Free webp to jpg
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Image MIME Reference
Epson-ERF

Epson Raw Format

image/x-epson-erf
VS

JPEG AI Image Sequence

image/jais
JPEG-AI-Sequence

A complete technical comparison of Epson Raw Format and JPEG AI Image Sequence — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.

Equal browser support

Feature Support

Feature Epson-ERF JPEG-AI-Sequence
Transparency (Alpha) ✕ No Yes
Animation Support ✕ No Yes
Progressive Loading ✕ No Yes
HDR Support Yes Yes
EXIF Metadata Yes Yes
ICC Color Profile ✕ No Yes
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
Full Epson-ERF reference →
JPEG AI Image Sequence
image/jais
Extension
.jais
Container ISOBMFF / HEIF Image Sequence
Compression Lossy (Variational Autoencoder / Neural Network)
Algorithm
Deep Neural Network (Variational Autoencoder with Hyperpriors)
Color Depth 8-bit, 10-bit, 12-bit, 16-bit, Wide-gamut & HDR
Developed by Joint Photographic Experts Group (ISO/IEC JTC 1 / ITU-T)
Released 2025
Magic Bytes
.. .. .. .. 66 74 79 70 6A 61 69 73 (Size + ftypjais)
Full JPEG-AI-Sequence reference →

Browser Support Comparison

Browser Epson-ERF JPEG-AI-Sequence
Chrome Chrome
✕ ✕
Firefox Firefox
✕ ✕
Safari Safari
✕ ✕
Edge Edge
✕ ✕
IE IE (Legacy)
✕ ✕
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
JPEG-AI-Sequence

JPEG-AI-Sequence Strengths

  • Extends the state-of-the-art compression efficiency of JPEG AI to multi-frame image sequences and short animations
  • Allows machine vision algorithms to process temporal sequences (like surveillance bursts) directly in the compressed latent domain, saving immense computational power
  • Utilizes the robust, industry-standard ISOBMFF container for metadata, timing, and multi-track encapsulation
Limitations
  • Lacks native decoding support in current web browsers, operating systems, and video players
  • Decoding neural-network-compressed sequences requires significant compute overhead on hardware lacking dedicated AI accelerators (NPUs/GPUs)
  • Adoption is hindered by competition with established sequence formats like AVIF, HEVC (HEICS), and modern video codecs

When to choose which format

Epson-ERF
Use Epson-ERF when…
  • Vintage Digital Photography (Epson R-D1)
  • Non-destructive Image Post-Processing
  • Raw Imaging Archival
JPEG-AI-Sequence
Use JPEG-AI-Sequence when…
  • Machine Vision and AI Video/Burst Workflows
  • Cloud Storage Animation Optimization
  • Focal Stacks and Medical Volumetric Slices
  • Visual Surveillance Sequences

More comparisons

Epson-ERF vs ACES → JPEG-AI-Sequence vs ACES → Epson-ERF vs APNG → JPEG-AI-Sequence vs APNG → Epson-ERF vs AVCI → JPEG-AI-Sequence vs AVCI → Epson-ERF vs AVCS → JPEG-AI-Sequence vs AVCS → Epson-ERF vs AVIF → JPEG-AI-Sequence vs AVIF → All comparisons →
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