With ELAN a user can add an unlimited number of annotations to audio and/or video streams. An annotation can be a sentence, word or gloss, a comment, translation or a description of any feature observed in the media. Annotations can be created on multiple layers, called tiers. Tiers can be hierarchically interconnected. An annotation can either be time-aligned to the media or it can refer to other existing annotations. The textual content of annotations is always in Unicode and the transcription is stored in an XML format.
ELAN provides several different views on the annotations, each view is connected and synchronized to the media playhead.

Up to 4 video files can be associated with an annotation document. Each video can be integrated in the main document window or displayed in its own resizable window.
ELAN delegates media playback to an existing media framework, like Windows Media Player, QuickTime or JMF (Java Media Framework). As a result a wide variety of audio and video formats is supported and high performance media playback can be achieved.

ELAN is written in the Java programming language and the sources are available for non-commercial use. It runs on Windows, Mac OS X and Linux.

Main other features

• navigate through the media with different step sizes
• easy navigation through existing annotations
• waveform visualization of .wav files
• support for template documents
• input methods for a variety of script systems
• multi-tier regular expression search, within a single document or in a selection of annotation documents
• support for user definable Controlled Vocabularies
• import and export of Shoebox/Toolbox, CHAT, Transcriber (import only), Praat and csv/tab-delimited text files
• export to interlinear text, html, smil and subtitles text
• printing of the annotations
• multiple undo/redo