Image MIME Reference
HEIC-Sequence
HEVC Image Sequence (HEIF Container)
image/heic-sequence
VS
JPEG XS Image (HEIF Container)
image/jxsi
JPEG-XS-(HEIF)
A complete technical comparison of HEVC Image Sequence (HEIF Container) and JPEG XS Image (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 | HEIC-Sequence | JPEG-XS-(HEIF) |
|---|---|---|
| Transparency (Alpha) | Yes | Yes |
| Animation Support | Yes | ✕ No |
| Progressive Loading | ✕ No | ✕ No |
| HDR Support | Yes | Yes |
| 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 XS Image (HEIF Container)
image/jxsi
Extension
.jxsi.jxs.hif
Container
HEIF / ISOBMFF (ISO/IEC 23008-12)
Compression
Lossy (Visually Lossless) / Mathematically Lossless
Algorithm
JPEG XS (ISO/IEC 21122-1)
Color Depth
8-bit, 10-bit, 12-bit, 14-bit, 16-bit
Developed by
Joint Photographic Experts Group (JPEG)
Released
2019
Magic Bytes
XX XX XX XX 66 74 79 70 6A 78 73 69
Browser Support Comparison
| Browser | HEIC-Sequence | JPEG-XS-(HEIF) |
|---|---|---|
Chrome
|
✕ | ✕ |
Firefox
|
✕ | ✕ |
Safari
|
✓ 11+
|
✕ |
Edge
|
✕ | ✕ |
IE (Legacy)
|
✕ | ✕ |
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
JPEG-XS-(HEIF)
JPEG-XS-(HEIF) Strengths
- Provides sub-millisecond encoding and decoding latency while retaining visually lossless quality
- Brings the extensive metadata, EXIF, XMP, and color-profiling capabilities of the HEIF container to JPEG XS
- Allows grouping of multiple high-quality JPEG XS frames into a single collection file
Limitations
- Zero web browser compatibility, limiting it entirely to professional and industrial hardware workflows
- Extremely niche adoption compared to standard HEVC-based HEIC or raw JPEG XS codestreams
- Requires custom parsing logic to extract the JPEG XS codestream from the HEIF boxes
When to choose which format
HEIC-Sequence
Use HEIC-Sequence when…
- Apple Live Photos
- Burst Photography
- High-Quality Animations
- Cinemagraphs
JPEG-XS-(HEIF)
Use JPEG-XS-(HEIF) when…
- Live Broadcast Infrastructure
- Medical Imaging & Archival
- Video over IP Networks
- Automotive & Drone Systems