Image MIME Reference
FACTI
BlockFact Image
image/vnd.blockfact.facti
VS
HEVC Image Sequence (HEIF Container)
image/heic-sequence
HEIC-Sequence
A complete technical comparison of BlockFact Image and HEVC Image Sequence (HEIF Container) — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.
HEIC-Sequence wins on browser support
Feature Support
| Feature | FACTI | HEIC-Sequence |
|---|---|---|
| Transparency (Alpha) | Yes | Yes |
| Animation Support | ✕ No | Yes |
| Progressive Loading | ✕ No | ✕ No |
| HDR Support | Yes | Yes |
| EXIF Metadata | Yes | Yes |
| ICC Color Profile | Yes | Yes |
BlockFact Image
image/vnd.blockfact.facti
Extension
.facti
Container
BlockFact Authenticated Container
Compression
Container (Inherits payload compression, e.g., JPEG/PNG)
Algorithm
None (Pass-through to embedded payload)
Color Depth
Inherited from payload
Developed by
BlockFact
Released
2025
Magic Bytes
Unknown (Proprietary Container)
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
Browser Support Comparison
| Browser | FACTI | HEIC-Sequence |
|---|---|---|
Chrome
|
✕ | ✕ |
Firefox
|
✕ | ✕ |
Safari
|
✕ |
✓ 11+
|
Edge
|
✕ | ✕ |
IE (Legacy)
|
✕ | ✕ |
FACTI
FACTI Strengths
- Provides undeniable, mathematically verifiable proof of a photo's origin (time, location, and device) via the StarkNet blockchain [1.3.1]
- Privacy-first design utilizes zero-knowledge proofs (Groth16), meaning the actual image is never uploaded to a central server or blockchain
- Invisible watermarking ensures that even if the image is screenshotted or cropped, tampering can be detected
Limitations
- Lacks native rendering support in web browsers and standard image viewers, requiring specialized software to view
- Requires blockchain registration at the moment of capture, making it incompatible with existing legacy photos
- The proprietary nature of the container limits integration to environments supporting the BlockFact SDK
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
When to choose which format
FACTI
Use FACTI when…
- Journalism and Media Authentication
- Legal and Insurance Evidence
- AI Deepfake Prevention
- Content Provenance and Authorship
HEIC-Sequence
Use HEIC-Sequence when…
- Apple Live Photos
- Burst Photography
- High-Quality Animations
- Cinemagraphs