Image MIME Reference
JPEG-XS-Codestream
JPEG XS Codestream
image/jxsc
VS
SealedMedia Portable Network Graphics
image/vnd.sealed.png
Sealed-PNG
A complete technical comparison of JPEG XS Codestream and SealedMedia Portable Network Graphics — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.
Equal browser support
Feature Support
| Feature | JPEG-XS-Codestream | Sealed-PNG |
|---|---|---|
| Transparency (Alpha) | Yes | ✕ No |
| Animation Support | ✕ No | ✕ No |
| Progressive Loading | ✕ No | ✕ No |
| HDR Support | Yes | ✕ No |
| EXIF Metadata | ✕ No | ✕ No |
| ICC Color Profile | ✕ No | ✕ No |
JPEG XS Codestream
image/jxsc
Extension
.jxsc.jxs
Container
None (Raw Codestream)
Compression
Lossy (Visually Lossless) / Mathematically Lossless
Algorithm
JPEG XS (ISO/IEC 21122-1)
Color Depth
8-bit, 10-bit, 12-bit, 14-bit, 16-bit
Developed by
Joint Photographic Experts Group (JPEG) / intoPIX
Released
2019
Magic Bytes
FF 10
SealedMedia Portable Network Graphics
image/vnd.sealed.png
Extension
.spng.sealed-png
Container
SealedMedia / Oracle IRM Wrapper
Compression
Encrypted Payload (Deflate)
Algorithm
AES EncryptionDeflate (Internal PNG payload)
Color Depth
Encrypted Payload
Developed by
SealedMedia (Acquired by Oracle Corporation)
Released
Late 1990s / Early 2000s
Magic Bytes
Unknown (Proprietary SealedMedia Container)
Browser Support Comparison
| Browser | JPEG-XS-Codestream | Sealed-PNG |
|---|---|---|
Chrome
|
✕ | ✕ |
Firefox
|
✕ | ✕ |
Safari
|
✕ | ✕ |
Edge
|
✕ | ✕ |
IE (Legacy)
|
✕ | ✕ |
JPEG-XS-Codestream
JPEG-XS-Codestream Strengths
- Eliminates container overhead, maximizing parsing speed and minimizing latency to fractions of a millisecond
- Highly optimized for direct hardware implementation in FPGAs and ASICs
- Perfect for continuous data streaming over IP networks without needing to establish file headers
Limitations
- Lacks standard container metadata (EXIF, XMP, ICC profiles), meaning color space and orientation data must be handled externally or out-of-band
- Zero support in web browsers or standard consumer operating systems
- Often requires specialized broadcast hardware or custom software libraries to decode
Sealed-PNG
Sealed-PNG Strengths
- Provided absolute control over intellectual property, allowing enterprise administrators to instantly revoke viewing rights of a local file globally
- Detailed audit trails tracked exactly who opened the image, when, and from what IP address
Limitations
- Completely proprietary and relies on a central authentication server; if the server goes offline, the image is permanently inaccessible
- No support in modern operating systems, web browsers, or standard image editing software without installing heavy enterprise DRM clients
- Oracle effectively deprecated the IRM product line, leaving legacy sealed documents difficult to recover
When to choose which format
JPEG-XS-Codestream
Use JPEG-XS-Codestream when…
- Hardware Decoding Pipelines (FPGA/ASIC)
- Live Broadcast Infrastructure
- Video over IP Transport
- Embedded Camera Systems
Sealed-PNG
Use Sealed-PNG when…
- Enterprise Information Rights Management (IRM)
- Secure Corporate Intellectual Property Distribution
- Revocable Medical or Legal Imaging