SAMI (Synchronized Accessible Media Interchange) is a file format designed to deliver synchronized text such as closed captioning, subtitles, or audio descriptions with digital media content. SAMI was released by Microsoft in 1998. The files may have either .smi or .sami file extensions.

At its most basic level SAMI can be used as an intermediate interchange format for encoding closed captions in the form of Line-21 for National Television System Committee (NTSC) and MPEG for DVDs. The audio, video and animation content is stored separately and synchronized with the SAMI content. Thus, Web content can come from different sites.

For example, video content may come from a main server while the captioning content may arrive from a local server. This allows for tailored captioning for different regions of the world. Furthermore, dynamic content like news clips can be posted to a Web site as they arrive while closed captioning can then be added by a local caption provider at a later time from any location in the world.

SAMI allows captioning content to be independent of audio format. For example, while Audio Video Interleave (AVI) cannot store captioned data, QuickTime can, SAMI captioning will work with both formats. As long as a metric of overall duration and elapsed time is generated, captions can be synchronized to audio content.

SAMI captions can also be seen by a user on a text-only device. Over a slow link, a user could access audio content without having to download the entire image or sound file. These would simply show up as a linear transcription. Furthermore, if a serial out option is provided, users can still enjoy the content of a movie or captioned radio via their Braille display.

SAMI supports 64 or more languages as well as many media formats, so it is extremely efficient to use SAMI for content indexing and retrieval then to have filters for every format and manner of encoding employed. A SAMI file can be easily searched for content and then allow the associated video, animation or audio content to be accessed.

In addition to standard fonts, SAMI can support other text styles, such as different colors, sizes, or languages to aid a variety of users. SAMI can be particularly useful for individuals who are hard-of-hearing or visually impaired. The SAMI format can also assist in educational purposes, such as teaching beginning readers or students learning a second language.

SAMI files are supported by Windows Media Player, Chameleo, GOM Player, K-Multimedia Player, Media Player Classic Home Cinema, Mplayer, PBS Cove, Perian, Plex, VLC Media Player, XBMC and Xine.