Quicktime Sorenson Codec

Action Plan: Quicktime File Format - Sorenson Codec

Last Updated 12/05/2013

Description:  A multimedia container file which can contain audio, video, effects and subtitles. A proprietary Apple, Inc. format with specifications available here, it is made up "atoms," the basic unit of data comprising a QuickTime file. The MPEG-4 file format is often described as having evolved from the second version of the QuickTime File Format (QTFF).

Codec: The Sorenson Codec is widely used in video filemaking. It is lossy compressed and often used as a middle state format for lower resolution streaming versions. It has also been observed to contain special features in some versions, such as multiple lines of audio/subtitles and even interactive elements.

Software:  Apple QuickTime Pro is used for saving or converting individual QTFF files. Files with the mov extension can be played with VLC media player , iTunes , Windows Media Player and many others. MediaInfo is useful for identification of codecs and file characteristics.

Long Term Preservation Plan: The Quicktime File Format is a proprietary format with an open, public specification. While still widely used, there are signs that it is being overtaken in popularity by file wrappers such as MPEG-4. The format remains popular and every major browser can support it. There have been versions of the Quicktime player over time, and some earlier versions supported special features, e.g., forms of interactivity, that are not supported in more recent versions of the player. Migration is not at present recommended, however some files may require older versions of QuickTime to play. Check the MediaInfo report to determine what version was used initially. Many unusable files can be played using VLC media player, however some interactive elements may be lost.

Division Specific Notes:

American Memory : "American Memory has produced QuickTime files for web service since the mid-1990s, typically using the Cinepak codec at 10 fps and 160x120 pixels. For the special videos associated with the Dance Instruction Manuals collection, a second set of higher-resolution QuickTime files was produced, using the Sorenson codec at 15 fps and 320x240 pixels. The audio stream in both types employs IMA (Interactive Multimedia Association) 4:1 compression, based on PCM sampling at 22 kHz. (http://www.digitalpreservation.gov/ )"

Motion Picture, Broadcasting, and Recorded Sound Division : "In 2004...collected a series of nine "enhanced" QuickTime movies produced by BMW (formerly available athttp://usa.bmwfilms.com/), with the main video object in the form of QTV_Sorenson.(http://www.digitalpreservation.gov/ )"  These videos are playable with VLC media player (some special elements included) or with QuickTime 5.0.5. (all special elements included)