Image MIME Reference
AVCI
AVC Image (HEIF Container)
image/avci
VS
Epson Raw Format
image/x-epson-erf
Epson-ERF
A complete technical comparison of AVC Image (HEIF Container) and Epson Raw Format — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.
Equal browser support
Feature Support
| Feature | AVCI | Epson-ERF |
|---|---|---|
| Transparency (Alpha) | Yes | ✕ No |
| Animation Support | ✕ No | ✕ No |
| Progressive Loading | ✕ No | ✕ No |
| HDR Support | Yes | Yes |
| EXIF Metadata | Yes | Yes |
| ICC Color Profile | Yes | ✕ No |
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
Epson Raw Format
image/x-epson-erf
Extension
.erf
Container
TIFF/EP
Compression
Uncompressed / Lossless JPEG (ITU-T81)
Algorithm
NoneLossless JPEG
Color Depth
12-bit (Per Channel)
Developed by
Seiko Epson Corporation
Released
2004
Magic Bytes
49 49 2A 00 or 4D 4D 00 2A
Browser Support Comparison
| Browser | AVCI | Epson-ERF |
|---|---|---|
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.
Epson-ERF
Epson-ERF Strengths
- Preserves original raw sensor data, allowing extreme recovery of highlights and shadows compared to in-camera JPEGs
- Utilizes the standard TIFF container structure, making it relatively easy for open-source software (like dcraw and LibRaw) to parse and decode
Limitations
- Completely obsolete proprietary format tied to a defunct line of digital cameras
- Requires parsing EXIF metadata to differentiate it from standard TIFF files programmatically
- Cannot be natively viewed in web browsers or standard operating system image viewers without specialized codecs
When to choose which format
AVCI
Use AVCI when…
- Digital Photography
- Camera Capture
- Archival Storage
Epson-ERF
Use Epson-ERF when…
- Vintage Digital Photography (Epson R-D1)
- Non-destructive Image Post-Processing
- Raw Imaging Archival