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| # dav1d |
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| **dav1d** is a new **AV1** cross-platform **d**ecoder, open-source, and focused on speed and correctness. |
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| The canonical repository URL for this repo is https://code.videolan.org/videolan/dav1d |
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| This project is partially funded by the *Alliance for Open Media*/**AOM**. |
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| ## Goal and Features |
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| 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. |
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| It supports all features from AV1, including all subsampling and bit-depth parameters. |
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| In the future, this project will host simple tools or simple wrappings *(like, for example, an MFT transform)*. |
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| ## License |
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| **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. |
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| 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). |
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| # Roadmap |
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| The plan is the folllowing: |
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| ### 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. |
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| ### 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. |
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| ### After |
| 10. Use more GPU, when possible. |
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| # Contribute |
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| Currently, we are looking for help from: |
| - C developers, |
| - asm developers, |
| - platform-specific developers, |
| - GPGPU developers, |
| - testers. |
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| Our contributions guidelines are quite strict. We want to build a coherent codebase to simplify maintenance and achieve the highest possible speed. |
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| Notably, the codebase is in pure C and asm. |
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| We are on IRC, on the **#dav1d** channel on *Freenode*. |
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| See the [contributions document](CONTRIBUTING.md). |
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| ## CLA |
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| There is no CLA. |
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| People will keep their copyright and their authorship rights, while adhering to the BSD 2-clause license. |
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| VideoLAN will only have the collective work rights. |
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| ## CoC |
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| The [VideoLAN Code of Conduct](https://wiki.videolan.org/CoC) applies to this project. |
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| # Compile |
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| 1. Install [Meson](https://mesonbuild.com/) (0.47 or higher), [Ninja](https://ninja-build.org/), and, for x86\* targets, [nasm](https://nasm.us/) (2.13.02 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 |
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| # Run tests |
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| 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 |
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| # Support |
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| This project is partially funded by the *Alliance for Open Media*/**AOM** and is supported by TwoOrioles and VideoLabs. |
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| These companies can provide support and integration help, should you need it. |
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| # FAQ |
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| ## Why do you not improve libaom rather than starting a new project? |
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| - 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*. |
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| ## Is dav1d a recursive acronym? |
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| - Yes. |
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| ## Can I help? |
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| - Yes. See the [contributions document](CONTRIBUTING.md). |
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| ## I am not a developer. Can I help? |
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| - Yes. We need testers, bug reporters, and documentation writers. |
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| ## What about the AV1 patent license? |
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| - This project is an implementation of a decoder. It gives you no special rights on the AV1 patents. |
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| Please read the [AV1 patent license](doc/PATENTS) that applies to the AV1 specification and codec. |
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| ## Will you care about <my_arch>? <my_os>? |
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| - We do, but we don't have either the time or the knowledge. Therefore, patches and contributions welcome. |
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