KR20040027219A - An apparatus for transmitting video using adaptive weighted error correction coding and multiple description coding and method thereof - Google Patents

Abstract

PURPOSE: A video transmission device using adaptive weighted error correction coding and multiple description coding functions is provided to differently apply weight of overheads of error correction codes for each description, and to determine descriptions to be transmitted according to states of transmission channels, thereby efficiently coping with video transmission errors. CONSTITUTION: A video transmission device(100) comprises as follows. Multiple description coding units(120,130) perform multiple description coding processes for video signals, and generate many correlation descriptions. Error correction coding units(140,150) perform error correction coding processes for the descriptions, and do not give the same error correction capabilities by putting weight to error correction capacities given to each description. A transmission channel switch(160) forms paths with many transmission channels to which the descriptions are to be transmitted. A channel exchange controller(170) controls the transmission channel switch(160) according to states of the transmission channels, and controls the formation of the paths.

Description

A video transmission apparatus using adaptive weighted error correction coding and multi-expression coding and its method {AN APPARATUS FOR TRANSMITTING VIDEO USING ADAPTIVE WEIGHTED ERROR CORRECTION CODING AND MULTIPLE DESCRIPTION CODING AND METHOD THEREOF}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video transmission apparatus. More particularly, the present invention relates to adaptive weighted error correction coding and multiple representation string coding in order to more effectively cope with transmission errors of channels that may occur during video transmission. The present invention relates to an apparatus and method for transmitting video using multiple description coding.

In general, low-speed transmissions such as existing telephone lines are less likely to cause an error, but there is no big problem. Since the quality of service is not guaranteed, the probability of error in video transmission is very high.

On the other hand, as the use of digital multimedia data is rapidly increasing, various video compression coding methods have been studied according to the necessity of storing and transmitting a large amount of digital data more efficiently.

The video compression coding method is a technique that minimizes spatial and temporal redundancy of a video signal by using a discrete cosine transform (DCT), motion compensation, and entropy code.

Therefore, the video compressed using this video compression coding method is reduced in capacity, but when transmitted over the Internet or a wireless channel, the video quality is damaged in a wide area even with a small transmission error, and the damaged video is propagated temporally and visually. It becomes noticeable.

In order to cope with such transmission errors, various error concealment techniques have been proposed in video decoders.However, in order to cope with burst errors occurring in wireless channels or packet bottlenecks in the Internet, image quality restoration is required. The effect is insufficient.

As an alternative, error correction codes can be used. These errors can be used to correct errors, but they are difficult to cope with clustering errors, and the error correction codes are used to increase the error correction ability to cope with clustering errors. Because the overhead must be increased, the bit rate of the video must be lowered or the total channel bandwidth capacity must be increased by the relatively increased overhead.

Another effort to cope with transmission error is Layered Coding, which is divided into Base Layer and Enhancement Layer according to the picture quality and the screen size, and encoded in different channels. Will be sent.

However, such hierarchical coding starts from the assumption that no transmission error occurs in the bit stream of the base layer. However, in the transmission through a wireless channel or the Internet, an error occurs in the base layer due to a clustering error or a network bottleneck, and the image quality is severely deteriorated.

In order to solve such a problem, a multiple-expression string encoding method has recently attracted attention.

The multi-expression encoding scheme is a method of compressing a video by dividing it into various expression strings, that is, correlated descriptions, and compressing the video to minimize redundancy.

Accordingly, a transmission apparatus according to a multiple representation string encoding technique encodes a video signal into two (or more) correlation representation strings, respectively, and transmits two (or more) representation strings to respective independent channels. The difference between these two (or more) expression sequences is generally the difference between the quantum groups.

If two (or more) expression strings are transmitted to the receiving device without a transmission error, the decoder reproduces high quality video using two (or more) expression string signals.

However, if an error occurs in a specific channel, the decoder can reproduce video of acceptable quality using only the representation string signal of the channel successfully transmitted.

1 is a block diagram of a video transmission apparatus using conventional multiple representation string encoding.

As shown in FIG. 1, a conventional video transmission apparatus includes two expression strings, ie, expression string 1 and expression string 2, which are generated through multiple expression string encoding of a video into two channels, that is, channel 1 20 and channel 2. Video transmitters 10 respectively transmitting via 30; And a video receiver 40 which receives two expression strings transmitted through the two channels 20 and 30, respectively, restores the original video signal, and reproduces and outputs the original video signal to the user.

The video transmitter 10 includes a video source 11, a multiple representation string encoder 1 (12) and a multiple representation string encoder 2 (13), and the video receiver 40 includes a multiple representation string decoder 1 (41), a multiple representation. A column decoder 2 (42) and a multiple representation string decoder (3).

The multiple representation string encoder 1 12 encodes and outputs a video signal provided from the video source 11 into the representation string 1, and the multiple representation string encoder 2 13 represents the video signal provided from the video source 11. Encoded in column 2 and output.

The expression string 1 is input to the multiple expression string decoder 1 (41) and the multiple expression string decoder 2 (42) through the channel 1 (20), and the expression string 2 is the multiple expression string decoder 2 (42) through the channel 2 (30). And multiple representation string decoder 3 (43).

The multiple representation string decoder 1 (41) restores the video signal using the representation string 1, and the multiple representation string decoder 2 (42) restores the video signal using the representation sequence 1 and the representation sequence 2, and the multiple representation string decoder 3 (43) reconstructs the video signal using the expression string 2 and reproduces and outputs the same to each user.

Therefore, it can be seen that the image quality of the video reproduced and output by the multiple expression decoder 2 (42) is the best image quality.

As such, when video is transmitted using multiple representation encoding, even if an error occurs in a path of some channels, effective data transmission is possible unless a simultaneous error occurs in all paths.

However, the conventional multiplex encoding does not consider an error correcting code, and since each channel to which two (or more) representations are transmitted is always treated equally, it is effective according to the quality difference of the transmission channel or the change of transmission state. There is a problem that is difficult to cope with.

Accordingly, an object of the present invention is to solve the above-mentioned problems. In the encoding of a multiple expression string of a video signal, an overhead weight of an error correction code for each expression string is differently applied and transmitted according to the state of a transmission channel. The present invention provides an apparatus and method for transmitting video using adaptive weighted error correction encoding and multiple expression string encoding for determining and transmitting a representation string to be transmitted.

1 is a block diagram of a video transmission apparatus using conventional multiple representation string encoding.

2 is a block diagram of a video transmission apparatus according to an embodiment of the present invention.

3 is a flowchart of a video transmission method according to an embodiment of the present invention.

4 is a flowchart of a video receiving method according to an embodiment of the present invention.

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

100: video transmitter 110: video source

120, 130: multiple representation string encoder 140, 150: error correction encoder

160: transmission channel switch 170: channel switching controller

200, 210: Transmission channel 300: Video receiver

310: receive channel switch 320, 330: error correction decoder

340, 350, 360: Multiple expression sequence decoder 370: Channel exchange controller

A video transmission apparatus according to a feature of the present invention for achieving the above object,

A video transmission apparatus for transmitting a plurality of correlation representation strings generated by encoding multiple representation strings through separate independent transmission channels,

A multiple representation string encoder for generating a plurality of correlation representation strings by performing multiple representation string encoding on a video signal to be transmitted; An error correction encoding unit for performing error correction encoding on a plurality of expression strings generated by the multiple expression string encoders, by weighting error correction capabilities given to each expression string so that the same error correction capability is not given; A transmission channel switch unit forming a path with a plurality of transmission channels to which a plurality of expression strings error corrected and encoded by the error correction coder are to be transmitted; And a channel controlling the path of the plurality of expression strings and the plurality of transport channels by controlling the transmission channel switch unit according to the state of the plurality of transport channels determined based on channel state information fed back from the plurality of transport channels. And an exchange control unit, wherein the channel exchange control unit controls to transmit an expression string having a relatively large error correction capability among the plurality of expression strings through a transmission channel having a relatively poor transmission state among the plurality of transmission channels, And the information representing the path formation between the plurality of expression strings and the plurality of transmission channels is included in the plurality of expression strings.

Here, the expression strings generated by the multiple expression string encoder are two first expression strings and two second expression strings, and the error correction code portion is an error correction function in which an error correction capability given to the first expression string is given to the second expression string. It is characterized by error correction coding with a weight greater than the capability.

In addition, a transmission channel for transmitting the two expression strings is two channels, a first channel and a second channel, and the channel exchange control unit has a state in which the transmission state of the first channel is equal to or worse than the transmission state of the second channel. In this case, the first expression string is transmitted through the first channel, and the transmission channel switch unit is controlled to transmit the second expression string through the second channel.

The channel switching controller may be configured to transmit the first expression string through the second channel when the transmission state of the second channel is inferior to that of the first channel, and the first expression string may be determined. The transmission channel switch unit is controlled to be transmitted through a second channel.

The channel exchange control unit may further include an expression string exchange bit representing information transmitted through the first channel and the second channel by exchanging the first expression string and the second expression string. It is characterized by including in the heat.

According to another aspect of the present invention, a video transmission method includes

A video transmission method for transmitting a plurality of correlation representation strings generated by multiple representation encoding of video through separate independent transport channels,

Generating a plurality of correlation representation strings by performing multiple representation string encoding on a video signal to be transmitted; A second step of performing error correction encoding on the plurality of expression strings generated in the first step, weighting the error correction capability given to each expression string so that the same error correction capability is not given; A third step of comparing the state information fed back from a plurality of transmission channels to which the plurality of weighted error corrected encoded sequences are to be transmitted; And the plurality of representations such that a representation string having a relatively large error correction capability is transmitted among the plurality of representation strings through a transmission channel having a relatively poor transmission state among the plurality of transmission channels. And a fourth step of forming a transmission path between a column and the plurality of transmission channels and including information indicative of path formation between the plurality of expression strings and the plurality of transmission channels in the plurality of expression strings.

According to another aspect of the present invention, a video receiving apparatus,

A video receiving apparatus for receiving a plurality of correlation representation strings transmitted from a video transmission apparatus through a separate independent transmission channel, wherein the plurality of correlation representation strings are generated by multiple representation string encoding, and reconstructing the original video.

A reception channel switch unit forming a path through which the plurality of correlation expression strings are received; An error correction decoding unit performing error correction decoding on a plurality of expression strings received through a path formed by the reception channel switch, and performing error correction decoding according to the weighted error correction capability given to each expression string; Controlling the reception channel switch unit according to the information representing the path formation between the plurality of expression strings included in the plurality of expression strings and the plurality of transmission channels to control path formation between the plurality of transmission channels and an input of the error correction decoder. A channel exchange control unit; And a multi-expression string decoder for decoding the multiple-expression string by using the plurality of expression strings that are error-corrected and output by the error-correcting decoder.

Here, the transmission channels are two first channels and two channels, and the expression strings received by the receiving channel switch unit through the two transmission channels are two first expression strings and two second expression strings, and the first expression. And weighted such that the error correction capability given to the column is greater than the error correction capability given to the second expression sequence.

The information representing path formation between the plurality of representation strings and the plurality of transmission channels is a representation string exchange bit, and the channel exchange control unit is configured to set the first representation string and the second representation when the representation string exchange bit is set. And controlling the receiving channel switch unit so that heat is exchanged and received and input to the error correction decoding unit.

The multiple representation string decoder may include: a first multiple representation string decoder configured to decode the multiple representation string using the first representation string that is output after the weighted error correction decoding; A third multiple representation string decoder configured to decode the multiple representation string by using the second representation string that is output after the weighted error correction decoding; And a second multiple expression string decoder configured to decode the multiple expression strings using the first expression string and the second expression string output after the weighted error correction decoding.

According to another aspect of the present invention, a video receiving method includes

A video receiving method for reconstructing an original video by receiving a plurality of correlation expression sequences transmitted from a video transmission apparatus through separate independent transmission channels, wherein the plurality of correlation expression strings are generated by multiple expression string encoding.

A first step of inspecting information indicating a path formation between the plurality of expression strings and the plurality of transmission channels included in the plurality of received correlation strings; A second step of exchanging receiving paths of the plurality of expression strings when the reception paths of the plurality of expression strings are required as a result of the inspection of the first step; Performing error correction decoding on the plurality of expression strings received through the reception path formed in the second step, and performing error correction decoding according to the weighted error correction capability given to each expression string; And a fourth step of decoding the multiple expression strings using the weighted error correction decoded plurality of expression strings and outputting the decoded strings to the user.

According to another aspect of the present invention, a video transmission device,

A plurality of correlation expressions generated by encoding multiple video sequences are weighted on the error correction capability given to each expression string to perform error correction encoding so that the same error correction capability is not given, and then transmitted through a plurality of independent transmission channels. However, according to the state of the plurality of transmission channels determined based on the channel state information feedback from the plurality of transmission channels to form the path of the plurality of expression strings and the plurality of transmission channels to transmit the plurality of expression strings A video transmitter; And reception paths of the plurality of expression strings formed on the basis of information indicating path formation between the plurality of expression strings and the plurality of transmission channels, included in the plurality of expression strings transmitted from the video transmitter via the plurality of transmission channels. And a video receiver configured to receive the plurality of expression strings, perform error correction decoding according to the weighted error correction capability given to each expression string, and then decode the multiple expression strings to restore the original video.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Before the description, the video transmission apparatus according to an embodiment of the present invention encodes a video signal into two or more correlation expression strings through multiple expression string encoding, and then transmits each through a separate independent transmission channel. For the sake of brevity, it is assumed that two correlation strings are encoded through multiple expression string encoding, and that each representation string is transmitted through two separate channels.

2 is a block diagram of a video transmission apparatus according to an embodiment of the present invention.

As shown in FIG. 2, the video transmission apparatus according to an embodiment of the present invention has two representation strings generated through multiple representation string encoding and weighted error correction encoding, ie, representation string 1 and representation string 2. A video transmitter 100 that transmits normally or exchanged according to channels, that is, channels 1 (200) and 2 (210); And a video receiver for receiving two expression strings transmitted through the two channels 200 and 210 so as to be in a normal transmission form, and performing error correction decoding, respectively, and decoding the multiple expression strings to restore the original video and output the same to the user. 300).

The video transmitter 100 may include a video source 110, a multiple representation encoder 1 120, a multiple representation encoder 2 130, an error correction encoder 1 140, an error correction encoder 2 150, and a transmission channel switch ( 160 and channel exchange controller 170.

The video source 110 is a medium that stores a plurality of videos to be transmitted to the video receiver 300 and output to the user. The video transmitter 100 may receive not only video stored in the video source 110 but also video input from the outside, stored in the video source 110, or transmitted directly to the receiver 300.

The multiple representation string encoder 1 120 and the multiple representation string encoder 2 130 receive a video signal provided from the video source 110, and output the multiple representation strings encoded into the representation string 1 and the representation string 2, respectively. The difference between the expression string 1 and the expression string 2 encoded in the multiple expression strings is the difference between the quantizers.

The error correction encoder 1 140 performs error correction encoding on the expression string 1 output from the multiple representation string encoder 1 120, and the error correction encoder 2 150 is output from the multiple representation string encoder 2 130. Error correction encoding is performed on the expression string 2. At this time, the overhead of the error correction code added by the error correction encoder 1 140 and the error correction encoder 2 150 is weighted so that the overhead used for the expression string 1 is greater than the overhead used for the expression string 2. Make it big. That is, the weight of the error correction code applied to each expression string (error correction ability) is weighted so that the same overhead is not applied. Here, the expression string 1 is applied to a larger overhead than the expression string 2. will be. Therefore, an error correction code is used for the expression string 1 and no error correction code is used for the expression string 2 may correspond to one special case.

The error correction code may be a Reed Solomon (RS) code.

In addition, the overhead of the error correction code used for the expression string 1 and the expression string 2 can be adjusted to an optimal value according to the characteristics of the transmission channel to be used.

On the other hand, the overhead of the error correction code used for each expression string as described above should be promised in advance in the video transmitter 100 and the video receiver 300, otherwise it is difficult to decode the error correction code.

Also, in the normal mode, the video transmitter 100 and the video receiver 300 transmit a representation string 1 having a large overhead through the channel 1 200, and a representation string 2 having a relatively low overhead. It is known in advance that it will be sent via.

As the overhead of the error correction code increases, the recoverability increases, and the decrease of the overhead decreases the ability to recover. Thus, the expression string 1 is inferior to the expression string 2 due to its high recoverability. It is more suitable for transmission over the transmission channel of.

The transmission channel switch 160 outputs the expression string 1, the expression string 2, and the channel 1 200 output from the error correction encoder 1 140 and the error correction encoder 2 150 according to the control signal of the channel switching controller 170, respectively. And a transmission path between channel 2 210.

The channel exchange controller 170 expresses the channel 1 (200) and the channel 2 (210) based on the packet forwarding state information, in particular, the transmission error rate information feedbacked from the channel 1 (200) and the channel 2 (210). A signal for controlling each connection to the column 2 is output to the transmission channel switch 160.

If the channel exchange controller 170 has the same packet forwarding state of the channel 1 200 and the channel 2 210 or there is no feedback information from each of the channels 200 and 210 (normal mode), the expression string 1 represents the channel. 1 through 200, and the expression string 2 is controlled to be transmitted through the channel 2 210. FIG.

If the state of the channel 1 (200) is feedback that the packet bottleneck or cluster error is more than the state of the channel 2 (210) (normal mode), the channel switching controller 170 is represented by channel 1 (channel 1 200). And the expression string 2 is controlled to transmit through the channel 2 210.

However, when it is determined from the feedback information from each channel 200 or 210 that the state of the channel 2 210 is more bottleneck or cluster error than the state of the channel 1 200 (switched mode), the channel exchange controller 170 Transmits the expression string 1 having a large overhead of an error correction code through the channel 2 210 having a poor transmission state, and transmits the expression string 2 having a low overhead through the channel 1 200.

In this case, since the transmitted expression strings are exchanged and transmitted in the video receiver 300, error correction decoding should be performed according to the exchanged overhead amount. Therefore, the video receiver 300 transmits to the respective channels 200 and 210. It should be possible to know whether the expression strings are interchanged. That is, since the video receiver 300 knows that the expression string 1 is transmitted through the channel 1 200, and the expression string 2 is transmitted through the channel 2 210, the expression string 1 and the expression as described above. This should be known to the video receiver 300 because column 2 is transmitted over channel 2 210 and channel 1 200, respectively, with different transmission paths.

The interchange division of the expression string 1 and the expression string 2 may be known in various forms. However, in the present embodiment, it is determined that only one bit of the expression string is interchangeable. It is used as the expression string exchange bit and used as the exchange distinguishing information of the expression string. That is, if the expression string exchange bit is not set, the expression string is not exchanged. On the other hand, if the expression string exchange bit is set, it can be determined that the expression string is exchanged. This expression string exchange bit is set by converting 0 to 1, for example.

Therefore, when the channel exchange controller 170 outputs a control signal to the transmission channel switch 160 to transmit and exchange the expression strings according to feedback information from each channel, the error correction encoder 1 140 and the error correction encoder. 2 150 sets the expression string exchange bits included in the expression string 1 and the expression string 2 to be output, respectively, and outputs them to the transmission channel switch 160.

Meanwhile, the channel 1 200 and the channel 2 210 are network transmission channels including the Internet, a wireless channel, and the like. The channel 1 200 and the channel 2 210 are transport channels capable of feeding back the packet transmission state of each channel to the video transmitter 100.

This feedback of network information can be performed by various means, for example, an ARQ (Automatic Repeat Request) or pilot packet, which is an error control protocol requiring the receiver to retransmit corrupted data. may be performed through a pilot packet.

Meanwhile, the video receiver 300 includes a reception channel switch 310, an error correction decoder 1 320, an error correction decoder 2 330, a multiple representation string decoder 1 340, a multiple representation string decoder 2 350, and a multiple Expression Decoder 3 360 and Channel Switch Controller 370 are included.

First, the receiving channel switch 310 forms an error correction decoder by forming a path of the expression string 1 and the expression string 2 received through the channel 1 200 and the channel 2 210 according to the control signal of the channel switching controller 370. 1 (320) and error correction decoder 2 (330).

The channel exchange controller 370 receives a control signal for setting a path according to whether the expression string exchange bits included in the expression string 1 and the expression string 2 received through the channel 1 200 and the channel 2 210 are set. Output to the switch 310.

That is, in the normal mode in which the expression string 1 is received through the channel 1 200 and the expression string 2 is received through the channel 2 210 when the expression string exchange bits included in the expression string 1 and the expression string 2 are not set. Therefore, the channel exchange controller 370 connects the channel 1 200 to the error correction decoder 1 320 and the channel 2 210 to the error correction decoder 2 330.

However, if the expression string exchange bits included in the expression string 1 and the expression string 2 are set, the expression strings are interchanged and transmitted by the video transmitter 100, that is, the expression string 2 is received through the channel 1 200. And the exchange mode in which the expression string 1 is received through the channel 2 210, the channel exchange controller 370 connects the channel 1 200 to the error correction decoder 2 320, and connects the channel 2 210 to the error. It is connected to the correction decoder 1 330 so that error correction decoding can be performed according to the correct overhead amount.

Meanwhile, in the above description, the expression string exchange bit is set in both the expression string 1 and the expression string 2, but only one of the expression string 1 and the expression string 2 is provided with the expression string exchange bit and only the expression string exchange bit of the expression string. It may be referred to.

The error correction decoder 1 320 performs error correction decoding according to an overhead of a predetermined weight with respect to the expression string 1 output from the reception channel switch 310, and the error correction decoder 2 330 is a reception channel switch ( The error correction decoding according to the overhead of the predetermined weight is performed on the expression string 2 output from 310. In this case, since the overhead used for the expression string 1 is larger than the overhead used for the expression string 2, the error correction decoder 1 320 uses the larger amount of overhead than the error correction decoder 2 330, thereby correcting the error correction. Will be performed.

The multiple expression string decoder 1 340 decodes the signal output from the error correction decoder 1 320, that is, the signal whose expression string 1 has been error correction decoded, and outputs the result to the user, and outputs the multiple expression string decoder 3 360. Denotes a signal output from the error correction decoder 2 (330), that is, the expression string 2 outputs the error correction decoded signal to the user by decoding the multiple representation string, and the multiple representation string decoder 2 (350) is the error correction decoder 1 (320). And the signal output from the error correction decoder 2 (330), that is, the expression string 1 and the expression string 2 are output to the user by decoding the multiple expression strings using the error correction decoded signals, respectively.

Accordingly, it can be seen that the image quality of the video output from the multiple representation string decoder 2 350 is the best image quality.

Hereinafter, a video transmission method according to an embodiment of the present invention will be described with reference to FIGS. 3 and 4.

3 is a flowchart of a video transmission method according to an embodiment of the present invention.

Referring to FIG. 3, first, the multiple representation string encoder 1 120 and the multiple representation string encoder 2 130 of the video transmitter 100 are respectively correlated with the representation string 1 with respect to the video signal provided from the video source 110. The multi-expression string encoding for generating and outputting the expression string 2 is performed (S10).

Next, the error correction encoder 1 140 performs error correction encoding with a specific overhead on the expression string 1 output from the multiple representation string encoder 1 120, and the error correction encoder 2 150 performs the multiple representation string encoder 2. An error correction encoding is performed on the expression string 2 output from the 130, but the error correction encoding is performed in a smaller amount, in particular, much less than the overhead of the error correction code performed by the error correction encoder 1 (140). (S12).

Next, the channel exchange controller 170 is a bottleneck state of the channel 1 (200) and the channel 2 (210) based on the channel information that is fed back through the ARQ or pilot packet in the channel 1 (200) and the channel 2 (210). B and compare the magnitude of the transmission error rate for determining the cluster error (S14).

If the transmission error rate of the channel 2 (210) is greater than the transmission error rate of the channel 1 (200) in the comparison step (S14) and the transmission state of the channel 2 (210) is worse than the transmission state of the channel 1 (200), the channel The exchange controller 170 causes the expression string 1 having a relatively large overhead of the error correction code output from the error correction encoder 1 140 to be transmitted through the channel 2 210 having a worse channel state, and the error correction encoder 2 The transmission channel switch 160 is controlled such that the expression string 2 having a relatively low overhead of the error correction code output from the 140 is transmitted through the channel 1 200 having a relatively good transmission state (S16).

At this time, the channel exchange controller 170 sets the expression string exchange bits included in the expression string 1 and the expression string 2 to inform the video receiver 300 that each expression string is transmitted by interchange of transmission channels (S18). .

Meanwhile, in the comparison step S14, the transmission error rates of the channel 1 200 and the channel 2 210 are the same, so that the transmission status is the same, or the transmission error rate of the channel 1 200 is the transmission error rate of the channel 2 210. If the transmission state of the channel 1 200 is greater than that of the channel 2 210, the channel switching controller 170 outputs the expression string 1 output from the error correction encoder 1 140 through the channel 1 200. The transmission channel switch 160 is controlled so that the expression string 2 output from the error correction encoder 2 140 is transmitted through the channel 2 210. Since this is a channel transmission path basically set by the transmission channel switch 160, no separate control by the channel switching controller 170 is required.

Next, the transmission channel switch 160 transmits the expression string 1 and the expression string 2 to the video receiver 300 through the channel 1 200 and the channel 2 210 according to the set transmission path (S20).

4 is a flowchart of a video receiving method according to an embodiment of the present invention.

Referring to FIG. 4, first, the channel exchange controller 370 of the video receiver 100 receives the expression string 1 and the expression string 2 through the channel 1 200 and the channel 2 210 (S30), and In order to determine whether the reception path needs to be exchanged, it is determined whether the expression string exchange bit is set (S32).

If the expression string exchange bit is set in the determination step (S32), that is, if each expression string is transmitted in the exchange mode, the channel exchange controller 370 error corrects the expression string 2 received through the channel 1 (200). The reception channel switch 310 is controlled to receive the decoder 2 330, and the error correction decoder 1 320 receives the representation string 1 received through the channel 2 210 (S34).

As a result, since the state of the channel 2 210 is worse than that of the channel 1 200, the video receiver 100 transmits the expression strings having different overhead weights of the error correction code and is transmitted interchangeably. The expression strings received at the switch 310 are interchanged.

On the other hand, if the expression string exchange bit is not set in the determination step (S32), that is, if each expression string is transmitted in the normal mode, the error correction decoder 1 (320) is received. Control the receiving channel switch 310 to receive) and also control the receiving channel switch 310 so that the error correction decoder 2 330 receives the expression string 2 received through the channel 2 210. In this case, since the channel transmission path is basically set by the reception channel switch 310, a separate control by the channel switching controller 370 may not be necessary.

Next, the error correction decoder 1 320 performs error correction decoding according to a relatively large overhead with respect to the expression string 1 output from the reception channel switch 310, and the error correction decoder 2 330 is a reception channel switch ( In operation S36, error correction decoding may be performed on the expression string 2 output from 310 according to a relatively small overhead. In this case, since the overhead used for the expression string 1 is larger than the overhead used for the expression string 2, the error correction decoder 1 320 uses the larger amount of overhead than the error correction decoder 2 330, thereby correcting the error correction. Will be performed.

Finally, the multi-expression decoder 1 340 decodes the error-corrected decoded signal of the error-correcting decoder 1 320 outputted from the error correction decoder 1 320 to the user, and outputs the multi-expression decoder 3 360 to the user. Is a representation string 2 output from the error correction decoder 2 (330) and outputs the error correction decoded signal to the user by decoding the multiple representation string, the multiple representation string decoder 2 (350) and error correction decoder 1 (320) and error correction The expression string 1 and the expression string 2 output from the decoder 2 330 decode the multiple expression strings using the error correction decoded signals, respectively, and output them to the user (S38).

As described above, when a video signal is multi-string encoded and transmitted on an independent channel, error correction coding is performed on each expression string weighted with error correction capability, and a channel with more error correction capability is transmitted through a channel having a poor transmission state. By transmitting and adaptively correcting transmission errors, it becomes much more efficient to deal with network bottlenecks and cluster errors.

Meanwhile, in the above description, the video transmitter 100 transmits each representation string encoded by multiple representation strings by performing only error correction encoding, and transmits them through the channels 200 and 210, but the technical scope of the present invention is not limited thereto. Conventional techniques such as increasing the effect of error correction encoding or reducing the occurrence of clustering errors may be further included. For example, in order to randomize the clustering error, an interleaving method in which the data to be transmitted is transmitted in a specific pattern instead of being continuously transmitted may be further used. In the case of such interleaving, for example, data to be transmitted is stacked by a specific length in the horizontal direction, and then the data in the vertical direction is made into a packet and transmitted, resulting in the loss of only one byte horizontally even if one specific packet is damaged. Dispersion is effective.

In addition, although the above description has been made only for generating and transmitting two expression strings, the technical scope of the present invention is not limited thereto, and it is easily understood by those skilled in the art that the present invention may be applied to generating and transmitting three or more expression strings. Will be. For example, in the case of generating three expression strings, the error correction capability used for each of the three expression strings is differentiated, and then the error correction capability is improved for the poor transmission channel based on the feedback information of the three transmission channels. By sending a large number of expression strings, network bottlenecks and clustering errors can be handled more efficiently.

Although the present invention has been described with reference to the most practical and preferred embodiments, the present invention is not limited to the above disclosed embodiments, but also includes various modifications and equivalents within the scope of the following claims.

According to the present invention, it is possible to cope with video transmission errors caused by network bottlenecks and radio channel aggregation errors very efficiently.

In addition, the transmission error rate of the video can be reduced to the maximum while adaptively coping with a time-varying network bottleneck or a wireless channel error condition.

In addition, the amount of overhead of the error correction code can be optimally adjusted according to the characteristics of the transmission channel.

You can also watch video constantly over networks or channels that aren't guaranteed Qos.

Claims (22)

A video transmitting apparatus for transmitting a plurality of correlation expression strings generated by multiple description coding of a video through separate independent transmission channels, A multiple representation string encoder for generating a plurality of correlation representation strings by performing multiple representation string encoding on a video signal to be transmitted; An error correction encoding unit for performing error correction encoding on a plurality of expression strings generated by the multiple expression string encoders, by weighting error correction capabilities given to each expression string so that the same error correction capability is not given; A transmission channel switch unit forming a path with a plurality of transmission channels to which a plurality of expression strings error corrected and encoded by the error correction coder are to be transmitted; And Channel exchange for controlling the path formation of the plurality of expression strings and the plurality of transport channels by controlling the transmission channel switch unit according to the state of the plurality of transport channels determined based on the channel state information feedbacked from the plurality of transport channels. Control Including; The channel switching control unit controls to transmit a representation string having a relatively large error correction capability among the plurality of representation strings through a transmission channel having a relatively poor transmission state among the plurality of transmission channels. Including the information representing the path formation between a plurality of transmission channels in the plurality of expression strings A video transmission device, characterized in that. The method of claim 1, The expression string generated by the multiple expression string encoder is two first expression strings and two second expression strings, The error correcting coder may weight the error correction encoding so that the error correction capability given to the first expression string is greater than the error correction capability given to the second expression string. A video transmission device, characterized in that. The method of claim 2, Transmission channels for transmitting the two expression strings are two first channels and two channels, The channel switching controller is configured to transmit the first expression string through the first channel when the transmission state of the first channel is equal to or worse than the transmission state of the second channel. Controlling the transmission channel switch unit to be transmitted through the second channel A video transmission device, characterized in that. The method of claim 2, The channel exchange controller is configured to transmit the first expression string through the second channel when the transmission state of the second channel is inferior to that of the first channel, and the first expression string may be transmitted to the second channel. Controlling the transmission channel switch to be transmitted through a channel A video transmission device, characterized in that. The method of claim 4, wherein The channel exchange control unit includes, in the first and second expression strings, an expression string exchange bit representing information transmitted through the first and second channels by exchanging the first and second expression strings. And a video transmission device. The method according to any one of claims 1 to 5, And the error correction capability is determined by an overhead of an error correction code. A video transmission method for transmitting a plurality of correlation representation strings generated by encoding multiple representation strings through a separate independent transport channel, Generating a plurality of correlation representation strings by performing multiple representation string encoding on a video signal to be transmitted; A second step of performing error correction encoding on the plurality of expression strings generated in the first step, weighting the error correction capability given to each expression string so that the same error correction capability is not given; A third step of comparing the state information fed back from a plurality of transmission channels to which the plurality of weighted error corrected encoded sequences are to be transmitted; And As a result of the comparison in the third step, the plurality of expression strings are transmitted such that an expression string having a relatively large error correction capability is transmitted through the transmission channel having a relatively poor transmission state among the plurality of transmission channels. A fourth step of forming a transmission path between the plurality of transmission channels, and including, in the plurality of expression strings, information representing the plurality of expression strings and path formation between the plurality of transmission channels; Video transmission method comprising a. The method of claim 7, wherein In the first step, the expression string generated by the multiple expression string encoding is two first expression strings and two second expression strings, In the second step, error correction coding is performed so that the error correction capability given to the first expression string is greater than the error correction capability given to the second expression string. A video transmission method, characterized in that. The method of claim 8, Transmission channels for transmitting the two expression strings are two first channels and two channels, In the fourth step, when the transmission state of the first channel is the same as or worse than the transmission state of the second channel, the first expression string is transmitted through the first channel, and the second expression string Is controlled to be transmitted on the second channel A video transmission method, characterized in that. The method of claim 8, In the fourth step, When the transmission state of the second channel is inferior to that of the first channel, the first expression string is transmitted through the second channel and the first expression string is transmitted through the second channel. Controlled A video transmission method, characterized in that. The method of claim 10, And the expression string exchange bit representing the information transmitted through the first channel and the second channel by exchanging the first expression string and the second expression string in the first expression string and the second expression string. Video transmission method. In a video receiving apparatus for receiving a plurality of correlation expression strings transmitted from a video transmission apparatus through a separate independent transmission channel, wherein the plurality of correlation expression strings are generated by multiple expression string encoding and reconstructing the original video. A reception channel switch unit forming a path through which the plurality of correlation expression strings are received; An error correction decoding unit performing error correction decoding on a plurality of expression strings received through a path formed by the reception channel switch, and performing error correction decoding according to the weighted error correction capability given to each expression string; Controlling the reception channel switch unit according to the information representing the path formation between the plurality of expression strings included in the plurality of expression strings and the plurality of transmission channels to control path formation between the plurality of transmission channels and an input of the error correction decoder. A channel exchange control unit; A multiple-expression string decoder for decoding the multiple-expression string using a plurality of expression strings that are error-corrected and outputted by the error-correcting decoder and outputting the same to the user. Video receiving device comprising a. The method of claim 12, The transmission channel is two first channels and two channels, The expression strings received by the receiving channel switch unit through the two transmission channels are two first expression strings and two second expression strings. Weighted such that the error correction capability given to the first representation is greater than the error correction capability given to the second representation Video receiving apparatus, characterized in that. The method of claim 13, Information representing a path formation between the plurality of representation strings and the plurality of transport channels is a representation string exchange bit, When the expression string exchange bit is set, the channel exchange controller controls the reception channel switch unit so that the first expression string and the second expression string are interchanged and received and input to the error correction decoder. Video receiving apparatus, characterized in that. The method according to claim 13 or 14, The multiple expression string decoder, A first multiple expression string decoder configured to decode the multiple expression strings using the first expression string that is output after the weighted error correction decoding; A second multiple-expression string decoder configured to decode the multiple-expression string by using the weighted error correction decoded second output string; And A third multiple-expression string decoder configured to decode the multiple-expression string by using the weighted error correction decoding outputted first and second expression strings Video receiving device comprising a. A video receiving method for reconstructing an original video by receiving a plurality of correlation expression sequences transmitted from a video transmission apparatus through a separate independent transmission channel, wherein the plurality of correlation expression strings are generated by multiple expression string encoding. A first step of inspecting information indicating a path formation between the plurality of expression strings and the plurality of transmission channels included in the plurality of received correlation strings; A second step of exchanging receiving paths of the plurality of expression strings when the reception paths of the plurality of expression strings are required as a result of the inspection of the first step; Performing error correction decoding on the plurality of expression strings received through the reception path formed in the second step, and performing error correction decoding according to the weighted error correction capability given to each expression string; And A fourth step of decoding the multiple expression string using the weighted error correction decoded plurality of expression strings and outputting the same to the user Video receiving method comprising a. The method of claim 16, The transmission channel is two first channels and two channels, Representation strings received through the two transport channels are two first expression strings and two second expression strings. Weighted such that the error correction capability given to the first representation is greater than the error correction capability given to the second representation Video receiving method, characterized in that. The method of claim 17, Information indicating a path formation between the plurality of representation strings and the plurality of transmission channels is an expression sequence exchange bit, When the expression string exchange bit is set, the first expression string and the second expression string are exchanged and received. Video receiving method, characterized in that. The method of claim 17 or 18, The fourth step, Decoding multiple representation strings using the first representation string that is output after the weighted error correction decoding; Decoding multiple representation strings using the second representation string that is output after the weighted error correction decoding; And Decoding multiple representation strings using the first representation string and the second representation string output after the weighted error correction decoding; Video receiving method comprising a. A plurality of correlation expressions generated by encoding multiple video sequences are weighted on the error correction capability given to each expression string to perform error correction encoding so that the same error correction capability is not given, and then transmitted through a plurality of independent transmission channels. However, according to the state of the plurality of transmission channels determined based on the channel state information feedback from the plurality of transmission channels to form the path of the plurality of expression strings and the plurality of transmission channels to transmit the plurality of expression strings A video transmitter; And Receiving paths of the plurality of expression strings formed on the basis of information indicating path formation between the plurality of expression strings and the plurality of transmission channels, included in the plurality of expression strings transmitted from the video transmitter via the plurality of transmission channels. A video receiver which receives the plurality of expression strings, performs error correction decoding according to the weighted error correction capability given to each expression string, and then decodes the multiple expression strings to restore the original video. Video transmission device comprising a. The method of claim 20, The video transmitter, A multiple representation string encoder for generating a plurality of correlation representation strings by performing multiple representation string encoding on a video signal to be transmitted; An error correction encoding unit for performing error correction encoding on a plurality of expression strings generated by the multiple expression string encoder, by weighting an error correction capability given to each expression string so that the same error correction capability is not given; A transmission channel switch unit forming a path with a plurality of transmission channels to which a plurality of expression strings error corrected and encoded by the error correction coder are to be transmitted; And Channel exchange for controlling the path formation of the plurality of expression strings and the plurality of transport channels by controlling the transmission channel switch unit according to the state of the plurality of transport channels determined based on the channel state information feedbacked from the plurality of transport channels. Control Including; The channel switching control unit controls to transmit a representation string having a relatively large error correction capability among the plurality of representation strings through a transmission channel having a relatively poor transmission state among the plurality of transmission channels. Including the information representing the path formation between a plurality of transmission channels in the plurality of expression strings And a video transmission device. The method of claim 20, The video receiver, A reception channel switch unit forming a path through which the plurality of correlation expression strings are received; An error correction decoding unit performing error correction decoding on a plurality of expression strings received through a path formed by the reception channel switch, and performing error correction decoding according to the weighted error correction capability given to each expression string; Controlling the reception channel switch unit according to the information representing the path formation between the plurality of expression strings included in the plurality of expression strings and the plurality of transmission channels to control path formation between the plurality of transmission channels and an input of the error correction decoder. A channel exchange control unit; And A multiple-expression string decoder for decoding the multiple-expression string using a plurality of expression strings that are error-corrected and outputted by the error-correcting decoder and outputting the same to the user. Video transmission device comprising a.