Video remultiplexer for dynamic remultiplexing, multi-mode operation and jitter reduced asynchronous communication

• US 20040136409A1
• Filed: 11/03/2003
• Published: 07/15/2004
• Est. Priority Date: 01/14/1998
• Status: Active Grant

• Current Assignee: Regis Gratacap, Robert Robinett, William Slattery
• Original Assignee: Regis Gratacap, Robert Robinett, William Slattery
• Inventors: Slattery, William, Robinett, Robert, Gratacap, Regis
• Granted Patent: US 7,693,188 B2
• Time in Patent Office: Days
• US Class Current: 370/535
• CPC Class Codes: H04N 21/23424 involving splicing one content stream with another content stream, e.g. for inserting or substituting an advertisement
• CPC Class Codes: H04N 21/23608 Remultiplexing multiplex streams, e.g. involving modifying time stamps or remapping the packet identifiers
• CPC Class Codes: H04N 21/63345 by transmitting keys key distribution for secret or secure communication H04L9/08; network support of key management H04L63/06
• CPC Class Codes: H04N 21/8547 involving timestamps for synchronizing content

Abstract

A method and system are provided for remultiplexing program bearing data. The remultiplexing method and system are applicable to MPEG-2 compliant transport streams carrying video programs. A descriptor based system is used for scheduling the timely output of transport packets wherein each descriptor records a dispatch time as well as a receipt time for each transport packet. The receipt time is used for estimating program clock reference adjustments, but final program clock reference adjustment is performed in hardware in relation to the precise output timing of each transport packets. A descriptor and transport packet caching technique is used for decoupling the synchronous receipt and transmission of transport packets from any asynchronous processing performed thereon. The descriptors can also be used for managing scrambling and descrambling control words (encryption and decryption keys). Remultiplexing functions may be distributed across a network. The remultiplexer can furthermore optimize the bandwidth of transport streams by replacing null transport packets with transport packet data to be inserted into the output transport stream. Program data transmitted via asynchronous communication links is re-timed and assistance is provided for outputting program data on such asynchronous communication links to reduce a variation in end-to-end delay incurred by the program data. Remultiplexing and program specific information can be seamlessly dynamically varied without stopping, or introducing a discontinuity in, the flow-of outputted transport packets. A technique is also provided for locking multiple internal reference clock generators.

Claims

1. A method for remultiplexing one or more bit streams containing compressed program data in an asynchronous communications network comprising plural nodes interconnected by one or more communication links comprising the steps of:

(a) receiving, from one of said communication links at a destination node of said asynchronous communications network, a first bit stream containing data of one or more programs, said first bit stream having one or more predetermined bit rates for portions thereof,

(b) choosing at least part of said received first bit stream for transmission, and

(c) scheduling transmission of said chosen part of said first bitstream so as to output said chosen part of said first bit stream in a transport stream at a rate depending on said predetermined rate of said chosen part of said first bit stream.

2. At multiple nodes of a communication network, a method for remultiplexing one or more portions of bit streams into one or more transport streams containing compressed video program data comprising the steps of:

(a) enabling communication amongst a plurality of nodes connected to a shared communication medium by one or more respective communication links,

(b) selecting a first set of one or more of said nodes for transmitting one or more bit streams onto said shared communications medium,

(c) selecting a second set of one or more of said nodes for receiving said transmitted bit streams from said shared communications medium, for selecting portions of said transmitted bit streams and for transmitting one or more remultiplexed transport streams as a bit stream containing said selected portions, each of said remultiplexed transport streams transmitted as a bit stream being different than said received ones of said transmitted bit streams, and

(d) causing said selected nodes to communicate said bit streams via said shared communication medium according one of plural different signal flow patterns, including at least one signal flow pattern that is different from a topological connection of said nodes to said shared communication medium.

3. The method of claim 2 wherein at least one node can receive bit streams from each of plural other ones of said nodes via a single one of said respective communication links, said method further comprising the step of selecting a subset of said plural other nodes and receiving bit streams at said at least one node from only said selected subset of nodes.

4. The method of claim 2 wherein at least one node receives bit streams from plural other ones of said nodes via a single one of said respective communication links.

5. A network distributed remultiplexer for remultiplexing one or more bit streams containing compressed program data comprising:

one or more communication links, and

a plurality of nodes, interconnected by said one or more communication links into a communications network, said plurality of nodes including a destination node receiving a first bit stream containing data of one or more programs via one of said communications links, said first bit stream having one or more predetermined bit rates for portions thereof, said destination node comprising;

a processor for choosing at least part of said received first bit stream for transmission, and for scheduling transmission of said chosen part of said first bit stream so as to output said chosen part of said first bit stream in a transport stream at a rate depending on said predetermined rate of said chosen part of said first bit stream.

6. A network distributed remultiplexer for remultiplexing one or more portions of bit streams into one or more transport streams containing compressed video program data comprising:

a shared communication medium comprising one or more communication links,

a plurality of nodes, each of said nodes being connected to said shared communication medium by a respective one or more of said communication links, said plurality of nodes including;

a first set of one or more of said nodes for transmitting one or more bit streams onto said shared communications medium,

a second set of one or more of said nodes for receiving said transmitted bit streams from said shared communications medium, for selecting portions of said transmitted bit streams and for transmitting one or more remultiplexed transport streams as a bit stream containing said selected portions, each of said remultiplexed transport streams transmitted as a bit stream being different than said received ones of said transmitted bit streams, and

a controller node for selecting said first and second sets of nodes and for causing said selected nodes to communicate said bit streams via said shared communication medium according one of plural different signal flow patterns, including at least one signal flow pattern that is different from a topological connection of said nodes to said shared communication medium.

7. The network distributed remultiplexer of claim 6 wherein said plurality of nodes further comprises at least one node that can receive bit streams from each of plural other ones of said nodes via a single one of said respective communication links, said controller node selecting a subset of said plural other nodes and said at least one node receiving bit streams from only said selected subset of nodes.

8. The network distributed remultiplexer of claim 6 wherein said plurality of nodes comprises at least one node that receives bit streams from plural other ones of said nodes via a single one of said respective communication links.