Image MIME Reference
AVCI
AVC Image (HEIF Container)
image/avci
VS
Network FlashPix
image/vnd.net-fpx
Net-FPX
A complete technical comparison of AVC Image (HEIF Container) and Network FlashPix — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.
Equal browser support
Feature Support
| Feature | AVCI | Net-FPX |
|---|---|---|
| Transparency (Alpha) | Yes | Yes |
| Animation Support | ✕ No | ✕ No |
| Progressive Loading | ✕ No | Yes |
| HDR Support | Yes | ✕ No |
| EXIF Metadata | Yes | Yes |
| ICC Color Profile | Yes | Yes |
AVC Image (HEIF Container)
image/avci
Extension
.avci.hif
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 69
Network FlashPix
image/vnd.net-fpx
Extension
.fpx
Container
Microsoft OLE Structured Storage (COM)
Compression
JPEG (Lossy) / Uncompressed / Single-color (Solid)
Algorithm
JPEGNone
Color Depth
8-bit (Grayscale/Indexed), 24-bit (RGB), 32-bit (CMYK/RGBA)
Developed by
Digital Imaging Group (Kodak, HP, Live Picture, Microsoft)
Released
1996
Magic Bytes
D0 CF 11 E0 A1 B1 1A E1
Browser Support Comparison
| Browser | AVCI | Net-FPX |
|---|---|---|
Chrome
|
✕ | ✕ |
Firefox
|
✕ | ✕ |
Safari
|
✕ | ✕ |
Edge
|
✕ | ✕ |
IE (Legacy)
|
✕ | ✕ |
AVCI
AVCI Strengths
- Shares the robust, flexible HEIF container architecture that allows for rich metadata, HDR, and depth maps.
- Backed by the highly ubiquitous AVC (H.264) codec, which is widely supported in hardware decoding.
- Supports rectangular cropping and rotation metadata without needing to re-encode the pixel data.
Limitations
- No native support within web browsers for HTML rendering.
- Inferior compression efficiency when compared to newer container formats like HEIC (HEVC) or AVIF (AV1).
- Easily confused with HEIC and AVIF, which use the same base ISOBMFF container.
Net-FPX
Net-FPX Strengths
- Revolutionized web imaging in the late 1990s by proving that massive gigapixel images could be navigated seamlessly over 56k dial-up modems
- Pioneered the tile-based, multi-resolution pyramid concepts that eventually evolved into modern standards like IIIF (International Image Interoperability Framework)
Limitations
- Completely obsolete, having been replaced by standard JPEG servers and modern tiling formats like Deep Zoom or JPEG 2000/XR
- Relied on proprietary Java applets or ActiveX controls to render the tiles dynamically in a web browser
- Extremely complex to parse server-side due to the heavy OLE filesystem container
When to choose which format
AVCI
Use AVCI when…
- Digital Photography
- Camera Capture
- Archival Storage
Net-FPX
Use Net-FPX when…
- Historical Internet Imaging Protocol (IIP) Streaming
- Early E-Commerce Deep Zoom Implementations
- Legacy High-Resolution Image Servers