chapter  4
16 Pages

Operational Patterns and Constraining MXF

For uncompressed essence, most audio compression schemes, DV, and some intra-frame compression schemes, this bit will always be set to "1." For most long-GOP MPEG-2 streams, the qualifier bit will be set to "0" because it is not possible to concatenate two arbitrary MPEG streams and expect the MPEG buffers to match at the boundary. Naive playback would cause buffer overflow or underflow with spectacular visual consequences. Help is at hand, however, in that the MPEG stream can be prepared by "pre-splicing" the content so that the resulting file can be played without any stream processing being performed by the MXF playback device. The advice to IvlXF encoder writers is that pre-splicing should always be done unless the operational environment in which the MXF cncoder is being used guarantees that the MXF decoder has the required splicing functionality.