KR100631947B1 - Method and apparatus for transmitting frames intelligently - Google Patents

Abstract

The present invention relates to a method and apparatus for intelligent frame discard, and more particularly, to a method and apparatus for discarding a frame through rate control based on frame priority information. The frame discarding method according to the present invention comprises the steps of: (a) assigning priority information preset to a frame stored in a queue according to the type of the frame; (b) scanning the queue to extract priority information for the frame; (c) sequentially extracting frames starting from a frame having a high priority information in a queue according to a bandwidth corresponding to a current RC control interval; And (d) discarding the remaining frames that have not been extracted when frame extraction is completed corresponding to the bandwidth.

Rate control, forecasting. Frame, discard, packet

Description

Method and apparatus for discarding intelligent frames {Method and apparatus for transmitting frames intelligently}             

1A is a diagram showing the configuration of a frame transmission apparatus according to a preferred embodiment of the present invention.

1B is a flowchart illustrating a configuration of a frame discard control unit according to a preferred embodiment of the present invention.

2 is a flowchart illustrating the operation of the frame transmission apparatus according to the preferred embodiment of the present invention.

3A is a table illustrating a priority information system according to a preferred embodiment of the present invention.

3B is a diagram illustrating a frame structure in which priority information is added according to a preferred embodiment of the present invention.

4A is a flowchart illustrating a method for setting priority information according to a preferred embodiment of the present invention.

4B illustrates a pseudo code according to the flowchart of FIG. 4A.

Figure 5 is a flow chart illustrating a frame discard method according to a preferred embodiment of the present invention.

6A and 6B illustrate pseudo codes according to the flowchart of FIG.

7 is a flowchart illustrating a method of discarding prediction frames according to a preferred embodiment of the present invention.

8A and 8B illustrate pseudo codes according to the flowchart of FIG.

<Description of the symbols for the main parts of the drawings>

100: frame transmission device

110: rate control unit

120: frame discard control unit

121: priority information setting unit

123: frame position information management unit

125: frame extraction unit

127: frame discard control unit

130: frame disposal

140: optimal packet scheduler

150: cue

The present invention relates to a method and apparatus for intelligent frame discard, and more particularly, to a method and apparatus for discarding a frame through rate control based on frame priority information.

Recently, due to the rapid development of multimedia and network technologies, the demand for streaming services based on various networks has increased exponentially. Streaming technology has a great advantage in terms of storage space and response time by not directly storing the media stream transmitted from the server to the client, but processing it directly in memory. However, it must satisfy the prerequisites to guarantee the transmission rate required by the client. In order to guarantee such a transmission rate, in order to provide a video streaming service on a limited resource and a network, a means for transmitting or discarding frame by frame must be provided. In this case, it is very important to prevent loss of important information about the frame.

Since the frame discard algorithm according to the prior art is mostly performed in the link layer, there is a problem that depends on the protocol protocol and network. In other words, in order to use such an algorithm, there is a costly loss and hassle of replacing hardware configuring the network. In addition, the frame discarding algorithm according to the prior art is very complicated, and there is a problem that an estimated sub-algorithm must be used to apply such a technique.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problem, and an object thereof is to provide a method and apparatus for discarding a frame through rate control based on priority information for each frame.

Another object of the present invention is to provide an intelligent frame discard method and apparatus for guaranteeing QoS of video transmission and guaranteeing individual QoS according to a limited and dynamic network bandwidth.

In addition, another object of the present invention is to provide an intelligent frame discard method and apparatus that can determine the frame discard by predicting the transmission of the frame. That is, according to the prior art, an optimal frame discard algorithm is implemented through scheduling, but the present invention does not use such a frame-by-frame scheduling or a packet-by-packet scheduling method, and is connected to a rate control of a network and a limited transmission rate. Intelligent frame discard method can be provided.

In addition, the present invention provides an intelligent frame discarding method that can control the discarding or transmission of a frame at an application level without being dependent on a network, and will be further embodied in the embodiments described below for other purposes.

According to an aspect of the present invention for achieving the above object, there can be provided a method for transmitting a frame through Rate Control based on the priority information per frame.

According to a preferred embodiment, the frame discard method comprises the steps of: (a) assigning priority information set in advance to a frame stored in a queue according to the type of the frame; (b) scanning the queue to extract priority information for the frame; (c) sequentially extracting frames from the frame having the higher priority information in the queue according to a bandwidth corresponding to a current RC control interval; And (d) discarding the remaining frames that have not been extracted when frame extraction is completed corresponding to the bandwidth.

The priority information may include basic priority information assigned according to a type of a frame; And sub-priority information for giving a frame having the same basic priority information based on the image quality displayed at the receiving end. The basic priority information may be assigned to a frame including at least one of an I frame, a P frame, a B frame, and a high quality frame according to the type of the frame. The step (a) may include determining whether a discarded frame exists in a previous rate control interval (RC). And if the discarded frame exists, a sub priority of a frame located between the discarded frame and an I frame of a current RC interval (Rate Control Interval) is set lower than a P frame located after the I frame. It may include a step.

Also, the step (b) may include scanning the queue and recognizing a string of frames having the same priority information as a packet; When extracting a frame according to priority information, in order to extract the packet unit of the column of the frame, storing the packet frame position information for the start position and end position corresponding to the column packet of the frame; Can be. And (c) extracting the packet frame based on the current priority and then reducing the bandwidth corresponding to the extracted packet frame; And when the extraction of the packet frame corresponding to the current priority is completed, extracting the packet frame corresponding to the next priority, and reducing the bandwidth corresponding to the extracted packet frame, wherein the bandwidth is increased. It may be repeated until it does not exist or until all the packet frames for the queue are extracted.

In addition, the step (d) may be performed in response to the extracted packet frame; And recognizing a packet frame not displayed, and discarding the packet frame. Determining whether the rate control interval (RC) starts; Generating a prediction frame corresponding to a frame to reach the rate control interval when the rate control interval begins; Adding the prediction frame as a virtual frame to the queue; And performing the steps (a) to (d) on the queue. Here, when the actual frame corresponding to the prediction frame arrives, the method further includes correcting an estimation error between the prediction frame size and the actual frame size, wherein the error correction step is performed until the last prediction frame is reached. Generating error correction information by summing the actual frame sizes that have reached the prediction frame sizes; And summing the size of the prediction frame to the bandwidth and subtracting the error correction information.

According to another aspect of the present invention for achieving the above object, there can be provided an apparatus for transmitting a frame through Rate Control based on the priority information per frame.

According to a preferred embodiment, the frame transmission apparatus comprises: a priority information setting unit for assigning priority information preset in accordance with the type of the frame, to a frame stored in a queue; A frame position information management unit for scanning the queue, extracting priority information of the frame, and storing position information of a frame to be extracted based on the priority information; A frame extractor configured to sequentially extract frames from the frame having the highest priority information in the queue according to a bandwidth corresponding to a current RC control interval; And a frame discard control unit for identifying and discarding the remaining frames that have not been extracted when frame extraction is completed corresponding to the bandwidth.

The priority information setting unit may include: basic priority information setting unit for giving basic priority information according to a type of frame; And a sub priority information setting unit for assigning sub priority information with respect to a frame having the same basic priority information based on the image quality displayed at the receiving end. The basic priority information setting unit may assign basic priority information to a frame including at least one of an I frame, a P frame, a B frame, and a high quality frame according to the type of the frame. The priority information setting unit determines whether a discarded frame exists in a previous RC interval (Rate Control Interval). When the discarded frame exists, the priority information setting unit determines whether the discarded frame and the current RC interval (Rate Control Interval) exist. The subpriority of the frames located between the I frames may be set lower than the P frames located after the I frames.

Here, the frame position information management unit scans the queue, recognizes a column of frames having the same priority information as a packet, and extracts a packet unit from the column of the frame when extracting a frame according to the priority information. In order to do this, packet frame position information on a start position and an end position corresponding to the packet may be stored. In addition, the frame extractor extracts the packet frame based on the current priority, reduces the bandwidth according to the extracted packet frame, and when the extraction of the packet frame corresponding to the current priority is completed, corresponds to the next priority. It is possible to extract a packet frame to reduce the bandwidth corresponding to the extracted packet frame.

Here, the frame discard control unit identifies a remaining packet frame that is not displayed for the queue in which the predetermined packet is marked with respect to the extracted packet frame, and discards the remaining packet frame in the queue. You can control wealth. Herein, the frame discard apparatus further includes a frame predictor, wherein the frame predictor determines whether the rate control interval (RC) starts, and if the rate control interval (RC) starts, the RC period. After generating a prediction frame corresponding to a frame to reach a rate control interval, the prediction frame may be added as a virtual frame to the queue. The frame predictor may correct an estimation error between the predicted frame size and the actual frame size when an actual frame corresponding to the predicted frame arrives.

Hereinafter, the configuration of an intelligent frame discard method and apparatus according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings, and in the following description with reference to the accompanying drawings, the same or corresponding components regardless of reference numerals Denotes the same reference numerals and duplicate description thereof will be omitted. Hereinafter, a combination of frames is defined as a packet, and a processing object is used as a frame or packet packet, and even when the processing object is specified and specified as one of the frames or packets in any part, the processing object is a frame and a packet. It is not limited to this, but can mix and process mutually.

It can include both packets or frames.

Overall configuration and operation

The present invention relates to a method and apparatus for intelligent frame discard, and more particularly, to a method and apparatus for discarding a frame through rate control based on priority information for each frame. will be. Hereinafter, a configuration of a frame transmission apparatus according to a preferred embodiment of the present invention will be described in FIG. 1A, and a configuration of a frame discard control unit according to a preferred embodiment of the present invention will be described in FIG. 1B.

1A is a diagram illustrating a configuration of a frame transmission apparatus according to a preferred embodiment of the present invention.

The intelligent frame transmission apparatus 100 according to the present invention may be installed at any position of a path from a source to a user destination to control transmission. First, referring to FIG. 1A, the intelligent frame transmission apparatus 100 according to the present invention includes a rate control unit 110, a frame discard control unit 120, a frame discard unit 130, and an optimal packet scheduler 140. ) And the queue 150. Here, the queue 150 refers to a memory for storing a frame reached from the source.

The rate control unit 110 calculates a transmission rate periodically or aperiodically, and according to an embodiment, may be configured to calculate a target transmission rate corresponding to a rate control interval. Can be. Here, the rate control unit 110 is a transmission rate based on the bottleneck point of the bandwidth, corresponding to the user's playback queue size or transmission path. The target transmission rate can be calculated. According to the present invention, when the input rate input to the control node is larger than the output rate, the predetermined amount of packets reaching each control interval is discarded in consideration of the actual output rate and the target output rate.

The frame discard control unit 120 may scan the current queue 150 and perform an optimal decision for determining a frame or packet to discard according to the relative importance of video quality. The decision information is transmitted to a frame discard unit for discarding a packet in the packet queue.

The frame discard unit 130 may perform a function of physically discarding a packet according to a control command of the frame discard control unit. When the optimal packet scheduler 140 receives the target rate from the rate controller 110, the optimal packet scheduler 140 may transmit the packet according to the target rate, thereby ensuring an optimal packet rate.

The apparatus for discarding frames according to the present invention may give priority information to different video frames according to their relative importance according to picture quality. In general, such a frame discard algorithm is not only applicable at the time of implementation in a content server, but may also perform on-fly frame discard at the packet or frame level of a gateway of a wireless network.

1B is a flowchart illustrating a configuration of a frame discard control unit according to a preferred embodiment of the present invention.

Referring to FIG. 1B, the frame discard control unit according to the present invention scans the queue and the priority information setting unit 121 for assigning priority information that is preset according to the type of the frame with respect to the frames stored in the queue. A bandwidth corresponding to a frame position information management unit 123 and a current rate control interval (RC) for extracting priority information of the frame and storing position information of a frame to be extracted based on the priority information. According to the frame extraction unit 125 for sequentially extracting the frame from the frame with the higher priority information in the queue and when the frame extraction is completed corresponding to the bandwidth, for identifying and discarding the remaining frame not extracted The frame discard control unit 127 may be included.

The priority information setting unit 121 subpriority based on the picture quality displayed at the receiving end for the frame having the same basic priority information and the basic priority information setting unit for giving basic priority information according to the type of frame. It may include a sub-priority information setting unit for giving information. Here, the basic priority information setting unit may assign basic priority information to a frame including at least one of an I frame, a P frame, a B frame, and a high quality frame according to the type of the frame. In addition, the priority information setting unit 121 determines whether a discarded frame exists in a previous RC interval (Rate Control Interval), and if the discarded frame exists, the discarded frame and the current RC interval (Rate). The sub-priority of the frames located between the I frames of the control interval may be set lower than the P frames located after the I frames.

When the frame position information management unit 123 scans the queue, recognizes a column of frames having the same priority information as a packet, and extracts a frame according to the priority information, the frame position information manager 123 extracts a packet unit from the column of the frame. In order to do this, packet position information about a start position and an end position corresponding to the frame packet may be stored.

After extracting the packet based on the current priority, the frame extractor 125 reduces the bandwidth corresponding to the extracted packet, and when the extraction of the packet corresponding to the current priority is completed, the frame priority corresponds to the next priority. The packet may be extracted, and the bandwidth may be reduced according to the extracted packet.

The frame discard control unit 127 identifies a remaining packet that has not been displayed for the queue that has been designated with respect to the extracted packet, and a frame discarding unit 130 for physically discarding the remaining packet from the queue. ) Can be controlled. Here, the frame discard apparatus further includes a frame predictor (not shown), wherein the frame predictor determines whether the rate control interval (RC) starts, and the rate control interval (RC) starts. In this case, after generating a prediction frame corresponding to a frame to reach the RC interval (Rate Control Interval), the prediction frame may be added to the queue as a virtual frame. The frame predictor may correct an estimation error between the predicted frame size and the actual frame size when an actual frame corresponding to the predicted frame arrives.

Frame Structure and Priority Information

Hereinafter, in describing the frame structure and priority information of the data transmitted according to the present invention, for convenience of explanation, on the basis of MPEG MPEG data, I, P, B frames and FGS (Fing Grain Scalable) layers A description will be given based on a frame (hereinafter referred to as high quality frame). 2 illustrates an operation of a frame transmission apparatus according to a preferred embodiment of the present invention, FIG. 3A illustrates a priority information system according to a preferred embodiment of the present invention, and FIG. 3B illustrates a preferred embodiment of the present invention. A frame structure to which priority information is given will be described.

2 is a flowchart illustrating an operation of a frame transmission apparatus according to an exemplary embodiment of the present invention.

Hereinafter, referring to FIG. 2, in operation S210, prediction of a frame to be reached in the future may be performed at the start of a rate control interval. That is, it is determined whether the RC interval (Rate Control Interval) starts, and when the RC interval (Rate Control Interval) starts, generating a prediction frame corresponding to the frame to reach the RC interval (Rate Control Interval) After that, the prediction frame may be added to the queue as a virtual frame.

In step S220, priority information preset according to the type of the frame is given to the frames stored in the queue. That is, it is determined whether a discarded frame exists in a previous rate control interval, and if the discarded frame exists, a position is located between the discarded frame and an I frame of a current rate control interval. The sub-priority for the frame is configured to be set lower than the P frame located after the I frame.

In step S230, the queue is scanned to extract priority information about the frame. When the queue is scanned and a column of frames having the same priority information is recognized as a packet, and the frame is extracted according to the priority information, the column of the frame corresponds to the packet to extract a packet unit. Packet position information for the start position and the end position can be stored.

In step S240, the frames are sequentially extracted from the frames having the high priority information in the queue according to the bandwidth corresponding to the current RC interval (Rate Control Interval). That is, after extracting a packet based on the current priority, the bandwidth is reduced according to the extracted packet, and when the extraction of the packet corresponding to the current priority is completed, the packet corresponding to the next priority is extracted, and The bandwidth is reduced according to the extracted packet, and this process may be repeated until the bandwidth does not exist or all packets for the queue are extracted.

When frame extraction is completed in correspondence with the bandwidth in step S250, the remaining frames not extracted are discarded. According to a preferred embodiment, the display may be performed in response to the extracted packet, and thereafter, the packet may not be marked, and the packet may be discarded.

3A is a table illustrating a priority information system according to a preferred embodiment of the present invention, and FIG. 3B is a diagram illustrating a frame structure in which priority information is added according to a preferred embodiment of the present invention.

Referring to FIG. 3A, a frame according to the present invention may be assigned a basic priority according to the type of a frame, and each frame may be assigned a sub priority based on an image quality or a time axis. The table shows that sub-priorities may be allocated to 2.1, 2.2, 2.3, etc. based on P frames (basic priority = 2). In addition, when the high quality layer is temporally coded, it is natural that the high quality layer may also be given a sub-priority such as 4.1, 4.2, and 4.3 corresponding to each I, P, and B frame.

Hereinafter, a method of discarding a frame according to the present invention will be described in detail with reference to FIG. 3B.

According to the present invention, real-time frame discard may be performed by additionally assigning sub-priority information to the basic priority information. For convenience of description, the description will be made based on two consecutive segments having 12 frames per second.

The first segment consists of an I frame I1 and eleven consecutive P frames P1 to P11, and the second segment also consists of an I frame I2 and eleven consecutive P frames P12 to P23. A description will be given on the basis of the case where the previous AL control interval interval ends in the P8 frame, and the current AL control interval interval starts in the P9 frame and ends in the P14 frame.

Here, in the previous interval, P5 to P8 frames are discarded by the discard algorithm, and P9 to P11 frames are incorrectly displayed by the terminal by the discard algorithm. On the other hand, in the second segment, P frames after the I frame will be displayed correctly. Therefore, when the current target rate is limited, it is preferable to configure higher priority information for P12 to P14 frames of the second segment than for the P9 to P11 frames. Accordingly, the present invention may assign high priority information 2.1 to P12 to P14 frames and low priority information 2.2 to P9 to P11 frames.

And if there is no discarded frame in the previous segment, it is configured to provide high priority information to the frame included in the segment earlier than the P12 ~ P14 frame. Through such a configuration, a frame stored in the queue can be transmitted. Here, the frames P9 to P11 have the same priority at level 2 and may be configured to be transmitted from left to right based on the time axis when they have the same priority. Priority information for each of these high quality layers is configured to continue at the beginning of each Rate Control Interval.

How to set priority information

4A is a flowchart illustrating a method of extracting priority information according to a preferred embodiment of the present invention, and FIG. 4B illustrates a pseudo code of FIG. 4A.

Hereinafter, referring to FIG. 4A, priority is allocated to each frame in step S410. Regardless of the type of the frame, priority may be assigned at the same time, may be assigned sequentially, and does not depend on the order of allocation according to the type of frame. Herein, for convenience of description, an I frame is first allocated, and then a description will be given based on a case of allocating a P frame, a B frame, and a high quality frame.

In step S420, it is determined whether a discarded frame exists in a previous RC interval (Rate Control Interval). If there is a discarded frame in the previous saliva interval, the priority of the P frame corresponding to the current RC interval (Rate Control Interval) is higher than the P frame existing after the discarded P frame of the previous RC interval (Rate Control Interval). It is configured to be. According to a preferred embodiment, in step S430 the P frame priority of the current RC interval (Rate Control Interval) is assigned to 2.1, and in step S440 of the P frame after the discarded frame in the previous RC interval (Rate Control Interval) You can assign a priority of 2.2.

In step S450, priority may be allocated in the order of the P frame, the B frame, and the high quality frame. According to a preferred embodiment, the priority of the P frame may be allocated to 2, the priority of the B frame to 3, and the priority information of the high quality layer frame to 4.

When the high quality layer is temporally coded in step S460, sub-priority information is given to high quality frames for each of I frames, P frames, and B frames. According to a preferred embodiment, it can be given in the order of 4.1, 4.2, 4.3. As described above, the sub-priority information may be allocated while going from left to right on the basis of the frame and the time axis.

How to dispose of Frey

5 is a flowchart illustrating a method of extracting enhancement priority information according to a preferred embodiment of the present invention, and FIGS. 6A and 6B illustrate pseudo codes of FIG. 5.

As described above, the present invention defines one packet for a frame having the same sub-priority with respect to transmitting a packet having a frame or a combination of. However, the above frame or packet may be used in combination. According to the present invention, after extracting frames sequentially from a frame having the high priority information in the queue according to a bandwidth corresponding to a current RC interval (Rate Control Interval), if the frame extraction is completed in response to the bandwidth, not extracted. Remaining frames may be discarded.

Hereinafter, referring to FIG. 5A, after extracting a packet based on the current priority in step S510, the bandwidth may be reduced according to the extracted packet in step S520, and the corresponding packet may be displayed in correspondence with the extracted packet.

When the extraction of the packet corresponding to the current priority is completed in step S525, it is determined whether or not the corresponding discard condition is set in step S530. According to an embodiment of the present invention, the discarding condition may include whether the bandwidth does not exist or whether all packets for the queue have been extracted. That is, if bandwidth is present or not all packets for the queue are extracted, the priority information is changed to the next priority in step S540, and the next priority is changed to the priority to extract the current packet.

Thereafter, the processes of steps S510 to S530 are repeated to extract packets corresponding to the priorities corresponding to each level, and to reduce the bandwidth corresponding to the extracted packets at all priority levels. In the case where the discarding condition corresponds to the discarding condition in step S550, the packet is not displayed and the packet is discarded.

Through the above steps, the frame discard according to the present invention can be performed. In this case, an area corresponding to an area not scanned in the previous RC interval (Rate Control Interval) is scanned at the beginning of each RC interval (Rate Control Interval). By identifying each successive packet at each priority level, a series of positions and each priority level of each packet can be stored in a preset array. In addition, each priority level is identifiable according to the high quality structure described above. The bandwidth is allocated in units of frames or packets from the highest priority level of the queue to the lowest priority level corresponding to the target output rate Rt, and when all the bandwidths are allocated, the remaining frames or packets are configured to be discarded.

Frame discard algorithm during transmission

In the frame discard algorithm through queue scanning according to the present invention, sufficient packets may not be present at the beginning of the current Rate Control Interval. In this case, in order to satisfy the target output rate, bandwidth should be allocated according to packets or frames in order of priority, not arrival order. Therefore, it is necessary to predict a frame to arrive corresponding to a current rate control interval (RC). need. Hereinafter, a method of discarding a prediction frame according to a preferred embodiment of the present invention will be described with reference to FIG. 7, and pseudo codes according to the flowchart of FIG. 7 will be described with reference to FIGS.

Hereinafter, referring to FIG. 7, in operation S710, it is determined whether the RC interval (Rate Control Interval) starts, and when the RC interval (Rate Control Interval) starts, the RC interval (Rate Control Interval) is started. Generate a predictive frame corresponding to the frame to be reached. In operation S720, the prediction frame may be added as the virtual frame to the queue, and then the frame discard method according to the present invention may be performed on the queue.

And in step S730, when the actual frame corresponding to the prediction frame arrives, correcting an estimation error between the prediction frame size and the actual frame size. Here, in the error correction step, the error correction information is generated by adding the size of the actual frame reaching the size of the prediction frame until the last prediction frame is reached, and adding the size of the prediction frame to the bandwidth, And subtract the error correction information.

Even if the frame does not arrive at the beginning of the Rate Control Interval through this step, the frame corresponding to each Rate Control Interval corresponds to a sufficient number of frames to be reached in the current Rate Control Interval. In anticipation, the frame discarding method according to the present invention can be performed. According to a preferred embodiment of the present invention, the collision occurs in the arrival order and the discarding method depending on the type of the frame, i frame and P frame. Therefore, it is necessary to predict the existence and size of the two kinds of frames. For example, suppose that only the ninth P frame P9 exists in the current queue with reference to FIG. 3B. At the beginning of the current interval, the present invention is configured to predict the twelfth to fourteenth P frames P12 to 14 together with the I frame I2. Subsequently, when the eighth frame P8 is discarded, priority information preset in the twelfth to fourteenth P frames P12 to 14 may be given.

Hereinafter, a method for predicting the existence and size of a frame according to the present invention will be described. Referring to Table 1 below, although there is a frame prediction method according to an embodiment of the present invention, it is not limited to the frame prediction method described below, it is natural that all frame prediction methods developed in the future or in the future can be used. .

Priority Explanation Previous Frame Size Method Use size of prey arrived Frame Size Time Series Prediction Use motion prediction algorithm Multi time scale prediction Use a multi-time scale model Frame Arrival Prediction After predicting whether a frame will arrive, predict the frame

According to the first embodiment of the frame prediction method of the present invention, it is possible to predict the size of a previously arrived I frame or P frame by the size of an I frame or P frame that has been reached. That is, the size of the I frame of the current RC interval (Rate Control Interval) is predicted to be the same as the size of the previous I frame, the next P frame can be estimated to be a P frame of the same size as the recently reached P frame. .

According to the second embodiment of the frame prediction method of the present invention, the size of an I frame or a P frame can be predicted using motion prediction. According to the present invention, the motion prediction method is not only motion prediction through motion estimation and motion compensation, but also I frame or P frame to be reached later through various motion prediction methods currently under study or developed in the future. It is natural that the size of can be predicted. That is, based on time scale, linear auto regressive analysis or linear auto regressive moving average may be used. Here, it is applicable to a P frame that is proportional to the amount of movement of an object currently on the video screen. Here, AR (Autoregressive) means that the past data affects the current data. {Y} _ {t-1} is regarded as an independent variable and {y} _ {t} is regarded as a dependent variable. } _ {t}-mu = phi ({y} _ {t-1} -mu) + {e} _ {t} You can build a regression model (where mu = parameter, ~ {e} _ {t} SIM N (0, ~ {sigma} ^ {2})). Here, {y} _ {t} is referred to as an autoregressive model of degree 1 and denoted by AR (1). The general AR (p) can be represented by Equation 1 as follows.

Yt = + 1Yt-1 + 2Yt-2 + ... + pYt-p + t

Where mu is a constant term, p is the order of AR, and Yt-p is the value of the t-p group.

The ARMA (p, q) model is autoregressive moving average model with orders p and q when {y} _ {t} is affected by orders p and q. We can assume that we follow. The ARMA can be displayed according to Equation 2 as follows.

Yt = 0 + 1Yt-1 + 2Yt-2 + ... + pYt-p-1t-1 + 2t-2 + ... + pt-p + t

According to the third embodiment of the frame prediction method of the present invention, when the RC interval (Rate Control Interval) has a relatively long time scale, a multi-time scale model may be used like a wavelet. In this case, the prediction of the frame size may be performed based on a time axis or based on a sub frame of the rate control interval (RC).

According to the fourth embodiment of the frame prediction method of the present invention, the frame is first predicted whether or not the I frame and the P frame dependent on the I frame are not reached, and the frame is predicted to arrive according to the prediction value. Configured to predict size. That is, frame prediction requires a significant amount of computation, and thus can be configured to perform prediction only on the frames that are expected to arrive.

The frame arrival prediction method according to the fourth embodiment may use length information required by a group of pictures (GOP) and a video encoder. For example, the MPEG MPEG structure generally uses 4 to 20 GOPs, and each GOP is composed of an I frame and a column of frames adjacent to the I frame. Therefore, by tracking how many frames have arrived and estimating the input rate, it is possible to predict the number and type of frames to be drawn in the current rate control interval. In addition, a detailed description of the above-described frame prediction method will be omitted.

As described above, it is necessary to predict the existence and size of two types of subsequent frames to be reached in the current RC interval, and in general, when the RC interval is not short, Long periods can be classified into cases and frame prediction methods can be used. When the last packet of the predictive frame arrives, the size of the predicted frame and the actually arrived frame is extracted and compared. The predicted frame and the actual frame are matched to adjust the remaining frame according to the difference between the predicted frame and the actual frame. do.

The foregoing drawings and detailed description of the invention are merely exemplary of the invention, which are used for the purpose of illustrating the invention only and are intended to limit the scope of the invention as defined in the claims or in the claims. It is not. Therefore, those skilled in the art will understand that various modifications and equivalent other embodiments are possible therefrom. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

As described above, the present invention has been made to solve the above-described problem, and it is possible to provide a method and apparatus for discarding a frame through rate control based on priority information for each frame. There is.

In addition, the present invention can provide an intelligent frame discard method and apparatus for guaranteeing QoS of video transmission and guaranteeing individual QoS according to a limited and dynamic network bandwidth.

In addition, the present invention has an effect that can provide an intelligent frame discard method and apparatus that can determine the frame discard by predicting the transmission of the frame. That is, according to the prior art, an optimal frame discard algorithm is implemented through scheduling, but the present invention does not use such a frame-by-frame scheduling or a packet-by-packet scheduling method, and is connected to a rate control of a network and a limited transmission rate. Intelligent frame discard method can be provided.

Although described above with reference to a preferred embodiment of the present invention, those skilled in the art that various modifications of the present invention without departing from the spirit and scope of the invention described in the claims below And can be changed.

Claims (20)

In the frame discard method. (a) assigning priority information preset to a frame stored in a queue according to the type of the frame; (b) scanning the queue to extract priority information for the frame; (c) sequentially extracting frames from the frame having the higher priority information in the queue according to a bandwidth corresponding to a current RC control interval; And (d) discarding the remaining frames that have not been extracted when frame extraction is completed corresponding to the bandwidth, The priority information may include basic priority information assigned according to the type of the frame and sub-priority information for assigning the frame having the same basic priority information on the basis of the image quality displayed at the receiving end. Way. delete The method of claim 1, And the basic priority information is assigned to a frame including at least one of an I frame, a P frame, a B frame, and a high quality frame according to the type of the frame. The method of claim 1, In step (a), Determining whether there is a discarded frame in a previous RC control interval; And If the discarded frame is present, setting a sub-priority for a frame located between the discarded frame and an I frame of a current RC interval (Rate Control Interval) is lower than a P frame located after the I frame. Frame discard method comprising a. The method of claim 1, In step (b), Scanning the queue and recognizing a column of a frame having the same priority information as a packet; When extracting a frame according to priority information, storing packet frame position information of a start position and an end position corresponding to a packet in the column of the frame, in order to extract a packet unit from the column of the frame; Frame discard method comprising a. The method of claim 1, In step (c), Extracting a packet frame based on a current priority, and then reducing a bandwidth corresponding to the extracted packet frame; And When the extraction of the packet frame corresponding to the current priority is completed, extracting the packet frame corresponding to the next priority, and reducing the bandwidth corresponding to the extracted packet frame Including, but repeating the step until the bandwidth does not exist or all packet frames for the queue are extracted. The method of claim 1, In step (d), Performing a display corresponding to the extracted packet frame; And Recognizing a packet frame not displayed, and discarding the packet frame Frame discard method comprising a. The method of claim 1, Determining whether the RC interval starts; Generating a prediction frame corresponding to a frame to reach the rate control interval when the rate control interval begins; Adding the prediction frame as a virtual frame to the queue; And Performing steps (a) to (d) on the queue. Frame discard method comprising a. The method of claim 8, The size of the prediction frame is predicted using at least one of the previous frame size prediction, time-base prediction, multi-time prediction, frame arrival prediction method. The method of claim 9, If an actual frame corresponding to the prediction frame arrives, correcting an estimation error between the prediction frame size and the actual frame size, further comprising: The error correction step Generating error correction information by summing the size of the actual frame reaching the size of the predicted frame until the last predicted frame is reached; And Adding the size of the prediction frame to the bandwidth and subtracting the error correction information Frame discard method comprising a. In the frame discard device. A priority information setting unit for assigning priority information preset in accordance with the type of the frame, to a frame stored in a queue; A frame position information manager for scanning the queue, extracting priority information of the frame, and storing position information of a frame to be extracted based on the priority information; A frame extractor configured to sequentially extract frames from the frame having the highest priority information in the queue according to a bandwidth corresponding to a current RC control interval; And A frame discard control unit for identifying and discarding the remaining frames that have not been extracted when frame extraction is completed corresponding to the bandwidth; Frame discard apparatus comprising a. The method of claim 11, The priority information setting unit A basic priority information setting unit for assigning basic priority information according to the type of frame; And Sub-priority information setting unit for assigning sub-priority information on the frame having the same basic priority information based on the image quality displayed at the receiving end. Frame discard apparatus comprising a. The method of claim 12, The basic priority information setting unit The frame discard apparatus according to claim 1, wherein basic priority information is assigned to a frame including at least one of an I frame, a P frame, a B frame, and a high quality frame according to the type of the frame. The method of claim 11, The priority information setting unit It is determined whether a discarded frame exists in a previous RC interval (Rate Control Interval), and if the discarded frame exists, a frame located between the discarded frame and an I frame of a current RC interval (Rate Control Interval). The sub-priority for the frame discard apparatus is set to be lower than a P frame located after the I frame. The method of claim 11, The frame position information management unit When the queue is scanned and a column of frames having the same priority information is recognized as a packet, and the frame is extracted according to the priority information, the column of the frame corresponds to the packet in order to extract a packet unit. And discarding packet frame position information about a start position and an end position. The method of claim 11, The frame extractor After extracting the frame packet based on the current priority, the bandwidth is reduced according to the extracted frame packet, and when the extraction of the frame packet corresponding to the current priority is completed, the frame packet corresponding to the next priority is extracted. And reducing the bandwidth corresponding to the extracted frame packet. The method of claim 11, The frame discard control unit And identifying a remaining packet frame that is not displayed, and controlling a frame discarding unit for physically discarding the remaining packet frame from the queue, with respect to the queue having a predetermined mark for the extracted packet frame. Frame disposal device. The method of claim 11, The frame discard device further includes a frame predictor, The frame predictor It is determined whether the RC interval (Rate Control Interval) starts, and when the RC interval (Rate Control Interval) starts, after generating a prediction frame corresponding to the frame to reach the RC interval (Rate Control Interval) And adding the prediction frame as a virtual frame to the queue. The method of claim 18, The size of the prediction frame is predicted by using at least one of the previous frame size prediction method, time axis prediction method, multi-time prediction method, frame arrival prediction method. The method of claim 19, The frame predictor And when the actual frame corresponding to the prediction frame arrives, correcting an estimation error between the prediction frame size and the actual frame size.

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