Image MIME Reference
DPX
Digital Picture Exchange
image/dpx
VS
AutoCAD Slide
image/vnd.sld
SLD
A complete technical comparison of Digital Picture Exchange and AutoCAD Slide — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.
Equal browser support
Feature Support
| Feature | DPX | SLD |
|---|---|---|
| Transparency (Alpha) | Yes | ✕ No |
| Animation Support | ✕ No | ✕ No |
| Progressive Loading | ✕ No | ✕ No |
| HDR Support | Yes | ✕ No |
| EXIF Metadata | ✕ No | ✕ No |
| ICC Color Profile | ✕ No | ✕ No |
Digital Picture Exchange
image/dpx
Extension
.dpx
Container
DPX (SMPTE ST 268)
Compression
Uncompressed / RLE (Rarely used)
Algorithm
Uncompressed
Color Depth
8-bit, 10-bit, 12-bit, 16-bit, 32-bit (Float)
Developed by
SMPTE (Society of Motion Picture and Television Engineers)
Released
1994
Magic Bytes
53 44 50 58 (Big-endian) / 58 50 44 53 (Little-endian)
AutoCAD Slide
image/vnd.sld
Extension
.sld
Container
AutoCAD Slide Container
Compression
Uncompressed (Vector Instructions)
Algorithm
None
Color Depth
8-bit (AutoCAD Indexed Color)
Developed by
Autodesk, Inc.
Released
1980s
Magic Bytes
41 75 74 6F 43 41 44 20 53 6C 69 64 65 0D 0A 1A 00
Browser Support Comparison
| Browser | DPX | SLD |
|---|---|---|
Chrome
|
✕ | ✕ |
Firefox
|
✕ | ✕ |
Safari
|
✕ | ✕ |
Edge
|
✕ | ✕ |
IE (Legacy)
|
✕ | ✕ |
DPX
DPX Strengths
- Industry standard for transferring uncompressed, high-fidelity film and VFX data
- Rich industry-specific metadata including timecode, keykode, and film stock information
- Supports logarithmic color spaces (LogC, Cineon) to preserve the massive dynamic range of film negatives
Limitations
- Massive file sizes (e.g., a single 4K 10-bit frame is ~50MB, resulting in ~1.2GB per second at 24fps)
- Zero native support in web browsers or consumer OS image viewers
- Requires heavy-duty, fast storage infrastructure (RAID/NVMe) to playback in real-time
SLD
SLD Strengths
- Allowed for instantaneous loading of highly complex architectural and engineering blueprints on low-memory MS-DOS systems
- Easy-to-parse binary structure containing simple opcodes for drawing vectors and polygons
Limitations
- Completely obsolete and heavily fragmented, largely replaced by PDF and lightweight web-based DXF viewers
- Destructive 'snapshot' format irrevocably strips all useful, editable CAD geometry data from the original drawing
- Zero support in web browsers or standard image processing libraries
When to choose which format
DPX
Use DPX when…
- Film Scanning
- Visual Effects (VFX)
- Digital Intermediate (DI)
- Color Grading
- Archival
SLD
Use SLD when…
- Legacy AutoCAD Slideshows
- AutoCAD Custom Icon Menus
- Historical CAD Archival