Image MIME Reference
HEIF-Sequence
High Efficiency Image File Format Sequence
image/heif-sequence
VS
Silicon Graphics Image
image/sgi
SGI
A complete technical comparison of High Efficiency Image File Format Sequence and Silicon Graphics Image — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.
Equal browser support
Feature Support
| Feature | HEIF-Sequence | SGI |
|---|---|---|
| Transparency (Alpha) | Yes | Yes |
| Animation Support | Yes | ✕ No |
| Progressive Loading | ✕ No | ✕ No |
| HDR Support | Yes | ✕ No |
| EXIF Metadata | Yes | ✕ No |
| ICC Color Profile | Yes | ✕ No |
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
Silicon Graphics Image
image/sgi
Extension
.sgi.rgb.rgba.bw.int.inta
Container
SGI Image Format
Compression
Uncompressed / Lossless (Run-Length Encoding)
Algorithm
RLENone
Color Depth
8-bit, 16-bit (Per Channel)
Developed by
Paul Haeberli (Silicon Graphics)
Released
1990
Magic Bytes
01 DA
Browser Support Comparison
| Browser | HEIF-Sequence | SGI |
|---|---|---|
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
SGI
SGI Strengths
- Pioneered multi-channel and 16-bit per channel imaging capabilities required for high-end 1990s visual effects
- Extremely robust and simple header structure
- Reliable Run-Length Encoding provided solid lossless compression for flat-shaded 3D renders
Limitations
- Completely obsolete for modern web and application development
- Zero native web browser compatibility
- Largely replaced by TIFF and OpenEXR in modern professional VFX and 3D pipelines
When to choose which format
HEIF-Sequence
Use HEIF-Sequence when…
- Burst Photography
- Focal Stacking
- Exposure Bracketing
- Time-Lapse Data
SGI
Use SGI when…
- Legacy 3D Animation & VFX
- Silicon Graphics IRIX Workflows
- Historical CGI Archiving