Image MIME Reference
JPEG-LS
JPEG-LS
image/jls
VS
Sony Alpha Raw Image
image/x-sony-arw
Sony-ARW
A complete technical comparison of JPEG-LS and Sony Alpha Raw Image — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.
Equal browser support
Feature Support
| Feature | JPEG-LS | Sony-ARW |
|---|---|---|
| Transparency (Alpha) | ✕ No | ✕ No |
| Animation Support | ✕ No | ✕ No |
| Progressive Loading | ✕ No | ✕ No |
| HDR Support | Yes | Yes |
| EXIF Metadata | ✕ No | Yes |
| ICC Color Profile | ✕ No | Yes |
JPEG-LS
image/jls
Extension
.jls.jl
Container
JPEG Bitstream
Compression
Lossless / Near-Lossless (Predictive Coding)
Algorithm
LOCO-I (Low Complexity Lossless Compression for Images)Golomb-Rice Coding
Color Depth
8-bit, 12-bit, 16-bit (Per Channel)
Developed by
Joint Photographic Experts Group (ISO/ITU-T) & HP Labs
Released
1999
Magic Bytes
FF D8 FF F7
Sony Alpha Raw Image
image/x-sony-arw
Extension
.arw
Container
TIFF-based (Proprietary)
Compression
Uncompressed / Lossless Compressed / Lossy Compressed
Algorithm
NoneSony Proprietary LosslessSony Proprietary Lossy
Color Depth
12-bit (Per Channel), 14-bit (Per Channel)
Developed by
Sony Corporation
Released
2006
Magic Bytes
49 49 2A 00
Browser Support Comparison
| Browser | JPEG-LS | Sony-ARW |
|---|---|---|
Chrome
|
✕ | ✕ |
Firefox
|
✕ | ✕ |
Safari
|
✕ | ✕ |
Edge
|
✕ | ✕ |
IE (Legacy)
|
✕ | ✕ |
JPEG-LS
JPEG-LS Strengths
- Provides state-of-the-art lossless compression ratios for continuous-tone images, often outperforming Lossless JPEG and JPEG 2000
- Extremely fast and computationally inexpensive to encode/decode, requiring no complex floating-point math or DCTs
- Highly resilient in constrained hardware environments, making it ideal for medical equipment and deep-space probes (e.g., Mars rovers)
Limitations
- Zero native support in web browsers or standard consumer operating systems
- Lacks the advanced resolution scalability and progressive decoding features found in JPEG 2000
- Primarily relegated to niche enterprise sectors (healthcare/DICOM and aerospace) rather than consumer adoption
Sony-ARW
Sony-ARW Strengths
- Retains absolute maximum sensor data, enabling massive shadow recovery and highlight protection compared to compressed in-camera JPEGs
- Embeds high-quality JPEG previews and robust metadata, allowing photographers to match in-camera color science (like Creative Looks) perfectly during raw processing
- Utilizes the standard TIFF container structure, ensuring broad compatibility with open-source decoding libraries (like LibRaw)
Limitations
- Proprietary format means it requires constant updates to raw processing engines every time Sony releases a new camera model
- Sony's historically controversial lossy compression algorithm (often called 'star eater' due to spatial filtering artifacts) was a drawback for astrophotography in older ARW versions, though largely resolved in newer models with uncompressed/lossless options
- Cannot be directly embedded into web pages or used in standard HTML/CSS contexts
When to choose which format
JPEG-LS
Use JPEG-LS when…
- Medical Imaging (DICOM Encapsulation)
- Space and Planetary Imaging (NASA/ESA)
- Industrial Machine Vision
- Scientific Archival Storage
Sony-ARW
Use Sony-ARW when…
- Professional Digital Photography
- Non-destructive Image Post-Processing
- High Dynamic Range (HDR) Imaging Archival