| 217 | | === |
| 218 | | |
| 219 | | **One line summary:** This project will implement an AArch64 NEON backend for the new swscale framework. |
| 220 | | |
| 221 | | **Description:** The recent swscale rewrite has transformed it into a flexible and reliable framework to handle scaling, with the logic being decoupled from the DSP code. This simplifies writing backends with all the benefits and deterministic behaviour of the reference C implementation. This project will extend the new swscale framework by implementing an AArch64 NEON backend, ensuring that ARM-based platforms (including mobile devices, servers, and single-board computers) benefit from the same deterministic and optimized pipeline as x86_64. This backend will be used to generate optimized NEON SIMD assembly code at runtime for platforms where just-in-time code execution (JIT) is supported, and it will also be used to generate static (non-JIT) assembly files that match the Continuation-Passing Style (CPS) code of the reference C and x86_64 implementations. |
| 222 | | |
| 223 | | **Expected results:** |
| | 217 | === libswscale AArch64 NEON backend === |
| | 218 | |
| | 219 | **One line summary:** This project will implement an AArch64 NEON backend for the new libswscale architecture. |
| | 220 | |
| | 221 | **Description:** The recent libswscale rewrite is transforming the library into a flexible and reliable architecture to handle scaling, with the logic being decoupled from the DSP code. This simplifies writing backends with all the benefits and deterministic behaviour of the reference C implementation. In order to achieve the goal of deprecating and phasing out the "legacy" code paths from FFmpeg, the new architecture must not introduce performance regressions for platforms with widespread use, such as x86_64 and AArch64, for Linux, macOS, and Windows. This project will extend the new libswscale architecture by implementing an AArch64 NEON backend, ensuring that ARM-based platforms (including mobile devices, servers, and single-board computers) benefit from the same deterministic and optimized pipeline as x86_64. This backend will be used to generate highly optimized NEON SIMD assembly code at runtime for platforms where just-in-time code execution (JIT) is supported, and it will also be used to generate static (non-JIT) assembly files that match the Continuation-Passing Style (CPS) code of the reference C and x86_64 implementations for platforms where JIT is not supported. |
| | 222 | |
| | 223 | **Expected results:** libswscale AArch64 NEON backend, both JIT and non-JIT, with feature parity to the reference C and x86_64 implementations. |
| 247 | | * **Description**: Using the assembly abstraction layer and the AArch64 NEON SIMD code from the asmjit validation backend, it will be possible to generate static assembly files that match the Continuation-Passing Style code of the reference C and x86_64 implementations. A tool (program or script) will be created to generate the static assembly files. This tool will be integrated into the FFmpeg codebase, and the static assembly files will be generated either at build-time or integrated into the FFmpeg codebase as well (to be determined). |
| 248 | | |
| 249 | | * **Deliverables**: Series merged to git master, effectively providing an initial AArch64 NEON backend for the new swscale framework. |
| | 253 | * **Description**: Using the assembly abstraction layer and the AArch64 NEON SIMD code from the asmjit validation backend, it will be possible to generate static assembly files that match the CPS code of the reference C and x86_64 implementations, even though they come with a certain overhead compared to the JIT code. A tool (program or script) will be created to generate the static assembly files. This tool will be integrated into the FFmpeg codebase, and the static assembly files will be generated either at build-time or integrated into the FFmpeg codebase as well (to be determined). |
| | 254 | |
| | 255 | * **Deliverables**: Series merged to git master, effectively providing an initial AArch64 NEON backend for the new libswscale architecture. |
| | 256 | |
| | 257 | * **Compensation:** 6,000 EUR |
| 259 | | * **Description**: The final AArch64 NEON JIT backend will be integrated into the FFmpeg codebase, based on the implementation selected by the community. Support will be added incrementally for each platform, only after they are each properly tested an validated. |
| 260 | | |
| 261 | | * **Deliverables**: A pull request to be reviewed by the FFmpeg community. |
| | 269 | * **Description**: The final AArch64 NEON JIT backend will be integrated into the FFmpeg codebase, based on the implementation selected by the community. Support will be added incrementally for each platform (Linux, macOS, Windows), only after they are each properly tested an validated. This JIT implementation will considerably reduce the overhead compared to the non-JIT code, ensuring that there are no performance regressions between the legacy code paths and the new architecture for AArch64 platforms. |
| | 270 | |
| | 271 | * **Deliverables**: A pull request with the final AArch64 NEON JIT backend, is either merged or has received at least one merge approval. |
| | 272 | |
| | 273 | * **Compensation:** 6,000 EUR |
