SELF-DESCRIBING ERROR CORRECTION OF CONSOLIDATED MEDIA CONTENT

• US 20170093522A1
• Filed: 12/12/2016
• Published: 03/30/2017
• Est. Priority Date: 11/03/2014
• Status: Active Application

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Bright-Thomas, Paul G., Hakonsen, Greg, Sandbakken, Geir, Prior, William Geoffrey, Caramma, Marcello, Ramalho, Michael A.
• Granted Patent: US 10,263,732 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 11/10 Adding special bits or symbols to the coded information, e.g. parity check, casting out 9's or 11's
• CPC Class Codes: H04L 1/0009 by adapting the channel coding H04L1/1812 takes precedence
• CPC Class Codes: H04L 1/0041 Arrangements at the transmitter end
• CPC Class Codes: H04L 1/0042 Encoding specially adapted to other signal generation operation, e.g. in order to reduce transmit distortions, jitter, or to improve signal shape H04L1/0067 takes precedence
• CPC Class Codes: H04L 1/0045 Arrangements at the receiver end
• CPC Class Codes: H04L 1/0057 Block codes H04L1/0061, H04L1/0064 take precedence
• CPC Class Codes: H04L 1/0076 Distributed coding, e.g. network coding, involving channel coding coding in both space and time H04L1/0618; cooperative diversity H04B7/022
• CPC Class Codes: H04L 1/0083 Formatting with frames or packets; Protocol or part of protocol for error control
• CPC Class Codes: H04L 1/009 arrangements specific to transmitters
• CPC Class Codes: H04L 1/0091 arrangements specific to receivers, e.g. format detection detection of data rate H04L25/0262; detection of coding rate H04L1/0046
• CPC Class Codes: H04L 2001/0092 Error control systems characterised by the topology of the transmission link
• CPC Class Codes: H04L 2001/0093 Point-to-multipoint
• CPC Class Codes: H04L 65/00 Network arrangements, protocols or services for supporting real-time applications in data packet communication real-time or near real-time messaging, e.g. instant messaging [IM] H04L51/04; selective video distribution H04N21/00
• CPC Class Codes: H04L 65/403 Arrangements for multi-party communication, e.g. for conferences data switching systems for conference H04L12/18; arrangements for connecting several subscribers to a common circuit, i.e. affording conference facilities H04M3/56; television conferencing systems H04N7/15
• CPC Class Codes: H04L 65/611 for multicast or broadcast systems for broadcast or conference H04L12/18; arrangements for broadcast or distribution combined with broadcast H04H20/00; arrangements for broadcast applications with a direct linkage to broadcast information or to broadcast space-time H04H60/00; selective distribution of broadcast services, e.g. multimedia broadcast multicast service [MBMS], H04W4/06
• CPC Class Codes: H04L 65/65 Network streaming protocols, e.g. real-time transport protocol [RTP] or real-time control protocol [RTCP]
• CPC Class Codes: H04L 65/70 Media network packetisation
• CPC Class Codes: H04L 7/04 Speed or phase control by synchronisation signals H04L7/0075 takes precedence
• CPC Class Codes: H04N 21/238 Interfacing the downstream path of the transmission network, e.g. adapting the transmission rate of a video stream to network bandwidth; Processing of multiplex streams hybrid fiber coaxial [HFC] networks for downstream channel allocation for video distribution H04L12/2801; flow control in packet networks H04L47/10; real-time communication protocols in data switching networks H04L65/00; scheduling or organising the servicing of application requests H04L67/60
• CPC Class Codes: H04N 21/6437 Real-time Transport Protocol [RTP]
• CPC Class Codes: H04N 7/152 : Multipoint control units therefor

Abstract

Presented herein are downstream recovery (error correction) techniques for an aggregated/consolidated media stream. In one example, a consolidated media stream that includes source media packets from one or more sources is sent to one or more downstream receiving devices. Based on the source media packets, one or more self-describing recovery packets for downstream error correction of the source media packets are generated. The self-describing recovery packets include a mapping to the source media packets used to generate the self-describing recovery packets, thereby avoiding the addition of error correction information in the consolidated media stream. The one or more self-describing recovery packets are sent to each of the downstream receiving devices as a separate stream.

Claims

1. A method comprising:

obtaining a plurality of source media streams, wherein each source media stream comprises one or more source media packets from one of a plurality of endpoint devices;

sending, to at least one downstream receiving device, a consolidated media stream that includes the source media packets from the plurality of source media streams and no error correction overhead;

generating, based on the source media packets, one or more self-describing recovery packets for downstream error correction of the source media packets, wherein the self-describing recovery packets include a mapping to the source media packets used to generate the self-describing recovery packets to avoid the addition of error correction overhead to the source packets of the consolidated media stream; and

sending the one or more self-describing recovery packets to the downstream receiving device.

2. The method of claim 1, wherein generating the one or more self-describing recovery packets for downstream error correction of the source media packets comprises:

composing a source block that includes the source media packets as source symbols;

generating one or more recovery source block headers that describe the composition of the source block; and

generating recovery symbols for the source media packets.

3. The method of claim 2, wherein the consolidated media stream sent to the downstream receiving device may be overlapping in composition with a consolidated media stream sent to an alternate downstream receiving device.

4. The method of claim 2, wherein the use and degree of recovery symbols may be dynamically configured based on distribution loss conditions between a sending device and the downstream receiving device.

5. The method of claim 2, wherein composing a source block comprises:

on a packet-by-packet basis, determining if any of the source media packets should be logically fragmented as two or more source symbols within the source block.

6. The method of claim 5, wherein determining if any of the source media packets should be logically fragmented comprises:

determining whether or not a length of a transport header for a self-describing recovery packet, when combined with the length of a recovery source block header and a maximum length of the recovery payload, exceeds a predetermined maximum packet length.

7. The method of claim 5, wherein determining if any of the source media packets should be logically fragmented comprises:

identifying a distribution for the lengths of the source media packets and correlated the size of the source symbols in the source block with the identified distribution of the source media packet lengths.

8. The method of claim 5, wherein the application of logical fragmentation to each source media packet is described by a compact map in the recovery source block header.

9. The method of claim 5, wherein the application of logical fragmentation to each source media packet is described by an ordered presentation of first and second fragments, enabling the determination of packet lengths in a split recovery process without the use of an explicit fragmentation map.

10. The method of claim 2, wherein generating the recovery symbols for the source media packets comprises:

performing forward error correction (FEC) encoding of the source media packets

11. The method of claim 2, wherein the recovery source block header includes a count of source media streams referenced in the recovery source block header and, for each referenced source media stream, a stream reference describing the source media packets from that stream that are used in the source block.

12. The method of claim 11, wherein a source media stream reference comprises a stream synchronization source identifier, a sequence number of the first packet from that source media stream referenced in this source block, and at least one of a count of contiguous packets or a bitmap which describes discontinuous packets.

13. An apparatus comprising:

one or more network interface devices;

a memory; and

a processor coupled to the memory and the network interface devices, wherein the processor is configured to;

obtain a plurality of source media packets from a plurality of end point devices,

send, to at least one downstream receiving device, a consolidated media stream that includes the source media packets from the plurality of end point devices and no error correction overhead;

generate, based on the source media packets, one or more self-describing recovery packets for downstream error correction of the source media packets, wherein the self-describing recovery packets include a mapping to the source media packets used to generate the self-describing recovery packets to avoid the addition of error correction overhead to the source packets of the consolidated media stream; and

send the one or more self-describing recovery packets to the downstream receiving device.

14. The apparatus of claim 13, wherein to generate the one or more self-describing recovery packets for downstream error correction of the source media packets, the processor is configured to:

compose a source block that includes the source media packets as source symbols;

generate one or more recovery source block headers that describe the composition of the source block; and

generate recovery symbols for the source media packets.

15. The apparatus of claim 13, wherein the recovery source block header includes a count of source media streams referenced in the recovery source block header and, for each referenced source media stream, a stream reference describing the source media packets from that stream that are used in the source block.

16. The apparatus of claim 15, wherein a source media stream reference comprises a stream synchronization source identifier, a sequence number of the first packet from that source media stream referenced in this source block, and at least one of a count of contiguous packets or a bitmap which describes discontinuous packets.

17. One or more computer readable storage media encoded with software comprising computer executable instructions and when the software is executed operable to:

obtain a plurality of source media streams, wherein each source media stream comprises one or more source media packets from one of a plurality of endpoint devices;

send, to at least one downstream receiving device, a consolidated media stream that includes the source media packets from the plurality of source media streams and no error correction overhead;

generate, based on the source media packets, one or more self-describing recovery packets for downstream error correction of the source media packets, wherein the self-describing recovery packets include a mapping to the source media packets used to generate the self-describing recovery packets to avoid the addition of error correction overhead to the source packets of the consolidated media stream; and

send the one or more self-describing recovery packets to the downstream receiving device.

18. The computer readable storage media of claim 17, wherein the instructions operable to generate the one or more self-describing recovery packets for downstream error correction of the source media packets comprise instructions operable to:

compose a source block that includes the source media packets as source symbols;

generate one or more recovery source block headers that describe the composition of the source block; and

generate recovery symbols for the source media packets.

19. The computer readable storage media of claim 17, wherein the recovery source block header includes a count of source media streams referenced in the recovery source block header and, for each referenced source media stream, a stream reference describing the source media packets from that stream that are used in the source block.

20. The computer readable storage media of claim 19, wherein a source media stream reference comprises a stream synchronization source identifier, a sequence number of the first packet from that source media stream referenced in this source block, and at least one of a count of contiguous packets or a bitmap which describes discontinuous packets.