install

Additional install commands

macOS

Homebrewverified · 100%

brew install alass

local Homebrew formula metadata

Windows

Scoopverified · 92%

scoop install main/alass

Scoop official bucket manifest trees · bucket/alass.json · source: api.github.com

overview

Package summary

Automatic Language-Agnostic Subtitle Synchronization

Project links

Commands and aliases

alass-cli

history

Project history and usage

alass is a Rust command-line tool for Automatic Language-Agnostic Subtitle Synchronization. It aligns subtitle timing to a movie or to another subtitle file, correcting offsets, splits, and framerate differences without depending on the spoken language.

Project history

The public GitHub repository was created in February 2017. The README ties the algorithmic basis to the author's bachelor's thesis and presentation, and notes that the program was previously called `aligner` before being renamed to `alass` because the old name was hard to find in search engines.

The workspace is split into `alass-core`, the reusable algorithm library, and `alass-cli`, the official command-line tool for end users. That split lets downstream code reuse the synchronization algorithm while package managers expose the practical CLI.

Adoption history

Official releases provide Windows and Linux executables, while source builds use Rust and Cargo. The supplied package-manager facts show distribution through Homebrew as `alass` and Scoop as `main/alass`.

The tool's adoption sits in the media-maintenance niche: users with mismatched subtitle files, different cuts, advertisement breaks, or framerate drift can run a local binary instead of manually editing subtitle timestamps.

How it is used

Basic use is `alass movie.mp4 incorrect_subtitle.srt output.srt`, or using a reference subtitle instead of a video file. For video references, `ffmpeg` and `ffprobe` are used to extract audio, with paths overridable through `ALASS_FFMPEG_PATH` and `ALASS_FFPROBE_PATH`.

The README documents tuning with `--split-penalty` and a faster `--no-splits` mode when only a constant shift is desired. Supported subtitle formats include `.srt`, `.ssa`, `.ass`, and `.idx`, while common video formats are supported through FFmpeg.

Why package nerds care

alass is a neat package-manager specimen because it wraps a specialized media algorithm into a normal CLI install. The package saves users from compiling a Rust workspace and C voice-activity component just to fix one badly timed subtitle file.

It also shows the recurring package-manager pattern where the executable name differs from the crate/workspace internals: Homebrew users get `alass-cli`, while the human-facing project name remains simply `alass`.

Timeline

2017: Public GitHub repository created.
Initial project period: README documents the bachelor's thesis and presentation behind the algorithm.
Later: Project renamed from `aligner` to `alass` for searchability.
2023: Repository metadata shows continued activity into late 2023.

Related projects

alass-core: reusable library crate containing the synchronization algorithm.
alass-cli: official command-line tool for end users.
FFmpeg and ffprobe: external tools used by alass to extract audio from video references.

Sources

https://api.github.com/repos/kaegi/alass
https://github.com/kaegi/alass
input source_facts.package-manager

security posture

Risk level: blue

broad file, network, media, or database tool signal.

Risk classifier

blue risk · medium confidence · tool

Why

broad file, network, media, or database tool signal

Signals

text:sync

Install behavior

No Homebrew post-install hook is recorded in formula metadata.
Homebrew bottle metadata is available for 12 platform targets.
Build metadata lists 1 build dependencies.

Recommended review

Before unattended agent use, check whether the tool reads plaintext credentials, writes remote state, publishes artifacts, or shells out to plugins.

executables

Installed executables

Command	Kind	Exposure	Note
`alass-cli`	cli	global executable

freshness

Version and freshness

These signals separate page generation age, package-manager activity, and upstream release comparison. Version lag is warned only when an evidence URL and comparable versions are present.

page generated2026-07-08

manager version2.0.0

manager updated

local dataok

upstreamcurrent

latest detectedv2.0.0

https://github.com/kaegi/alass

infoNo package-manager update timestamp was available.low confidence

install metadata

Package metadata

Package key	brew:alass
Version	2.0.0
Package manager	Homebrew
Package manager page	https://formulae.brew.sh/formula/alass
Homepage	https://github.com/kaegi/alass
Repository	https://github.com/kaegi/alass
Upstream docs	https://github.com/kaegi/alass
License	GPL-3.0-or-later
Source archive	https://github.com/kaegi/alass/archive/refs/tags/v2.0.0.tar.gz
Build dependencies	rust
Bottle	available (on arm64_big_sur, arm64_linux, arm64_monterey, arm64_sequoia, arm64_sonoma, arm64_tahoe, arm64_ventura, big_sur, monterey, sonoma, ventura, x86_64_linux)
Homebrew post-install	not defined
Service	none declared

registry facts

Source database details

Source Database	Homebrew formula API
Tap	homebrew/core
Full Name	alass
Version Scheme	0
Revision	0
Bottle Stable Root URL	https://ghcr.io/v2/homebrew/core
Deprecated	no
Disabled	no
Keg Only	no
URL Keys	stable

source database matches

Other package-manager records

Matches are pulled from external package-manager indexes and kept separate from local Automic Vault package links.

Scoop95%

main/alass

scoop install main/alass

normalized package name match
Matched by: Alass

Scoop official bucket manifest trees · api.github.com · Scoop official bucket manifest trees: bucket/alass.json from https://api.github.com/repos/ScoopInstaller/Main/git/trees/master?recursive=1

package graph

Links come from deterministic package relationships, av.db category and tag curation, ecosystem matches, and package hub membership.

source trail

Generated from repository data

This page is generated by av-web from the private package SQLite artifact built by scripts/generate-pkg-sqlite.py.

Combined YAML source

View the package source record on GitHub.

combined/alass.yml

Used sources

Geiger risk classifier
Nucleus package database
av.db category and tag curation
cross-ecosystem install command graph
curated package history
external package-manager database matches
package relationship graph
package version freshness
package-page enrichment

Install alass with Homebrew, scoop