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VTX

VTX is an open, self-describing binary format for real-time state data, plus a C++20 SDK for writing, reading, diffing, and inspecting it. A VTX file holds frame-by-frame complete state snapshots (entities, transforms, skeletal bones, events, statistics) and carries its own schema so any reader can interpret it without outside context. Whatever produces the data (your game, your engine, a third-party capture tool) writes it into VTX; anything that can read a binary file reads it back.

VTX was born in games but is not tied to games. The same format is designed to work for any real-time interactive system that produces structured state: MOBA, FPS, racing sim, sports broadcast, simulation, telemetry feed.

Why VTX exists

Broadcast overlays, esports companion apps, training pipelines, and analytics dashboards all need the same thing: structured, frame-accurate state from a running experience. Historically that data has been locked behind publisher SDKs, proprietary replay formats tied to a specific engine version, or reconstructed from video.

VTX is the open container that sits under all of it. One format, multiple engines, one reader.

What's in this wiki

• Getting Started: build the SDK, write your first replay, read it back.
• Concepts: the data model, dual-schema architecture, generic property container.
• File Format: header, embedded schema, chunks, footer, compression, serialisation backends.
• SDK Architecture: the Core + Extensions layout and which modules ship in the SDK.
• SDK API and Examples: entry points and copy-pasteable recipes for common integration tasks.
• Runtime Contracts: thread safety, ownership, error model, memory, limits.
• Stability and Versioning: API, on-disk format, and schema versioning policy.
• Performance: headline numbers from real fixtures (CS2, Rocket League) and where the sharp edges are.
• Tools: the GUI Inspector, the headless CLI, and the Schema Creator.
• Use Cases: broadcast replay, AI training data, analytics, coaching, second-screen, 3D Twins.
• FAQ: questions we keep getting.
• Glossary: terminology used across the docs.

At a glance

Language	C++20
Serialisation backends	Protocol Buffers, FlatBuffers
Compression	Zstd (chunk-level)
Random access	Footer index (binary search) + one chunk decompress
Platforms	Windows, Linux
Maturity	Pre-1.0. Format and API can change before 1.0. See Stability.
Licence	Apache-2.0
Repository	github.com/ZenosInteractive/VTX

Quick links

• Full README: VTX/README.md
• Reference docs in-tree: docs/. Includes ARCHITECTURE.md, BUILD.md, FILE_FORMAT.md, PERFORMANCE.md, SAMPLES.md, SDK_API.md.
• Changelog: CHANGELOG.md
• Security policy: SECURITY.md
• Contribution guide: CONTRIBUTING.md

Licence

VTX is Apache-2.0 licensed. Copyright 2026 Zenos Interactive. VTX bundles or links against third-party components under MIT, BSD-2-Clause, BSD-3-Clause, Apache-2.0, and zlib/libpng licences. See NOTICE and THIRD_PARTY_LICENSES.md for the full attribution and texts.