
Over a three-month period, gramner@twoorioles.com developed and optimized VP9 video codec features for the ossrs/ffmpeg-webrtc and FFmpeg/FFmpeg repositories, focusing on low-level performance improvements. They implemented AVX-512ICL and AVX2 assembly optimizations for VP9 decoding, including new decoding paths, inverse transforms, and sub-pixel motion compensation, targeting both 8-bit and 10-bit video. Using C and x86 assembly, gramner enhanced throughput and reduced CPU usage on modern hardware, while also refactoring legacy code to streamline maintenance. The work demonstrated deep expertise in SIMD instructions and video codec internals, delivering robust, maintainable solutions for real-time and streaming video workloads.

September 2025 (FFmpeg/FFmpeg) focused on performance optimization for 8-bit VP9 decoding on AVX2-capable CPUs, plus targeted maintenance to simplify the codebase. Delivered two AVX2-based optimizations for 8-bit VP9 intra prediction and inverse transforms and removed an obsolete 8-bit AVX2 VP9 inverse transform implementation to reduce code size and compilation time. These changes improve decoding throughput on supported hardware, lower maintenance burden, and illustrate robust low-level optimization and refactoring capabilities.
September 2025 (FFmpeg/FFmpeg) focused on performance optimization for 8-bit VP9 decoding on AVX2-capable CPUs, plus targeted maintenance to simplify the codebase. Delivered two AVX2-based optimizations for 8-bit VP9 intra prediction and inverse transforms and removed an obsolete 8-bit AVX2 VP9 inverse transform implementation to reduce code size and compilation time. These changes improve decoding throughput on supported hardware, lower maintenance burden, and illustrate robust low-level optimization and refactoring capabilities.
August 2025: FFmpeg/FFmpeg delivered a high-impact performance optimization for VP9 sub-pixel motion compensation using AVX-512ICL. The change introduces AVX-512ICL assembly optimizations for 8-bit-per-pixel sub-pixel interpolation, along with new helper functions/macros and updates to initialization routines to cover multiple sub-pixel scenarios. Expected throughput improvements on AVX-512-capable CPUs for VP9 workloads; commit referenced below. This work strengthens encoding/decoding efficiency and contributes to better streaming performance on modern hardware.
August 2025: FFmpeg/FFmpeg delivered a high-impact performance optimization for VP9 sub-pixel motion compensation using AVX-512ICL. The change introduces AVX-512ICL assembly optimizations for 8-bit-per-pixel sub-pixel interpolation, along with new helper functions/macros and updates to initialization routines to cover multiple sub-pixel scenarios. Expected throughput improvements on AVX-512-capable CPUs for VP9 workloads; commit referenced below. This work strengthens encoding/decoding efficiency and contributes to better streaming performance on modern hardware.
May 2025 — ossrs/ffmpeg-webrtc: Delivered VP9 AVX-512ICL optimization, targeting 16x16 and 32x32 blocks for 8-bit and 10-bit decoding. The change includes new decoding paths and inverse transforms, enabling faster VP9 decode on AVX-512ICL-capable hardware and improving real-time WebRTC throughput.
May 2025 — ossrs/ffmpeg-webrtc: Delivered VP9 AVX-512ICL optimization, targeting 16x16 and 32x32 blocks for 8-bit and 10-bit decoding. The change includes new decoding paths and inverse transforms, enabling faster VP9 decode on AVX-512ICL-capable hardware and improving real-time WebRTC throughput.
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