Method for addressing a bit stream recording

摘要

In bitstream recording presentation data is organised into Video Object Units. These have a variable size but have also a variable duration. To allow access to any Video Object Unit in the bitstream a mapping list is used which is based on pieces (SOBU#n) of the bitstream of constant size per piece. The mapping list additionally contains for each of these pieces a specific delta duration (IAPAT#n) which indicates the difference between the arrival time of the first packet of a piece and the arrival time of the packet following immediately the last packet of that piece, and contains an initialisation value (IAPAT#0) which allows to have a share of equal bits between a predetermined amount of MSBs of application time stamps (ATS) and the same amont of LSBs of said delta time durations (IAPAT#n). The computation of the target SOBU address includes the following steps: accumulate the initialisation value and the delta durations until the given time value is most closely reached towards the target SOBU; the running index of this table entry multiplied by the constant piece size directly results in the address value to be accessed. <IMAGE>