Image MIME Reference
AVIF
AV1 Image File Format
image/avif
VS
North American Presentation Level Protocol Syntax
image/naplps
NAPLPS
A complete technical comparison of AV1 Image File Format and North American Presentation Level Protocol Syntax — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.
AVIF wins on browser support
Feature Support
| Feature | AVIF | NAPLPS |
|---|---|---|
| Transparency (Alpha) | Yes | ✕ No |
| Animation Support | Yes | Yes |
| Progressive Loading | ✕ No | Yes |
| HDR Support | Yes | ✕ No |
| EXIF Metadata | Yes | ✕ No |
| ICC Color Profile | Yes | ✕ No |
AV1 Image File Format
image/avif
Extension
.avif
Container
HEIF / ISOBMFF
Compression
AV1 Lossy / AV1 Lossless
Algorithm
AV1
Color Depth
8-bit, 10-bit, 12-bit
Developed by
Alliance for Open Media (AOMedia)
Released
2019
Magic Bytes
XX XX XX XX 66 74 79 70 61 76 69 66
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)
Browser Support Comparison
| Browser | AVIF | NAPLPS |
|---|---|---|
|
|
✓ 85+
|
✕ |
|
|
✓ 93+
|
✕ |
|
|
✓ 16+
|
✕ |
|
|
✓ 121+
|
✕ |
|
|
✕ | ✕ |
AVIF
AVIF Strengths
- Best-in-class compression — typically 20–50% smaller than WebP at equivalent quality
- Native HDR and wide color gamut (BT.2020) support
- Supports 8, 10, and 12-bit color depth
Limitations
- Encoding is highly CPU-intensive — significantly slower than JPEG or WebP
- Requires Edge 121+ (not supported in earlier Edge versions)
- Limited support in native desktop image viewers
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
AVIF
Use AVIF when…
- Next-Gen Websites
- HDR Photography
- High-Quality Web Images
NAPLPS
Use NAPLPS when…
- 1980s Videotex Services
- Prodigy Online Service Graphics
- Historical BBS Terminal Graphics
- Legacy Teletext Broadcasts