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timestamp (TS)

In general, a timestamp (TS) is information that represents a trusted indication. It represents a time information with date and time and is added as an addition to a document when it is generated or received. For example, digital signatures add a timestamp to the document.

  1. Timestamps come in a variety of file formats. A widely used format for date and time consists of four digits for the year, two for the month and day, and two each for the hours, minutes, seconds, and milliseconds: YYYY/MM/DD/ hh:mm:ss:ms.

  2. The Signature Act (SiG) defines a time stamp as follows: For the purposes of this Act, a time stamp is a digital attestation by a certification authority, provided with a digital signature, that it has received certain digital data at a certain point in time.

  3. In the data streams of digital TV, the Program Clock Reference (PCR) is transmitted as a time stamp from which the decoders derive their time reference and the playback time for the respective data packet.

  4. In the Precision Time Protocol (PTP), a time server distributes the reference time by means of time stamps to the subordinate clocks, which are evaluated by them after receiving it.

  5. In various IP-based protocols such as the Realtime Transport Protocol (RTP), there is a data field for the time stamp (TS) in the header. This data field is used to synchronize audio or video. The time stamp for the synchronization of real-time capable services is entered in the Timestamp (TS) data field, which comprises 4 octets.

  6. In ATM, time stamping is used to determine the cell transfer delay (CTD) on a connection. Time Stamping is done using OAM cells, Operation, Administration, and Maintenance (OAM), and is used to compare the time between an incoming and outgoing cell.

  7. In MPEG-2, there are two time stamps that are inserted into the Program Stream (PS) and the Packetized Elementary Stream (PES), respectively. There is the Decode Timestamp (DTS), which defines the start of decoding, and the Presentation Time Stamp (PTS), which defines the start of presentation.

  8. There are also timestamps in log files with which the individual events are marked in detail with date and time, start and end of the event, an identification of the event etc..

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Englisch: timestamp - TS
Updated at: 10.09.2019
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