Crate pixie_anim_lib 

Pixie-Anim

A zero-dependency, SIMD-accelerated GIF optimizer.

Pixie-Anim

A high-performance, zero-dependency short-form animation optimizer written in Rust and WebAssembly.

Inspired by Lee Robinson’s pixo, Pixie-Anim follows a similar philosophy: building mission-critical codecs from scratch without heavy runtime dependencies, optimized for both native CLI performance and zero-latency in-browser execution.

• 📖 Read more: Optimizing GIFs with Pixo: Extending Lessons Learned - A technical writeup on the architecture and philosophy behind Pixie-Anim.

🚀 Key Features

• Zero-Dependency Core: From-scratch implementation of GIF89a and LZW.
• Superior Compression: Achieves 20-30% smaller files than Gifsicle -O3 through advanced heuristics.
• Perceptual Quantization: Uses CIELAB color space and K-Means++ for superior color fidelity.
• Fuzzy Delta Compression: Temporal denoising that treats “nearly identical” pixels as transparent, dramatically reducing size for real-world video.
• Parallelized & SIMD: Multi-threaded quantization via Rayon and Planar AVX2 kernels for nearest-color search.
• WASM Playground: Fully functional, client-side optimizer with direct MP4-to-GIF support.
• Subjective LLM Judge: Automated quality evaluation via Gemini 3 Flash.

📊 Performance Matrix (720p HD)

Tool	Mode	Speed (per frame)	Size (KB)	Subjective (1-10)
Gifsicle -O3	Standard	~123ms	76,312	-
FFmpeg	2-Pass HQ	~270ms	78,340	-
Pixie-Anim	Quality/Lossy	~110ms	66,620	7

Benchmarked on an 8-second high-motion drone sequence. Pixie-Anim provides a significant size advantage while maintaining competitive speed.

🧠 Algorithms

Zeng Palette Reordering

By ordering the 256-color palette by visual similarity, we maximize the length of LZW strings, gaining “free” compression with negligible compute cost.

Lossy LZW (Fuzzy Neighbor Matching)

A unique optimization where the encoder can match visually similar “neighbor” indices in the Zeng-ordered palette to continue an LZW sequence, further collapsing file size.

Planar SIMD Search

We discovered that standard interleaved RGB SIMD is often slower than scalar for small palettes. Pixie-Anim uses a Planar data layout to unlock the true potential of AVX2/NEON for nearest-color search.

🛠 Usage

CLI

Build the native binary:

cargo build --release --features="cli"

The binary will be available at target/release/pixie-anim.

Optimize an image sequence:

./target/release/pixie-anim frames/*.png --output optimized.gif --fps 15 --lossy 8 --fuzz 10

Web Playground

The web UI is a Lit-based application that leverages the Rust core via WASM.

1. cd web
2. pnpm install
3. pnpm run dev (This automatically triggers build-wasm to generate bindings)
4. Drop an MP4 or GIF into the browser to optimize locally.

Note: To prevent browser memory exhaustion, the web playground currently scales video to 640px and caps extraction at 300 frames. Use the CLI for unlimited high-resolution processing.

📊 Benchmarking & Evaluation

Pixie-Anim includes a unified benchmarking tool to compare performance and visual quality against Gifsicle, FFmpeg, and gifski.

See tests/README.md for detailed instructions on the Hill-Climbing workflow and iterative performance tuning.

Quick Benchmark:

./target/release/pixie-bench --input video.mp4 --name my_test --lossy 8 --report tests/benchmarks.md

This tool automatically:

1. Extracts frames via ffmpeg.
2. Runs the optimization suite across all four engines.
3. Invokes the Gemini Subjective Judge for quality scoring.
4. Generates a detailed Markdown report with size, speed, and visual critique.

👁️ Automated Evaluation

Pixie-Anim includes a judge tool that uses Gemini 3 Flash to perform a comparative analysis of the output, identifying artifacts like banding or temporal jitter that traditional metrics (PSNR/SSIM) might miss.

📋 Prerequisites

Core Development

• Rust (1.70+)
• Node.js & npm/pnpm (For Web Playground)
• wasm-bindgen-cli (cargo install wasm-bindgen-cli)

Benchmarking & Evaluation

To run the comparative benchmarks and the subjective judge, you’ll need:

• FFmpeg: For frame extraction and judge frame analysis.
• Gifsicle: For baseline compression comparison.
• gifski: For high-quality comparison.
• bc: For benchmark timing calculations.
• Gemini API Key: Set as GEMINI_API_KEY in your environment or .env file for the judge tool.

Install on macOS via Homebrew:

brew install ffmpeg gifsicle gifski bc

---

Part of the Pixie family of high-performance media tools

Re-exports

pub use error::Error;

pub use error::Result;

Modules

bits

Bit-level reading and writing utilities. Bit-level reading and writing utilities.

color

Color space conversions and perceptual distance. Color space conversions and perceptual distance.

delta

Inter-frame Delta Compression. Inter-frame Delta Compression.

error

Error handling. Error handling.

gif

GIF89a Structure and Writing. GIF89a Structure and Writing.

lzw

LZW Encoder for GIF89a. LZW Encoder for GIF89a.

quant

Quantization algorithms for GIF. Quantization algorithms for GIF.

simd

SIMD acceleration module for performance-critical operations. SIMD acceleration module for performance-critical operations.