Free webp to jpg
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Image MIME Reference
ACES

ACES Image Container File

image/aces
VS

JPEG 2000 Codestream

image/j2c
J2C

A complete technical comparison of ACES Image Container File and JPEG 2000 Codestream — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.

Equal browser support

Feature Support

Feature ACES J2C
Transparency (Alpha) Yes Yes
Animation Support ✕ No ✕ No
Progressive Loading ✕ No Yes
HDR Support Yes Yes
EXIF Metadata ✕ No ✕ No
ICC Color Profile ✕ No ✕ No
ACES Image Container File
image/aces
Extension
.exr
Container OpenEXR (SMPTE ST 2065-4)
Compression Lossless / Uncompressed
Algorithm
PIZZIPRLEB44Uncompressed
Color Depth 16-bit (Half-float), 32-bit (Float)
Developed by Academy of Motion Picture Arts and Sciences (AMPAS) / SMPTE
Released 2013
Magic Bytes
76 2F 31 01
Full ACES reference →
JPEG 2000 Codestream
image/j2c
Extension
.j2c.j2k.jpc
Container None (Raw Bitstream)
Compression JPEG 2000 (Discrete Wavelet Transform) / Lossless / Lossy
Algorithm
Discrete Wavelet Transform (DWT)
Color Depth 8-bit, 10-bit, 12-bit, 16-bit (Per Channel)
Developed by Joint Photographic Experts Group (JPEG)
Released 2000
Magic Bytes
FF 4F FF 51
Full J2C reference →

Browser Support Comparison

Browser ACES J2C
Chrome Chrome
✕ ✕
Firefox Firefox
✕ ✕
Safari Safari
✕ ✕
Edge Edge
✕ ✕
IE IE (Legacy)
✕ ✕
ACES

ACES Strengths

  • Industry standard for high-end visual effects, compositing, and color grading
  • Supports 16-bit half-float data, accurately capturing immense dynamic range without clipping
  • Standardized by SMPTE (ST 2065-4) to guarantee universal color interoperability across different post-production facilities
Limitations
  • Considerably larger file sizes than conventional consumer image formats
  • Completely unsupported in web browsers and most standard desktop viewers
  • Requires specialized compositing or color grading software to interpret and view the scene-linear data correctly
J2C

J2C Strengths

  • Provides state-of-the-art wavelet compression for high-end professional workflows (Digital Cinema)
  • Allows for highly efficient progressive decoding (by resolution or quality layer) natively within the stream
  • Supports lossless mathematical compression and high bit-depths (up to 16-bit per channel) natively
Limitations
  • Lacks a standard container to store color space info or metadata, requiring external systems (like MXF or DICOM) to map colors correctly
  • Extremely computationally expensive to encode and decode compared to standard DCT-based JPEG
  • Zero web browser support

When to choose which format

ACES
Use ACES when…
  • Visual Effects (VFX)
  • Digital Intermediate (DI)
  • Color Grading
  • Archival
J2C
Use J2C when…
  • Digital Cinema Packages (DCP)
  • Medical Imaging (DICOM Payloads)
  • Professional Broadcast and Archiving
  • Embedded Hardware Encoding

More comparisons

ACES vs APNG → J2C vs APNG → ACES vs AVCI → J2C vs AVCI → ACES vs AVCS → J2C vs AVCS → ACES vs AVIF → J2C vs AVIF → All comparisons →
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