CN106937155B

CN106937155B - Access device, Internet Protocol Television (IPTV) system and channel switching method

Info

Publication number: CN106937155B
Application number: CN201511020106.9A
Authority: CN
Inventors: 张燊; 张锦辉; 魏启坤
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2015-12-29
Filing date: 2015-12-29
Publication date: 2020-06-02
Anticipated expiration: 2035-12-29
Also published as: CN106937155A

Abstract

An access device, an Internet Protocol Television (IPTV) system and a channel switching method are used for solving the problem of low channel switching speed in the current channel switching scheme. The application provides an access device comprising: the receiving module is used for receiving a message of a video media stream from video source equipment; the buffer module is used for buffering the message received by the receiving module; the receiving module is also used for receiving a channel switching request sent by the user equipment; and the sending module is used for sending the message of the video media stream to the user equipment from the independently decodable message in the messages cached by the caching module. The access device starts to send the message of the video media stream to the user device from the independently decodable message, so that the user device can immediately decode and play when receiving the independently decodable message, and the problem of low channel switching speed when channel switching occurs is solved.

Description

Access device, Internet Protocol Television (IPTV) system and channel switching method

Technical Field

The present invention relates to the technical field of IPTV (Internet Protocol Television), and in particular, to an access device, an IPTV system, and a channel switching method.

Background

The IPTV technology is a video transmission and playing technology integrating multiple technologies such as internet, multimedia, and communication, and provides multiple interactive services such as digital tv, internet browsing, entertainment, education, and commerce to home users by using a broadband network, and the home users can enjoy the interactive services provided by the IPTV system through a computer, a mobile phone, a set-top box, and a user device such as a television, which are connected to the internet.

IPTV generally performs audio-video compression coding using an audio-video compression coding algorithm, and generates an image sequence including I frames, P frames, and B frames. The I frame is formed by completely coding the whole picture, can be independently decoded and displayed, and can provide reference for decoding of related P frames and B frames; p frames cannot be decoded independently and must be decoded after receiving the referenced I frame or the previous P frame; b frames are also not independently decodable and must be decoded after receiving the referenced previous frame (I frame or P frame) and the next frame (P frame).

Since the number of P frames and B frames is much greater than that of I frames, when a user switches channels, most of the users encounter P frames or B frames, which results in long time consumption for waiting for I frames, and thus results in slow channel switching speed and affects end user experience.

In summary, when the user equipment is performing channel switching, it needs to wait for an independently decodable message such as an I frame, which results in a slow channel switching speed.

Disclosure of Invention

The application provides an access device, a channel switching method and an IPTV system, which are used for solving the problem of low channel switching speed in the currently adopted channel switching method.

In a first aspect, the present application provides an access device, including: the receiving module is used for receiving a message of a video media stream of one channel from video source equipment;

the cache module is used for caching the message of the video media stream of the channel received by the receiving module;

the receiving module is further configured to receive a channel switching request sent by user equipment, where the channel switching request is used to indicate that the user equipment requests to play a video media stream of the channel;

a sending module, configured to send the packet of the video media stream of the channel to the user equipment, starting from an independently decodable packet in the packet of the video media stream of the channel cached by the caching module.

The access device provided in the first aspect starts to transmit the independently decodable message in the video media stream message cached by the caching module when transmitting the message of the video media stream to the user device, so that the user device can immediately decode and play when receiving the independently decodable message, and the problem of slow channel switching speed when channel switching occurs can be solved.

With reference to the first aspect, in a first possible implementation manner, the access device further includes: a processing module, configured to identify an independently decodable packet in a packet of the video media stream of the channel cached by the caching module before the sending module sends the packet of the video media stream of the channel to the user equipment from the independently decodable packet in the packet of the video media stream of the channel cached by the caching module;

the sending module is specifically configured to, when starting from an independently decodable packet in the packet of the video media stream of the channel cached by the caching module, send the packet of the video media stream of the channel to the user equipment: and starting from the independently decodable message identified in the messages of the video media streams of the channels cached by the caching module, sending the messages of the video media streams of the channels to the user equipment.

In a first possible implementation manner of the first aspect, the independently decodable packet in the packet of the video media stream of the channel cached by the cache module is identified, and the packet of the video media stream of the channel is sent to the user equipment from the identified independently decodable packet, so that different independently decodable packets can be identified, and the sending can be selectively started from a specific independently decodable packet.

With reference to the first aspect or the first possible implementation manner of the first aspect, in a second possible implementation manner, when the sending module sends the packet of the video media stream of the channel to the user equipment, starting from an independently decodable packet in the packet of the video media stream of the channel cached by the caching module, the sending module is specifically configured to: and in the messages of the video media streams of the channels cached by the cache module, starting from the independently decodable message with the message receiving time closest to the time when the receiving module receives the channel switching request, sending the messages of the video media streams of the channels to the user equipment.

In a second possible implementation manner of the first aspect, the sending module sends the packet of the video media stream of the channel to the user equipment from the independently decodable packet whose packet receiving time is closest to the time at which the receiving module receives the channel switching request, so that a difference between a packet sending progress of the video media stream of the channel sent by the user equipment and a packet sending progress of the video media stream normally played by the channel is minimized.

With reference to the first aspect, in a third possible implementation manner, the access device further includes: a processing module, configured to synchronize a message sending progress of the video media stream of the channel for the user equipment with a message sending progress of the video media stream that is normally played by the channel after the sending module sends the message of the video media stream of the channel to the user equipment from an independently decodable message in the message of the video media stream of the channel that is cached by the caching module;

the sending module is further configured to stop sending the packet of the video media stream of the channel cached by the caching module to the user equipment when the processing module completes the synchronization, and send the packet of the video media stream normally played by the channel to the user equipment.

In a third possible implementation manner of the first aspect, the message sending progress of the video media stream of the channel for the user equipment is synchronized with the message sending progress of the video media stream that is normally played in the channel, and the message of the video media stream that is normally played in the channel is sent to the user equipment when synchronization is completed, so that the processing load of the access equipment can be reduced, and the continuity of the video media stream that is played by the user equipment in the channel switching process can be ensured as much as possible.

With reference to the first aspect or any one of the foregoing possible implementation manners of the first aspect, in a fourth possible implementation manner, when the sending module sends the packet of the video media stream of the channel to the user equipment starting from an independently decodable packet in the packet of the video media stream of the channel cached by the caching module, the sending module is specifically configured to: and based on an internet group management protocol IGMP, starting from an independently decodable packet in the packets of the video media stream of the channel cached by the caching module, sending the packets of the video media stream of the channel to the user equipment.

In a fourth possible implementation manner of the first aspect, the packets of the video media stream of the channel cached by the cache module are sent to the user equipment based on an IGMP protocol, while the existing access device uses a multicast protocol, such as an IGMP protocol, when sending the packets of the video media stream that is normally played to the user equipment, and uses a unicast protocol when sending the packets of the video media stream for the user equipment to the user equipment. The multicast protocol and the unicast protocol are different protocols and thus different protocols need to be used during the channel switching process. By adopting the implementation mode, the user equipment can still use the protocol adopted when receiving the normally played multicast video media stream in the channel switching process without using other protocols, thereby reducing the change to the user equipment.

With reference to the first aspect or any one of the foregoing possible implementation manners of the first aspect, in a fifth possible implementation manner, the independently decodable packet is a group of pictures, GOP, start packet.

In a second aspect, the present application provides an IPTV system, comprising: the video source equipment is used for sending a message of a video media stream of one channel;

the access device provided in the first aspect or any one of the possible implementation manners of the first aspect is configured to receive and process a packet of a video media stream of the channel sent by the video source device; and

the user equipment is used for sending a channel switching request to the access equipment, wherein the channel switching request is used for indicating the user equipment to request to play the video media stream of the channel; the user equipment is further configured to: and receiving the message of the video media stream of the channel sent by the access equipment according to the channel switching request, and playing the video media stream of the channel on a connected video player according to the received message of the video media stream of the channel.

The IPTV system provided in the second aspect starts to send the independently decodable packet in the packet of the video media stream cached by the access device when sending the packet of the video media stream to the user equipment, so that the user equipment can decode and play the independently decodable packet immediately when receiving the independently decodable packet, and can solve the problem of slow channel switching speed when channel switching occurs.

In a third aspect, the present application provides a channel switching method, including: the access equipment receives a message of a video media stream of a channel sent by video source equipment;

the access equipment caches the received message of the video media stream of the channel;

the access equipment receives a channel switching request sent by user equipment, wherein the channel switching request is used for indicating the user equipment to request to play a video media stream of the channel;

and the access equipment sends the messages of the video media streams of the channels to the user equipment from the independently decodable messages in the cached messages of the video media streams of the channels.

The channel switching method provided in the third aspect starts to send the independently decodable message in the video media stream message cached by the access device when sending the message of the video media stream to the user device, so that the user device can immediately decode and play when receiving the independently decodable message, and the problem of slow channel switching speed when channel switching occurs can be solved.

With reference to the third aspect, in a first possible implementation manner, before the sending, by the access device, the packet of the video media stream of the channel to the user equipment from the independently decodable packet of the buffered packets of the video media stream of the channel, the method further includes: the access equipment identifies the independently decodable message in the cached messages of the video media stream of the channel;

the method for sending, by the access device, the packet of the video media stream of the channel to the user equipment, starting from the independently decodable packet in the buffered packet of the video media stream of the channel, specifically includes: and the access equipment sends the message of the video media stream of the channel to the user equipment from the independently decodable message carrying out the identification in the cached message of the video media stream of the channel.

In a first possible implementation manner of the third aspect, an independently decodable packet in a packet of the video media stream of the channel cached by the access device is identified, and the packet of the video media stream of the channel is sent to the user equipment starting from the identified independently decodable packet, different independently decodable packets may be identified, and the sending may be selectively started from a certain specific independently decodable packet.

With reference to the third aspect or the first possible implementation manner of the third aspect, in a second possible implementation manner, the sending, by the access device, the packet of the video media stream of the channel to the user equipment starting from an independently decodable packet in the buffered packet of the video media stream of the channel includes:

in the messages of the video media stream of the channel cached by the access device, the access device sends the messages of the video media stream of the channel to the user equipment from the independently decodable message with the message receiving time closest to the time when the access device receives the channel switching request.

In a second possible implementation manner of the third aspect, the access device sends the packet of the video media stream of the channel to the user equipment from the independently decodable packet whose packet receiving time is closest to the time at which the access device receives the channel switching request, so that a difference between a packet sending progress of the video media stream of the channel sent by the user equipment and a packet sending progress of the video media stream normally played by the channel is minimized.

With reference to the third aspect or any one of the foregoing possible implementation manners of the third aspect, in a third possible implementation manner, after the sending, by the access device, the message of the video media stream of the channel to the user equipment starting from an independently decodable message in the buffered message of the video media stream of the channel, the method further includes:

the access equipment synchronizes the message sending progress of the video media stream of the channel aiming at the user equipment with the message sending progress of the video media stream normally played by the channel;

and when the synchronization is completed, stopping sending the message of the video media stream of the channel cached by the access equipment to the user equipment, and sending the message of the video media stream normally played by the channel to the user equipment.

In a third possible implementation manner of the third aspect, the message sending progress of the video media stream of the channel for the user equipment is synchronized with the message sending progress of the video media stream that is normally played in the channel, and the message of the video media stream that is normally played in the channel is sent to the user equipment when synchronization is completed, so that the processing load of the access equipment can be reduced, and the continuity of the video media stream that is played by the user equipment in the channel switching process can be ensured as much as possible.

With reference to the third aspect or any one of the foregoing possible implementation manners of the third aspect, in a fourth possible implementation manner, the sending, by the access device, a packet of the video media stream of the channel to the user equipment starting from an independently decodable packet in the buffered packet of the video media stream of the channel includes:

and the access equipment transmits the messages of the video media streams of the channels to the user equipment from the independently decodable messages in the cached messages of the video media streams of the channels based on an Internet Group Management Protocol (IGMP).

In a fourth possible implementation manner of the third aspect, the packets of the video media stream of the channel are sent to the user equipment based on an IGMP protocol, whereas in the existing channel switching method, a multicast protocol, such as an IGMP protocol, is used when the packets of the video media stream that is normally played are sent to the user equipment, and a unicast protocol is used when the packets of the video media stream for the user equipment are sent to the user equipment. The multicast protocol and the unicast protocol are different protocols and thus different protocols need to be used during the channel switching process. By adopting the implementation mode, the user equipment can still use the protocol adopted when receiving the normally played multicast video media stream in the channel switching process without using other protocols, thereby reducing the change to the user equipment.

With reference to the third aspect or any one of the foregoing possible implementation manners of the third aspect, in a fifth possible implementation manner, the independently decodable packet is a group of pictures, GOP, start packet.

The access equipment sends the message of the video media stream of the channel to the user equipment from the independently decodable message in the message of the video media stream of the channel, so that the first message received when the user equipment switches channels can be an independently decodable message, and the user equipment can start decoding and playing from the independently decodable message; however, with the channel switching method in the existing scheme, most of the cases, the first message received by the user equipment is not an independently decodable message, and therefore decoding and playing cannot be started immediately. Therefore, the problem of low channel switching speed in the channel switching process can be solved by adopting the scheme provided by the application.

Drawings

Fig. 1 is a schematic diagram of a relationship between a packet of a video media stream of a certain channel sent by an access device for a user equipment and a packet of a video media stream normally played by the channel sent by the access device according to the present application;

fig. 2 is a schematic structural diagram of an IPTV system provided in the present application;

fig. 3 is a flowchart of a channel switching method provided in the present application;

fig. 4 is a schematic diagram of a channel switching scheme provided in the present application;

fig. 5 is a schematic diagram illustrating a relationship between a transmission start point of a multicast IP (Internet Protocol) packet of a channel a of a certain Set Top Box (STB) and a play position of a real-time multicast IP packet of the channel a in a channel switching scheme provided in the present application;

fig. 6 is a schematic structural diagram of an access device provided in the present application;

fig. 7 is a hardware structure diagram of an implementation of the access device shown in fig. 6;

fig. 8 is a flowchart of another channel switching method provided in the present application.

Detailed Description

The following detailed description is provided for a better understanding of the above-described objects, aspects and advantages of the present application. The detailed description sets forth various embodiments of the devices and/or methods via the use of diagrams and/or examples of block diagrams, flowcharts, and the like. In these block diagrams, flowcharts, and/or examples, one or more functions and/or operations are included. Those skilled in the art will understand that: the various functions and/or operations within these block diagrams, flowcharts or examples can be implemented, individually and collectively, by a wide variety of hardware, software, firmware, or any combination of hardware, software and firmware.

In this application, the IPTV system includes a video source device, an access device, and at least one user device. The method comprises the steps that video source equipment sends a message of a video media stream, access equipment receives the message of the video media stream sent by the video source equipment and sends the received message of the video media stream to user equipment, and the user equipment plays the video media stream on video players which are connected respectively according to the message of the video media stream received from the access equipment. Specifically, the access device receives a packet of a video media stream of a channel sent by the video source device, and caches the received packet of the video media stream of the channel. When the access device receives a channel switching request which is sent by user equipment and requests to play the video media stream of the channel, aiming at the user equipment, the access device sends the message of the video media stream of the channel to the user equipment from the message which can be independently decoded in the message of the video media stream of the channel.

The access equipment sends the message of the video media stream of the channel to the user equipment from the independently decodable message in the message of the video media stream of the channel, so that the first message received when the user equipment switches channels can be an independently decodable message, and the user equipment can start decoding and playing from the independently decodable message; however, with the channel switching method in the prior art, most of the cases, the first message received by the user equipment is not an independently decodable message, and therefore decoding and playing cannot be started immediately. Therefore, the problem of low channel switching speed in the channel switching process can be solved by adopting the scheme provided by the application.

In the following, for ease of understanding, the concepts involved in the present application are described.

I, P, B frames

In an IPTV system, video and audio compression is generally performed using a video and audio compression and encoding algorithm. In video and audio compression, pictures are encoded to generate an image sequence including I, P and B frames. The I frame is formed by completely coding the whole picture, can be independently decoded and displayed, and can provide reference for decoding of related P frames and B frames; p frames cannot be decoded independently and must be decoded after receiving the referenced I frame or the previous P frame; b-frames are also not independently decodable and must be decoded after receiving the referenced previous frame (I-frame or P-frame) and the next frame (P-frame).

Two, can decode the message independently

The independently decodable message is a frame in which the entire picture is completely encoded, such as the aforementioned I frame, and the user equipment can independently decode and display the independently decodable message after receiving the independently decodable message.

In the application, when the access device receives a channel switching request which is sent by the user equipment and requests to switch to a certain channel, the access device sends the message of the video media stream to the user equipment from the independently decodable message in the message of the video media stream of the channel, so that the user equipment can start decoding and playing from the independently decodable message when the channel is switched, and the problem of low channel switching speed is avoided.

Thirdly, video media stream sent by user equipment in the channel switching process and video media stream played normally

In the application, in the process of switching channels by one user equipment, the access equipment aims at that the video media stream sent by the user equipment is different from the normally played video media stream sent by the access equipment to other user equipment in a multicast mode.

In the channel switching process, after receiving a channel switching request for requesting switching to a certain channel sent by a user equipment, an access device sends a message of a video media stream of the channel for the user equipment to the user equipment from an independently decodable message in a message of the video media stream of the channel cached by the access device. And starting to send the video media stream to the user equipment, wherein the video media stream sent by the user equipment is the independently decodable message in the messages of the video media stream of the channel cached from the access equipment.

The normally played message of the video media stream is a message sent by the access device to multiple user devices at the same time, that is, the multiple user devices receive a multicast video media stream together.

In the application, optionally, the access device may synchronize a message sending progress of a video media stream of a certain channel of one user equipment with a message sending progress of a video media stream normally played in the channel during the channel switching process, and when the synchronization is completed, stop sending the message of the video media stream cached by the access device to the user equipment, and simultaneously send the message of the video media stream normally played to the user equipment, so that a processing load of the access device may be reduced, and continuity of the video media stream played by the user equipment during the channel switching process may also be ensured as much as possible.

Fig. 1 shows a relationship between a message of a video media stream of a certain channel of a user equipment and a message of a video media stream normally played by the channel.

In fig. 1, A, B, C, D represents a message of a video media stream, and when a video media stream that is normally played in a certain channel is to be played C, the access device receives a channel switching request sent by the user equipment, and requests to switch to the channel. Since a is an independently decodable packet, the access device C sends a packet of the video media stream from a to the user equipment that initiated the channel switch request. When a video media stream that is normally played in a certain channel is to be played D (at this time, a user equipment is to play B), the user equipment may be switched to a video media stream that is normally played in the channel by synchronizing a message sending progress of the video media stream for the user equipment with a message sending progress of the video media stream that is normally played in the channel through a method of discarding a part of messages (i.e., B and C) as shown in fig. 1, that is, sending a message of the video media stream that is normally played in the channel to the user equipment (i.e., starting playing from D).

As can be seen from fig. 1, since the messages of the video media stream of a certain channel for a user equipment start from the independently decodable messages in the messages of the video media stream of the channel cached by the access equipment, the progress of the messages is slower than that of the messages of the video media stream normally played by the channel.

Next, each embodiment of the present application will be described in detail.

Fig. 2 shows a schematic structural diagram of an IPTV system in the present application. As shown in fig. 2, the IPTV system includes: the video source device 203, the access device 202 and the user device 201, here only one user device is shown for the sake of a brief illustration, in fact, one access device may be connected to a plurality of user devices. The IPTV system may also include a plurality of access devices 202 and a plurality of video source devices 203, and only one access device 202 and one video source device 203 are shown here for the sake of brief illustration.

The video source device 203 may be an IPTV headend. The video source device 203 may obtain messages for the video media stream from a satellite television system or forward messages for the video media stream from other cable networks.

The Access Device 202 may be an Access Network Device (Access Network Device), such as a Digital Subscriber Line Access Multiplexer (DSLAM) Device, an Optical Line Terminal (OLT) Device, or the like; the Access Device 202 may also be an aggregation network Device (aggregation network Device), such as a Service Router (SR), a Broadband Remote Access Server (BRAS), and the like. The video source device 203 and the access device 202 may be connected through a core network, a metropolitan area network, a convergence network, or other networking methods.

The user device 201 may be an STB, or may be a computer, a mobile phone, etc. accessing the internet.

A Home subscriber-side Gateway dialing device, such as a Home Gateway router (HG), may also be included between the user device 201 and the access device 202.

In the present application, the access device 202 may receive messages of video media streams of one or more channels from the video source device 203.

When the video source device 203 sends a packet of a video media stream of a certain channel to the access device 202, the video source device 203 may be implemented in a static multicast configuration manner, that is, whether any user device in the user devices connected to the access device 202 is receiving the video media stream of the channel, the video source device 203 sends the video media stream of the channel to the access device 202; when the video source device 203 sends a packet of a video media stream of a certain channel to the access device 202, it may also be implemented in a manner of dynamically joining in a multicast group, that is, if none of the user devices connected to the access device 202 receives the video media stream of the channel, the video source device 203 will not send the video media stream of the channel to the access device 202, and only when a user device receives the video media stream of the channel, the video source device 203 will send the video media stream of the channel to the access device 202.

Fig. 3 is a flowchart of a channel switching method provided in the present application. As shown in fig. 3, the process includes the following steps:

s301: the access device 202 caches a packet of a video media stream of one channel received from the video source device 203;

the access device 202 receives a packet of a video media stream of a channel from the video source device 203, and buffers the packet of the video media stream of the channel.

The cached message of the video media stream of the channel is obtained by caching the message of the video media stream played in the normal playing process of the video media stream of the channel.

Alternatively, the length of the buffer queue may be preset according to the capacity of the access device 202.

S302: the access device 202 identifies the independently decodable message in the cached messages of the video media stream of the channel;

the access device 202 may identify a start position of an independently decodable packet in the buffered packets of the video media stream of the channel.

Alternatively, access device 202 may employ Deep Packet Inspection (DPI) techniques to identify a starting location of an independently decodable packet in the Packets of the video media stream.

Such as: if the video media stream is encoded in h.264 or h.265 and transmitted in the original encoded encapsulation format, the access device 202 can recognize that the packet containing the I frame identifier is an I frame packet when recognizing the I frame identifier, where the I frame packet is an independently decodable packet.

For another example: if the video media Stream is encoded in h.264 or h.265, and is encapsulated in MPEG2TS (moving picture Experts Group2Transport Stream), the access device 202 may recognize that the packet containing the I frame identifier is an independently decodable packet when recognizing the Program Association Table (PAT) identifier, the Program Map Table (PMT) identifier, and the subsequent I frame identifier.

After identifying the independently decodable message, the access device 202 may add an identifier to the identified message to mark the message as an independently decodable message.

Optionally, the access device 202 may identify each of the buffered messages of the video media stream of the channel that may be independently decoded, such as: the access device 202 may identify, among the cached messages of the video media stream of the channel, an independently decodable message whose message receiving time is closest to the time when the access device receives the channel switching request. In this way, when the access device 202 performs the following step S304 to transmit the message of the video media stream for the user device to the user device, the message of the video media stream of the channel may be transmitted to the user device starting from the identified independently decodable message.

S303: the user equipment 201 sends a channel switching request to the access equipment 202, wherein the channel switching request is used for indicating that the user equipment 201 requests to switch to the channel;

alternatively, the user equipment 201 may transmit the channel switching request based on the IGMP protocol when transmitting the channel switching request to the access equipment 202. When the channel switching request is transmitted using the IGMP protocol, the channel switching request may include an IGMP join (IGMP join) request or may include an IGMP leave (IGMP leave) request and an IGMP join (IGMP join) request. Taking the user equipment 201 as an STB as an example, the channel switching request may be sent to the access device 202 by the set top box STB after receiving an instruction for switching channels sent by a Remote Control (Remote Control) device.

S304: the access device 202 sends the message of the video media stream of the channel to the user device 201, starting from the independently decodable message in the cached message of the video media stream of the channel;

optionally, the mode of sending the message by the access device 202 may refer to the sending mode of the video media stream sent by one user equipment in the channel switching process shown in fig. 1.

Alternatively, the access device 202 may transmit based on IGMP protocol when transmitting the packets of the video media stream of the channel to the user device 201.

One user equipment can perform negotiation communication with the access equipment through an IGMP protocol, and when the access equipment sends a message of a video media stream to one user equipment independently, a multicast protocol such as IGMP can also be used. IGMP is a group management protocol, and thus, when a packet of a video media stream is transmitted based on the IGMP protocol, even if the packet is transmitted to one user device separately, the packet can be regarded as being transmitted by a multicast method.

If a plurality of user equipments request to switch to the channel, in the process of switching the channel for the user equipments, the multicast streams sent for different user equipments are different, that is, the schedules of the multicast streams sent are different.

S305: the access device 202 synchronizes the message sending progress of the video media stream for the user device 201 with the message sending progress of the video media stream that is normally played in the channel;

s306: when the synchronization is completed, the access device 202 stops sending the video media stream message of the channel cached by the access device 202 to the user device 201, and sends the video media stream message of the channel normally played to the user device 201 at the same time.

The synchronization process may synchronize the playback progress of the user device 201 with the normal playback progress of the channel.

In the above step S305 and step S306, there are various specific implementation manners for synchronizing the message sending progress of the video media stream for the user equipment 201 with the message sending progress of the video media stream normally played in the channel and switching to the video media stream normally played, and three alternative implementation manners are given below, and the actual implementation manner is not limited to these three.

First alternative implementation

When the access device 202 detects that a scene switching occurs in the message of the video media stream that is normally played in the channel, it stops sending the message of the video media stream of the channel that is cached by the access device 202 to the user device 201, and starts sending the message of the video media stream that is normally played in the channel to the user device 201 at the same time.

Here, the time when the scene switching occurs in the message of the normally played video media stream may be regarded as the aforementioned time when the synchronization is completed.

The scene switching refers to switching from a current shooting picture to another picture without connection, and does not include lens advancing, stretching, rotating, moving, focus changing and the like. Scene switching is a common phenomenon in video, and since the message of the corresponding video media stream is generally an I-frame when scene switching occurs, the message of the video media stream that is normally played in the channel is sent to the user equipment 201 from the I-frame, a video viewer of the user equipment 201 cannot easily perceive that some frames are discarded in the message of the video media stream sent by the user equipment 201, and the problem of screen splash does not occur during playing.

Second alternative implementation

In the process of sending the message of the video media stream for the user equipment 201 to the user equipment 201, the access equipment 202 reduces sending of some B frames until the message sending progress of the video media stream for the user equipment 201 is consistent with the message sending progress of the video media stream normally played in the channel, and the access equipment 202 stops sending the message of the video media stream cached in the access equipment 202 to the user equipment 201 and simultaneously starts sending the message of the video media stream normally played in the channel to the user equipment 201.

Here, when the message transmission progress of the video media stream for the user equipment 201, which is transmitted to the user equipment 201 by the access equipment 202, is consistent with the message transmission progress of the video media stream normally played on the channel, the access equipment 202 may determine that the synchronization is completed. The time when the message transmission progress of the video media stream for the user equipment 201 is consistent with the message transmission progress of the video media stream normally played in the channel may be regarded as the aforementioned "synchronization completion" time.

In addition, optionally, before the access device 202 sends the cached message of the video media stream of the channel to the user device 201, the access device 202 may further obtain the identification information of the user device 201, and the access device 202 may send the cached message of the video media stream of the channel to the user device 201 identified by the obtained identification information.

The identification information of the user equipment 201 may be a user identity used when the user of the user equipment 201 logs in the IPTV system, such as: a user of the ue 201 logs in the IPTV system by dialing a Point-to-Point protocol over Ethernet (PPPoE); the identification information of the user equipment 201 may be a port on the access equipment 202 used when the user equipment 201 is connected to the access equipment 202.

Referring to fig. 4, a channel switching scheme provided in the present application is illustrated.

As shown in fig. 4, the IPTV system is composed of STB (a kind of user equipment), AN (AN access device, such as DSLAM, OLT, SR, BRAS, etc.), and Head-End (a kind of video source device), and the system may further include a home subscriber side gateway dialing device, such as HG. The specific flow of the channel switching scheme based on the IPTV system is as follows:

s401: the AN caches the multicast IP message of the channel A received from the Head-End;

s402: the AN identifies the multicast IP message which can be independently decoded in the cached multicast IP message of the channel A;

the multicast IP packet is the aforementioned packet of the video media stream.

The multicast IP packet can be independently decoded, which is the aforementioned "independently decodable packet".

The AN may identify the start position of the independently decodable multicast IP packet in the cached multicast IP packet of the channel a in the multicast IP packet of the channel a.

S403: the STB sends a channel switching request to the AN to request to switch to a channel A;

the channel switch request is used to indicate that the STB requests a switch to channel a. The channel switch request may include an IGMP leave request and an IGMP join request. Where the IGMP leave request is used to indicate that the STB requests to leave the channel now being watched and the IGMP join request is used to indicate that the STB requests to switch to channel a.

S404: after receiving a channel switching request sent by the STB, the AN individually copies a group of multicast IP messages aiming at the STB from the cached multicast IP messages of the channel A;

here, the meaning of individual replication may be: and the AN acquires the identification information of the STB, and sends the multicast IP message aiming at the STB identified by the acquired identification information from the initial position of the identified multicast IP message capable of independently decoding in the cached multicast IP message of the channel A. The first multicast IP packet sent to the STB may be AN independently decodable multicast IP packet whose packet receiving time is closest to the time when the AN receives the channel switching request of the channel a, and may be, for example, a GOP start packet, that is, a packet including AN I frame. The relationship between the transmission starting point of the multicast IP packet for the channel a of the STB and the playing position of the real-time multicast IP packet for the channel a can be as shown in fig. 5. As can be seen from fig. 5, the transmission start point of the multicast IP packet for channel a of the STB lags behind the playing position of the real-time multicast IP packet for channel a.

S405: the AN synchronizes the sending progress of the multicast IP message aiming at the STB with the sending progress of the real-time multicast IP message of the channel A;

the synchronization process may be performed when the AN detects a scene change of the real-time multicast IP packet of the channel a. Scene cut detection can be achieved through a detection algorithm (ITU-T P1201-2E) and can also promote standard shot cut marking in multicast IP messages.

The specific implementation manner of synchronization may be that, when the AN detects that the scene switching occurs to the real-time multicast IP packet of the channel a, the multicast IP packet of the channel a is continuously copied for the STB from the I frame corresponding to the scene switching, which is equivalent to discarding some multicast IP packets during the copying process.

In order to make the audience not easily perceive that the multicast IP messages are discarded in the synchronization process, the maximum discarded message number in one synchronization process can be limited, and if the discarded multicast IP message number in one time cannot realize synchronization, the synchronization process can be carried out for many times.

In addition, after the synchronization process is executed, if there are a small number of unsynchronized multicast IP packets, the AN may discard a small number of non-reference B frames in the subsequent replication process to complete the final synchronization.

S406: and the AN stops sending the cached multicast IP message of the channel A to the STB and simultaneously sends the real-time multicast IP message of the channel A to the STB.

No matter which synchronization method is adopted, when S405 is completed, the AN stops sending the cached multicast IP packet of the channel a to the STB, and sends the real-time multicast IP packet of the channel a to the STB at the same time.

Fig. 6 is a schematic structural diagram of an access device provided in the present application. The access device may be applied to the IPTV system shown in fig. 2, and as shown in fig. 6, the access device includes:

a receiving module 601, configured to receive a packet of a video media stream of one channel from a video source device;

a caching module 602, configured to cache the message of the video media stream of the channel received by the receiving module 601;

the receiving module 601 is further configured to receive a channel switching request sent by the user equipment, where the channel switching request is used to instruct the user equipment to request to play a video media stream of the channel;

the sending module 603 is configured to send the message of the video media stream of the channel to the user equipment, starting from the independently decodable message in the message of the video media stream of the channel cached by the caching module 602.

Optionally, the processing module is configured to identify, before the sending module 603 starts sending the packet of the video media stream of the channel from the independently decodable packet in the packet of the video media stream of the channel cached by the caching module 602 to the user equipment, the independently decodable packet in the packet of the video media stream of the channel cached by the caching module 602;

the sending module 603 is specifically configured to, when starting from an independently decodable packet in the packet of the video media stream of the channel cached by the caching module 602 and sending the packet of the video media stream of the channel to the user equipment: the message of the video media stream of the channel is sent to the user equipment starting from the independently decodable message identified in the message of the video media stream of the channel cached by the caching module 602.

Optionally, when starting from the independently decodable packet in the packet of the video media stream of the channel cached by the caching module 602 and sending the packet of the video media stream of the channel to the user equipment, the sending module 603 is specifically configured to:

in the messages of the video media stream of the channel cached by the caching module 602, the message of the video media stream of the channel is sent to the user equipment from the independently decodable message whose message receiving time is closest to the time when the receiving module 601 receives the channel switching request.

Optionally, the access device further includes a processing module, configured to synchronize, after the sending module 603 starts sending the message of the video media stream of the channel to the user equipment from the independently decodable message in the message of the video media stream of the channel cached by the caching module 602, a message sending progress of the video media stream of the channel for the user equipment with a message sending progress of the video media stream that is normally played by the channel;

the sending module 603 is further configured to stop sending the message of the video media stream of the channel cached by the caching module 602 to the user equipment when the processing module completes synchronization, and send the message of the video media stream normally played in the channel to the user equipment.

based on the internet group management protocol IGMP, the message of the video media stream of the channel is sent to the user equipment, starting from the independently decodable message in the message of the video media stream of the channel cached by the caching module 602.

Alternatively, the independently decodable packet is a group of pictures, GOP, start packet.

An alternative hardware implementation of the access device may refer to fig. 7, where the receiving module 601 may be implemented by the receiver 701 in fig. 7, the buffering module 602 may be implemented by the processor and the memory 702, and the sending module 603 may be implemented by the sender 703 in fig. 7. The processor controls to cache the message received by the receiver 701 in the memory 702, and controls to send the message cached in the memory 702 through the sender 703, and the processing module may be implemented by the processor. The transmitter 703 and the receiver 701 may also be implemented by a unified input/output (I/0) interface. The I/O interface, the memory 702, and the processor may be connected by a bus through which data and messages may be exchanged.

Fig. 8 is a flowchart of another channel switching method provided in the present application. The method can be applied to the IPTV system shown in fig. 2. As shown in fig. 8, the method includes:

s801: the access equipment receives a message of a video media stream of a channel sent by video source equipment;

s802: the access equipment caches the received message of the video media stream of the channel;

s803: the access equipment receives a channel switching request sent by user equipment, wherein the channel switching request is used for indicating the user equipment to request to play a video media stream of a channel;

s804: and the access equipment sends the message of the video media stream of the channel to the user equipment from the independently decodable message in the cached message of the video media stream of the channel.

Optionally, before the access device sends the message of the video media stream of the channel to the user equipment, starting from the independently decodable message in the cached message of the video media stream of the channel, the method further includes: the access equipment identifies the independent decoding message in the cached message of the video media stream of the channel;

the access device sends the packet of the video media stream of the channel to the user equipment starting from the independently decodable packet in the buffered packet of the video media stream of the channel, and specifically includes: the access equipment sends the message of the video media stream of the channel to the user equipment from the independently decodable message identified in the cached message of the video media stream of the channel.

Optionally, the sending, by the access device, the packet of the video media stream of the channel to the user equipment, starting from the independently decodable packet in the buffered packet of the video media stream of the channel, includes:

in the message of the video media stream of the channel cached by the access device, the access device sends the message of the video media stream of the channel to the user equipment from the independently decodable message with the message receiving time closest to the time that the access device receives the channel switching request.

Optionally, after the access device sends the message of the video media stream of the channel to the user equipment, starting from the independently decodable message in the cached message of the video media stream of the channel, the method further includes:

Optionally, the sending, by the access device, the packet of the video media stream of the channel to the user equipment starting from the independently decodable packet in the buffered packet of the video media stream of the channel includes:

and the access equipment transmits the messages of the video media stream of the channel to the user equipment from the independently decodable messages in the cached messages of the video media stream of the channel based on the Internet Group Management Protocol (IGMP).

Other alternative implementations of the method may refer to the processing of access device 202 described above.

In summary, since the access device sends the message of the video media stream of the channel to the user equipment from the independently decodable message in the message of the video media stream of the channel, the first message received when the user equipment switches channels can be an independently decodable message, and the user equipment can start decoding and playing from the independently decodable message; however, with the channel switching method in the prior art, most of the cases, the first message received by the user equipment is not an independently decodable message, and therefore decoding and playing cannot be started immediately. Therefore, the problem of low channel switching speed in the channel switching process can be solved by adopting the scheme provided by the application.

As will be appreciated by one skilled in the art, embodiments of the present invention may be provided as a method, system, or computer program product. Accordingly, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.

The present invention is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

While preferred embodiments of the present invention have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims be interpreted as including preferred embodiments and all such alterations and modifications as fall within the scope of the invention.

It will be apparent to those skilled in the art that various modifications and variations can be made in the embodiments of the present invention without departing from the spirit or scope of the embodiments of the invention. Thus, if such modifications and variations of the embodiments of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to encompass such modifications and variations.

Claims

1. An access device, comprising:

the receiving module is used for receiving a message of a video media stream of one channel from video source equipment;

the receiving module is further configured to receive a channel switching request sent by user equipment, where the channel switching request is used to instruct the user equipment to request to play a video media stream of the channel;

a sending module, configured to send, to the user equipment, a packet of the video media stream of the channel from an independently decodable packet in the packet of the video media stream of the channel cached by the caching module;

a processing module, configured to detect whether a scene switch occurs in a message of a video media stream that is normally played by the channel after the sending module sends the message of the video media stream of the channel to the user equipment starting from an independently decodable message in the message of the video media stream of the channel that is cached by the caching module;

the sending module is further configured to: when the processing module detects that scene switching occurs in the message of the video media stream played normally in the channel, the sending of the message of the video media stream of the channel cached by the access device to the user equipment is stopped, and the message of the video media stream played normally in the channel is sent to the user equipment.

2. The access device of claim 1, wherein the processing module is further configured to:

before the sending module sends the message of the video media stream of the channel to the user equipment from the independently decodable message in the message of the video media stream of the channel cached by the caching module, identifying the independently decodable message in the message of the video media stream of the channel cached by the caching module;

3. The access device according to claim 1 or 2, wherein the sending module, when starting from an independently decodable packet in the packets of the video media stream of the channel cached by the caching module, sends the packet of the video media stream of the channel to the user device, is specifically configured to:

and in the messages of the video media streams of the channels cached by the cache module, starting from the independently decodable message with the message receiving time closest to the time when the receiving module receives the channel switching request, sending the messages of the video media streams of the channels to the user equipment.

4. The access device according to claim 1 or 2, wherein the sending module, when starting from an independently decodable packet in the packets of the video media stream of the channel cached by the caching module, sends the packet of the video media stream of the channel to the user device, is specifically configured to:

and based on an internet group management protocol IGMP, starting from an independently decodable packet in the packets of the video media stream of the channel cached by the caching module, sending the packets of the video media stream of the channel to the user equipment.

5. The access device of claim 1 or 2, wherein the independently decodable message is a group of pictures, GOP, start message.

6. An internet protocol television, IPTV, system comprising:

the video source equipment is used for sending a message of a video media stream of one channel;

the access device according to any one of claims 1 to 5, configured to receive and process a packet of a video media stream of the channel sent by the video source device; and

7. A method of channel switching, the method comprising:

the access equipment receives a message of a video media stream of a channel sent by video source equipment;

the access equipment sends the messages of the video media streams of the channels to the user equipment from the independently decodable messages in the cached messages of the video media streams of the channels;

wherein, after the access device starts from the independently decodable packet in the buffered packet of the video media stream of the channel, sending the packet of the video media stream of the channel to the user equipment, the method further includes:

and when the access equipment detects that scene switching occurs in the message of the video media stream which is played normally in the channel, stopping sending the message of the video media stream of the channel cached by the access equipment to the user equipment, and sending the message of the video media stream which is played normally in the channel to the user equipment.

8. The method of claim 7,

before the access device sends the packets of the video media stream of the channel to the user equipment starting from the independently decodable packets in the buffered packets of the video media stream of the channel, the method further includes: the access equipment identifies the independently decodable message in the cached messages of the video media stream of the channel;

9. The method of claim 7 or 8, wherein the access device sending the packets of the video media stream of the channel to the user device starting from the buffered independently decodable packets of the video media stream of the channel, comprises:

10. The method of claim 7 or 8, wherein the access device sending the packets of the video media stream of the channel to the user device starting from an independently decodable packet of the buffered packets of the video media stream of the channel, comprising:

11. The method according to claim 7 or 8, wherein the independently decodable packet is a group of pictures, GOP, start packet.