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Image MIME Reference
KTX2

Khronos Texture 2.0

image/ktx2
VS

PTI Image (Personal/Vanity Tree)

image/prs.pti
PTI

A complete technical comparison of Khronos Texture 2.0 and PTI Image (Personal/Vanity Tree) — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.

Equal browser support

Feature Support

Feature KTX2 PTI
Transparency (Alpha) Yes ✕ No
Animation Support ✕ No ✕ No
Progressive Loading ✕ No ✕ No
HDR Support Yes ✕ No
EXIF Metadata ✕ No ✕ No
ICC Color Profile ✕ No ✕ No
Khronos Texture 2.0
image/ktx2
Extension
.ktx2
Container KTX 2.0
Compression Basis Universal (ETC1S / UASTC) / Zstandard (zstd) Supercompression / Uncompressed
Algorithm
ETC1SUASTCZstandard (zstd)Raw GPU Formats (ASTC, BCn)
Color Depth 8-bit, 16-bit, 32-bit (Float)
Developed by Khronos Group
Released 2021
Magic Bytes
AB 4B 54 58 20 32 30 BB 0D 0A 1A 0A
Full KTX2 reference →
PTI Image (Personal/Vanity Tree)
image/prs.pti
Extension
.pti
Container Proprietary
Compression Unknown / Proprietary
Algorithm
Unknown
Color Depth Unknown
Developed by Jürn Laun
Released 1999
Magic Bytes
Unknown
Full PTI reference →

Browser Support Comparison

Browser KTX2 PTI
Chrome Chrome
✕ ✕
Firefox Firefox
✕ ✕
Safari Safari
✕ ✕
Edge Edge
✕ ✕
IE IE (Legacy)
✕ ✕
KTX2

KTX2 Strengths

  • Universal hardware compatibility: write once, transcode anywhere to the target GPU's preferred format (ASTC, BC7, PVRTC, etc.)
  • Drastically reduces transmission size over networks thanks to Basis Universal and Zstandard supercompression
  • Seamless integration with the glTF ecosystem for optimized 3D asset delivery
Limitations
  • Requires WebAssembly (Wasm) decoders and JavaScript loaders for web viewing, increasing initial application payload slightly
  • Encoding textures into high-quality Basis Universal UASTC can be computationally intensive and slow
  • Zero support in traditional 2D image viewers or native OS previews
PTI

PTI Strengths

  • Provided a registered MIME type namespace for a specific application's proprietary image format without conflicting with standard web types
Limitations
  • Completely undocumented and unsupported in modern ecosystems
  • Zero web browser compatibility
  • Falls into the 'vanity' tree, making it irrelevant for standard cross-platform data exchange

When to choose which format

KTX2
Use KTX2 when…
  • glTF 3D Models (KHR_texture_basisu)
  • WebGPU and WebGL Applications
  • Game Engines (Unity, Unreal, Godot)
  • Augmented and Virtual Reality (AR/VR)
PTI
Use PTI when…
  • Legacy Application Specific Workflows
  • Proprietary Image Storage

More comparisons

KTX2 vs ACES → PTI vs ACES → KTX2 vs APNG → PTI vs APNG → KTX2 vs AVCI → PTI vs AVCI → KTX2 vs AVCS → PTI vs AVCS → KTX2 vs AVIF → PTI vs AVIF → All comparisons →
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