Image MIME Reference
AVCS
AVC Image Sequence (HEIF Container)
image/avcs
VS
Simple Vector Format
image/vnd.svf
SVF
A complete technical comparison of AVC Image Sequence (HEIF Container) and Simple Vector Format — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.
Equal browser support
Feature Support
| Feature | AVCS | SVF |
|---|---|---|
| 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 |
AVC Image Sequence (HEIF Container)
image/avcs
Extension
.avcs.heifs
Container
HEIF / ISOBMFF (ISO/IEC 14496-12)
Compression
Lossy / Lossless
Algorithm
AVC (Advanced Video Coding / H.264)
Color Depth
8-bit, 10-bit, 12-bit
Developed by
Moving Picture Experts Group (MPEG) / ISO/IEC JTC 1
Released
2015
Magic Bytes
XX XX XX XX 66 74 79 70 61 76 63 73
Simple Vector Format
image/vnd.svf
Extension
.svf
Container
Custom Binary/Text (Legacy) or ZIP (Autodesk Forge)
Compression
Uncompressed / Deflate (in modern Autodesk SVF implementations)
Algorithm
None
Color Depth
Vector Data (Not Applicable)
Developed by
SoftSource & NCSA (National Center for Supercomputing Applications)
Released
1995
Magic Bytes
Unknown (SoftSource SVF)
Browser Support Comparison
| Browser | AVCS | SVF |
|---|---|---|
Chrome
|
✕ | ✕ |
Firefox
|
✕ | ✕ |
Safari
|
✕ | ✕ |
Edge
|
✕ | ✕ |
IE (Legacy)
|
✕ | ✕ |
AVCS
AVCS Strengths
- Efficiently stores bursts of images or animations utilizing inter-frame compression
- Leverages the highly compatible and widely hardware-accelerated AVC (H.264) codec
- Robust HEIF container supports extensive metadata, alpha channels, and depth maps
Limitations
- Zero native support in web browsers
- Largely superseded in efficiency by newer sequence formats like HEICS (HEVC) or Animated AVIF (AV1)
- Complicated container structure requires specialized parsing libraries
SVF
SVF Strengths
- Acted as a crucial pioneering stepping-stone in proving that scalable, zoomable vector graphics were viable and necessary for the World Wide Web
Limitations
- Completely obsolete and unsupported by modern web standards
- Required end-users to install bulky, proprietary browser plugins
- Causes significant developer confusion today due to Autodesk adopting the exact same acronym and file extension for a completely different technology
When to choose which format
AVCS
Use AVCS when…
- Burst Photography
- Short Animations
- Camera Capture
- Archival Storage
SVF
Use SVF when…
- Historical Web-based CAD Viewers (1990s)
- Legacy 2D Vector Archival
- Autodesk Platform Services (Forge) Model Translation (Name Collision)