Patent ID: 7321720
Filing Date: 2008-01-22
Classification: G11B

Abstract:
1. Method for preliminarily erasing a part or parts of a bitstream recorded, or to be recorded, on a storage medium, wherein: the recorded bitstream is formatted into stream object units each containing at least one application data packet with a corresponding application time stamp or one stuffing data packet or both, of which stream object units one or more form a cell, wherein each succeeding stuffing data packet also has an application time stamp; bitstream parts can be marked as being preliminarily erased cells denoted TE cells; following marking TE cells, such TE cells can be either permanently erased or completely reconstructed; the start and the end of a cell are defined by a cell start time value and a cell end time value; the start and the end of a re-usable part of a TE cell are defined by a TE cell start time value and a TE cell end time value; said cell and TE cell start and end time values are stored in a separate memory allowing fast access, wherein in case a TE cell includes at least one boundary between succeeding stream object units and one of said succeeding stream object units includes at least one application data packet and another one of said succeeding stream object units includes at least one stuffing data packet, involved ones and further adjacent stream object units containing only stuffing data packets are included in said TE cell even if said TE cell would thereby overlap with one or two adjacent TE cells, wherein the corresponding ones of said time values of a current TE cell are selected as follows: the cell start time value corresponds to the application time stamp of the first application packet of said current TE cell; the cell end time value corresponds to the application time stamp of the last application packet of said current TE cell; if the start recording packet arrival time value of said current TE cell describes the start of a stream object unit, or the TE cell contains the start of the stream object, then the TE cell start time value corresponds to the application time stamp of the first application packet or stuffing packet starting in that stream object unit which contains the application packet or stuffing packet with the start recording packet arrival time of said current TE cell, otherwise the TE cell start time value corresponds to the application time stamp of the first application packet or stuffing packet starting in that stream object unit which follows immediately the stream object unit containing the application packet with the corresponding recording packet arrival time value cell start time value; the TE cell end time value corresponds to the first application time stamp of the first stream object unit following said current TE cell.