Splicing compressed packetized digital video streams
US5917830A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 18, 1996 |
| Grant date | Jun 29, 1999 |
| Priority date | — |
| Expiry date | Oct 18, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N21/812
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A secondary packetized data stream, such as a commercial, is spliced with a primary packetized data stream, such as a network television program. The system does not require decompression of the data in the primary data stream, and is particularly suitable for use at a cable system headend to allow the insertion of commercials from local businesses into a nationally broadcast television program. When a start signal is received, a pre-splicing packet of the primary stream is determined. The pre-splicing packet is the packet closest to the start time which carries an anchor frame (e.g., I or P frame) start code. To prevent a potential discontinuity at the decoder, the pre-splicing packet is processed to discard the anchor frame data, and to insert a number of stuffing bytes which is equal to the number of bytes discarded into an adaptation field of the pre-splicing packet. To further maintain continuity at the decoder, identifying data of the primary stream such as PID and PSI data, is retrieved and provided to the secondary stream. A number of null packets are inserted into the output stream at the transition point between the main program and the commercial to prevent a buffer over…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.