Image MIME Reference
J2C
JPEG 2000 Codestream
image/j2c
VS
SealedMedia SoftSeal JPEG
image/vnd.sealedmedia.softseal.jpg
SoftSeal-JPEG
A complete technical comparison of JPEG 2000 Codestream and SealedMedia SoftSeal JPEG — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.
Equal browser support
Feature Support
| Feature | J2C | SoftSeal-JPEG |
|---|---|---|
| Transparency (Alpha) | Yes | ✕ No |
| Animation Support | ✕ No | ✕ No |
| Progressive Loading | Yes | ✕ No |
| HDR Support | Yes | ✕ No |
| EXIF Metadata | ✕ No | ✕ No |
| ICC Color Profile | ✕ No | ✕ No |
JPEG 2000 Codestream
image/j2c
Extension
.j2c.j2k.jpc
Container
None (Raw Bitstream)
Compression
JPEG 2000 (Discrete Wavelet Transform) / Lossless / Lossy
Algorithm
Discrete Wavelet Transform (DWT)
Color Depth
8-bit, 10-bit, 12-bit, 16-bit (Per Channel)
Developed by
Joint Photographic Experts Group (JPEG)
Released
2000
Magic Bytes
FF 4F FF 51
SealedMedia SoftSeal JPEG
image/vnd.sealedmedia.softseal.jpg
Extension
.sjpg.sealed-jpg.sealed-jpeg
Container
SealedMedia SoftSeal Wrapper
Compression
Encrypted Payload (DCT)
Algorithm
AES EncryptionDiscrete Cosine Transform (Internal JPEG payload)
Color Depth
Encrypted Payload (Historically 24-bit RGB)
Developed by
SealedMedia (Acquired by Oracle Corporation)
Released
Late 1990s
Magic Bytes
Unknown (Proprietary SealedMedia Container)
Browser Support Comparison
| Browser | J2C | SoftSeal-JPEG |
|---|---|---|
Chrome
|
✕ | ✕ |
Firefox
|
✕ | ✕ |
Safari
|
✕ | ✕ |
Edge
|
✕ | ✕ |
IE (Legacy)
|
✕ | ✕ |
J2C
J2C Strengths
- Provides state-of-the-art wavelet compression for high-end professional workflows (Digital Cinema)
- Allows for highly efficient progressive decoding (by resolution or quality layer) natively within the stream
- Supports lossless mathematical compression and high bit-depths (up to 16-bit per channel) natively
Limitations
- Lacks a standard container to store color space info or metadata, requiring external systems (like MXF or DICOM) to map colors correctly
- Extremely computationally expensive to encode and decode compared to standard DCT-based JPEG
- Zero web browser support
SoftSeal-JPEG
SoftSeal-JPEG Strengths
- Offered persistent document security; if a sensitive photo was emailed outside the company, it remained encrypted and unviewable without server authentication
- Administrators possessed the ability to remotely revoke viewing rights to a specific image globally at any time
Limitations
- Completely proprietary and relies on a central authentication server; if the server goes offline or the product is deprecated, the image is permanently inaccessible
- Zero support in modern operating systems, web browsers, or standard image editing suites without heavy enterprise client installations
- Oracle effectively discontinued the IRM product line, stranding many legacy sealed documents
When to choose which format
J2C
Use J2C when…
- Digital Cinema Packages (DCP)
- Medical Imaging (DICOM Payloads)
- Professional Broadcast and Archiving
- Embedded Hardware Encoding
SoftSeal-JPEG
Use SoftSeal-JPEG when…
- Enterprise Information Rights Management (IRM)
- Secure Distribution of Sensitive Photography
- Revocable Corporate Document Access