and their authorship rights, while adhering to the BSD 2-clause license. 74 75VideoLAN will only have the collective work rights. 76 77## CoC 78 79The [VideoLAN Code of Conduct](https://wiki.videolan.org/CoC) applies to this project. 80 81# Compile 82 831. Install [Meson](https://mesonbuild.com/) (0.49 or higher), [Ninja](https://ninja-build.org/), and, for x86\* targets, [nasm](https://nasm.us/) (2.14 or higher) 842. Run `mkdir build && cd build` to create a build directory and enter it 853. Run `meson setup ..` to configure meson, add `--default-library=static` if static linking is desired 864. Run `ninja` to compile 87 88## Cross-Compilation for 32- or 64-bit Windows, 32-bit Linux 89 90If you're on a linux build machine trying to compile .exe for a Windows target/host machine, run 91 92``` 93meson setup build --cross-file=package/crossfiles/x86_64-w64-mingw32.meson 94``` 95 96or, for 32-bit: 97 98``` 99meson setup build --cross-file=package/crossfiles/i686-w64-mingw32.meson 100``` 101 102`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. 103 104For 32-bit linux, run 105 106``` 107meson setup build --cross-file=package/crossfiles/i686-linux32.meson 108``` 109 110## Build documentation 111 1121. Install [doxygen](https://www.doxygen.nl/) and [graphviz](https://www.graphviz.org/) 1132. Run `meson setup build -Denable_docs=true` to create the build directory 1143. Run `ninja -C build doc/html` to build the docs 115 116The result can be found in `build/doc/html/`. An online version built from master can be found [here](https://videolan.videolan.me/dav1d/). 117 118# Run tests 119 1201. 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 1212. During meson configuration, specify `-Dtestdata_tests=true` 1223. Run `meson test -v` after compiling 123 124# Support 125 126This project is partially funded by the *Alliance for Open Media*/**AOM** and is supported by TwoOrioles and VideoLabs. 127 128These companies can provide support and integration help, should you need it. 129 130 131# FAQ 132 133## Why do you not improve libaom rather than starting a new project? 134 135- We believe that libaom is a very good library. It was however developed for research purposes during AV1 design. 136We think that an implementation written from scratch can achieve faster decoding, in the same way that *ffvp9* was faster than *libvpx*. 137 138## Is dav1d a recursive acronym? 139 140- Yes. 141 142## Can I help? 143 144- Yes. See the [contributions document](CONTRIBUTING.md). 145 146## I am not a developer. Can I help? 147 148- Yes. We need testers, bug reporters and documentation writers. 149 150## What about the AV1 patent license? 151 152- This project is an implementation of a decoder. It gives you no special rights on the AV1 patents. 153 154Please read the [AV1 patent license](doc/PATENTS) that applies to the AV1 specification and codec. 155 156## Will you care about <my_arch>? <my_os>? 157 158- We do, but we don't have either the time or the knowledge. Therefore, patches and contributions welcome. 159
