ATSC M/H Frame [EtherGuide Glossary]
The ATSCM/H Frame is a basic time unit and conceptual element employed in multiplexing ATSC M/H data into 8-VSB (main) content. In terms of time, an ATSC M/H frame contains exactly 20 8-VSB data frames, which take 967,887,927 nanoseconds (which is usually expressed as 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.
There are 12,480 packets totaling 18,769,920 bits in each ATSC M/H frame.
Each ATSC M/H Frame can be composed independent of preceeding and succeeding ATSC M/H Frames to account for instantaneous data needs. This means that the organization of M/H Ensembles, M/H Groups and M/H Parades can dynamically change from one M/H Frame to the next. Within any ATSC M/H frame, the composition of each ATSC M/H sub-frame is identical.
The diagram below illustrates the relationships between ATSC M/H Frames, ATSC M/H sub-frames and 8-VSB data frames.