Image MIME Reference
KTX2
Khronos Texture 2.0
image/ktx2
VS
Sony SRF Raw Image
image/x-sony-srf
Sony-SRF
A complete technical comparison of Khronos Texture 2.0 and Sony SRF Raw Image — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.
Equal browser support
Feature Support
| Feature | KTX2 | Sony-SRF |
|---|---|---|
| Transparency (Alpha) | Yes | ✕ No |
| Animation Support | ✕ No | ✕ No |
| Progressive Loading | ✕ No | ✕ No |
| HDR Support | Yes | Yes |
| EXIF Metadata | ✕ No | Yes |
| ICC Color Profile | ✕ No | Yes |
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
Sony SRF Raw Image
image/x-sony-srf
Extension
.srf
Container
TIFF-based (Proprietary)
Compression
Uncompressed
Algorithm
None
Color Depth
12-bit (Per Channel)
Developed by
Sony Corporation
Released
2003
Magic Bytes
49 49 2A 00
Browser Support Comparison
| Browser | KTX2 | Sony-SRF |
|---|---|---|
Chrome
|
✕ | ✕ |
Firefox
|
✕ | ✕ |
Safari
|
✕ | ✕ |
Edge
|
✕ | ✕ |
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
Sony-SRF
Sony-SRF Strengths
- Retains perfectly raw, unprocessed sensor data from legacy early-2000s cameras, allowing modern raw processors to extract much better dynamic range and color than the camera's original internal JPEG engine could
- Utilizes a standard TIFF container structure, ensuring broad compatibility with community-maintained open-source decoding libraries like LibRaw
Limitations
- Completely obsolete format that has long been abandoned in favor of ARW
- MIME detection via magic bytes is unreliable due to TIFF header spoofing, requiring deeper EXIF inspection for accurate routing
- Cannot be natively viewed in web browsers or standard operating system image viewers without specialized decoders
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)
Sony-SRF
Use Sony-SRF when…
- Legacy Sony Cyber-shot Photography
- Non-destructive Image Post-Processing
- Early 2000s Raw Imaging Archival