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Image MIME Reference
JPM

JPEG 2000 Compound Image File Format

image/jpm
VS

SealedMedia SoftSeal JPEG

image/vnd.sealedmedia.softseal.jpg
SoftSeal-JPEG

A complete technical comparison of JPEG 2000 Compound Image File Format and SealedMedia SoftSeal JPEG — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.

Equal browser support

Feature Support

Feature JPM SoftSeal-JPEG
Transparency (Alpha) Yes ✕ No
Animation Support ✕ No ✕ No
Progressive Loading Yes ✕ No
HDR Support ✕ No ✕ No
EXIF Metadata Yes ✕ No
ICC Color Profile Yes ✕ No
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
Full JPM reference →
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)
Full SoftSeal-JPEG reference →

Browser Support Comparison

Browser JPM SoftSeal-JPEG
Chrome Chrome
✕ ✕
Firefox Firefox
✕ ✕
Safari Safari
✕ ✕
Edge Edge
✕ ✕
IE IE (Legacy)
✕ ✕
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
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

JPM
Use JPM when…
  • Scanned Document Archiving
  • Mixed Raster Content (MRC) Imaging
  • Digital Libraries
SoftSeal-JPEG
Use SoftSeal-JPEG when…
  • Enterprise Information Rights Management (IRM)
  • Secure Distribution of Sensitive Photography
  • Revocable Corporate Document Access

More comparisons

JPM vs ACES → SoftSeal-JPEG vs ACES → JPM vs APNG → SoftSeal-JPEG vs APNG → JPM vs AVCI → SoftSeal-JPEG vs AVCI → JPM vs AVCS → SoftSeal-JPEG vs AVCS → JPM vs AVIF → SoftSeal-JPEG vs AVIF → All comparisons →
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