4.1 Introduction

Standardized as SMPTE 360M, ^[1] the General Exchange Format (GXF) is an established stream/file format used in professional broadcast applications when finished material is readied for air or is exchanged between facilities. It is commonly used for the distribution of commercials and some program material. It also is a format used within the facility for staging material being readied for air; for instance, edited stories in the newsroom are transferred from the edit suite to replay servers or to and from the facility archive also use GXF. Systems using GXF were first installed in 1997. As the products using GXF were enhanced, the interchange format was extended to support new capabilities, including compression formats used for advanced digital television. In 1999, GXF was offered to the Society of Motion Picture and Television Engineers (SMPTE) for standardization, resulting in the adoption of the first standard for compressed file interchange in 2001. Since that time, the standard has been revised to reflect new features and capabilities. More than 15 manufacturers have implemented SMPTE 360M for use in professional broadcast systems.

The first version of GXF transferred simple, uncut shots with JPEG video, uncompressed audio, and time codes. The second version added support for MPEG compression, complex compositions (i.e., material edited with cuts), and a facility to encapsulate user-defined metadata. Later enhancements added support for DVCPRO, high definition MPEG-2, and MPEG-1 video compression, as well as compressed audio formats including Dolby Digital and Dolby E.