Image MIME Reference
HTJ2K-Codestream
High-Throughput JPEG 2000 Codestream
image/jphc
VS
Sigma X3F RAW Image
image/x-sigma-x3f
Sigma-X3F
A complete technical comparison of High-Throughput JPEG 2000 Codestream and Sigma X3F RAW Image — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.
Equal browser support
Feature Support
| Feature | HTJ2K-Codestream | Sigma-X3F |
|---|---|---|
| Transparency (Alpha) | Yes | ✕ No |
| Animation Support | ✕ No | ✕ No |
| Progressive Loading | Yes | ✕ No |
| HDR Support | Yes | Yes |
| EXIF Metadata | ✕ No | Yes |
| ICC Color Profile | ✕ No | Yes |
High-Throughput JPEG 2000 Codestream
image/jphc
Extension
.jhc
Container
None (Raw Codestream)
Compression
Lossy / Lossless
Algorithm
High-Throughput JPEG 2000 (HTJ2K)
Color Depth
8-bit, 16-bit, 32-bit, 38-bit
Developed by
Joint Photographic Experts Group (JPEG)
Released
2019
Magic Bytes
FF 4F FF 51
Sigma X3F RAW Image
image/x-sigma-x3f
Extension
.x3f
Container
Foveon Proprietary Header
Compression
Uncompressed / Proprietary Lossless
Algorithm
NoneFoveon Proprietary Huffman-based
Color Depth
12-bit (Per Channel), 14-bit (Per Channel)
Developed by
Foveon, Inc. / Sigma Corporation
Released
2002
Magic Bytes
46 4F 56 62
Browser Support Comparison
| Browser | HTJ2K-Codestream | Sigma-X3F |
|---|---|---|
Chrome
|
✕ | ✕ |
Firefox
|
✕ | ✕ |
Safari
|
✕ | ✕ |
Edge
|
✕ | ✕ |
IE (Legacy)
|
✕ | ✕ |
HTJ2K-Codestream
HTJ2K-Codestream Strengths
- Extremely fast encoding and decoding capabilities due to the parallelizable block coder
- Minimal file overhead since it lacks container headers and metadata
- Ideal for streaming applications or embedded systems where parsing a full container is unnecessary
Limitations
- Lacks standard metadata support (like EXIF, XMP, or ICC color profiles) since there is no container structure
- Zero native web browser compatibility
- Difficult to distinguish from standard JPEG 2000 codestreams without deeply parsing the internal marker segments
Sigma-X3F
Sigma-X3F Strengths
- Provides absolute per-pixel color accuracy without the interpolation artifacts or moiré patterns typical of Bayer-sensor RAW files
- Unique 'FOVb' magic byte signature prevents accidental misidentification by standard file sniffers, unlike many TIFF-based raw formats
- Incredible sharpness and detail resolution at the raw sensor level
Limitations
- Decoding is extremely computationally expensive and completely proprietary, meaning third-party software often struggles to match the color science of Sigma's own (famously slow) Photo Pro application
- Massive file sizes because it records three complete RGB channels for every single spatial pixel coordinate
- Zero support in web browsers or standard OS image viewers
When to choose which format
HTJ2K-Codestream
Use HTJ2K-Codestream when…
- Medical Imaging Pipelines
- Geospatial Data Streaming
- Digital Cinema
- Embedded Systems
Sigma-X3F
Use Sigma-X3F when…
- Professional Digital Photography
- Sigma / Foveon High-Acuity Imaging
- Non-destructive RAW Post-Processing