The UHD World Association has open-sourced reference code for Spatial Vivid, its standard for six degrees of freedom 3D images built on Gaussian splatting.
The standard, T/UWA 050-2026, was published on May 28 and announced on June 4. The codec, toolkit and viewer repositories were created on GitHub in mid September and are also hosted on GitCode, and UWA presented the release at the 2026 UWA Summit in Shenzhen, held October 21 to 24. The full English and Chinese text of the standard followed in a documents repository on October 15.
Spatial Vivid stores splats in glTF. The standard places the base representation under the KHR_gaussian_splatting extension from Khronos and nests compressed bitstreams inside it through a UWA_gaussian_splatting_compression_EGSC extension. Further UWA extensions carry camera trajectories, viewing constraints, spatial audio, HDR metadata, and wide gamut color spaces including BT.2100 PQ, HLG and Display P3. UWA says it coordinated the work with the 3D Formats Working Group of the Khronos Group.
EGSC, the Efficient Gaussian Splatting Codec, is Chapter 8 of the standard and arrives alongside Niantic Spatial's SPZ, now at version 4, and PlayCanvas's SOG. Each attribute group travels as a sub-bitstream decoded by entropy decoding, as a compressed texture, or as video frames, and the reference encoder defaults to packing attributes into x265 video. Spherical harmonic coefficients stay ASTC-compressed in memory and are decoded on demand during rendering. The Python and C++ encoders and decoders run entirely on the CPU, take a standard 3DGS PLY in and return one, and expose a 0 to 100 quality setting, x264, x265, HM and VTM codec choices, and spherical harmonic degrees 0 to 3.
UWA claims an average compression ratio of 20x, and up to 30x, while remaining visually lossless on mobile devices, with a million Gaussians encoded in under 4 seconds and decoded in under 400 milliseconds. UWA's June announcement, the source of those figures, does not name the scenes or hardware behind them.
The Spatial Vivid Toolkit compresses a PLY into a GLB alongside cameras, trajectories, audio, HDR metadata and viewing constraints, packages that GLB with a still image as HEIF or with a video as MP4, and unpacks any of the three back to PLY plus metadata. Both containers derive from the ISO base media file format, which UWA says lets existing media libraries, CDNs and sharing channels carry the 3D scene. A separate FFmpeg fork, FFmpegSpatialVivid, performs the same GLB encapsulation under FFmpeg's own licensing, LGPL 2.1 or later with optional GPL components.
The web viewer is a fork of GaussianSplats3D, Mark Kellogg's three.js renderer, with a C++ decoder compiled to WebAssembly. It keeps upstream PLY, splat, ksplat and SPZ loading and adds UWA GLB files carrying the compressed payload, though its README states it does not load arbitrary glTF or GLB files. According to IT Home's report of the summit announcement, UWA tested the viewer on seven phones and tablets, with loads under 0.9 seconds and frame rates above 45 FPS.
The codec, toolkit and viewer are available now on GitHub under the MIT license.
