KR20070121240A - Method for video data delivery using partial divide broadcasting - Google Patents

Abstract

A method for transmitting video data by using partial division broadcasting is provided to reduce the number of video data segments and reduce the number of channels which are used at once. A video data transmitting method comprises the following steps of: dividing the whole video data(D) into two parts of a forgoing part(D1) and a following part(D2); and transmitting the D1 through a data division mode and transmitting the D2 through a staggered mode for repeatedly transmitting the D2 at certain periods. A length of the D1 is shorter than the D2. The above first step is performed by a division coefficient(h) of the video data.

Description

Method for video data delivery using partial divide broadcasting}

1 is a block diagram showing the configuration of divided video data according to an embodiment of the present invention.

2 is a block diagram illustrating a configuration of divided video data when transmitting video data from a server according to an exemplary embodiment of the present invention.

3 is an exemplary diagram illustrating a case where video data is transmitted by a partial division transmission method according to an exemplary embodiment of the present invention.

4 is a diagram illustrating a graph comparing the maximum waiting time of a viewer in a video data transmission method and a conventional NVoD video data transmission method according to an embodiment of the present invention.

FIG. 5 is a diagram illustrating a graph comparing a maximum buffer requirement of a viewer in a video data transmission method and a conventional NVoD video data transmission method according to an embodiment of the present invention. FIG.

6 is a graph showing a relationship between a viewer maximum waiting time and a video partition coefficient by a video data transmission method according to an exemplary embodiment of the present invention.

7 is a graph showing the relationship between the maximum viewer buffer demand and the video partition coefficient according to the video data transmission method according to an embodiment of the present invention.

The present invention relates to a method of transmitting video data, and more particularly, to a method of transmitting video data using a partial division transmission scheme.

 Video data is a collection of large-capacity data such as video and audio, and when it is provided to viewers via a network, a large channel bandwidth is required, and a large cost is required to secure a large channel bandwidth.

However, with recent advances in communication technologies and digital processing devices, the VoD (Video on Demand) service, which is a video service that enables users to watch desired programs at any time through a computer or television connected to a communication network, is becoming more widespread. It is increasing.

In general, the video data transmission method in this VoD service is always provided with a true video on demand (TVoD) method which occupies and uses one channel by immediately giving one channel to a subscriber when a subscriber video viewing request is requested. Specific video is broadcasted at regular intervals, and is divided into a near video on demand (NVoD) method in which several subscribers can simultaneously watch a single video.

The NVoD method has the advantage of accommodating a large number of subscribers with the same channel bandwidth as compared to the TVoD method.

Therefore, many studies have been conducted to improve the performance of the NVoD method mainly due to the characteristics of the VoD, which is generally performed on a large number of subjects, and these studies are largely divided into a patch method and a batch method.

The patch method is configured in such a manner that the video data is repeatedly transmitted through a static channel at regular intervals and the channel is added during the video data repetition period.

The patch method has the advantage of being simple to implement, but the channel bandwidth efficiency is inferior, service is limited to a limited viewer, and as the number of viewers increases, the required bandwidth also increases.

On the other hand, the batch method is a method of dividing the video data in various ways based on the bandwidth and length and broadcast it.

Although the layout method has an advantage of excellent channel bandwidth efficiency, the complexity of the configuration of the transmission method of the video data increases, so there is a problem in that there are many restrictions in the actual implementation.

In order to solve the conventional problems as described above, the present invention provides a high-bandwidth efficiency of the video data, the service is available to a large number of viewers, and even if the number of viewers increases the required bandwidth of the VoD service capable video data with the advantage It is to propose a transmission method.

Another object of the present invention is to propose a method of transmitting video data having the above advantages and having a simple configuration.

Still other objects of the present invention will be readily understood through the following description of the embodiments.

In order to achieve the above object, according to an aspect of the present invention, a video data transmission method is provided.

According to a preferred embodiment of the present invention, there is provided a method of transmitting video data, comprising: dividing the entire video data (D) into two parts, a leading part (D ₁ ) and a trailing part (D ₂ ); And (b) transmitting D ₁ in a data division scheme and D ₂ in a staggered manner repeatedly transmitting at regular intervals. .

The D ₁ may be shorter than the D ₂ .

The step of dividing the entire video data D into two parts, the leading part D ₁ and the trailing part D ₂ , may be performed by the partition coefficient h of the video data.

Wherein D ₁ is transmitting a staggered (Staggered) method of transferring, and transmitting to said D ₂ is repeated at regular intervals as a data division method may be performed to match the transmission period of the D ₁ and D _2.

The channel to the D ₁ it is possible to divide the D ₁ to 2 ^m -1 of the same size, if assigned m (a natural number) pieces.

Also dog 2 ⁱ in the 2 ^m -1 of the D ₁ is divided into the same size D ₁ is divided i-th data channel for transmitting the channel ^{_{C i D1 (i = 0,}} 1, ..., m-1) of This can be performed by periodically transmitting as many video data segments.

에 의해 결정되되, h는 비디오 데이터의 분할 계수일 수 있다. And, the maximum viewer waiting time (δ) of the video data is

It is determined by, where h may be a partition coefficient of the video data.

The amount of bandwidth B allocated for the transmission of the video data may be determined by equation B = β X b (any number of β ≧ 1 and b is the playback consumption rate of the video data).

에 의해 결정될 수 있다.In addition, the user maximum buffer request amount Z of the video data

Can be determined by.

According to another aspect of the present invention, there is provided a recording medium recording a program for implementing the video data transmission method.

According to a preferred embodiment of the present invention, a recording medium on which a program of instructions that can be executed by a digital processing apparatus is tangibly implemented so that a video data transmission method can be implemented, and records a program that can be read by the digital processing apparatus. (A) dividing the entire video data D into two parts, a leading part D ₁ and a trailing part D ₂ ; And transmitting (b) the D ₁ in a data division scheme and transmitting the D ₂ in a staggered scheme repeatedly transmitting at regular intervals. A recording medium for recording the program is provided.

The D ₁ may be shorter than the D ₂ .

The step of dividing the entire video data D into two parts, the leading part D ₁ and the trailing part D ₂ , may be performed by the partition coefficient h of the video data.

Wherein D ₁ is transmitting a staggered (Staggered) method of transferring, and transmitting to said D ₂ is repeated at regular intervals as a data division method may be performed to match the transmission period of the D ₁ and D _2.

The channel to the D ₁ it is possible to divide the D ₁ to 2 ^m -1 of the same size, if assigned m (a natural number) pieces.

As the invention allows for various changes and numerous embodiments, particular embodiments will be illustrated in the drawings and described in detail in the written description. However, this is not intended to limit the present invention to specific embodiments, it should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention.

In describing the drawings, similar reference numerals are used for similar elements. In the following description of the present invention, if it is determined that the detailed description of the related known technology may obscure the gist of the present invention, the detailed description thereof will be omitted.

Terms such as first and second may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another.

For example, without departing from the scope of the present invention, the first component may be referred to as the second component, and similarly, the second component may also be referred to as the first component.

The term and / or includes any item of a plurality of related items or a combination of a plurality of related items.

When a component is referred to as being "connected" or "connected" to another component, it may be directly connected to or connected to that other component, but it may be understood that other components may be present in between. Should be.

On the other hand, when a component is said to be "directly connected" or "directly connected" to another component, it should be understood that there is no other component in between.

The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting of the present invention.

Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, the terms "comprise" or "have" are intended to indicate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, and one or more other features. It is to be understood that the present invention does not exclude the possibility of the presence or the addition of numbers, steps, operations, components, components, or a combination thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art.

Terms such as those defined in the commonly used dictionaries should be construed as having meanings consistent with the meanings in the context of the related art, and, unless expressly defined in this application, are construed in ideal or excessively formal meanings. It doesn't work.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings, and the same or corresponding components will be denoted by the same reference numerals regardless of the reference numerals and redundant description thereof will be omitted.

The configuration of video data applied to such a partial division transmission scheme will be described with reference to FIG. 1.

1 is a block diagram showing the configuration of divided video data according to an embodiment of the present invention.

In the present invention, video data is transmitted in a partial division transmission scheme.

The partial division transmission scheme according to the preferred embodiment of the present invention divides the video data into a short preceding portion and a long trailing portion, and transmits the short preceding portion by applying a transmission scheme using data division, and the long trailing portion is a conventional NVoD scheme. It is a method of transmitting using a staggered method of repeatedly transmitting video data at regular intervals.

In this case, each part is repeatedly transmitted through a periodic broadcast, and the staggered repetition period is matched to match the repetition period of the transmission method using data partitioning.

Broadcast sends all packet data to a network connected to a server at once, thus sending information to multiple stations at the same time.

As shown in FIG. 1, the entire video length D is divided into a short leading part D ₁ and a long trailing part D ₂ , and the D ₁ part is transmitted using a transmission method using data partitioning, and D ₂ is a staggered method. To send. In order to apply a transmission method using the data partitioning in D ₁ is transmitted by dividing the D ₁ back to the same size, D ₂ has a structure without dividing the transmission period of repetition of the same interval in one size.

This transmission method will be described in more detail.

First, the video data transmission is performed in the server in the partial split transmission method.

As shown in FIG. 1, assuming that the length of the video transmitted from the server to the client is D and the playback consumption rate of the video is b, the size V of the entire video is expressed as V = D X b.

If the size of the bandwidth allocated for video transmission is B, it can be expressed as B = β X b, where β ≧ 1.

Partial split transmission at the server first divides the length D of the video into two parts: the short video D _{1 before} and the long video D ₂ . At this time, the relationship between D ₁ and D ₂ is expressed as Equation 1 below.

[Equation 1]

Where h is a video partition coefficient and δ is one data segment length obtained by dividing D ₁ by the same size. The segmented short video leading size V ₁ is V ₁ = D ₁ X b and the long trailing size V ₂ = is D ₂ X b.

The bandwidth B allocated for video transmission is divided by k logical channels of equal size. Their relationship is represented by the following [Equation 2].

[Equation 2]

And the number of the channel assigned to the short video earlier D ₁ part of a transmission system using a data division that is applied is assumed that m and staggered manner is assumed to be n the number of the channel assigned to the long video later D ₂ are applied .

In this case, the relation k = m + n is established in the logical channel.

은 데이터 분할을 이용한 전송 방식이 적용되는 부분의 채널을 말하고,

은 스태거드 전송 방식이 적용되는 부분의 채널을 나타낸다. C_l ^Di(i=1, 2)의 표기법은 D_i부분의 l번째 채널을 나타낸다.

Means a channel of a part to which a transmission scheme using data partitioning is applied,

Denotes a channel of a part to which a staggered transmission scheme is applied. The notation C ₁ ^Di (i = 1, 2) indicates the l th channel of the D _i part.

The full video length D is divided into N segments. The _first part of the video D ₁ is divided into 2 ^m -1 equal parts, and the _second part of the video D ₂ is divided into one segment. Therefore, N holds the following relation (Equation 3).

[Equation 3]

The divided video may be represented by S, and S _i represents an i-th video segment. All segments are concatenated in numerical order, and the sum of all the concatenated videos together makes up the entire video. The lengths of S ₀ to S _N-1 belonging to the front portion D ₁ of the video are equal to δ.

Within ^{Ci D1 (i = 0, ...} , m-1) is sent to the transmission system 2, a video data segment by using the ⁱ pieces of data divided into a periodically carried out.

In Cj ^D2 (j = 0, ..., n-1), the S _N segment is periodically transmitted in a staggered manner. At this time, the repetition period T _S of the staggered method must be T _S = D ₁ + δ to match the period with the transmission method using data partitioning.

The channel n allocated to the staggered method may be represented by n = [D ₂ / T _S ] = [h]. Therefore, a channel allocated to a transmission scheme using data partitioning may be represented by m = k − [h].

When the video data is transmitted from the server, the configuration of the divided video data will be described in more detail with reference to FIG. 2.

As shown in FIG. 2, the length D of the video is divided into D ₁ and D ₂ by the video partition coefficient h. Where C _l ^d represents the l-th channel of the d portion.

m represents the number of channels allocated for transmitting D ₁ in a transmission scheme using data partitioning, and n represents the number of channels allocated for transmitting D ₂ in a staggered manner.

The transmission period T _S of D2 to which the staggered method is applied is D ₁ + δ where δ is equally divided into lengths of D ₁ / (2 ^m −1) to transmit D ₁ through a data division. The length of one segment. Video data segments transmitted periodically and repeatedly on channel C _i ^D1 are S ₂ ^l to S ₂ ^{l +1} ₋₁ .

When the video data is divided and transmitted in this manner, the client receives the video data to display the video data.

A process in which the video data received by the client receiving the video data transmitted by the aforementioned split transmission scheme is processed will be described.

First, based on the point in time at which the viewer wants to watch the video, the viewer can immediately view the segment S ₁ of the video data starting with the channel C ₀ ^D1 . At the same time, video data segments between channel C ₁ ^D1 and channel C _{m- 1} ^D1 begin to download as needed.

At this time, when the video transmission start point of the last video data segment S _{N and} the video data start point of S ₁ are the same, S _N is stored simultaneously with the start of S ₁ . If the starting point of S ₁ and S _N is different, S _N is stored as soon as it starts from the starting point of S1.

When the video transmission start point of the last video data segment S _{N and} the video data start point of S ₁ are the same, S _N must be stored at the same time as the start of S _{1 so that} the viewer can watch the video without interruption.

All video data segments are downloaded from S ₁ to S ₂ ,... In this order, viewing is possible without breaking in the order of S _N.

Channel ^{_{C i D1 (i = 0,1,}} ..., m-1) in the 2 ⁱ Once received second video data segment in the corresponding channel stops downloading. In channel C _j ^D2 (j = 0,1,… n-1), the download stops when the last video data segment S _N is received in one channel.

Referring to FIG. 3, an example in which a video data transmission method using a partial division transmission scheme is actually implemented will be described.

FIG. 3 is an exemplary diagram actually implementing a case where video data is transmitted by a partial division transmission method according to an exemplary embodiment of the present invention.

In FIG. 3, the case where the partial division schemes are k = 6, β = 6, h = 3, m = 3 and n = 3 illustrates the divided video data. Since m = 3, D ₁ is divided into seven segments and broadcasted periodically on three channels C ₀ ^D1 , C ₁ ^D1, and C ₂ ^D1 . The period of the staggered channel is 8δ. Where δ appears as D / 31, which is the viewer's maximum latency.

The minimum viewer buffer requirement is when the viewer receives a video data segment from t ₁ , in which case no buffer is required. In other words, viewers can watch without a buffer.

The maximum viewer buffer requirement is when the video data segment is received from t ₀ , in which case V ₁ must be downloaded as well as V ₂ .

Hereinafter, a description will be given with reference to FIGS. 4 and 5 of a viewer waiting time and a maximum buffer demand when video data is transmitted by an actual divided transmission scheme according to an exemplary embodiment of the present invention.

The viewer waiting time and the maximum buffer demand of FIG. 4 and FIG. 5 were performed by comparing the lengths of the channels D to 100 minutes and the video splitting coefficients h and 3 to 5, while changing the number of channels.

First, the viewer waiting time will be described with reference to FIG. 4.

Viewer latency is the length of video data S ₁ on channel C ₀ ^D1 . Because, if the viewer misses the first data segment S ₁ of the video on channel C ₀ ^D1 , the maximum viewer latency is the length of S ₁ because the viewer must wait for the length of S ₁ to start the video. The length of S ₁ may be represented by D ₁ b / (N-1) = D ₁ b / (2 ^m −1).

The bandwidth of channel C ₀ ^D1 is expressed in B / k at the given bandwidth for video transmission. Therefore, the maximum viewer waiting time required to watch the video when transmitting the video using the partial division transmission scheme in the given transmission bandwidth B can be expressed by Equation 4 below.

[Equation 4]

When β is an integer, k = β and the above expression is simply expressed in the form of δ = D ₁ / (2 ^m −1). Here, the total length D of the video is D = D ₁ + D ₂ , and since D ₂ = h (D ₁ + δ), using these relational expressions, Equation 4 can be expressed as Equation 5 below. Do.

[Equation 5]

In the above equation, when β is an integer, k = β, so using these relational expressions, the maximum viewer waiting time can be expressed as Equation 6 below.

[Equation 6]

As shown in FIG. 4, when the video splitting factor h is 3, the viewer maximum waiting time of the partial split transmission scheme is smaller than that of Pyramid Broadcasting and is almost similar to Fast Broadcasting and Staircase Broadcasting.

In addition, in the partial transmission scheme, as the video partition coefficient h decreases, the maximum viewer waiting time δ also decreases. However, as the channel bandwidth increases, the viewer maximum latency difference is almost eliminated.

As shown in Fig. 4, if the length D of the video is 100 minutes, the total number of channels k allocated for video transmission is 8, and the video partition coefficient h is 3, the condition for video transmission. In the case of using the partial transmission scheme, the maximum viewer waiting time is about 46 seconds and the average viewer waiting time is about 23 seconds.

However, under the same conditions, the staggered maximum viewer latency is about 12.5 minutes.

As shown in this simple comparison, the partial partitioned transmission scheme has a simpler structure than the conventional scheme, thereby increasing the efficiency of bandwidth usage.

Meanwhile, a viewer buffer request amount, which is a buffer request amount required by the client side, in the video data transmission method using the partial division transmission method will be described with reference to FIG. 5.

In the partial partitioning scheme, a buffer is required to watch a video according to a viewer's request. This is because, from the viewer's perspective, the playback speed of video data is slower than the reception speed of video data in a set-top box.

If the method of transmitting video data according to an embodiment of the present invention the viewer is looking buffer requirement is a maximum with reference to Figure 3, a t _0. In this case, the buffer consumption rate is less than the increase rate until the last channel C _m-1 ^D1 to which the data division transmission scheme is applied. The buffer requirement increases until the last channel to which the preceding method is applied. Therefore, the maximum user buffer requirement can be expressed as Equation 7 below.

[Equation 7]

The maximum user buffer requirement is generated in the last channel C _m-1 ^D1 to which the data division transmission scheme is applied, and in the channel to which the staggered scheme is applied, the buffer requirement is maintained but decreases after reception of the video data S _N.

If the video splitting coefficient h of the partial division transmission scheme is given as 3 and 5, the relationship between the user maximum buffer requirement Z and the required bandwidth B is shown as shown in FIG.

As shown in FIG. 5, the maximum buffer requirement converges to 50% of video data, 37% of Harmonic Broadcasting, and 25% of Staircase Broadcasting in Fast Broadcasting.

In FIG. 5, the result is too large and is not shown. However, in Pyramid Broadcasting, about 75% of the video data is represented as a buffer requirement.

The maximum buffer demand of the partial division transmission scheme converges to about 17% of the total video data when the video partition coefficient h is 5 and about 25% of the total video data when h is 3.

In addition, it can be seen from FIG. 5 that the maximum viewer buffer size Z decreases as the video partition coefficient h increases in the partial division transmission scheme.

Meanwhile, the relationship between the partition coefficient, the viewer waiting time, and the viewer maximum buffer demand will be described with reference to FIGS. 6 and 7 with reference to the viewer waiting time and the viewer maximum buffer demand by the video data transmission method according to the present invention.

First, FIG. 6 is a diagram illustrating a graph showing a relationship between a viewer maximum waiting time and a video partition coefficient according to a video data transmission method according to an exemplary embodiment of the present invention.

FIG. 6 shows the relationship between the video splitting factor h and the viewer maximum waiting time when the number of logical channels k is determined and the video length D is 100 minutes.

Within the fixed number of logical channels, as the video partition coefficient h increases, the viewer maximum latency δ also increases. As the number of logical channels k is allocated and the video partition coefficient h is set to a large value, the maximum viewer waiting time increases quickly.

That is, under the same condition of the video data transmission method according to the partial division transmission method according to the present invention, as the number of channels allocated to the transmission method using the data division increases, the viewer maximum waiting time is shortened.

FIG. 7 is a graph illustrating a relationship between a maximum viewer buffer demand and a video partition coefficient according to a video data transmission method according to an exemplary embodiment of the present invention.

7 shows the relationship between the video partition coefficient h and the viewer maximum buffer demand for a given logical channel number k. As the video partition coefficient h increases, the maximum buffer demand decreases.

The smaller the number of logical channels k is assigned and the larger the video partition coefficient h is, the larger the maximum viewer buffer requirement can be. When the value of the video splitting factor h is small, the maximum viewer buffer requirement does not show a difference.

These results show that the larger the number of channels allocated to the staggered method, the smaller the viewer maximum buffer requirement is under the same conditions of the partial data transmission method.

Therefore, when building a VoD service system using the video data transmission method according to the present invention, it is possible to significantly increase the channel bandwidth efficiency under the same conditions (for example, the same channel bandwidth, the same delay time, and the same storage device). In addition, the number of video data division, the number of channel hopping, the number of simultaneous channels, etc. can be reduced compared to the conventional method of transmitting video data.

Preferred embodiments of the present invention described above are disclosed for purposes of illustration, and those skilled in the art will be able to make various modifications, changes, and additions within the spirit and scope of the present invention. Additions should be considered to be within the scope of the following claims.

As described above, the video data transmission method according to the present invention has the advantage of reducing the number of video data segments and the number of channels used at one time.

In addition, since there is no change in performance according to the change in the number of viewers, there is an effect that can be applied to a large-scale service, there is an advantage that can adjust the waiting time and the amount of buffer required by the partition of the video data.

Claims (14)

In the transmission method of video data, Dividing the entire video data D into two parts, a leading part D ₁ and a trailing part D ₂ ; And And transmitting (D ₎ the data in a staggered manner in which D ₁ is transmitted in a data division scheme and D ₂ is repeatedly transmitted in a predetermined cycle. The method of claim 1, And the D ₁ is shorter than the D ₂ . The method of claim 1, Step (a) is, Video data transmission method characterized by the partition coefficient (h) of the video data. The method of claim 1, Step (b) is, And transmitting the transmission periods of the D ₁ and the D ₂ in correspondence with each other. The method of claim 1, And dividing D ₁ into 2 ^m -1 equal sizes when m channels are allocated to D ₁ . The method of claim 5, The 2 ^m -1 of the D ₁ D ₁ is divided by the same size of the i-th division of the data channel for transmitting the channel ^{_{C i D1 (i = 0,}} 1, ..., m-1) 2 ⁱ of two as in the And periodically transmitting the video data segments of the video data transmission method. The method of claim 6, The maximum viewer waiting time (δ) of the video data is expressed by the following equation.

And h is a partition coefficient of the video data. The method of claim 6, The amount of bandwidth B allocated for the transmission of the video data is determined by the equation B = β X b (any number of β ≥ 1 and b is the playback consumption rate of the video data). Transmission method. The method of claim 8, The user maximum buffer request amount Z of the video data

Video data transmission method, characterized in that determined by. A recording medium in which a program of instructions that can be executed by a digital processing apparatus is tangibly implemented so that a video data transmission method can be implemented, and which records a program that can be read by the digital processing apparatus, Dividing the entire video data D into two parts, a leading part D ₁ and a trailing part D ₂ ; And The D ₁ is transmitted by a data division scheme, and the D ₂ is a program implementing the video data transmission method comprising the step (b) of transmitting in a staggered manner to transmit repeatedly in a certain period Recording medium. The method of claim 10, The recording medium recording a program implementing the video data transmission method, characterized in that the D ₁ is shorter than the D ₂ . The method of claim 10, Step (a) is, A recording medium having recorded thereon a program implementing the video data transmission method, characterized in that it is performed by the partition coefficient (h) of the video data. The method of claim 10, Step (b) is, And a program embodying a program implementing the video data transmission method according to the transmission period of the D ₁ and the D ₂ . The method of claim 10, If a channel is allocated to the m pieces D ₁ recording medium recording a program that implements the video data transmission method characterized by dividing the D ₁ to 2 ^m -1 of the same size.

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