Hai Gopal,
I think u have no knowledge about how an remote of a TV work. In a remote control all keys are assigned some format of data. whenever u press a key these pattern of data are transmitted from IR transmitter. Each pattern will have its own start and stop formats and levels( high or low). The exact start/ stop format and level can be found in any remote controller IC datasheet.

And now coming to ur doubt about continues key. Each remote controller will what is known as contunuous key press code.
This continues key press code will be following the data code of the key pressed. So if say u have pressed `VOL+` key continuously on a TV remote controller, the remote controller will first send data corresponding to `VOL+` and then the continuous key press code.
By detecting the Key code and Coninuous key press code u can assertain the key which is pressed continuously.
I think with this ur doubt is clear ??.

Good luck
-sathish