ATSC M/H Ensemble [EtherGuide Glossary]
An ATSC M/H Ensemble is a conceptual element that is comprised of 20 8-VSB data frames and which encompasses 967887927 nanoseconds (usually rounded up to 968 milliseconds). Each M/H frame encompasses exactly 5 M/H sub-frames. If an ATSC M/H frame contains the maximum amount of M/H data permitted by candidate standard A/153, all but 4,723,852.703 bits per second of the 8-VSB output of 19,392,658.46 bits per second would be devoted to ATSC M/H data.
The diagram below illustrates the relationships between ATSC M/H Frames, ATSC M/H sub-frames and 8-VSB data frames.
Each 8-VSB data frame spans 624 MPEG-2 packets (938,496 bits). In ATSC M/H usage, each 8-VSB data frame can contain either 72 contiguous MPEG-2 packets (108,288 bits) and 552 contiguous ATSC M/H packets (830,208 bits) or, if no ATSC M/H data is present in a particular data frame, 624 MPEG-2 packets (938,496 bits).
Therefore, there are 12,480 packets totaling 18,769,920 bits in each ATSC M/H frame.
The organization of M/H Ensembles, M/H Groups and M/H Parades can dynamically change from one M/H Frame to the next.