KR20080004561A - Rapid media channel changing mechanism and access network node comprising same - Google Patents

Abstract

A method is provided for enabling rapid media stream channel changes in conjunction with increasing network resource utilization efficiency. A media stream is multicast for reception by a plurality of requesting decoders. The media stream includes packets containing groups of pictures (GOPs), which are stored in a buffer of an access node. At least a portion of the packets are unicast from the access node for reception by a new requesting decoder in response to receiving from the new requesting decoder a request for reception designating a media stream identifier corresponding to the media stream. Thereafter, the media stream is multicast to the new decoder after bringing packet transmission of the unicast media stream into alignment with packet transmission of the multicast media stream.

Description

RAPID MEDIA CHANNEL CHANGING MECHANISM AND ACCESS NETWORK NODE COMPRISING SAME

Cross Reference of Related Applications

This patent application is a concurrent patent application filed on April 1, 2005, entitled “Rapid Video Channel Change Mechanism In Access Node”. Claims priority to application 60 / 667,357, the entire contents of which are incorporated herein by reference. This application is also concurrently assigned with the title "Access Node Capable of Dynamic Channel Caching" (Agent No. 139434), filed concurrently with this application. US Patent Application No. 11 / 311,081. Related to. The contents of this document are incorporated herein by reference.

The disclosure described herein relates to a communication network as a whole, and more particularly to media channel changes in a communication network. It's about the mechanism.

Standard video compression algorithms, such as the MPEG2 standard of the International Telecommunication Union's Moving Picture Experts Group and H.264 from the Video Coding Experts Group, compress video sequences known as Groups of Pictures (GOPs). Each GOP has a respective start and / or end boundary and contains video content that lasts from a few minutes to a few seconds. Video is an example streaming media in the context of the present invention, but is not the only form of streaming media. Broadly speaking, streaming media includes other forms of media, such as audio media and non-video forms of visual media.

Channel change latency is important for a satisfactory television viewing experience and other types of streaming media experiences. The conversion to a highly compressed digital video stream may take one second or more before the picture begins to be displayed. For example, the video decoder cannot begin decoding the video stream until the GOP boundary is recognized. Thus, while the GOP transmission of the previous video stream is in progress upon channel change, the decoder begins to receive a new video stream, and the video decoder waits for the next GOP boundary of that video stream before starting to decode the GOPs of the new stream. Should be.

This need to wait for the next GOP boundary increases the channel change latency by almost the "wait time" in which the next GOP boundary appears by itself. One conventional method for reducing latency is to have short GOPs, thereby making the latency relatively short. However, compressing video with short GOPs is less efficient than with long GOPs. Thus, there is a trade off between compression efficiency and channel change latency. Another conventional approach to reducing latency is to start streaming at the beginning of the GOP upon receipt of a channel change request. However, channel change requests between different viewers are not synchronous, so that each media stream can be connected to a particular decoder until another mechanism allows alignment and subsequent combining of unicast media streams to the corresponding multicast media streams. Must be unicast

Conventional approaches for media stream channel change also adversely affect network resource usage. If a unicast media stream associated with a channel change must traverse the core and aggregation networks starting from a remote source, a huge amount of traffic must be sent. In addition, since the channel change request tends to be concentrated for 1 hour and 30 minutes (ie, at program start), the amount of traffic associated with the channel change is also quite variable. Finally, depending on the channel change concurrency, and the duration of the unicasting phase with respect to the channel change request, the network resources available for rapid channel change may exceed the network resources required for the transmission of voice, video and data services.

Accordingly, a media channel change mechanism is useful and desirable that at least partially addresses the drawbacks associated with conventional approaches for changing the media channel.

Embodiments of the present invention provide a mechanism for facilitating rapid change of media channels via an access node, significantly reducing intra-company traffic. According to the present invention, the media stream change function is frequently requested and is implemented through an access node for a media stream provided through an access node. Packets containing Groups of Pictures (GOPs) for these frequently requested media streams are stored in the access node's buffer, thereby allowing at least a portion of the media stream to be unicast from the access node. Unlike conventional fast channel change techniques, which are implemented through a centralized server and correspondingly impose a huge amount of traffic across most of the associated network, incorporating a media channel change mechanism within an access node advantageously results in channel change latency. It can reduce, contributing to improving network resource utilization efficiency. By adding a quick channel change function for any channels (eg, popular channels) within the access node, the amount of traffic over the network is significantly reduced compared to conventional fast channel change techniques. Accordingly, embodiments of the present invention advantageously address one or more drawbacks associated with conventional approaches for facilitating a quick channel change function within a communication network.

In one embodiment of the present invention, a method is provided for enabling fast media stream channel changes in connection with improving network resource utilization efficiency. Packets containing one or more GOPs of the media stream are stored in a buffer of the access node. A request to receive the media stream is received from the decoder. At least some of the packets are unicast from the access node for reception by the decoder.

In another embodiment of the present invention, a method is provided for enabling fast media stream channel changes in connection with improving network resource utilization efficiency. The media stream is multicast for reception by a plurality of request decoders, and packets containing one or more Groups of Pictures (GOPs) of the media stream are stored in a buffer of an access node. At least some of the packets are unicast from the access node for receipt by the new request decoder in response to receiving a receive request from the new request decoder that specifies a media stream identifier corresponding to the media stream.

In another embodiment of the present invention, the access network element is at least one data processing device, a buffer connected to the data processing device, a memory connected to the data processing device, and accessible from and capable of being processed by the data processing device. Contains instructions. The instructions include at least a portion of the packets from the access node for receipt by the decoder in response to the data processing device storing the packets of the media stream in a buffer, receiving a request to receive the media stream from the decoder, and receiving the request. Configured to facilitate unicast.

Turning now to certain aspects of the invention, in at least one embodiment, the information is evaluated in which a determination is made to store the packets of the media stream in a buffer, in response to the information indicating that the packets of the media stream should be stored in the buffer. Thus, an operation is performed in which packets of the media stream are stored.

In at least one embodiment of the present invention, the information for determining whether the packets of the media stream stored in the buffer correspond to the designated media stream identifier in the request to receive is evaluated so that at least some of the packets of the media stream stored in the buffer are evaluated. An operation is performed in which unicasting of packets of the media stream is performed in response to determining that it corresponds to the designated media stream identifier in the reception request.

In at least one embodiment of the present invention, an access node for reception by a more centrally located network element in response to determining that none of the packets of the media stream stored in the buffer correspond to the media stream identifier specified in the reception request. The operation of forwarding the receive request from the server is performed.

In at least one embodiment of the invention, the operation of multicasting the designated media stream to a new decoder after the packet transmission of the unicast media stream is aligned with the packet transmission of the multicast media stream corresponding to the unicast media stream Is performed.

In at least one embodiment of the present invention, packet transmission of unicasting is aligned with packet transmission of a corresponding media stream provided to a plurality of decoders via multicasting, and the packet transmission of unicasting is a packet of a corresponding multicast media stream. After being aligned with the transmission, unicasting of the packets is performed in such a way that the media stream is provided to the decoder via multicasting.

These and other objects, embodiments, advantages, and / or features of the present invention will become apparent upon reading the following specification, corresponding drawings, and claims.

1 illustrates an embodiment of a method for facilitating a quick media channel change function in accordance with the present invention.

FIG. 2 illustrates one embodiment of an access network mode configured to perform a method for facilitating a quick media channel change function shown in FIG.

1 shows one embodiment of a method according to the invention, referred to herein as method 100. The method 100 is performed by an access node of an access network and facilitates rapid media stream channel change through the channel change function that the access node has. Television channels are a preferred embodiment of such media stream channels. In this case, the method 100 advantageously reduces channel change latency and contributes to improved network resource utilization efficiency, thereby eliminating one or more drawbacks associated with conventional approaches for changing media channels in a communication network.

The method 100 begins with an operation 102 of receiving a multicast media stream, such as, for example, a multicast video stream. Media streams include streams of packet groups referred to in the art as Groups of Pictures (GOPs). In response to receiving the media stream, an operation 104 of evaluating storage determination information is performed wherein a determination is made as to whether to store the packets of the media stream in a buffer of the access node, and at the same time receiving downstream receivers of the access node. An operation 106 is performed to forward the multicast media stream (ie, packets of the media stream) to the. For clarity, it should be understood that what is evaluated is whether to store all received packets of the media stream in time as they are received, and what is not evaluated is whether to store selected packets of the media stream. Examples of such storage decision information include a static configuration indicating that packets of a particular media stream should be stored, a specific number of requests to receive a media stream received at an access node within a particular time period, the video stream currently being viewed. The number of recipients, viewership history information of the media stream, and the like. Although described herein that the media stream can be statically selected or dynamically determined due to factors such as popularity, for example, the present invention also provides specific means for facilitating such selection and / or determination. State that it is not limited to

In response to evaluating the storage determination information indicating that the packets of the media stream should be stored in the buffer, an operation 108 is performed to store the packets of the media stream in the buffer of the access node. The storage operation 108 includes continuously storing packets of the most recently received media stream at the access node in a buffer. Thus, at any point in time while the media stream is multicast, the most recently received GOPs of the media stream can be utilized for retrieval so that the quick media channel change function according to the present invention can be performed.

In one embodiment, the storage of packets corresponding to the most recent few seconds of the media stream is sufficient to enable the media channel change function according to the present invention. The buffer according to the invention can be thought of functionally as a delay line or circular buffer. The delay line provides the ability to introduce the calculated delay into the transmission of the signal. The circular buffer provides the ability to hold data written in one process and read in another process. In these cases, separate read and write pointers are used that are not allowed to cross each other so that unread data cannot be overwritten with new data. When the circular buffer is filled, writing of new data at the head of the buffer begins.

Since most viewers spend most of their time watching mainly co-configured channels, storing packets of media streams at the access node for only the most popular channels provides a great benefit in terms of network resource usage. Advantageously, facilitating channel change in accordance with the present invention does not require all media stream channels available (ie stored) at the access node. The method of the present invention is configured to continuously or periodically evaluate storage decision information for determining conditions under which a media stream should be stored in a buffer. Thus, in response to evaluating the storage decision information indicating that packets of the media stream should not be stored in the buffer, the operation 104 of evaluating the storage decision information is repeated in a continuous or periodic manner.

It is described herein that the fast media channel change function according to the present invention is not limited to one media stream. Within a single access node, the fast media channel change function according to the present invention can be facilitated for multiple media channels. A single buffer may be suitably configured and / or used to facilitate this quick media channel change function, or alternatively, a plurality of buffers may be suitably configured and / or used to facilitate this quick media channel change function. .

Referring back to FIG. 1, an operation 110 of receiving a request for receiving a media stream from a request decoder (eg, a decoder of a subscriber set top box STB) is performed. The receive request is transmitted from the request decoder upstream to the request decoder for receipt by a network element configured for delivery of the designated media stream on demand and capable of facilitating delivery. The reception request includes a media stream identifier such as a channel identifier, a media stream title identifier, a media stream reference number identifier, and the like. In response to receiving the receive request, an operation 112 is performed to evaluate information for determining whether packets of the media stream stored in the buffer correspond to a media stream identifier specified in the receive request. In response to determining that at least some of the packets of the media stream stored in the buffer correspond to the specified media stream identifier upon receipt request, an operation 114 is performed to unicast the packets of the media stream for receipt by the request decoder. Unicasting of packets of the media stream involves retrieving packets from the buffer and, at the process being received, begins at the GOP boundary of the most recent GOP stored in the buffer. It is described herein that a complete GOP need not be present in the buffer at the time unicasting starts. This buffering function can be achieved through the use of circular buffers or delay lines. In this manner, the same media content multicasted via operation 106 is provided to the request decoder by operation 114 for unicasting packets of the media stream.

A more centrally located network element (i.e., closer to the core of the access network or within the aggregation network) in response to determining that none of the packets of the media stream stored in the buffer correspond to the media stream identifier specified upon receipt request. An operation 116 is performed to forward the receive request from the access node for receipt by the. Optionally, the set top box may know which server is responsible for which streams. Thus, the access node does not need to forward receive requests to other servers or does not receive a request for a stream that it does not want to transmit. In accordance with this optional feature, operation 116 is omitted.

Unicasting consumes unnecessary network resources when the media stream is multicast simultaneously to other decoders. Thus, unlike one or more decoders that receive the media stream via separate unicasts, it receives a particular media stream from a source providing the media stream via an access node to receive such media stream exclusively via a single multicast. Is advantageous for all decoders. Thus, operation 118 is performed to perform unicasting such that the packet transmission of unicasting is aligned with the packet transmission of the media stream being multicasted (ie, the stream multicasted through the same access node). After the packet transmission of the unicast media stream is aligned in time with the packet transmission of the corresponding multicast media stream, an operation 120 of providing the media stream to the request decoder via the multicast video stream is then performed. An operation 122 of terminating unicasting of packets is performed.

This sorting can be achieved by sending the unicast stream faster than real time. However, this method is practiced by consuming insufficient DSL bandwidth capacity. Alignment can also be achieved by rationally discarding packets with minor damage to the reconstructed video so that the temporal alignment of the unicast media streams can be aligned with the temporal alignment of the multicast streams. For example, B-frames generally make up about half of the frames in a GOP, so there is little visual recognition of the absence of frames.

According to the present invention, the delay between multicasting the media stream and unicasting the video stream can be passed from the access node to the request decoder by transmitting the unicast stream faster than real time. Through the real-time faster unicast stream transmission, the buffering device of the request decoder can serve as a delay device. If the transmission of the unicast media stream at the access node is aligned in time with the transmission of the multimedia stream at the access node, the requesting device starts receiving media via multicasting, and the unicasting of the media stream is terminated. Since the media stream is output at real time speed during playback, playback by the request decoder is delayed in time compared to playback on decoders that started receiving the media stream faster through multicasting. Thus, the displayed pictures output through the request decoder will be delayed in time compared to decoders that started receiving media streams faster through multicasting.

In view of the disclosure described herein, those skilled in the art will appreciate that the content displayed from the request decoder may have a faster time, the same time, or a later time than other decoders receiving the same media stream. For other decoders the specific temporal relationship of the displayed content depends on when each channel change is required with respect to the time of the most recent GOP boundary. For example, the first decoder may require a channel where the GOP boundary was most of the GOP in the past, while the second decoder may require a channel where the GOP boundary has just occurred, so the first decoder will be delayed compared to the second decoder. .

Also, if there is sufficient bandwidth between the access node and the decoder, unicasting through the buffer can be used indefinitely. This is not possible in the case of a fast channel change method deployed at a more central point of the network. However, it is fully possible through the implementation of the quick channel change function according to the present invention.

2 illustrates one embodiment of an access network node (ie, access node) in accordance with the present invention, referred to herein as access network node 200. As discussed in more detail below, the access network node 200 is configured to perform a quick channel change function in accordance with the present invention. For example, the access network node 200 is suitably configured to perform the method 100 described above with reference to FIG.

The access node 200 includes a data processing unit 205, a buffer 210, a memory 215, a network to network interface 220 and a customer premise equipment (CPE) to network interface 223. . Data processing unit 205, buffer 210, memory 215, network to network interface 200, and CPE to network interface 223 are interconnected for conversation between them. Network-to-network interface 220 receives packets of the media stream from the upstream source, and CPE-to-network interface 223 transmits packets of the media stream for reception via the downstream customer premise device.

The memory 210 has, among other functions, instructions 225 for performing a quick media channel change function in accordance with the present invention. The instructions 225 are accessible from within the memory 215 and are processable through the data processing device 205. The instructions 215 cause the data processing apparatus to store the packets of the media stream in the buffer 210, receive a request to receive the media stream from the decoder, and receive the reception by the decoder in response to receiving the receive request. To facilitate unicasting at least some of the packets from the access network node. Transmit operations, such as multicasting, unicasting, receiving and forwarding receive requests, are facilitated via network interface 220.

In the foregoing detailed description, reference is made to the accompanying drawings, which form a part hereof, and which illustrate certain embodiments in which the invention may be practiced. These embodiments and any variations thereof have been described in sufficient detail to enable those skilled in the art to practice the embodiments of the present invention. It is to be understood that other suitable embodiments may be utilized and that logical, mechanical, chemical and electrical changes may be made without departing from the spirit or scope of the disclosure of the present invention. In order to avoid unnecessary explanation, in the detailed description, any information known to those skilled in the art is omitted. Thus, the foregoing detailed description is not intended to be limited to the particular forms disclosed herein, but on the contrary is intended to cover alternatives, modifications, and equivalents as may be reasonably included within the spirit and scope of the appended claims.

Claims (20)

Storing the packets of the media stream in a buffer of the access node; Receiving a request to receive the media stream from a decoder; And Unicasting at least some of the packets of the media stream from the access node for reception by the decoder in response to receiving the reception request. How to include. The method of claim 1, Evaluating information for which a determination is made to store packets of the media stream in the buffer, wherein the storage is performed in response to the information indicating that packets of the media stream should be stored in the buffer. Way. The method of claim 1, Evaluating information for determining whether packets of the media stream stored in the buffer correspond to a media stream identifier specified in the reception request, wherein the unicasting is performed by at least a portion of the packets of the media stream stored in the buffer. And responsive to determining that it corresponds to the media stream identifier specified in the receipt request. The method of claim 3, The reception request from the access node for reception by a more centrally located network element in response to determining that none of the packets of the media stream stored in the buffer correspond to the media stream identifier specified in the reception request. The method further comprises the step of forwarding. The method of claim 3, Evaluating information for which a determination is made to store packets of the media stream in the buffer, wherein the storage is performed in response to the information indicating that packets of the media stream should be stored in the buffer. Way. The method of claim 1, Performing the unicasting such that the packet transmission of the unicasting is aligned with the packet transmission of a corresponding media stream provided to a plurality of other decoders via multicasting; And Providing the media stream to the decoder via the multicasting after the packet transmission of the unicasting is aligned with the packet transmission of the corresponding media stream. The method of claim 6, Evaluating information for which a decision is made to store packets of the media stream in the buffer, wherein the storage is performed in response to the information indicating that packets of the media stream should be stored in the buffer; Evaluating information for determining whether packets of the media stream stored in the buffer correspond to a media stream identifier specified in the reception request, wherein the unicasting is performed by at least a portion of the packets of the media stream stored in the buffer. Performed in response to determining that it corresponds to the media stream identifier specified in the reception request; And The reception request from the access node for reception by a more centrally located network element in response to determining that none of the packets of the media stream stored in the buffer correspond to the media stream identifier specified in the reception request. The method further comprises the step of forwarding. Multicasting the media stream for reception by a plurality of request decoders; Storing packets of the media stream in a buffer of an access node; And Unicasting at least some of the packets of the media stream from the access node for reception by the new request decoder in response to receiving a receive request from the new request decoder that specifies a media stream identifier corresponding to the media stream. How to include. The method of claim 8, After the packet transmission of the unicasting is aligned with the packet transmission of the multicasting, providing the media stream to the new decoder via the multicasting. The method of claim 8, Evaluating information for which a determination is made to store packets of the media stream in the buffer, wherein the storage is performed in response to the information indicating that packets of the media stream should be stored in a buffer. . The method of claim 8, Evaluating information for determining whether packets of the media stream stored in the buffer correspond to a media stream identifier specified in the reception request, wherein the unicasting is performed by at least a portion of the packets of the media stream stored in the buffer. And responsive to determining that it corresponds to the media stream identifier specified in the receipt request. The method of claim 11, The reception request from the access node for reception by a more centrally located network element in response to determining that none of the packets of the media stream stored in the buffer correspond to the media stream identifier specified in the reception request. Further comprising the step of forwarding The method of claim 11, Evaluating information for which a determination is made to store packets of the media stream in the buffer, wherein the storage is performed in response to the information indicating that packets of the media stream should be stored in a buffer. . As an access network element, At least one data processing device; A buffer connected to the at least one data processing apparatus; A memory connected to the at least one data processing apparatus; And Instructions accessible from the memory and processable by the at least one data processing apparatus, the instructions comprising: the at least one data processing apparatus; Storing the packets of the media stream in the buffer, Receive a request to receive the media stream from a decoder, Be configured to facilitate unicasting at least some of the packets of the media stream from the access node for receipt by the decoder in response to receiving the receipt request. Access network element comprising a. The method of claim 14, The instructions are further configured to facilitate the at least one data processing apparatus to evaluate information on which a determination is made to store packets of the media stream in the buffer, And said storing is performed in response to said information indicating that packets of said media stream should be stored in said buffer. The method of claim 14, The instructions are further configured to facilitate the at least one data processing apparatus to determine whether packets of the media stream stored in the buffer correspond to a media stream identifier specified in the reception request, And the unicasting is performed in response to determining that at least some of the packets of the media stream stored in the buffer correspond to the media stream identifier specified in the reception request. The method of claim 16, The instructions further comprise a more centrally located network in response to the at least one data processing device determining that none of the packets of the media stream stored in the buffer correspond to the media stream identifier specified in the reception request. And further configured to facilitate forwarding the receive request from the access node for receipt by the element. The method of claim 16, The instructions are further configured to facilitate the at least one data processing apparatus to evaluate information on which a determination is made to store packets of the media stream in the buffer, And said storing is performed in response to said information indicating that packets of said media stream should be stored in said buffer. The method of claim 14, The instructions, the at least one data processing device, Perform the unicasting so that the packet transmission of the unicasting is aligned with the packet transmission of the corresponding media stream provided to a plurality of other decoders via multicasting, And cause the packet transmission of the unicasting to be aligned with the packet transmission of the corresponding media stream, and then facilitate providing the media stream to the decoder via the multicasting. The method of claim 19, The instructions are further configured to facilitate the at least one data processing apparatus to evaluate information on which a determination is made to store packets of the media stream in the buffer, The storage is performed in response to the information indicating that packets of the media stream should be stored in a buffer, The instructions are further configured to facilitate the at least one data processing apparatus to determine whether packets of the media stream stored in the buffer correspond to a media stream identifier specified in the reception request, The unicasting is performed in response to determining that at least some of the packets of the media stream stored in the buffer correspond to the media stream identifier specified in the reception request, The instructions further comprise a more centrally located network element in response to the at least one data processing device determining that none of the packets of the media stream stored in the buffer correspond to the media stream identifier specified in the reception request. And further facilitate facilitating forwarding of the receive request from the access node for receipt by the.

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