Definition: The generic container is the method for placing essence in an MXF file, defined in SMPTE 379M.

Description: One of the requirements in the design of MXF was that it should be agnostic of the underlying compression type. One mechanism that helps make this possible is the creation of the generic container. SMPTE 3 79M allows MXF applications to be written that work at the MXF/KLV level and can process the essence container without necessarily having to know what type of essence is in the essence container. The generic container categorizes essence into five categories:

• System elements

• Picture elements

• Sound elements

• Data elements

• Compound elements

To simplify processing, each of these element types must be grouped together into Items. Groups of contiguous items with the same time duration are referred to as content packages. This is shown in Figure 3.11.

Figure 3.11: Content package, items, and elements

The generic container specification also defines the two major wrapping modes that are used in MXF:

• Frame wrapping

• Clip wrapping

Frame wrapping is the most common mode, and each content package has the duration of a single video frame. Clip wrapping is the wrapping mode where there is a single element for the entire content of the file. The duration of the file is the same as the duration of each of the individual elements. These two wrapping modes are shown in Figure 3.12, and other wrapping modes are...