Ascii85 Variant
Ascii85 variants are encodings that adjust the alphabet or alignment rules of standard Ascii85 (PostScript/PDF), such as btoa and the IPv6 style.
Purpose
They tailor Ascii85's character set or padding rules to a specific application so that the output does not conflict with host syntax.
Mechanism
The core is still the 4-byte-to-5-character mapping, but the alphabet's starting character, special compression markers (such as z for four zero bytes), and alignment strategies differ per variant.
Use cases
- PDF object stream encoding
- PostScript data embedding
- Compact IPv6 address representation