Definition: SMPTE 392M: Operational pattern 2a, 2b, or 2c qualifier informing MXF decoders that playout without additional processing is possible.

Description: Operational patterns are fully described in Chapter 4. Sequencing or playlist functionality is intended to be provided by the operational patterns in column two of Figure 4.1. For many essence types, this is a trivial issue: one merely sends the stream of bytes, in the order they appear in the file, to a decoder codec. An example of such a structure is shown in Figure 3.1 on the next page.

Figure 3.1: OP2a multiplex containing interleaved DV and uncompressed BWF audio elements

There are certain essence types, however, that rely on predictive coding in order to achieve high compression ratios or alternatively employ buffer models that must be respected for continuous playback. Examples of this sort of essence are:

• Long-GOP MPEG

• H.264

• SMPTE VC-1 video

• MP3 audio

• AAC audio

If these essence types are contained in MXF using a standardized or a private mapping, then care needs to be taken when constructing an OP2x multiplex. In order to create a system as shown in Figure 3.1, the application that created the MXF file must be sure that any buffer/prediction conditions required at the start of the second essence container(s) are satisfactorily established at the end of the first essence container(s). This is shown in Figure 3.2, where each essence element requires some form of...