TWO TIER MULTIPLE SLIDING WINDOW MECHANISM FOR MULTIDESTINATION MEDIA APPLICATIONS

• US 20130028263A1
• Filed: 07/28/2012
• Published: 01/31/2013
• Est. Priority Date: 07/29/2011
• Status: Active Grant

• Current Assignee: Roku, Inc.
• Original Assignee: Blackfire Research Corporation
• Inventors: RAJAPAKSE, Ravi U.
• Granted Patent: US 8,837,488 B2
• Time in Patent Office: Days
• US Class Current: 370/394
• CPC Class Codes: H04L 1/08 by repeating transmission, e.g. Verdan system H04L1/1858 and H04L1/189 take precedence
• CPC Class Codes: H04L 43/0829 Packet loss
• CPC Class Codes: H04L 45/586 of virtual routers
• 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 65/613 for the control of the source by the destination control signals issued by the client directed to the server or network components specially adapted for selective content distribution H04N21/637
• 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 65/75 Media network packet handling
• CPC Class Codes: H04L 65/752 adapting media to network capabilities
• CPC Class Codes: H04L 65/80 Responding to QoS
• CPC Class Codes: H04L 67/108 characterised by resources being split in blocks or fragments
• CPC Class Codes: H04L 67/1095 Replication or mirroring of data, e.g. scheduling or transport for data synchronisation between network nodes
• CPC Class Codes: H04L 69/163 In-band adaptation of TCP data exchange; In-band control procedures
• CPC Class Codes: H04L 69/166 IP fragmentation; TCP segmentation
• CPC Class Codes: H04L 69/324 in the data link layer [OSI layer 2], e.g. HDLC
• CPC Class Codes: H04N 13/161 Encoding, multiplexing or demultiplexing different image signal components for multi-view video sequence encoding H04N19/597
• CPC Class Codes: H04N 13/194 Transmission of image signals
• CPC Class Codes: H04N 21/20 Servers specifically adapted for the distribution of content, e.g. VOD servers; Operations thereof
• 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 21/40 Client devices specifically adapted for the reception of or interaction with content, e.g. set-top-box [STB]; Operations thereof
• CPC Class Codes: H04N 21/438 Interfacing the downstream path of the transmission network originating from a server, e.g. retrieving encoded video stream packets from an IP network

Abstract

Some media applications use media that contains multiple types of media components in it and media sources with access to this media must send each type of media component to one or more media rendering destination devices. Furthermore there may be multiple destinations that can receive a particular type of media component and the media must be received at each destination without losses. This invention describes a two tier packet buffer structure at the media source with primary and virtual packet buffers that ensures minimal memory use at the media source and minimal network use. Furthermore the use of a sliding window with each virtual packet buffer associated with each destination, independently keeps control and track of destination state, ensuring the correct receipt of media data at each destination.

Claims

1. A system for sending media over an IP network to media rendering devices, comprising:

An internet protocol communication network;

a first plurality of one or more first media rendering devices that take a first media data type having a means for communication with said communication network;

a second plurality of zero or more second media rendering devices that take other media data types that are different from the said first media data type and having a means for communication with said communication network;

a media source that has a means for communication with said communication network and access to media containing media data of said first media data type and said other media data type and said media data being grouped into packets of data where each packet has a set of media data, a reference counter field and a unique sequentially incrementing packet sequence number field; and

said media source having a primary packet buffer for data packets of said first media data type and a plurality of one or more first virtual packet buffers that can hold references to packets of said first media data type and each said virtual packet buffer being associated with only one of each said first media rendering devices; and

a packet of the said first media data type being put in the said first primary packet buffer and a reference to this said packet being placed in each said first virtual packet buffers and the said references counter field of the said packet being set to the number of said first virtual packet buffers that have a reference to this said packet and

sending a packet in the said first virtual packet buffer to a said first media rendering device.

2. The system of claim 1 in which the said media source receives from a said first media rendering device a received number that is the highest consecutive packet sequence number field in said packets it has received and;

the said media source removing references to all packets with a sequence number that are lower than and equal to the said received number from the virtual packet buffer associated with the said media rendering device and decrementing the said reference number field in each packet removed from the said virtual packet buffer.

3. The system of claim 1 in which each said virtual packet buffer in the said media source maintains a first packet index, referencing the first packet in the said virtual packet buffer and maintains a next packet index referencing the next packet in the said virtual packet buffer that may be sent to the said first media rendering devices associated with the said virtual packet buffer and

sending the packet referenced by the said next packet index to the said first media rendering devices and incrementing this said next packet index after sending the said packet.

4. The system of claim 3 that for each said virtual packet buffer, will not send the packet reference by the said next packet index if the size of the difference between the said next packet index and the said first packet index is larger than a window threshold.

5. The system of claim 1 wherein said primary packet buffer hold a reference to the packet data.