Image MIME Reference
HTJ2K-Codestream
High-Throughput JPEG 2000 Codestream
image/jphc
VS
JPEG 2000 Compound Image File Format
image/jpm
JPM
A complete technical comparison of High-Throughput JPEG 2000 Codestream and JPEG 2000 Compound Image File Format — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.
Equal browser support
Feature Support
| Feature | HTJ2K-Codestream | JPM |
|---|---|---|
| Transparency (Alpha) | Yes | Yes |
| Animation Support | ✕ No | ✕ No |
| Progressive Loading | Yes | Yes |
| HDR Support | Yes | ✕ No |
| 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
JPEG 2000 Compound Image File Format
image/jpm
Extension
.jpm.jpgm
Container
ISOBMFF / JPM (ISO/IEC 15444-6)
Compression
Lossy / Lossless / Mixed Raster Content (MRC)
Algorithm
JPEG 2000JBIG2JPEGMMR
Color Depth
1-bit (Text/Masks), 8-bit, 16-bit, 24-bit
Developed by
Joint Photographic Experts Group (JPEG)
Released
2003
Magic Bytes
00 00 00 0C 6A 50 20 20 0D 0A 87 0A ... 66 74 79 70 6A 70 6D 20
Browser Support Comparison
| Browser | HTJ2K-Codestream | JPM |
|---|---|---|
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
JPM
JPM Strengths
- Highly optimized for scanned documents, drastically reducing file sizes without sacrificing the readability of text or the quality of embedded photos
- Supports multi-page documents within a single file
- Object-based architecture allows for complex layout representation and independent extraction of elements
Limitations
- Failed to achieve widespread adoption, largely being overshadowed by PDF/A and DjVu
- Zero native web browser compatibility
- Requires complex, specialized software to properly encode and decode the multi-layered MRC structure
When to choose which format
HTJ2K-Codestream
Use HTJ2K-Codestream when…
- Medical Imaging Pipelines
- Geospatial Data Streaming
- Digital Cinema
- Embedded Systems
JPM
Use JPM when…
- Scanned Document Archiving
- Mixed Raster Content (MRC) Imaging
- Digital Libraries