## Vulkan Video

Safe bindings to [Vulkan Video](https://www.khronos.org/blog/an-introduction-to-vulkan-video) via [ash](https://github.com/ash-rs/ash).

- Rust-only GPU-accelerated Vulkan Video (we don't depend on FFMPEG, NVDEC, ...)
- Builds everywhere ash builds, minimal dependencies
- Exposes all<sup>†</sup> decode / encode operations supported by Vulkan (e.g., H.264, H.265, ...)
- Exposes compute functionality for post-processing
- Import / export foreign memory for interop<sup>†</sup>


### Status

- **October 1st, 2023** - <sup>†</sup> Right now this is a 'proof of concept', as it can only decode one H.264 frame on the author's graphics card, and is many weeks away from being useful.


### FAQ

- **Feature X is missing or broken, will you fix it?**

    Right now I only have time to implement what I need. However, I will gladly accept PRs.

- **How can I interop with DirectX, Torch, CUDA ...**

    The idea is to support [Vulkan external memory](https://registry.khronos.org/vulkan/specs/1.3-extensions/man/html/VK_KHR_external_memory.html), and expose additional (feature-gated) APIs to ingest or export to external device memory.
    The exact details how to best interface with each external API are work-in-progress. Based on some initial tinkering zero-copy GPU-memory interop with other Vulkan instances is probably going to be 'easyish', with Torch probably 'hard'.

- **Can I use this to decode MP4?**

    We probably won't add container support to the core library. Instead you'd use another crate to parse your MP4 (or similar), and then feed the H.26x frames into this library.

- **What's your UB policy?**

    All Rust code in here should be safe and must never cause undefined behavior (UB). If you find anything that could cause UB, please file an issue.
    That said, right now most functions don't check their arguments properly and it might be easy to submit operations to Vulkan that cause fishy behavior.
    Also there is a chance that a bad compute shader could mess things up through the Vulkan backdoor. Whether that means all shader invocations should be `unsafe` I'm not yet sure, as that is similar to the `/proc/self/mem` file I/O issue in vanilla Rust.


### Contributing

PRs are very welcome. Feel free to submit trivial PRs right away. Architectural issues should be discussed first, but are also greatly appreciated.


### License

- BSD 2-Clause, Ralf Biedert