Fable introduces novel .splat4d file format for 4D streaming and storage

Overview of .splat4d Format

The .splat4d file format consists of a header, static section, and GOP (Group of Pictures) chunks. The header provides essential information such as bounds, quantization steps, and chunk indices needed for effective data fetching by clients.

The static section contains per-splat masks and base values, allowing a complete scene to be loaded in one fetch. GOP chunks handle roughly one second of video, simplifying the data structure for efficient decoding.

Technical Details

Each splat in a decoded frame remains within a user-defined bound of the source, ensuring deterministic reconstruction. This is achieved through error-bounded quantization methods similar to SZ/ZFP, resulting in integer-only processing post-quantization.

Decoders written in Rust and JavaScript ensure that reconstructed values match the original data, enhancing the reliability of the format.

Streaming with .splat4d

The .splat4d format is optimized for HTTP Range requests, accommodating various static hosting solutions like S3, GCS, or R2 without requiring complex server configurations. Clients interact directly with the file using specified byte ranges, making data management straightforward.

Performance and Use Cases

Fable tested the format with multiple capture techniques, including dynamic 3D Gaussian representations and animated cooking scenes. Various benchmarks indicate that .splat4d offers significant advantages over existing lossless compression methods.

For practical application, developers can use the provided Python package 'splats4d' to encode frames into the new format, facilitating easier integration into graphics and video projects.