Image MIME Reference
DICOM-RLE
DICOM Run-Length Encoding
image/dicom-rle
VS
Valve Texture Format
image/vnd.valve.source.texture
VTF
A complete technical comparison of DICOM Run-Length Encoding and Valve Texture Format — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.
Equal browser support
Feature Support
| Feature | DICOM-RLE | VTF |
|---|---|---|
| Transparency (Alpha) | ✕ No | Yes |
| Animation Support | Yes | Yes |
| Progressive Loading | ✕ No | ✕ No |
| HDR Support | Yes | Yes |
| EXIF Metadata | ✕ No | ✕ No |
| ICC Color Profile | Yes | ✕ No |
DICOM Run-Length Encoding
image/dicom-rle
Extension
.dcm.dicom
Container
DICOM (PS3.10)
Compression
Lossless (RLE)
Algorithm
Run-Length Encoding (RLE)
Color Depth
8-bit, 16-bit, 24-bit
Developed by
National Electrical Manufacturers Association (NEMA) / ACR
Released
1993
Magic Bytes
44 49 43 4D (at byte offset 128)
Valve Texture Format
image/vnd.valve.source.texture
Extension
.vtf
Container
Valve Texture Format Header
Compression
DXTC (DXT1, DXT3, DXT5) / Uncompressed (BGRA8888, RGB888, etc.)
Algorithm
DXT1-DXT5None
Color Depth
8-bit, 24-bit (RGB), 32-bit (RGBA), 16-bit Floating Point (HDR)
Developed by
Valve Corporation
Released
2004
Magic Bytes
56 54 46 00
Browser Support Comparison
| Browser | DICOM-RLE | VTF |
|---|---|---|
Chrome
|
✕ | ✕ |
Firefox
|
✕ | ✕ |
Safari
|
✕ | ✕ |
Edge
|
✕ | ✕ |
IE (Legacy)
|
✕ | ✕ |
DICOM-RLE
DICOM-RLE Strengths
- Guarantees lossless preservation of critical medical data necessary for diagnostics
- Extremely robust metadata structure containing patient information, modality, and spatial geometry
- Faster to encode and decode than complex compression schemes like JPEG 2000
Limitations
- RLE compression offers very low compression ratios compared to modern codecs like JPEG-LS or JPEG 2000
- Zero support in web browsers or standard consumer image viewers
- Strict data privacy regulations (HIPAA/GDPR) make handling DICOM files complex due to embedded PHI
VTF
VTF Strengths
- Extremely fast loading within the Source Engine because the block-compressed data goes directly into the GPU's VRAM without CPU decompression overhead
- Bundles mipmaps, volumetric slices, cubemap faces, and animation frames entirely within a single file
- Openly documented by the Valve Developer Community, leading to a massive ecosystem of third-party modding tools
Limitations
- Strictly tied to the Source Engine ecosystem; entirely useless in standard web or print contexts
- No native support in standard image editors without hunting down and installing specialized plugins
- Block compression algorithms (DXT) are lossy and can cause visible artifacting, especially on normal maps or smooth gradients
When to choose which format
DICOM-RLE
Use DICOM-RLE when…
- Medical Imaging
- Ultrasound
- X-Rays / CT / MRI
- PACS Archives
VTF
Use VTF when…
- Source Engine Game Textures
- Custom Maps and Modding (Garry's Mod, CS:GO)
- Animated In-Game Decals and Sprays
- Environment Cubemaps (Skyboxes)