Image MIME Reference
HSJ2
JPEG 2000 Image Sequence (Obsolete)
image/hsj2
VS
Olympus Raw Format
image/x-olympus-orf
Olympus-ORF
A complete technical comparison of JPEG 2000 Image Sequence (Obsolete) and Olympus Raw Format — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.
Equal browser support
Feature Support
| Feature | HSJ2 | Olympus-ORF |
|---|---|---|
| Transparency (Alpha) | Yes | ✕ No |
| Animation Support | Yes | ✕ No |
| Progressive Loading | Yes | ✕ No |
| HDR Support | Yes | Yes |
| EXIF Metadata | Yes | Yes |
| ICC Color Profile | Yes | Yes |
JPEG 2000 Image Sequence (Obsolete)
image/hsj2
Extension
.hsj2
Container
HEIF / ISOBMFF (ISO/IEC 15444-16 Obsolete)
Compression
Lossy / Lossless
Algorithm
Motion JPEG 2000 (ISO/IEC 15444-3)
Color Depth
8-bit, 10-bit, 12-bit, 16-bit
Developed by
ISO/IEC JTC 1 / ITU-T
Released
2019
Magic Bytes
XX XX XX XX 66 74 79 70 68 73 6A 32
Olympus Raw Format
image/x-olympus-orf
Extension
.orf
Container
TIFF-based (with proprietary variants)
Compression
Uncompressed / Proprietary Lossless
Algorithm
NoneOlympus Proprietary Lossless
Color Depth
12-bit (Per Channel)
Developed by
Olympus Corporation (Now OM Digital Solutions)
Released
2000
Magic Bytes
49 49 52 4F (IIRO) or 4D 4D 4F 52 (MMOR) or 49 49 53 52 (IIRS)
Browser Support Comparison
| Browser | HSJ2 | Olympus-ORF |
|---|---|---|
Chrome
|
✕ | ✕ |
Firefox
|
✕ | ✕ |
Safari
|
✕ | ✕ |
Edge
|
✕ | ✕ |
IE (Legacy)
|
✕ | ✕ |
HSJ2
HSJ2 Strengths
- Historically attempted to combine Motion JPEG 2000 sequences with the flexible metadata capabilities of the HEIF container
- Supported mathematically lossless compression and scalable wavelet decoding
Limitations
- Officially deprecated by the standardization body (ISO/IEC JTC 1)
- Completely superseded by image/hej2k, rendering hsj2 files obsolete for any new development or archiving
- Zero web browser compatibility and negligible modern software support
Olympus-ORF
Olympus-ORF Strengths
- Retains maximum sensor data, allowing extreme recovery of highlights and shadows that would be permanently lost in a JPEG
- White balance, sharpening, and color profiling are saved as metadata instructions, meaning they can be completely altered in post-production
- Unique magic byte signatures make programmatic file sniffing highly reliable compared to other camera manufacturers' TIFF-spoofing headers
Limitations
- Proprietary format means it requires constant updates to raw processing engines every time a new camera model is released
- Produces very large file sizes (often 15MB to 30MB+ per image depending on sensor resolution)
- Cannot be directly embedded into web pages or used in standard HTML/CSS contexts
When to choose which format
HSJ2
Use HSJ2 when…
- Legacy Archival
- Deprecated Workflows
Olympus-ORF
Use Olympus-ORF when…
- Professional Digital Photography
- Non-destructive Image Post-Processing
- High Dynamic Range (HDR) Imaging Archival