Image MIME Reference
HEIF-Sequence
High Efficiency Image File Format Sequence
image/heif-sequence
VS
TIFF for Facsimile eXtended
image/tiff-fx
TIFF-FX
A complete technical comparison of High Efficiency Image File Format Sequence and TIFF for Facsimile eXtended — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.
Equal browser support
Feature Support
| Feature | HEIF-Sequence | TIFF-FX |
|---|---|---|
| Transparency (Alpha) | Yes | ✕ No |
| Animation Support | Yes | ✕ No |
| Progressive Loading | ✕ No | ✕ No |
| HDR Support | Yes | ✕ No |
| EXIF Metadata | Yes | ✕ No |
| ICC Color Profile | Yes | Yes |
High Efficiency Image File Format Sequence
image/heif-sequence
Extension
.heifs.heif.hif
Container
HEIF / ISOBMFF (ISO/IEC 14496-12)
Compression
Lossy / Lossless
Algorithm
Codec Agnostic (HEVC, AVC, JPEG, AV1)
Color Depth
8-bit, 10-bit, 12-bit, 16-bit
Developed by
Moving Picture Experts Group (MPEG)
Released
2015
Magic Bytes
XX XX XX XX 66 74 79 70 6D 73 66 31
TIFF for Facsimile eXtended
image/tiff-fx
Extension
.tiff.tif
Container
TIFF 6.0 Tag Directory Structure
Compression
MH / MR / MMR (CCITT Group 3 & 4) / JBIG / JPEG
Algorithm
CCITT Group 3/4JBIGJPEG
Color Depth
1-bit (Monochrome B&W), 8-bit (Grayscale/Color Indexed), 24-bit (RGB Color)
Developed by
IETF (Internet Engineering Task Force)
Released
1998
Magic Bytes
49 49 2A 00 (Little-Endian) / 4D 4D 00 2A (Big-Endian)
Browser Support Comparison
| Browser | HEIF-Sequence | TIFF-FX |
|---|---|---|
Chrome
|
✕ | ✕ |
Firefox
|
✕ | ✕ |
Safari
|
✕ | ✕ |
Edge
|
✕ | ✕ |
IE (Legacy)
|
✕ | ✕ |
HEIF-Sequence
HEIF-Sequence Strengths
- Codec-agnostic container allows for extreme flexibility when storing multi-frame photographic data
- Maintains the space-saving benefits of ISOBMFF shared frame data blocks
- Excellent for archiving computational photography workloads like exposure brackets or focal stacks
Limitations
- Codec ambiguity means a decoder might be able to parse the container but fail to decode the underlying pixels
- Zero native web browser support
- Complex container structure requires specialized parsing libraries to extract individual frames
TIFF-FX
TIFF-FX Strengths
- Provides a universal, standardized format for transmitting multi-page documents over IP networks and email (Internet Fax)
- Supports highly efficient telecom-centric compression algorithms (MMR, JBIG) that produce very small files for text documents
- Maintains backwards compatibility with standard TIFF parsers
Limitations
- Not supported natively by web browsers
- Requires complex parsing of TIFF IFD tags to differentiate a true TIFF-FX file from a standard TIFF file
- Usage is slowly declining as traditional faxing is replaced by secure PDF transmission and e-signature platforms
When to choose which format
HEIF-Sequence
Use HEIF-Sequence when…
- Burst Photography
- Focal Stacking
- Exposure Bracketing
- Time-Lapse Data
TIFF-FX
Use TIFF-FX when…
- Internet Fax (T.37)
- Enterprise Fax Servers
- Document Archiving
- Telecommunications