Method and system for decoding data in the horizontal overscan portion of a video signal

A method for detecting a first line of a data sequence encoded in a digital video signal, comprising the steps of:

• (a) receiving a digital video signal having a first field and a second field, each field comprising a plurality of lines;
• (b) scanning a first line of the first field for the presence of an intelligent signal detect word;
• (c) in the event that the intelligent signal detect word is not found, incrementing a counter by one;
• (d) scanning the line of the first field corresponding to a count of the counter for the presence of the intelligent signal detect word;
• (e) repeating steps (c) and (d) until the intelligent signal detect word is found;
• and
• (f) flagging the line on which the intelligent signal detect word is found as a first data line.

A decoding device comprising a controller, for recovering data from a video signal divided into fields, wherein each field comprises a plurality of horizontal scan lines consecutively illuminated on a display device, wherein each scan line comprises a prescan portion comprising a pre-data encoding zone, wherein the controller scans the prescan portion for the presence of encoded data in the pre-data encoding zone over a plurality of subsequent fields, the controller being operable to perform the steps of:

• determining a plurality of horizontal scan lines within a prescan portion;
• searching the plurality of horizontal scan lines for the presence of a data start key;
• detecting a data start key within a horizontal scan line within the prescan portion;
• and
• setting the line containing the data start key as the first line of the pre-data encoding zone.

In a system comprising a digital encoder, a transmitter, and a receiver, a method for receiving correctly ordered digital data, comprising the steps of:

• digitally encoding a data stream as a series of data packets;
• transmitting the data packets within a television signal, in order, from a first packet to a last packet, each packet being carried on a separate line;
• receiving the data packets;
• determining whether the data packets arrive in the same order as transmitted;
• and
• in the event that the data packets arrive in a different order, reordering the data packets to the order in which the data packets were transmitted.