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Image MIME Reference
AZV

AirZip Accelerator Image

image/vnd.airzip.accelerator.azv
VS

North American Presentation Level Protocol Syntax

image/naplps
NAPLPS

A complete technical comparison of AirZip Accelerator Image and North American Presentation Level Protocol Syntax — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.

Equal browser support

Feature Support

Feature AZV NAPLPS
Transparency (Alpha) ✕ No ✕ No
Animation Support ✕ No Yes
Progressive Loading Yes Yes
HDR Support ✕ No ✕ No
EXIF Metadata ✕ No ✕ No
ICC Color Profile ✕ No ✕ No
AirZip Accelerator Image
image/vnd.airzip.accelerator.azv
Extension
.azv
Container Proprietary AirZip Container
Compression Lossy (Proprietary) / Lossless (Proprietary)
Algorithm
AirZip Proprietary Compression
Color Depth 8-bit (Indexed), 24-bit (RGB)
Developed by AirZip, Inc.
Released 1999
Magic Bytes
Unknown (Proprietary)
Full AZV reference →
North American Presentation Level Protocol Syntax
image/naplps
Extension
.nap.naplps
Container NAPLPS Byte Stream
Compression Uncompressed (Tokenized ASCII Commands)
Algorithm
None (Coordinate encoding)
Color Depth 16-color palette (Indexed from larger color spaces)
Developed by ANSI / CSA (Based on Canadian CRC's Telidon)
Released 1983
Magic Bytes
1B (Variable / ESC sequences)
Full NAPLPS reference →

Browser Support Comparison

Browser AZV NAPLPS
Chrome Chrome
✕ ✕
Firefox Firefox
✕ ✕
Safari Safari
✕ ✕
Edge Edge
✕ ✕
IE IE (Legacy)
✕ ✕
AZV

AZV Strengths

  • Historically allowed internet users to browse the web up to 5x faster over 56k dial-up modems by drastically reducing image payload sizes
  • Officially registered in the IANA vendor tree, preventing MIME type conflicts on early web proxy servers
Limitations
  • Completely obsolete in the modern broadband era
  • Closed-source and proprietary, meaning no modern image manipulation libraries (like ImageMagick or libvips) can decode it
  • Zero support in standard web browsers
NAPLPS

NAPLPS Strengths

  • Extremely bandwidth-efficient, enabling colorful graphical interfaces over early 300 baud dial-up connections
  • Resolution-independent vector scaling allowed the exact same file to be displayed accurately on varied early PC monitors and television sets
Limitations
  • Completely obsolete and unsupported by modern web technologies
  • Relies heavily on stateful parsing and terminal emulators rather than straightforward file decoding
  • Easily misidentified by MIME sniffers as plain text or generic binary streams due to the lack of a standardized file header

When to choose which format

AZV
Use AZV when…
  • Dial-up Web Acceleration
  • Bandwidth Optimization (Historical)
  • Legacy Proxy Servers
NAPLPS
Use NAPLPS when…
  • 1980s Videotex Services
  • Prodigy Online Service Graphics
  • Historical BBS Terminal Graphics
  • Legacy Teletext Broadcasts

More comparisons

AZV vs ACES → NAPLPS vs ACES → AZV vs APNG → NAPLPS vs APNG → AZV vs AVCI → NAPLPS vs AVCI → AZV vs AVCS → NAPLPS vs AVCS → AZV vs AVIF → NAPLPS vs AVIF → All comparisons →
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