Editing Serial digital interface (section)

===Line counter and CRC===
In the high definition serial digital interface (and in dual-link HD), additional check words are provided to increase the robustness of the interface. In these formats, the four samples immediately following the EAV packets (but not the SAV packets) contain a [[cyclic redundancy check]] field, and a line count indicator. The CRC field provides a CRC of the preceding line (CRCs are computed independently for the Y and C streams) and can be used to detect [[bit error]]s in the interface. The line count field indicates the line number of the current line.

The CRC and line counts are not provided in the SD and ED interfaces. Instead, a special ancillary data packet known as an '''EDH packet''' may be optionally used to provide a CRC check on the data.