Wrapper files-the key to network technology

The last IBC in 1996 saw the start of a joint EBU/SMPTE Task Force with a mandate to study the consequences of introducing compressed video bitstreams into broadcast operations. The results of intensive studies by both the user and manufacturing communities saw the publication of a comprehensive user requirements report at the NAB in Las Vegas, April 1997. One section of that report was on the combined topics of Wrappers and Metadata and this paper will introduce some of the work covered by that section. The paper will explain what makes a Wrapper file and why it may to become a key part of broadcast operations in the future. Many readers will be familiar with the concept of files through their use of computers. A Wrapper file can contain either or both the individual program essence or make reference to where the program essence can be found via a pointer. The other key component is Metadata which provides descriptive information about the program essence. There are many other aspects to the needs of a Wrapper file and this paper will attempt to address some of them. It should be noted that a Wrapper file format does not yet exist. The specification is a complex and ongoing process now under study but which should become available by the end of 1997.