Image MIME Reference
Sealed-PNG
SealedMedia Portable Network Graphics
image/vnd.sealed.png
VS
Simple Vector Format
image/vnd.svf
SVF
A complete technical comparison of SealedMedia Portable Network Graphics and Simple Vector Format — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.
Equal browser support
Feature Support
| Feature | Sealed-PNG | SVF |
|---|---|---|
| Transparency (Alpha) | ✕ No | Yes |
| Animation Support | ✕ No | ✕ No |
| Progressive Loading | ✕ No | ✕ No |
| HDR Support | ✕ No | ✕ No |
| EXIF Metadata | ✕ No | ✕ No |
| ICC Color Profile | ✕ No | ✕ No |
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)
Simple Vector Format
image/vnd.svf
Extension
.svf
Container
Custom Binary/Text (Legacy) or ZIP (Autodesk Forge)
Compression
Uncompressed / Deflate (in modern Autodesk SVF implementations)
Algorithm
None
Color Depth
Vector Data (Not Applicable)
Developed by
SoftSource & NCSA (National Center for Supercomputing Applications)
Released
1995
Magic Bytes
Unknown (SoftSource SVF)
Browser Support Comparison
| Browser | Sealed-PNG | SVF |
|---|---|---|
Chrome
|
✕ | ✕ |
Firefox
|
✕ | ✕ |
Safari
|
✕ | ✕ |
Edge
|
✕ | ✕ |
IE (Legacy)
|
✕ | ✕ |
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
SVF
SVF Strengths
- Acted as a crucial pioneering stepping-stone in proving that scalable, zoomable vector graphics were viable and necessary for the World Wide Web
Limitations
- Completely obsolete and unsupported by modern web standards
- Required end-users to install bulky, proprietary browser plugins
- Causes significant developer confusion today due to Autodesk adopting the exact same acronym and file extension for a completely different technology
When to choose which format
Sealed-PNG
Use Sealed-PNG when…
- Enterprise Information Rights Management (IRM)
- Secure Corporate Intellectual Property Distribution
- Revocable Medical or Legal Imaging
SVF
Use SVF when…
- Historical Web-based CAD Viewers (1990s)
- Legacy 2D Vector Archival
- Autodesk Platform Services (Forge) Model Translation (Name Collision)