Image MIME Reference
HEIC-Sequence
HEVC Image Sequence (HEIF Container)
image/heic-sequence
VS
JPEG 2000 Compound Image File Format
image/jpm
JPM
A complete technical comparison of HEVC Image Sequence (HEIF Container) and JPEG 2000 Compound Image File Format — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.
HEIC-Sequence wins on browser support
Feature Support
| Feature | HEIC-Sequence | JPM |
|---|---|---|
| Transparency (Alpha) | Yes | Yes |
| Animation Support | Yes | ✕ No |
| Progressive Loading | ✕ No | Yes |
| HDR Support | Yes | ✕ No |
| EXIF Metadata | Yes | Yes |
| ICC Color Profile | Yes | Yes |
HEVC Image Sequence (HEIF Container)
image/heic-sequence
Extension
.heics.heic
Container
HEIF / ISOBMFF (ISO/IEC 14496-12)
Compression
Lossy / Lossless
Algorithm
HEVC (H.265)
Color Depth
8-bit, 10-bit, 12-bit, 16-bit
Developed by
Moving Picture Experts Group (MPEG) / Apple
Released
2017
Magic Bytes
XX XX XX XX 66 74 79 70 68 65 76 63
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 | HEIC-Sequence | JPM |
|---|---|---|
|
|
✕ | ✕ |
|
|
✕ | ✕ |
|
|
✓ 11+
|
✕ |
|
|
✕ | ✕ |
|
|
✕ | ✕ |
HEIC-Sequence
HEIC-Sequence Strengths
- Incredibly efficient storage for bursts and short animations compared to GIF or motion JPEG
- Supports 16-bit color, HDR, and alpha channel transparency across all frames
- Shares frame data blocks, meaning the base image and animation data are heavily optimized for space
Limitations
- Zero support in web browsers outside the Apple ecosystem (Chrome, Firefox, Edge do not support it)
- Heavily encumbered by HEVC patent pools, hindering open-source adoption
- Complex container structure makes parsing and decoding difficult without specialized libraries
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
HEIC-Sequence
Use HEIC-Sequence when…
- Apple Live Photos
- Burst Photography
- High-Quality Animations
- Cinemagraphs
JPM
Use JPM when…
- Scanned Document Archiving
- Mixed Raster Content (MRC) Imaging
- Digital Libraries