ass-compiler

library0.1.16jsnpmunverified

Parses and compiles ASS/SSA subtitle format into an easy-to-use data structure. Current stable version: 0.1.16. Released as needed with minor fixes and enhancements. Key differentiators: provides both low-level parse/stringify and high-level compile/decompile with validation, tag merging, drawing transformation, and default style support. Ships TypeScript types. Alternatives require more manual parsing or lack validation.

serialization data

npm install ass-compiler

github ↗package ↗homepage ↗

INSTALL

IMPORT

SIG · ASS-COMPILER

ass-compiler

serializationjavascriptv0.1.16

harness data pending

Install & Compatibility

Where this runs

No compatibility data collected yet for this library.

Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

parse

✓ import { parse } from 'ass-compiler'

✗ const parse = require('ass-compiler').parse

ESM-only since v0.1.13; CommonJS require will not work with default import.

compile

✓ import { compile } from 'ass-compiler'

✗ import compile from 'ass-compiler'

compile is a named export, not default. ESM-only.

stringify

✓ import { stringify } from 'ass-compiler'

Converts parsed JSON back to ASS text.

Demonstrates parsing, compiling with options, and round-tripping ASS text using parse, compile, stringify, and decompile.

import { parse, compile, stringify, decompile } from 'ass-compiler'; const assText = `[Script Info] ScriptType: v4.00+ PlayResX: 384 PlayResY: 288 [V4+ Styles] Format: Name, Fontname, Fontsize, PrimaryColour, SecondaryColour, OutlineColour, BackColour, Bold, Italic, Underline, StrikeOut, ScaleX, ScaleY, Spacing, Angle, BorderStyle, Outline, Shadow, Alignment, MarginL, MarginR, MarginV, Encoding Style: Default,Arial,20,&H00FFFFFF,&H000000FF,&H00000000,&H00000000,0,0,0,0,100,100,0,0,1,2,2,2,10,10,10,1 [Events] Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text Dialogue: 0,0:00:01.00,0:00:04.00,Default,,0,0,0,,Hello world! `; const parsed = parse(assText); console.log(parsed); const compiled = compile(assText, { defaultInfo: { PlayResX: 384, PlayResY: 288 }, defaultStyle: { Name: 'Default', Fontname: 'Arial', Fontsize: '20', PrimaryColour: '&H00FFFFFF&', SecondaryColour: '&H000000FF&', OutlineColour: '&H00000000&', BackColour: '&H00000000&', Bold: '0', Italic: '0', Underline: '0', StrikeOut: '0', ScaleX: '100', ScaleY: '100', Spacing: '0', Angle: '0', BorderStyle: '1', Outline: '2', Shadow: '2', Alignment: '2', MarginL: '10', MarginR: '10', MarginV: '10', Encoding: '1' } }); console.log(compiled); const backToText = stringify(parsed); const decompiledText = decompile(compiled); console.log(backToText === decompiledText);

Debug

Known issues

breakingESM-only since v0.1.13; CommonJS require will not work.

fix

Use ESM imports: import { parse } from 'ass-compiler'.

affects: >=0.1.13

gotchaThe first \r tag must be before other override tags; otherwise it can cause incorrect style resolution.

fix

Ensure \r appears at the start of override tags in Dialogue text.

affects: >=0.1.10

gotchaWhen multiple \pos or \move tags exist, only the first one is used; later ones are ignored.

fix

Remove duplicate \pos/\move tags; keep only the first.

affects: >=0.1.15

gotchaTimestamps with rounding precision issues may cause slight time shifts; force rounding not applied.

fix

Upgrade to v0.1.11+ which fixes rounding via #16.

affects: <=0.1.10

Errors

Common errors & fixes

TypeError: Cannot read properties of undefined (reading 'Fontname')

Default style not defined in ASS file and no defaultStyle option provided.

fix

Provide a defaultStyle option including Fontname, or add a 'Default' style in the ASS file.

SyntaxError: Invalid or unexpected token

ASS text contains mismatched brackets (e.g., unclosed { or }).

fix

Ensure all brackets are balanced; update to v0.1.15+ which better handles mismatched brackets.

ERR_REQUIRE_ESM

Trying to require() the package with CommonJS after v0.1.13.

fix

Switch to ESM imports (import { parse } from 'ass-compiler') or downgrade to v0.1.12.

Upgrade

Version history

0.1.16latest on npm

Audit

Dependencies

No dependency data recorded yet.

Agent activity

27 hits · last 30 days

node

OpenAI (training)

Resources

githubhttps://github.com/weizhenye/ass-compiler ↗

packagehttps://www.npmjs.com/package/ass-compiler ↗

homepagehttps://ass.js.org/ass-compiler/ ↗