WO2015154518A1

WO2015154518A1 - Flow control method, apparatus and system for variable bitrate media stream

Info

Publication number: WO2015154518A1
Application number: PCT/CN2014/094425
Authority: WO
Inventors: 陆忠孝
Original assignee: 中兴通讯股份有限公司
Priority date: 2014-07-10
Filing date: 2014-12-19
Publication date: 2015-10-15
Also published as: CN105245946B; CN105245946A

Abstract

A flow control method, apparatus and system for variable bitrate media stream. The flow control method for variable bitrate media stream is applied to the scenario that a player of a set-top box plays the variable bitrate media stream from a stream media server. The method comprise that: a control apparatus monitors a first current value of the set-top box cache usage rate; the control apparatus judges whether the first current value is bigger than or equal to an overflow threshold; when the first current value is bigger than or equal to the overflow threshold, the control apparatus performs the flow control by separating the statuses of the player and the stream media server, until a second current value of the set-top box cache usage rate is smaller than the overflow threshold.

Description

Flow rate control method, device and system for variable rate media stream

Technical field

The present invention relates to, but is not limited to, the field of video, and in particular to a flow control method, apparatus and system for a variable rate media stream.

Background technique

Currently, there are three main ways of streaming media transmission: Unicast, Multicast, and Broadcast. Point-to-point is generally called unicast, and unicast is based on two basic transport protocols: TCP (Transmission Control Protocol) and UDP (User Datagram Protocol). TCP is a reliable transport protocol, but it is less efficient. UDP is an unreliable transmission protocol, and the transmission quality is guaranteed by the user, but has higher transmission efficiency. Streaming media usually uses UDP transport.

The UDP protocol does not define a control method for the transmission speed between two communication nodes. In an IPTV (Internet TV) system, the buffer for storing data of a user terminal (usually a set top box) has a size limitation, so the streaming media of UDP transmission needs a method of controlling the transmission speed to ensure that the transmission speed does not occur. The problem that the set-top box buffer overflow data is lost. Currently, the commonly used telecommunication standard is controlled by adding a control field in the RTSP (Real-Time Streaming Protocol), since the set-top box is sent to the streaming server for adjusting the transmission speed. This method generally works well when transmitting CBR (fixed code rate) sources, but has drawbacks when transmitting VBR (Variable Rate) sources.

VBR dynamic bit rate, as the name suggests, the code rate changes dynamically with time, so the transmission code rate will also change dynamically during transmission. This may lead to a situation where the flow is out of control. For example, the code rate transmitted during a certain period of time is a low code rate, followed by a high bit rate for a period of time. The low bit rate code stream is relatively easy to transfer to the set top box and accumulates in the cache. At the same time, the low code rate code stream consumes slower during playback, and the high code rate code stream that follows is due to the front. The cache is not consumed in time, and will soon cause the set-top box to have insufficient buffer space and overflow. This phenomenon is more obvious when transmitting the source of the HD bit rate. If the traffic control method of the telecommunication standard is used to request the streaming server to send a slow message (the transmission rate is lower than the source code rate), there are two problems, one problem is: slow transmission Compared with the source code rate, the adjustment rate is not very low, resulting in no rapid decrease in traffic, and the adjustment effect on the source code stream of the VBR chip is not obvious. Another problem is that the slow-motion adjustment process is a time-consuming process, and it is very likely that the set-top box cache has overflowed at high-definition bit rates, and the transmission rate has not dropped to a sufficiently low rate.

Summary of the invention

The embodiment of the invention provides a flow control method, device and system for variable rate media streams, which can solve the problem of flow control failure caused by code stream rate change.

A flow rate control method for a variable rate media stream is applied to a scenario in which a player of a set top box plays a variable rate media stream from a streaming media server, the method comprising:

The control device monitors a first current value of the set top box cache usage rate;

The control device determines whether the first current value is greater than or equal to an overflow threshold;

When the first current value is greater than or equal to the overflow threshold, the control device performs flow control by separating the states of the player and the streaming media server until the second current cache of the set top box cache usage rate The value is less than the overflow threshold.

Optionally, the step of controlling, by the control device, the flow control by separating the states of the player and the streaming media server comprises:

The control device sends a first pause command to the streaming media server, and does not forward the response message to the player after receiving the response message of the streaming media server for the first pause command, so that the streaming media server Switching to the suspend transmission state directly without notifying the player.

Optionally, the method further includes:

After the controlling device performs the flow control step by separating the states of the player and the streaming server, when the second current value of the set top box cache usage rate is less than the overflow threshold, the control The device sends a first recovery command to the streaming media server, and does not forward the response message to the player after receiving the response message of the streaming media server for the first recovery command, so that the streaming media server does not notify In the case of the player, it is directly switched to the transmission state.

Optionally, after the step of controlling, by the control device, the flow control by separating the state of the player and the streaming media server, and sending, by the control device, the streaming media server Before the step of restoring the command, the method further includes:

When the control device receives the second pause command of the user, the control device forwards the second pause command to the player of the set top box, and notifies the player of the set top box not to forward to the streaming server The second pause command causes the player to directly switch to the pause play state without forwarding the second pause command to the streaming server;

When the control device receives the second resume command of the user, and the last user command of the second resume command is a pause command, the control device sends the second resume command to the player of the set top box. Notifying the player that the second recovery command is not forwarded to the streaming media server, so that the player directly switches to the playing state without forwarding the second recovery command to the streaming media server. ;

And when the control device receives the fast forward or rewind command of the user, sending the fast forward or fast reverse command to the streaming media server and the player, so that the streaming media server and the playing Both switches to fast forward or rewind status.

Optionally, after the step of determining, by the control device, that the first current value is greater than or equal to an overflow threshold, the method further includes:

When the first current value is less than the overflow threshold and greater than the underflow threshold, the control device sends a request for fast or slow command to the streaming server; the overflow threshold is greater than the underflow threshold ;

When the first current value is less than the underflow threshold, the control device sends a request fast command to the streaming server.

A flow rate control device for a variable rate media stream is applied to a scenario in which a player of a set top box plays a variable rate media stream from a streaming media server, wherein the device comprises:

a monitoring unit that monitors a first current value of the set top box cache usage rate;

a determining unit, determining whether the first current value is greater than or equal to an overflow threshold;

a control unit, when the first current value is greater than or equal to the overflow threshold, performing flow control by separating states of the player and the streaming server until a second current value of the set top box cache usage rate Less than the overflow threshold.

Optionally, the control unit includes:

Sending a subunit, sending a first pause command to the streaming server;

Receiving a subunit, receiving a response message of the streaming media server for the first pause command, and not forwarding to the player, so that the streaming media server directly switches to a pause without notifying the player send status.

Optionally, the device further includes:

After the flow control is performed, the first sending unit sends a first resume command to the streaming media server when the second current value of the set top box cache usage rate is less than the overflow threshold;

Receiving, by the receiving unit, the response message of the streaming media server for the first recovery command, and not forwarding to the player, so that the streaming media server directly switches to sending without notifying the player. status.

Optionally, the device further includes:

a second sending unit, when the first current value is smaller than the overflow threshold and greater than an underflow threshold, sending a request for a fast or slow command to the streaming server; the overflow threshold is greater than the underflow Threshold value

The third sending unit sends a request fast sending command to the streaming server when the first current value is less than the underflow threshold.

A flow rate control system for variable rate media streams is applied to a scenario in which a player of a set top box plays a variable rate media stream from a streaming media server, including: a set top box, a streaming media server, and the above flow control device.

Embodiments of the present invention also provide a computer program comprising program instructions that, when executed by a computer, cause the computer to perform the method described above.

Embodiments of the present invention also provide a computer readable storage medium carrying the computer program.

In the embodiment of the present invention, the player and the streaming media state are separated to implement flow control, and the dynamic rate adjustment of the transmission rate is not required, and the dynamic adjustment is fast and slow, and the implementation is simple, and the VBR code stream rate change is caused to cause the traditional flow control. The problem of failure.

BRIEF abstract

1 is a schematic flowchart of a flow control method of a variable rate media stream according to an embodiment of the present invention;

2 is a schematic diagram showing the connection of a flow rate control device for a variable rate media stream according to an embodiment of the present invention;

3 is a schematic diagram of connection of a flow rate control system of a variable rate media stream according to an embodiment of the present invention;

4 is a schematic diagram of a system architecture of an application scenario of a flow rate control method for a variable rate media stream according to an embodiment of the present invention;

FIG. 5 is a schematic diagram of partitioning of a cache space in an application scenario according to an embodiment of the present invention;

FIG. 6 is a schematic diagram of a flow control method in an application scenario according to an embodiment of the present invention; FIG.

FIG. 7 is a schematic flowchart of state separation and recovery synchronization of a player and a streaming media in an application scenario according to an embodiment of the present invention.

Preferred embodiment of the invention

The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings, and the features of the embodiments and the embodiments of the present invention can be arbitrarily combined with each other without conflict.

As shown in FIG. 1 , an embodiment of the present invention provides a flow control method for a variable rate media stream, which is applied to a scenario in which a player of a set top box plays a variable rate media stream from a streaming media server, where the method includes :

Step 11, the control device monitors a first current value of the set top box cache usage rate;

Step 12: The control device determines whether the first current value is greater than or equal to an overflow threshold; the overflow threshold may be preset according to a situation.

Step 13: When the first current value is greater than or equal to the overflow threshold, the control device performs flow control by separating states of the player and the streaming media server until the set top box cache usage rate The second current value is less than the overflow threshold. That is to say, in this step, the value of the set top box cache usage rate is monitored in real time, and the flow control is stopped until the real time value of the cache usage rate is less than the overflow threshold. The step of controlling the flow control by the control device includes: the control device sending a first pause command to the streaming media server, and not forwarding the response message to the first pause command after receiving the streaming media server The player causes the streaming server to directly switch to a suspended transmission state without notifying the player. That is, the streaming server intercepts the response message.

Step 14: When the first current value is less than the overflow threshold and greater than a underflow threshold, The control device sends a request to the streaming media server to request a quick or slow command; the overflow threshold is greater than the underflow threshold; wherein the sending request fast or slow command can be adjusted according to the actual usage scenario, for example, As much as possible, the cache usage rate is increased, and a fast transmission is requested as long as the first current value does not reach the overflow threshold, and a slow transmission is requested when the first current value approaches the overflow threshold. The control device intercepts the response message of the streaming media server, so that the response message does not affect the state of the player, wherein the fast transmission means that the transmission rate is higher than the source code encoding rate.

Step 15: When the first current value is less than the underflow threshold, the control device sends a request fast command to the streaming server.

The method further includes:

Step 16. After the step of performing flow control, when the second current value of the set top box cache usage rate is less than the overflow threshold, the control device sends a first resume command to the streaming media server. And after receiving the response message of the streaming media server for the first recovery command, the device does not forward the message to the player, so that the streaming media server directly switches to the sending state without notifying the player. That is to say, the control device intercepts the response message of the streaming media server, so that the response message does not affect the state of the player.

After step 13, before step 16, the method further includes:

Step 13A, when the control device receives the second pause command of the user, the control device forwards the second pause command to the player of the set top box, and notifies the player of the set top box not to the stream The media server forwards the second pause command, so that the player directly switches to the suspended play state without forwarding the second pause command to the streaming server;

Step 13b, when the control device receives the second resume command of the user, and the previous user command of the second resume command is a pause command, the control device sends the first message to the player of the set top box. Recovering the command, and notifying the player that the second recovery command is not forwarded to the streaming media server, so that the player directly switches without forwarding the second recovery command to the streaming media server. To the playback state;

Step 13c, when the control device receives the fast forward or fast reverse command of the user, sending the fast forward or fast reverse command to the streaming media server and the player, so that the streaming media server and The players are all switched to a fast forward or fast reverse state. The control device may send a fast forward or fast reverse command to the streaming media server through the set top box, or directly serve the streaming media service. The device sends a fast forward or rewind command.

The above scenario describes the processing flow of receiving the user's instruction before canceling the flow control process after performing flow control.

As shown in FIG. 2, a flow rate control device for a variable rate media stream is applied to a scenario in which a player of a set top box plays a variable rate media stream from a streaming media server, The device includes:

The monitoring unit 21 monitors a first current value of the set top box cache usage rate;

The determining unit 22 determines whether the first current value is greater than or equal to an overflow threshold;

The control unit 23, when the first current value is greater than or equal to the overflow threshold, performs flow control by separating the states of the player and the streaming server until the second current cache of the set top box is used. The value is less than the overflow threshold.

The control unit 23 includes:

Sending a subunit, sending a first pause command to the streaming server;

The device further includes:

After the flow control is performed, the first sending unit 24 sends a first resume command to the streaming media server when the second current value of the set top box cache usage rate is less than the overflow threshold.

The receiving unit 25 receives the response message of the streaming media server for the first recovery command, and does not forward the message to the player, so that the streaming media server directly switches to the player without notifying the player. send status.

The device further includes:

The second sending unit 26, when the first current value is smaller than the overflow threshold and greater than the underflow threshold, sends a request for fast or slow command to the streaming server; the overflow threshold is greater than the lower Overflow threshold

The third sending unit 27 sends a request fast command to the streaming server when the first current value is less than the underflow threshold.

As shown in FIG. 3, a flow rate control system for a variable rate media stream according to the present invention is applied to a scenario in which a player of a set top box plays a variable rate media stream from a streaming media server, including: a set top box 31. , streaming server 32 and control device 33;

The control device 33 monitors a first current value of the cache usage rate of the set top box 31; determines whether the first current value is greater than or equal to an overflow threshold; and when the first current value is greater than or equal to the overflow threshold Flow control is performed by separating the states of the player and the streaming server until the second current value of the set top box cache usage is less than the overflow threshold.

The first application scenario of the embodiment of the present invention is described below.

This application scenario is a transmission flow control method for improving an IPTV network interactive television transmission VBR variable rate media stream.

Device architecture: The embodiment of the present invention can be applied to the set-top box side in the IPTV system (see FIG. 4), and only needs to be modified on the set-top box side in the IPTV system, and does not need to modify the existing IPTV architecture, and has no effect on other devices in the system. . In the IPTV playback process, RTSP (Real Time Streaming Protocol) is used to interact with the streaming server for playback control.

Includes the following steps:

Step 1. The set-top box cache usage rate is divided into three sections using two thresholds (underflow threshold and overflow threshold): an underflow interval, a normal interval, and an overflow interval.

The underflow threshold means that when the cache usage rate is lower than the value, the underflow interval is; the overflow threshold is: when the cache usage rate is higher than the value, it belongs to the overflow interval; the cache usage rate is at the overflow threshold and The underflow threshold is attributed to the normal interval.

In step 2, the cache usage rate in different intervals is processed. There are generally four situations in the process:

(1) When the underflow interval is in the underflow interval, the set-top box requests fast transmission through the flow control mode (refers to the flow rate is greater than the source code rate);

(2) When the device is in the normal interval, the set-top box requests fast transmission or resumes normal flow or slow transmission through flow control mode as needed;

(3) When the overflow box is in the overflow interval, the set-top box issues a PAUSE pause command through the RTSP protocol, so that the streaming media server pauses the flow.

(4) In the overflow interval and wait for the cache usage to return to positive after issuing the PAUSE command The normal interval or the underflow interval, and then the PLAY command is issued through the RTSP protocol.

Step 3, allowing the player and streaming status to be out of sync. If the set-top box cache usage rate is in the overflow interval, after the RTP PAUSE command is issued by the set-top box, the streaming media state and the player state are separated, that is, the player keeps playing state, and the streaming media is in a pause state.

Step 4: After the cache usage is restored from the overflow interval to the normal or underflow interval, the player state and the streaming media state are restored.

At this point, flow control is complete.

A second application scenario of the embodiment of the present invention is described below.

First, in conjunction with FIG. 5, the set-top box cache usage rate is divided into three sections for use in the process of FIG.

Combined with Figure 6, the specific steps are as follows:

Step 601, the set top box starts to play a unicast program;

Step 602, requesting the server to send a fast message;

Step 603, detecting the current cache usage rate of the set top box (the following cache judgments are all determining the set top box cache usage rate);

Step 604, it is determined whether the cache usage rate is in the underflow interval, yes, proceeds to step 605, no, proceeds to step 608;

Step 605, it is determined whether the step of issuing an RTSP PAUSE command to the streaming server in step 609, yes, proceeds to step 607, and proceeds to step 606;

Step 606, requesting the server to quickly send the code stream, returning to step 603;

Step 607, issuing a PLAY command to the streaming server through the RTSP protocol. Requesting the server to send the code stream, the player is synchronized with the streaming media state recovery, and returning to step 603;

In step 608, it is determined whether the cache usage rate is in the normal interval. If yes, there is no action according to the requirement or the process proceeds to step 606; otherwise, the process proceeds to step 609.

Step 609, determining whether the cache usage rate is in the overflow interval, is, issuing a PAUSE command to the streaming server through the RTSP protocol, proceeds to step 610;

Step 610, separating the player and the streaming media state, so that the player continues to play the state, and the streaming media is in the suspended state, and returns to step 603.

FIG. 7 is a schematic diagram of state separation and recovery of a player and a streaming media, including the following steps:

After entering the flow control, PAUSE starts to separate the player and the streaming media state. Specifically, the PAUSE response of the streaming media needs to be intercepted, so that the player cannot be perceived. At this time, the player is in the playing state, and the streaming media is in the suspended state. Synchronize.

When the player and the streaming media state are out of step, if the set-top box receives the user's playback control command, it needs to be differentiated: (1) If it is a PAUSE command, the interception makes the streaming media unperceive, and at the same time outputs PAUSE to the player, and directly enters the pause. (2) If the user issues a RESUME command after PAUSE, the same interception makes the streaming media undetectable, and outputs RESUME to the player to resume playback directly. (3) If it is another user command, such as fast forward, fast rewind, etc., it is sent to the streaming media, and the player is synchronized with the streaming media state.

When the player and the streaming media state are out of synchronization, if the flow control pause is to be canceled, the PLAY command is sent to the streaming media, and the interception response is made to prevent the player from being perceived. At this time, the streaming media resumes playing state and resumes synchronization with the player.

At this point, the flow control is completed during the entire playback before the end of playback.

The IPTV system terminal according to the embodiment of the present invention controls the flow of the media stream based on the UDP protocol, and uses the RTSP command to separate the player and the streaming media state to implement flow control, and can cope with various extreme situations that cause the set top box to overflow. Not limited to transmitting VBR code streams. In addition, there is no need to care about the change of the transmission code rate to frequently adjust the fast and slow dynamics, and the implementation is simple, and has good application value. The flow control method for improving the IPTV transmission VBR code stream in the embodiment of the present invention solves the problem that the traditional flow control fails due to the VBR code stream rate change.

The above is a preferred embodiment of the present invention, and it should be noted that those skilled in the art can also make several improvements and retouchings without departing from the principles of the present invention. It should be considered as the scope of protection of the present invention.

One of ordinary skill in the art will appreciate that all or a portion of the steps of the above-described embodiments can be implemented using a computer program flow, which can be stored in a computer readable storage medium, such as on a corresponding hardware platform (eg, The system, device, device, device, etc. are executed, and when executed, include one or a combination of the steps of the method embodiments.

Optionally, all or part of the steps of the foregoing embodiments may also be implemented by using an integrated circuit, and the steps may be separately fabricated into integrated circuit modules, or multiple modules thereof or The steps are made into a single integrated circuit module. Thus, the invention is not limited to any specific combination of hardware and software.

The devices/function modules/functional units in the above embodiments may be implemented by a general-purpose computing device, which may be centralized on a single computing device or distributed over a network of multiple computing devices.

When each device/function module/functional unit in the above embodiment is implemented in the form of a software function module and sold or used as a stand-alone product, it can be stored in a computer readable storage medium. The above mentioned computer readable storage medium may be a read only memory, a magnetic disk or an optical disk or the like.

Variations or substitutions are readily conceivable within the scope of the present invention by those skilled in the art and are within the scope of the present invention. Therefore, the scope of the invention should be determined by the scope of the claims.

Industrial applicability

Claims

A flow rate control method for a variable rate media stream is applied to a scenario in which a player of a set top box plays a variable rate media stream from a streaming media server, the method comprising:

The control device monitors a first current value of the set top box cache usage rate;

The control device determines whether the first current value is greater than or equal to an overflow threshold;

When the first current value is greater than or equal to the overflow threshold, the control device performs flow control by separating the states of the player and the streaming media server until the second current cache of the set top box cache usage rate The value is less than the overflow threshold.
The method according to claim 1, wherein said controlling means performs flow control by separating states of said player and said streaming server comprises:

The control device sends a first pause command to the streaming media server, and does not forward the response message to the player after receiving the response message of the streaming media server for the first pause command, so that the streaming media server Switching to the suspend transmission state directly without notifying the player.
The method of claim 1 further comprising:

After the controlling device performs the flow control step by separating the states of the player and the streaming server, when the second current value of the set top box cache usage rate is less than the overflow threshold, the control The device sends a first recovery command to the streaming media server, and does not forward the response message to the player after receiving the response message of the streaming media server for the first recovery command, so that the streaming media server does not notify In the case of the player, it is directly switched to the transmission state.
The method according to claim 2, wherein after said controlling means performs flow control by separating states of said player and said streaming server, and said control means transmits to said streaming server Before the step of recovering the command, the method further includes:

When the control device receives the second pause command of the user, the control device forwards the second pause command to the player of the set top box, and notifies the player of the set top box not to forward to the streaming server The second pause command causes the player to directly switch to the pause play state without forwarding the second pause command to the streaming server;

When the control device receives the second resume command of the user, and the previous user command of the second resume command is a pause command, the control device sends the message to the player of the set top box. a second recovery command, and notifying the player that the second recovery command is not forwarded to the streaming server, so that the player directly directly forwards the second recovery command to the streaming server Switch to the playback state;

And when the control device receives the fast forward or rewind command of the user, sending the fast forward or fast reverse command to the streaming media server and the player, so that the streaming media server and the playing Both switches to fast forward or rewind status.
The method of claim 1, wherein the method further comprises: after the step of determining, by the control device, that the first current value is greater than or equal to an overflow threshold, the method further comprising:

When the first current value is less than the overflow threshold and greater than the underflow threshold, the control device sends a request for fast or slow command to the streaming server, where the overflow threshold is greater than the underflow threshold ;

When the first current value is less than the underflow threshold, the control device sends a request fast command to the streaming server;

Among them, fast sending means that the sending rate is higher than the source coded code rate, and slow sending means that the sending rate is lower than the source coded code rate.
A flow rate control device for a variable rate media stream is applied to a scenario in which a player of a set top box plays a variable rate media stream from a streaming media server, the device comprising:

a monitoring unit configured to monitor a first current value of the set top box cache usage rate;

a determining unit, configured to determine whether the first current value is greater than or equal to an overflow threshold;

a control unit, configured to perform flow control by separating states of the player and the streaming media server when the first current value is greater than or equal to the overflow threshold, until the set top box cache usage rate is The two current values are less than the overflow threshold.
The apparatus of claim 6 wherein said control unit comprises:

a sending subunit configured to send a first pause command to the streaming server;

a receiving subunit, configured to receive a response message of the streaming media server for the first pause command, and not forwarding to the player, so that the streaming media server directly directly without notifying the player Switch to the paused transmission state.
The apparatus of claim 6 further comprising:

a first sending unit, configured to send a first resume command to the streaming server when the second current value of the set top box cache usage rate is less than the overflow threshold after the flow control is performed;

a receiving unit, configured to receive a response message of the streaming media server for the first recovery command, and not forwarding the message to the player, so that the streaming media server directly directly without notifying the player Switch to the sending state.
The apparatus of claim 6 further comprising:

a second sending unit, configured to send a request for a fast or slow command to the streaming server when the first current value is less than the overflow threshold and greater than a flood threshold; the overflow threshold is greater than Underflow threshold; and

And a third sending unit, configured to send a request fast command to the streaming server when the first current value is less than the underflow threshold.
A flow rate control system for variable rate media streams, which is applied to a scenario in which a player of a set top box plays a variable rate media stream from a streaming media server, including: a set top box, a streaming media server, and claims 6-9 A control device as claimed in any of the preceding claims.
A computer program comprising program instructions which, when executed by a computer, cause the computer to perform the method of any of claims 1-5.
A computer readable storage medium carrying the computer program of claim 11.