WO2010115376A1 - Media stream switching method, apparatus and system - Google Patents

Abstract

The present invention relates to the field of network communications. A media stream switching method, apparatus and system are provided. The method includes: receiving and buffering messages, wherein said messages are used for bearing the media stream; obtaining the visual sensitivity of said messages; when a media stream switching request is received from a terminal, selecting the messages with high visual sensitivity from said buffered messages; rearranging the serial numbers of said messages with high visual sensitivity; and sending the messages, whose serial numbers have been rearranged, with high visual sensitivity to the terminal. With the technical scheme provided by the embodiments of the present invention, because only the messages with high visual sensitivity are sent to the terminal, the requirement of the media stream switching on the transmission bandwidth is reduced, and the number of the pushable unicast bit streams is increased. And because the serial numbers of the sent messages have been rearranged, the terminal need not request retransmission of the messages, and the problems are solved that the requirement of the media stream switching on transmission bandwidth is high, the number of the pushable unicast bit stream is limited and the duration of the push is long.

Description

 A media stream switching method, device and system The present application claims to be submitted to the Chinese Patent Office on April 10, 2009, and the application number is 200910106639. 7. The invention is entitled "A Media Stream Switching Method, Apparatus and System" Chinese Patent Priority of the application, the entire contents of which are incorporated herein by reference. The present invention relates to the field of network communications, and in particular, to a media stream switching method, apparatus, and system. BACKGROUND OF THE INVENTION Internet Protocol Television (IPTV) is becoming more and more popular, but one problem that plagues users and operators is that there is a large delay in IPTV channel switching.

 The IPTV channel switching delay is composed of multiple factors, such as: the time spent leaving the old media stream multicast group, the time consumed by adding the new media stream multicast group, and the set top box (STB) jitter buffer filling data consumption time. , waiting for the time consumed by the I frame. Among them, waiting for the I frame time is the most critical part.

IPTV, Digital Television (DTV) is generally using the Moving Picture Experts Group Compression Standard Version 2 (MPEG- 2, Moving Picture Experts Group Compression Standard Version 2), H.264/AVC (MPEG-4 Advanced Video Coding, Advanced Video Coding), video codec 1 (VC-1), audio and video coding standard (AVS, Audio Coding Standard) and other video and audio compression coding algorithms, TV pictures are encoded as internal coded frames ( A sequence of images consisting of I frames), forward predictive frames (P frames), and bidirectionally interpolated frames (B frames). The I frame is a frame completely encoded by the entire picture, and is also referred to as a complete frame or a key frame. The I frame can be independently decoded and displayed, and can also provide reference for decoding of related P frames and B frames. The P frame is a frame that is different from the previous frame. The P frame cannot be decoded and displayed independently. It must be decoded before the I frame it refers to. The B frame is a frame that encodes a difference from the previous frame and the subsequent frame. The B frame cannot be independently decoded and displayed, and must be decoded and displayed when the I frame it refers to is received in advance. Since most of the pictures are continuous, the two consecutive frames are substantially the same and the difference is small. The P frame and the B frame mainly encode inter-frame differences, and it is not necessary to encode the entire picture, and thus has higher coding efficiency than the I frame. In the broadcast TV operation, the code sequence used to obtain a higher compression ratio usually has an I frame interval of about 0.55 seconds, which forms a form such as IBBPBBPBBPBBIBBPBBP..., since the number of P frames and B frames is far more than I frame. When a user switches channels, P-frames or B-frames are encountered in most cases. However, since P-frames and B-frames must be decoded by the preceding I-frames, the received P-frames and B-frames can only be discarded. It is only possible to start decoding after waiting for the next I frame, thus causing a problem of slow speed when switching channels. H.264 has a better data compression rate. In the case of the same visual experience, the H.264 encoded video stream is about 1/2 to 1/3 of MPEG-2, so H.264 is more suitable for IPTV. Media encoding format.

 However, since a group of pictures (GOP) of H.264 has a long time, it can be set to 4 to 8 seconds according to the actual environment, so the interval between I frames is longer. When the channel is switched, the terminal needs to wait for a complete I frame to receive decoding before starting the process. The process of waiting for I may be 0 to 8 seconds, which causes the problem of slow speed when the media stream is switched.

 In an IP network, packet loss is difficult to avoid completely, and packet loss can result in a bad visual experience such as a picture screen or pause. In order to solve the problem of lost packets, the STB generally uses the lost error message retransmission technique, that is, when receiving an error message or not receiving a data message, it actively requests the server for a lost or incorrect message, and the server unicasts The terminal retransmits the message requested by the terminal.

 When the media stream is switched, the STB decoder of the terminal must buffer a complete I frame to start decoding. In order to solve the problem of the media stream switching time process introduced by the I frame waiting, the existing media stream is switched as follows:

(1) The server caches the multimedia data stream corresponding to the IPTV media stream;

 (2) When the media stream is switched, the STB initiates a session requesting a burst media code stream from the server, and the content thereof is a Real-time Transport Protocol (RTP) continuous code stream starting at the I frame;

 (3) The server pushes the RTP code stream starting from the I frame to the terminal through unicast;

 (4) The RTP code stream obtained by the terminal buffer starts to decode and display;

 (5) The terminal requests to join the media stream corresponding to the multicast group, and the multicast group code stream starts to reach the terminal;

 (6) When the terminal finds that the RTP code stream obtained from the server and the real-time multicast stream are repeated in the RTP, the terminal stops acquiring the burst media code stream from the server;

 (7) When the terminal finds a lost message, it actively requests the server to retransmit the error message.

 When the live TV is in the H.264 format, because the I frame interval is relatively long, when the end user requests media stream switching, the burst stream that the server needs to push quickly will be relatively large, so that the STB buffer has Higher requirements, the low-end STB will lose packets due to buffer overflow, affecting picture quality; media stream switching has higher requirements on transmission bandwidth, and the number of unicast streams that can be pushed under the same transmission bandwidth is limited, and push continues. The time is long.

Summary of the invention The embodiment of the invention provides a passive optical network protection method, an active/standby switching control device and a system, and can use a standby 0LT to implement backup of multiple primary OLTs. An object of the embodiments of the present invention is to provide a media stream switching method and apparatus, which solves the problem that media stream switching has high requirements on transmission bandwidth.

 The purpose of the embodiment of the present invention is achieved by the following technical solutions:

 A media stream switching method includes:

 Receiving and buffering a packet, where the packet is used to carry a media stream;

 Obtaining visual sensitivity of the message;

 When receiving the media stream switching request of the terminal, selecting a message with high visual sensitivity in the cached message; and rearranging the serial number of the message with high visual sensitivity;

 The message with high visual sensitivity that has been rearranged by the serial number is sent to the terminal.

 A media stream switching server includes: a storage module, an obtaining module, a selecting module, a programming module, and a sending module; wherein

 The storage module is configured to receive and cache a packet, where the packet is used to carry a media stream;

 The obtaining module is configured to acquire visual sensitivity of a message buffered in the storage module;

 The selecting module is configured to: when receiving the media stream switching request of the terminal, select a message with high visual sensitivity in the message buffered by the storage module;

 The orchestration module is configured to re-arrange the serial number of the message selected by the selection module;

 The sending module is configured to send a message that is re-arranged by the programming module to the terminal. A media stream switching system includes a media stream switching server and a head end; wherein

 The media stream switching server is configured to receive and cache a packet sent by the head end, where the packet is used to carry a media stream, obtain a visual sensitivity of the packet, and receive a media stream switching request of the terminal. And selecting, in the cached message, a message with high visual sensitivity, rearranging the sequence number of the message with high visual sensitivity, and re-arranging the message with high visual sensitivity after reordering the serial number. Sent to the terminal;

 The header is configured to send a packet, where the packet is used to carry a media stream.

The technical solution provided by the embodiment of the present invention, because only the message with high visual sensitivity is sent to the terminal, the requirement for the transmission bandwidth of the media stream switching is reduced, the number of pushable unicast code streams is increased, and the sent message is sent. After the serial number is re-arranged, the terminal does not need to request retransmission of the message, which solves the problem that the media stream switching has high requirements on the transmission bandwidth, the number of pushable unicast streams is limited, and the push duration is long. DRAWINGS In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings to be used in the embodiments or the description of the prior art will be briefly described below. Obviously, the drawings in the following description are only It is a certain embodiment of the present invention, and other drawings can be obtained from those skilled in the art without any inventive labor.

 1 is a flowchart of a method for switching a media stream according to an embodiment of the present invention;

 2 is a schematic diagram of continuously mapping one end of a selected packet with a larger RTP sequence number in the selected embodiment of the present invention; FIG. 3 is a block diagram of a media stream switching server according to an embodiment of the present invention;

 4 is a schematic diagram of a media stream switching system according to an embodiment of the present invention;

 FIG. 5 is a flowchart of a method for switching a media stream according to an embodiment of the present invention;

 6 is a schematic diagram of continuously mapping one end of a selected packet with a smaller RTP sequence number according to an embodiment of the present invention; FIG. 7 is a block diagram of a media stream switching server according to an embodiment of the present invention;

 FIG. 8 is a schematic diagram of a media stream switching system according to an embodiment of the present invention. The embodiments of the present invention will be further described in detail with reference to the drawings and specific embodiments.

 The technical solutions in the embodiments of the present invention are clearly and completely described in the following with reference to the accompanying drawings in the embodiments of the present invention. It is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts are within the scope of the present invention.

 An embodiment of the present invention will be described below with reference to FIGS. 1 through 4:

 FIG. 1 is a flowchart of a method for switching a media stream according to an embodiment of the present invention. The method includes:

 102. Receive and cache a packet, where the packet is used to carry a media stream.

 For example, the media stream switching server caches each media stream, and the cached content is a packet carrying the media stream. The media stream switching server may be one or a group of dedicated servers, or may be integrated into a network device such as a network access node or a router.

 104. Obtain a visual sensitivity of the message.

In the first specific application scenario of the embodiment of the present invention, the media stream switching server identifies the key information of the video by means of Deep Packets Inspect (DPI), and acquires a Group of Pictures (GOP) and an I frame. Information such as P frames and B frames as visual sensitivity information, and can be independently decoded The message and the starting position of each frame. In addition, for different encoding formats, other information can also be detected. For example, for the MPEG-TS (Transport Stream) format, a Program Association Table (PAT) and a Program Map Table can be detected for the buffered message. , PMT) and so on. The media stream switching server may also identify the video key information and obtain the independently decodable message and the frame according to the special information of the video source, that is, the head end (Head End) in some fields or bits in the message header. starting point.

 In the second specific application scenario of the embodiment of the present invention, the visual sensitivity is a motion vector richness of the media stream switching server according to the content corresponding to the message, a position in the picture, an error hiding mechanism at the decoding end, and a decoding reference. Relationships, brightness and chrominance, frame type or stripe (SLICE) type, picture position and residuals, or some of these factors are evaluated. The unit of definition of the visual sensitivity is a message. The visual sensitivity may also be obtained by comprehensively evaluating the upstream node according to the above various factors of the content of the message. For example, the upstream node may be a head end, a dedicated evaluation device, or a network device having an evaluation function. The media stream switching server receives the packet of the bearer media stream that is sent by the head end and includes the visual sensitivity, and obtains the visual sensitivity of the message.

 106. When receiving the media stream switching request of the terminal, select a message with high visual sensitivity in the cached message.

 In the first specific application scenario of the embodiment of the present invention, the media stream switching server discards the packets of the B frame and selects the packets of the I frame and the P frame according to the starting position of each frame. The selected message is executed 108. The media stream switching server discards the packets of the B frame and the P frame in units of frames according to the starting position of each frame, selects the message of the I frame, and performs 108 on the selected message.

 In the second specific application scenario of the embodiment of the present invention, the media stream switching server discards the packets with low visual sensitivity in units of frames or packets according to the visual sensitivity of each frame or each packet, and selects the visual sensitivity. A high-level message performs 108 on the selected message. The standard of high visual sensitivity is given by a preset threshold. For example, when a message with high visual sensitivity is selected in units of frames, an average value of visual sensitivity of each frame may be calculated or estimated, and a visual sensitivity is selected in units of frames according to the average value and a preset threshold. Message. When a message with high visual acuity is selected in units of messages, a message with low visual sensitivity may be derived from a B frame image, and may be from a P frame image or an I frame image.

 108. Rearrange the serial number of the message with high visual sensitivity.

For example, the media stream switching server continuously maps the RTP sequence number of the selected packet to the end of the selected packet with the larger RTP sequence number. For example, the RTP sequence number of the selected first message is X, and the RTP sequence number of the last message is ¥, and a total of n messages that are evaluated as having high visual sensitivity are selected. Put the RTP sequence of these n messages The column number is rearranged, the RTP sequence number of the selected first message is rearranged to Y-n+l, the RTP sequence number of the second message is rearranged to Υ-η+2, and so on, the last one The RTP sequence number of the message is still Υ.

 Referring to FIG. 2, FIG. 2 is a schematic diagram of continuously mapping one end of a selected packet with a larger RTP sequence number according to an embodiment of the present invention. The RTP sequence number of the selected message starts with 100 and ends with 112, for a total of 7 messages. The RTP sequence numbers of the seven messages are rearranged into consecutive sequence numbers from 106 to 112. The RTP sequence number of the packet to be received by the terminal is consecutive, and when the selected packet is correctly transmitted, the terminal will not initiate a retransmission request.

 110. Send the message with high visual sensitivity of the re-arranged message sequence number to the terminal.

 For example, the media stream switching server pushes the visually sensitive message unicast that has been rearranged by the serial number to the terminal. During the packet push process, the unicast push code stream rate may be greater than the real-time multicast code stream rate, so that the unicast push code stream can catch up with the real-time multicast code stream. The unicast push rate may be equal to or lower than the real-time multicast stream rate. The media stream switching server discards some packets with low visual sensitivity and does not send the packets to the terminal. Therefore, the unicast push rate can be equal to Or less than the real-time multicast stream rate, as long as the sum of the code rate sent to the user and the discarded message stream rate is greater than the real-time multicast stream rate, so that the unicast-push stream can catch up with the real-time multicast code. flow.

 In some specific application scenarios of the embodiment of the present invention, the mapping relationship between the re-arranged packet sequence number and the original packet sequence number may be recorded in the media stream switching server, or the mapping relationship may be sent to the terminal, or The mapping relationship is also recorded in the media stream switching server and sent to the terminal. The media stream switching server or the terminal that stores the mapping relationship sends the mapping relationship to the head end, or the terminal obtains the original sequence number of the lost packet according to the mapping relationship, and sends the packet to the head end. The original serial number is given to the head end.

 FIG. 3 is a block diagram of a media stream switching server according to an embodiment of the present invention. The media stream switching server may be one or a group of dedicated servers, or may be integrated into a network device such as a network access node or a router. The media stream switching server includes a storage module 302, an obtaining module 304, a selecting module 306, a scheduling module 308, and a sending module 310.

 The storage module 302 is configured to receive and cache a packet, where the packet is used to carry a media stream.

 For example, the storage module 302 caches each media stream, and the cached content is a packet carrying the media stream. The obtaining module 304 is configured to obtain the visual sensitivity of the message buffered in the storage module 302.

In the first specific application scenario of the embodiment of the present invention, the obtaining module 304 identifies the video key information of the message buffered in the storage module 302 by means of DPI, and the like, and obtains a group of pictures (GOP), an I frame, and a P. Information such as frames and B frames is used as visual sensitivity information, and a message that can be independently decoded and a starting position of each frame are obtained. In addition, other information can be detected for different encoding formats, for example, for MPEG-TS format, it can be detected slowly. PAT, PMT, etc. of stored messages. The obtaining module 304 may also identify the video key information according to the special information of the video source, that is, the certain field or bit in the header of the video header, and obtain the message that can be independently decoded and the starting position of each frame.

 In the second specific application scenario of the embodiment of the present invention, the visual sensitivity is obtained by the acquiring module 304 according to the media stream switching server according to the motion vector richness of the content corresponding to the packet, the position in the screen, and the error hiding on the decoding end. Mechanism, decoding reference relationship, luminance and chrominance, frame type or SLICE type, picture position and residual or some of the factors are evaluated. The unit of definition of the visual sensitivity is a message. The data in the non-important data message of the low visual sensitivity identifier can be from the B frame image, and can be from the P frame image or from the I frame image. The visual sensitivity can also be obtained by comprehensively evaluating the head end according to the above various factors of the content of the message. The obtaining module 304 acquires the visual sensitivity in the message of the bearer media stream including the visual sensitivity sent by the head end.

 The selecting module 306 is configured to: when receiving the media stream switching request of the terminal, select a message with high visual sensitivity in the message buffered by the storage module 302.

 In the first specific application scenario of the embodiment of the present invention, the selecting module 306 discards the B-frame packet in the frame-based unit according to the initial position of the identified frame, and selects I in the packet buffered by the storage module 302. The message of the frame and the P frame, the selected message is delivered to the orchestration module 308. Or the media stream switching server discards the packets of the B frame and the P frame in units of frames according to the starting position of each frame, selects the message of the I frame, and delivers the selected message to the orchestration module 308.

 In the second specific application scenario of the embodiment of the present invention, the selecting module 306 discards the packet with low visual sensitivity in units of frames or packets according to the visual sensitivity of each frame or each packet, in the storage module 302. A message with high visual sensitivity is selected in the buffered message, and the selected message is delivered to the orchestration module 308. The visually sensitive standard is given by a preset threshold in the selection module 306.

 The orchestration module 308 is configured to rearrange the serial number of the selected message of the selection module 306.

 For example, the orchestration module 308 continuously maps the RTP sequence number of the packet selected by the module 306 to the end of the selected packet with the larger RTP sequence number. For example, the RTP sequence number of the first packet selected by the selection module 306 is X, and the RTP sequence number of the last packet is Y, and a total of n packets are selected. The orchestration module 308 rearranges the RTP sequence numbers of the n messages, and the RTP sequence number of the selected first message is rearranged to Υ-η+1, and the RTP sequence number of the second message is rearranged to Y. -n+2, and so on, the RTP sequence number of the last message is still Υ.

 The sending module 310 is configured to send the message that has been re-arranged by the orchestration module 308 to the terminal.

For example, the sending module 310 unicasts the message unicast by the orchestration module 308 to the terminal. During the packet push process, the unicast push code stream rate may be greater than the real-time multicast code stream rate, so that the unicast push code stream can catch up with the real-time multicast code stream. The unicast push code stream rate can also be equal to or less than the real-time multicast stream rate. Because the selection module 306 discards some packets with low visual sensitivity and does not send the packets to the terminal, the code stream rate of the unicast push may be equal to or smaller than the real-time multicast code stream rate, as long as the code stream rate sent to the user is discarded. The sum of the message stream rates is greater than the real-time multicast stream rate, so that the unicast-push stream can catch up with the real-time multicast stream.

 In some specific application scenarios of the embodiment of the present invention, the sending module 310 is further configured to send the mapping relationship between the re-arranged message sequence number and the original message sequence number to the terminal. When the head end needs to collect statistics on the packet loss, the terminal sends the mapping relationship to the head end, or obtains the original sequence number of the lost packet according to the mapping relationship, and sends the original sequence number to the head end.

 In some specific application scenarios of the embodiment of the present invention, the media stream switching server may further include: a recording module, configured to record a mapping relationship between the re-arranged message sequence number and the original message sequence number. When the head end needs to collect statistics on the packet loss situation, the recording module sends the mapping relationship to the head end.

 FIG. 4 is a schematic diagram of a media stream switching system according to an embodiment of the present invention. The system includes a media stream switching server 402 and a head end 404;

 The media stream switching server 402 is configured to receive and cache the packet sent by the head end, where the packet is used to carry the media stream, and obtain the visual sensitivity of the packet. When receiving the media stream switching request of the terminal, Selecting a message with high visual sensitivity, re-arranging the sequence number of the message with high visual sensitivity, and transmitting the message with high visual sensitivity after re-arranging the sequence number to the terminal in the cached message .

 The media stream switching server 402 can be a dedicated server or a group of dedicated servers, or can be integrated into network devices such as network access nodes or routers.

 The head end 404 is configured to send a message, where the message is used to carry a media stream.

 The head end 404 is a source device initiated by the media stream, and the manner of obtaining the media stream may be recording from a satellite television, or forwarding from another wired network, etc., and the head end 404 may also be other network devices, such as a side-mounted network device. Edge server.

 The network connection between the headend 404 and the media stream switching server or access node can be in various ways, for example, through a core network, a metropolitan area network, an aggregation network, or other network connection.

The access node may be a Digital Subscriber Line Access Multiplexer (DSLAM) device, an optical line terminal (OLT) device, or an Underlay Provider Edge (UPE) device. A device such as an IP switch may also be applied to other devices at the access node network location, such as an aggregation router. The connection between the access node and the terminal may include various access technologies, such as Digital Subscriber Line (DSL), Passive Optical Network (PON), Ethernet, and the like. With the technical solution provided by the embodiment, only the message with high visual sensitivity is sent to the terminal, the requirement for the transmission bandwidth of the media stream switching is reduced, the number of pushable unicast streams is increased, and the selected message is selected. The sequence number is continuously mapped to the end of the selected message with the larger sequence number, so that the sequence number of the message to be received by the terminal is continuous. When the selected message is correctly transmitted, the terminal will not initiate a retransmission request. Therefore, the terminal does not need to support retransmission suppression, and the problem that the media stream switching has high requirements on the transmission bandwidth, the number of pushable unicast streams is limited, and the push duration is relatively long can be solved. An embodiment of the present invention will be described below with reference to FIGS. 5 through 6:

 FIG. 5 is a flowchart of a method for switching a media stream according to an embodiment of the present invention. The method includes:

 502. Receive and cache a packet, where the packet is used to carry a media stream.

 For example, the media stream switching server caches each media stream, and the cached content is a packet carrying the media stream. The media stream switching server may be one or a group of dedicated servers, or may be integrated into a network device such as a network access node or a router.

 504. Obtain a visual sensitivity of the packet.

 In the first specific application scenario of the embodiment of the present invention, the media stream switching server identifies the video key information by means of DPI, etc., and obtains information such as a group of pictures (GOP), an I frame, a P frame, and a B frame as visual Sensitivity information, and get the message that can be decoded independently and the starting position of each frame. In addition, other information can be detected for different coding formats. For example, for the MPEG-TS format, PAT, PMT, etc. of the buffered message can be detected. The media stream switching server may also identify the video key information and obtain the independently decodable message and the starting position of each frame according to the special information of the video source, that is, the certain field or bit in the header of the message header.

 In the second specific application scenario of the embodiment of the present invention, the visual sensitivity is a motion vector richness of the media stream switching server according to the content corresponding to the message, a position in the picture, an error hiding mechanism at the decoding end, and a decoding reference. Relationships, brightness and chrominance, frame type or SLICE type, picture position and residual or some of the factors are evaluated. The unit of definition of the visual sensitivity is a message. The data in the non-important data message with low visual sensitivity can be from the B frame image, and can be from the P frame image or from the I frame image. The visual sensitivity can also be obtained by comprehensively evaluating the head end according to the above various factors of the content of the message. The media stream switching server receives the message of the bearer media stream that is sent by the head end and includes the visual sensitivity, and obtains the visual sensitivity of the message.

506. When receiving a media stream switching request of the terminal, select a packet with high visual sensitivity in the cached message. In the first specific application scenario of the embodiment of the present invention, the media stream switching server discards the packets of the B frame and selects the packets of the I frame and the P frame according to the initial position of the identified frame. 508 is performed on the selected message. Or the media stream switching server discards the packets of the B frame and the P frame in units of frames according to the starting position of each frame, selects the message of the I frame, and performs 508 on the selected message.

 In the second specific application scenario of the embodiment of the present invention, the media stream switching server discards the packets with low visual sensitivity in units of frames or packets according to the visual sensitivity of each frame or each packet, and selects the visual sensitivity. A high-level message performs 108 on the selected message. The standard of high visual sensitivity is given by a preset threshold.

 508. Rearrange the sequence number of the message with high visual sensitivity.

 For example, the media stream switching server continuously maps the RTP sequence number of the selected packet to the smaller end of the selected packet with the smaller RTP sequence number. For example, the RTP sequence number of the selected first message is X, and the RTP sequence number of the last message is ¥, and a total of n messages evaluated as having high visual sensitivity are selected. The RTP sequence numbers of the n messages are rearranged, the RTP sequence number of the selected first message is still X, the RTP sequence number of the second message is rearranged to X+l, and so on, and finally The RTP sequence number of a message is rearranged to X+nl. After the media stream is switched, the start sequence number of the multicast packet received by the terminal starts from Y+1. The sequence of the selected packet is re-arranged and is not continuous with the start sequence number of the multicast packet. For X+n The discontinuous serial number to Y is performed 510, 512.

 Referring to FIG. 6, FIG. 6 is a schematic diagram of continuously mapping one end of a selected packet with a smaller RTP sequence number according to an embodiment of the present invention. The RTP sequence number of the selected message starts with 100 and ends with 112, for a total of 7 messages. The RTP sequence numbers of these 7 messages are rearranged into consecutive serial numbers from 100 to 106. After the media stream is switched, the start sequence number of the multicast packet received by the terminal starts from 113. The sequence of the selected packet is re-arranged and is not continuous with the start sequence number of the multicast packet. For the segment 107 to 111. The discontinuous serial numbers are executed 510, 512.

 510. Generate retransmission suppression information, where the retransmission suppression information includes identifier information of the discontinuous sequence number of the re-arranged message.

 Taking the discontinuity of the RTP sequence number from X+n to Y as an example, the retransmission suppression information may be generated at this time, and the retransmission suppression information includes information of the discontinuous sequence number, for example, the discontinuous sequence. The first RTP sequence number (X+n) and the last RTP sequence number (Y).

 512. Send the retransmission suppression information to the terminal, where the retransmission suppression information is used to prevent the retransmission of the packet corresponding to the identifier information when the terminal receives the packet corresponding to the identifier information.

 For example, the retransmission suppression information may be sent by the extended RTCP message to the receiving node.

514. Send the message with high visual sensitivity of the re-arranged message sequence number to the terminal. For example, the media stream switching server unicasts the visually sensitive message unicast that has been rearranged by the sequence number to the terminal. During the packet push process, the unicast push code stream rate may be greater than the real-time multicast code stream rate, so that the unicast push code stream can catch up with the real-time multicast code stream. The unicast push rate may be equal to or lower than the real-time multicast stream rate. The media stream switching server discards some packets with low visual sensitivity and does not send the packets to the terminal. Therefore, the unicast push rate can be equal to Or less than the real-time multicast stream rate, as long as the sum of the code rate sent to the user and the discarded message stream rate is greater than the real-time multicast stream rate, so that the unicast-push stream can catch up with the real-time multicast code. flow.

 It will be understood by those skilled in the art that the purpose of rearranging the serial number in the embodiment shown in FIG. 5 is to reduce or simplify the retransmission suppression information that needs to be transmitted. Other conceivable ones can reduce or simplify the retransmission suppression information that needs to be sent. The method of programming the serial number can be used as the method of rearranging the serial number of the message with high visual sensitivity.

 A person of ordinary skill in the art can understand that the generation and transmission of retransmission suppression information in 510 and 512 in the embodiment shown in FIG. 5 is not strictly time-ordered to push the unicast media stream to the terminal in 514. The retransmission suppression information may be sent to the terminal before the unicast media stream is pushed, or may be sent to the terminal after a part of the unicast media stream has been pushed.

 In some specific application scenarios of the embodiment of the present invention, the mapping relationship between the re-arranged packet sequence number and the original packet sequence number may be recorded in the media stream switching server, or the mapping relationship may be sent to the terminal, or The mapping relationship is also recorded in the media stream switching server and sent to the terminal. The media stream switching server or the terminal that stores the mapping relationship sends the mapping relationship to the head end, or the terminal obtains the original sequence number of the lost packet according to the mapping relationship, and sends the packet to the head end. The original serial number is given to the head end.

 FIG. 7 is a block diagram of a media stream switching server according to an embodiment of the present invention. The media stream switching server may be one or a group of dedicated servers, or may be integrated into a network device such as a network access node or a router. The media stream switching server includes a storage module 702, an obtaining module 704, a selecting module 706, a scheduling module 708, a generating module 710, and a sending module 712. The storage module 702, the obtaining module 704, and the selecting module 706 are respectively associated with FIG. 3. The memory module 302, the acquisition module 304, and the selection module 306 in the illustrated embodiment function substantially the same. The difference is that the functions of the orchestration module 708 are slightly different, and the generation module 710 is added correspondingly, and the function of the transmission module 712 is added.

 The storage module 702 is configured to receive and cache a packet, where the packet is used to carry a media stream.

 The obtaining module 704 is configured to obtain visual sensitivity of the message buffered in the storage module 702.

The selecting module 706 is configured to select a packet with high visual sensitivity in the packet buffered by the storage module 702 when receiving the media stream switching request of the terminal. The orchestration module 708 is configured to rearrange the serial number of the message selected by the selection module 706.

 For example, the orchestration module 708 continuously maps the RTP sequence number of the packet selected by the module 706 to the smaller end of the selected packet with the smaller RTP sequence number. For example, the RTP sequence number of the first message selected by the selection module 706 is X, and the RTP sequence number of the last message is ¥, and a total of n messages that are evaluated as having high visual sensitivity are selected. The orchestration module 708 rearranges the RTP sequence numbers of the n messages, and the RTP sequence number of the selected first message is still X, and the RTP sequence number of the second message is rearranged to X+l. By analogy, the RTP sequence number of the last message is rearranged to X+nl.

 The generating module 710 is configured to generate retransmission suppression information, where the retransmission suppression information includes identifier information of a discontinuous sequence number of the re-arranged message.

 Taking the discontinuity of the RTP sequence number from X+n to Y as an example, the generating module 710 can generate retransmission suppression information, and the retransmission suppression information includes information of the discontinuous sequence number, for example, this segment does not The first RTP sequence number (X+n) and the last RTP sequence number (Y) of consecutive serial numbers.

 The sending module 712 is configured to send, to the terminal, the re-arrangement suppression message generated by the generating module 710, and send the retransmission suppression information to the terminal. When the packet corresponding to the identifier information is lost, the packet corresponding to the identifier information is not requested to be retransmitted.

 For example, the sending module 712 can send the retransmission suppression information to the receiving node with the extended RTCP message. For example, the sending module 712 unicasts the visually sensitive message with the reordered serial number to the terminal. During the packet push process, the unicast push code stream rate may be greater than the real-time multicast code stream rate, so that the unicast push code stream can catch up with the real-time multicast code stream. The unicast push code stream rate may also be equal to or lower than the real-time multicast code stream rate, because the selection module 706 discards some of the packets with low visual sensitivity and does not send the message to the terminal, so the unicast push code stream rate may also be equal to or Less than the real-time multicast stream rate, as long as the sum of the code stream rate sent to the user and the discarded message stream rate is greater than the real-time multicast stream rate, so that the unicast-push stream can catch up with the real-time multicast stream. .

 In some specific application scenarios of the embodiment of the present invention, the sending module 712 is further configured to send the mapping relationship between the re-arranged message sequence number and the original message sequence number to the terminal. When the head end needs to collect statistics on the packet loss, the terminal sends the mapping relationship to the head end, or obtains the original sequence number of the lost packet according to the mapping relationship, and sends the original sequence number to the head end.

In some specific application scenarios of the embodiment of the present invention, the media stream switching server may further include: a recording module, configured to record a mapping relationship between the re-arranged message sequence number and the original message sequence number. When the head end needs to collect statistics on the packet loss situation, the recording module sends the mapping relationship to the head end. FIG. 8 is a schematic diagram of a media stream switching system according to an embodiment of the present invention. The system includes a media stream switching server 802 and a head end 804;

 The media stream switching server 802 is configured to receive and cache the packet sent by the head end, where the packet is used to carry the media stream, and obtain the visual sensitivity of the packet. When receiving the media stream switching request of the terminal, Selecting a message with high visual sensitivity, re-arranging the sequence number of the message with high visual sensitivity, and transmitting the message with high visual sensitivity after re-arranging the sequence number to the terminal in the cached message And the retransmission suppression information includes the identifier information of the discontinuous sequence number of the re-arranged message, and the retransmission suppression information is sent to the terminal, where The transmission suppression information is such that when the terminal receives the packet corresponding to the identifier information, the terminal does not request to retransmit the packet corresponding to the identifier information.

 The media stream switching server 802 can be a dedicated server or a group of dedicated servers, or can be integrated into network devices such as network access nodes or routers.

 The head end 804 is configured to send a message, where the message is used to carry a media stream.

 The head end 804 is a source device initiated by the media stream, and the manner of obtaining the media stream may be recording from a satellite television, or forwarding from another wired network, etc., and the head end 804 may also be other network devices, for example, hanging on a metropolitan area network device. Edge server.

 The network connection between the headend 804 and the media stream switching server or access node can be in various ways, for example, through a core network, a metropolitan area network, an aggregation network, or other network connection.

 The access node may be a Digital Subscriber Line Access Multiplexer (DSLAM) device, an optical line terminal (OLT) device, or an Underlay Provider Edge (UPE) device. A device such as an IP switch may also be applied to other devices at the access node network location, such as an aggregation router. The connection between the access node and the terminal can include various access technologies, such as Digital Subscriber Line (DSL), Passive Optical Network (PON), Ethernet, and the like.

With the technical solution provided by the embodiment, only the message with high visual sensitivity is sent to the terminal, the requirement for the transmission bandwidth of the media stream switching is reduced, the number of pushable unicast streams is increased, and the sent message is After the sequence number is re-arranged, only a small amount of retransmission suppression information is sent, so that the terminal does not need to request retransmission of the message, which solves the problem that the media stream switching has high requirements on the transmission bandwidth, the number of pushable unicast streams is limited, and the push A problem that lasts longer. A person skilled in the art can understand that all or part of the steps of implementing the above embodiments may be completed by a program to instruct related hardware, and the program may be stored in a computer readable storage medium, and the storage medium may be a ROM. /RAM, disk or CD, etc.

 The above is only a preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily think of changes or within the technical scope disclosed by the present invention. Alternatives are intended to be covered by the scope of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

Rights request  A media stream switching method, comprising:  Receiving and buffering a packet, where the packet is used to carry a media stream;  Obtaining visual sensitivity of the message;  When receiving the media stream switching request of the terminal, selecting a message with high visual sensitivity in the cached message; and rearranging the serial number of the message with high visual sensitivity;  The message with high visual sensitivity that has been rearranged by the serial number is sent to the terminal.  The method according to claim 1, wherein the rearranging the serial number of the message with high visual sensitivity includes:  The sequence number of the message with high visual sensitivity is continuously mapped to the end with the larger sequence number.  The method according to claim 1 or 2, wherein the obtaining the visual sensitivity of the message comprises:  Evaluating the message to obtain the visual sensitivity; or  Obtaining a visual sensitivity obtained by the upstream node to evaluate the message carried in the packet. The method according to claim 1 or 2, wherein the selecting a message with high visual sensitivity in the cached message includes:  A message with high visual sensitivity is selected in the cached message in units of frames.  The method according to claim 3, wherein the selecting a message with high visual sensitivity in the cached message in a frame unit comprises:  The packets of the I frame and the P frame are selected in the buffered message.  The method according to claim 1 or 2, wherein the selecting a message with high visual sensitivity in the cached message includes:  Selecting a message with high visual sensitivity in the cached message in units of messages.  The method according to claim 1 or 2, further comprising: after the rearranging the serial number of the message with high visual sensitivity, further comprising:  Recording the mapping relationship between the re-arranged message sequence number and the message sequence number before re-arrangement; and/or transmitting the mapping relationship between the re-arranged message sequence number and the re-arranged message sequence number to the terminal. The method according to claim 1, wherein the rearranging the serial number of the message with high visual sensitivity includes: The sequence number of the message with high visual sensitivity is continuously mapped to the end with the smaller sequence number. The method according to claim 8, wherein after rearranging the serial number of the message with high visual sensitivity, the method further comprises:  Generating retransmission suppression information, where the retransmission suppression information includes identification information of a discontinuous sequence number of the re-arranged message;  The retransmission suppression information is sent to the terminal, and the retransmission suppression information is used to prevent the retransmission of the packet corresponding to the identifier information when the terminal receives the packet corresponding to the identifier information.  A media stream switching server, comprising: a storage module, an obtaining module, a selecting module, a scheduling module, and a sending module;  The storage module is configured to receive and cache a packet, where the packet is used to carry a media stream;  The obtaining module is configured to acquire visual sensitivity of a message buffered in the storage module;  The selecting module is configured to: when receiving the media stream switching request of the terminal, select a message with high visual sensitivity in the message buffered by the storage module;  The orchestration module is configured to re-arrange the serial number of the message selected by the selection module;  The sending module is configured to send a message that is re-arranged by the programming module to the terminal. The media stream switching server according to claim 10, wherein the orchestration module is configured to continuously map the sequence number of the message with high visual sensitivity to one end with a larger serial number.  12. The media stream switching server according to claim 10, further comprising a generating module; wherein  The generating module is configured to generate retransmission suppression information, where the retransmission suppression information includes identifier information of a discontinuous sequence number of the re-arranged message;  The sending module is further configured to send the retransmission suppression information generated by the generating module to the terminal, where the retransmission suppression information is such that the terminal does not request heavy when the packet corresponding to the identifier information is lost. The packet corresponding to the identifier information is transmitted.  A media stream switching system, comprising: a media stream switching server and a head end; wherein the media stream switching server is configured to receive and cache a packet sent by the head end, where the packet is used by the packet And receiving the media stream, and acquiring the visual sensitivity of the packet. When receiving the media stream switching request of the terminal, selecting a packet with high visual sensitivity in the cached packet, and rearranging the visual sensitivity. The sequence number of the high message is sent to the terminal by the re-arranged sequence number of the message with high visual sensitivity; The header is configured to send a packet, where the packet is used to carry a media stream. The media stream switching system according to claim 13, wherein the rearranging the sequence number of the message with high visual sensitivity includes: - the sequence of the message with high visual sensitivity Number, continuously mapped to the larger end of the serial number.  The media stream switching system according to claim 13, wherein the media stream switching server is further configured to generate retransmission suppression information, and send the retransmission suppression information to the terminal, where the retransmission is performed. The suppression information includes the identifier information of the discontinuous sequence number of the re-arranged message, and is used to enable the terminal to not retransmit the identifier information when the packet corresponding to the identifier information is lost. Message.