JPH0993136A - Method and device for editing compression data - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid overflow and underflow of data in advance in a data buffer by compressing again unit data after expansion into a compression object value or a value close thereto and combining compression data already re-compressed and existing compression data while selecting them. SOLUTION: The device is made up of an expansion section 1, a compression section 2, a compression object value calculation section 3, and changeover switches 4A, 4B. Some expansion units in the expansion unit group are expanded by the expansion section 1 as expansion unit data, the compression object value calculation section 3 calculates a proper compression object so as not to cause an overflow or an underflow in a data buffer. Then the compression section 2 compresses again the after-expansion unit data to be the same as or close to sub-object value and the data changeover switches 4A, 4B are used to select the compression data compressed again and existing compression data and to combine them and a new required expansion unit group is formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for editing compressed data.

[0002]

2. Description of the Related Art There is moving image compressed data in which a frame or a field is used as an image unit and the data amount of each image unit after compression is indefinite.

FIG. 6 shows the structure of a decompressor for decompressing moving image compressed data. In FIG. 6, 5 is a data buffer for temporarily storing the input moving image compressed data,
Reference numeral 6 is a decompression unit that decompresses the data stored in the data buffer.

FIG. 7 shows the amount of data occupied in a certain time zone in the data buffer 5 when the moving image compressed data of the program A is input to the decompressor. In FIG. 7, the horizontal axis represents time and the vertical axis represents data occupancy. The speed at which the data is input to the data buffer 5 is constant, and the data from the data buffer 5 is divided by each image unit (the portion in which the data occupancy in FIG. 7 is decreasing vertically) at each time interval t (i). Is output. In FIG. 7, t (i) is t (fixed) as an example. Since the data amount of each image unit is indefinite, the speed at which each image unit is output fluctuates. However, as shown in FIG.
It is compressed so that it does not overflow or underflow.

From the program A, an arbitrary necessary image unit is taken out to make one scene. Then, a plurality of scenes are connected in an arbitrary order to create a new program B. In the example shown in FIG. 7, the image unit of F10 to F15 is scene 1, F20 to F25 is scene 2, and scene 1 and scene 2 are connected to create program B. Program B is shown in FIG.

The data amount of each image of scene 1 and scene 2 is smaller than the data amount input to the data buffer 5 at time t.

[0007]

In the above case, since the data amount of the program B to be output is smaller than the data amount to be input to the data buffer 5, as shown in FIG. Data overflow occurs at. In the above example, the data amount of each image unit of scene 1 and scene 2 is smaller than the data amount input to the data buffer 5 at time t, but conversely, the data amount of each image unit changes at time t. Underflow may occur if the amount of data input to the data buffer 5 is larger than that. When overflow or underflow occurs in this way, there is a problem that it is difficult for the decompression unit 6 in FIG. 6 to properly decompress the data to be decompressed.

The present invention provides a compressed data editing method and apparatus for avoiding the above problems.

[0009]

In order to solve the above problems, a compressed data editing method and apparatus according to the present invention include at least one of compressed data composed of decompression units whose data size is indefinite. At least one decompressing unit that decompresses the decompression unit into decompressed unit data and a compression target value calculation unit that calculates and determines a compression target value by setting a target data amount when compressing the decompressed unit data as a compression target value. It has a compression means for recompressing one decompressed unit data to a compression target value or a data amount close to the compression target value to obtain recompressed unit data, and a data switching means for coupling while switching the compressed data.

[0010]

According to the present invention, by editing the compressed data by the above-mentioned configuration, some expansion units of the expansion unit group necessary for editing are expanded by the expansion means to be expanded unit data, By the compression target value calculation determining means,
An appropriate compression target value that does not cause overflow or underflow is calculated in the data buffer 5 of FIG. 8, and the compression unit recompresses the decompressed unit data to a value equal to or close to the compression target value, By the data switching means, the recompressed compressed data and the existing compressed data are switched and combined to form a new necessary decompression unit group, so that data overflow in the data buffer 5 as shown in FIG. Alternatively, compressed data that avoids underflow can be generated.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of a compressed data editing apparatus according to an embodiment of the present invention, and FIG. 2 is a flow chart of a compressed data editing process according to an embodiment of the present invention.

In this embodiment, the compressed data to be edited is the moving image compressed data.

In FIG. 1, reference numeral 1 denotes several image units near the beginning and the end of each scene arbitrarily extracted from moving image compressed data (hereinafter referred to as program A) before being edited (hereinafter referred to as recompression target image). , Or a recompression target image and decompression auxiliary data for decompressing the recompression target image, and decompresses and outputs the input recompression target image. 2 is an output of the decompression unit 1 and a compression target value. A compression unit that inputs g (n) (described later), compresses the input output of the decompression unit 1 (hereinafter referred to as recompression), and outputs the recompressed unit data as a unit 3.
Calculates the value of the common target buffer occupancy Bc [bit] at the beginning and end of each scene in the data buffer 5 of FIG. 6, and also calculates and outputs the compression target value g (n) for each image unit. In the compression target value calculation unit, 4A and 4B are changeover switches for connecting the compressed data.

The input of the compression target value calculation unit 3 is the number N of consecutive recompression target images and the speed R [bit / s] (= program A when the program A is input to the data buffer 5 in FIG.
And the time interval t (i) at which each image unit in program A is output from the data buffer 5 in FIG.
[S] (= t [s]) and one of the recompression target images of each scene that is ahead of the non-recompression target image in time is 1; When re-compressing the object, a signal S indicating 0, the maximum allowable amount Bmax [bit] of the data buffer 5 of FIG. 6, the re-compression target image group of each scene in the data buffer 11 of FIG. The data occupancy Bv at the contact point of the target image group and the recompressed unit data output from the compression unit 2.

The n of the output g (n) of the compression target value calculation unit 3 is an integer of 1 or more. The compression target value calculation unit 3 counts the data amount of the recompressed unit data and sets it as g (n-1), which is used to calculate the compression target value g (n).

Here, FIGS. 3, 4, and 5 will be described. FIG. 3 shows a data occupation state in the data buffer 5 in a time zone when the program A is decompressed by the decompressor of FIG. It should be noted that scenes 1 and 2 used when editing later are respectively F10 to F15 and F20 to F25, and the range to be recompressed is, for example, the first and last two image units of each scene (F10, F11, F14, F1
5, F20, F21, F24, F25).

FIG. 4 is a data buffer in the case where the first and last two image units of each scene are recompressed, and the program B created by connecting scene 1 and scene 2 is expanded by the expander of FIG. 5 shows the data occupation state within 5.

FIG. 5 shows a part of the recompression portion shown in FIG. Here, when recompressing is performed, the following formulas are arranged when the conditions for preventing data overflow and underflow in the data buffer 5 of FIG. 6 are arranged.

[0020]

(Equation 13)

[0021]

[Equation 14]

[0022]

(Equation 15)

[0023]

(Equation 16)

[0024]

[Equation 17]

[0025]

(Equation 18)

[0026]

[Equation 19]

[0027]

(Equation 20)

[0028]

(Equation 21)

[0029]

(Equation 22)

[0030]

(Equation 23)

[0031]

(Equation 24)

Bs of (Equation 15) and (Equation 16) is the sum of the compression target values g (n) of the continuous recompression target images.

In the compression target value calculation unit 3 of FIG. 1, the compression target value g (n) satisfying the above (Equation 13) to (Equation 24) is satisfied.
Is calculated.

The derivation process from (Equation 13) to (Equation 24) will be described below. First, the range of the value of Bc, which is the common target buffer occupancy at the beginning and the end of each scene, is clarified.

In consideration of making the recompressed data size of each image unit to be recompressed larger than 0, the following expression (13) is derived for the range of the value of Bc. FIG. 5 shows an example in which F10 and F11 of scene 1 are recompressed, but F10 and F11 are located temporally ahead of the non-recompression target image in scene 1 (that is, S =
1). In this case, in order to make the recompressed data size of each image unit to be recompressed larger than 0, the value of Bc is Bv.
Considering the value of as a reference, it must be larger than the value obtained by subtracting the product of R, t and N (2 in this case) from Bv. Contrary to the example of FIG. 5, when F10 and F11 are located temporally posterior to the non-recompression target image in scene 1 (that is, S = 0), the values of Bc are R and t. And N
Must be smaller than the value obtained by multiplying Bv by Bv. These can be summarized as (Equation 13). However, the value of Bv is not constant, Bv is 0 or more, and
It is not more than the value obtained by subtracting Rt from max.

Further, when the range of the value of Bc at which overflow or underflow does not occur in the data buffer 5 of FIG. 6 is obtained, (Equation 14) is derived.

Next, the method of calculating the value of Bs, which is the sum of the compression target values g (n) of consecutive recompression target images, will be clarified. When recompressing one of the recompression-target images of each scene that is temporally ahead of the non-recompression-target image (that is, S = 1 and the same as in FIG. 5), Bs is (equation 1).
It can be calculated in 5). When recompressing one of the recompression target images of each scene that is temporally behind the non-recompression target image (that is, S = 0), Bs can be calculated by (Equation 16). The value of Bs must be greater than 0.

Next, the range of the compression target value g (n) is clarified. First, measures against overflow will be described.

In the example of FIG. 5, it is necessary to consider so that the values of B1 and B3 do not overflow.

For example, FIG. 5 shows F10 and F1 to be recompressed.
1 is located ahead of the non-recompression target image in time (that is, S = 1). At this time, consider a condition for B3 not to overflow. The value of B2 is obtained by adding a value obtained by multiplying R and t to Bc, and further subtracting g (1). In order for B3 not to overflow, the value of B2 must be less than or equal to the value obtained by subtracting the value obtained by multiplying R and t from Bmax. When this condition is arranged, S = 1 and
The range of the value of g (n) when n is 1 is (Equation 18). Similarly, when n is 2 or more, the same can be obtained (Equation 1)
7). Contrary to the example of FIG. 5, when F10 and F11 to be recompressed are temporally behind the non-recompression target image (that is, S = 0), g (n) for preventing overflow The ranges are as in (Equation 19) and (Equation 20), and these are obtained by replacing the Bc portion of (Equation 17) and (Equation 18) with Bv, respectively.

Next, measures against underflow will be described. In the example of FIG. 5, it is necessary to consider so that the value of B2 does not underflow.

For example, FIG. 5 shows F10 and F1 to be recompressed.
1 is located ahead of the non-recompression target image in time (that is, S = 1).

At this time, in order that the value of B2 does not underflow, the value of g (1) may be B1 or less.

Therefore, g when S = 1 and n = 1
The range of the value of (n) is as shown in (Equation 22). Similarly, when n is 2 or more, the same equation is obtained (Equation 21).

Contrary to the example of FIG. 5, when F10 and F11 to be recompressed are temporally behind the non-recompressed image (that is, S = 0), underflow is prevented. The range of g (n) is as in (Equation 23) and (Equation 24), and these are obtained by replacing the Bc portions of (Equation 21) and (Equation 22) with Bv.

The operation of the compressed data editing apparatus configured as described above will be described below with reference to FIGS. 1, 2, 3, 4, and 5.

As an example, scene 1 and scene 2 of program A shown in FIG. 3 are connected to create program B as shown in FIG.

The outline of the operation is as follows. The image units of scene 1 and scene 2 in FIG. 3 are input to the switch 4A in FIG. 1 in a compressed state. The input image unit is a recompression symmetrical image (for example, F10, F11 in FIG.
In the case of F14, F15, F20, F21, F24, and F25), the switch 4A and the switch 4B of FIG. 1 are connected to the b side, respectively, and the image unit is expanded by the expansion unit 1. The decompressed image unit is recompressed by the compression unit 2 with the compression target value g (n) calculated by the compression target value calculation unit 3 as a target. When the image unit input to the switch 4A is not a recompression symmetric image, the switch 4A and the switch 4B are connected to the a side, respectively, and are passed through c of the switch 4B. In this way, the recompressed symmetric image is recompressed, and the other than the recompressed symmetric image is passed through and output to c of the switch 4B, thereby obtaining the program B without overflow or underflow as shown in FIG.

The details of the operation will be described below. In FIG.
First, the values of R and Bmax are input to the compression target value calculation unit 3 (S201 in FIG. 2).

Next, input the values of t (1) to t (N),
Substitute 1 for n (S202 in FIG. 2). In the example, t (1)
Each value from t to (N) is t.

Next, the image unit of scene 1 of each scene used for editing is input to the switch 4A of FIG. 1 (S203 of FIG. 2).

It is determined whether the image unit input here is a recompression target image (S204 in FIG. 2).

If the input image unit is not the image to be recompressed, the switch 4A and the switch 4B are connected to a (206 of S in FIG. 2), and the process returns to the step of S203 in FIG.

When the image to be recompressed is input, the switch 4
A and switch 4B are respectively connected to b (see S20 in FIG. 2).
5) Next, N, S, and Bv are input to the compression target value calculation unit 3 (S207 in FIG. 2).

In the example, the number N of consecutive recompression target images is set to 2, and F10 and F11 in FIG. 3 are first recompressed. The value of S is 1 between F10 and F11.
And

Thereafter, in steps S208 to S227 of FIG. 2, all steps other than S210 and S224 are performed by the compression target value calculation unit 3 of FIG.

Here, in step S208 of FIG. 2, it is determined whether or not the series of processing up to this point is the first time. If it is not the first time, go to step 210 in FIG.
If it is the first time, the value of Bc is determined within the range that satisfies (Equation 13) and (Equation 14) (209 in FIG. 2).

Next, the decompression unit 1 in FIG. 1 decompresses the n-th recompression target image (F10 in FIG. 3) (S21 in FIG. 2).
0).

Next, it is judged whether the value of S is 1 (FIG. 2).
S211). Next, it is determined whether the value of N is 1 (S212 and S213 in FIG. 2).

If the value of S is 1 and the value of N is 1,
G (n) is calculated using only (Equation 15) (S in FIG. 2).
214).

If the value of S is 0 and the value of N is 1, then
G (n) is calculated using only (Equation 16) (S in FIG. 2).
215).

If the value of N is 2 or more, then it is determined whether n is 1 (S216 and S217 in FIG. 2).

If the value of S is 1 and the value of N is 2 or more, n
If the value of is 1, (Equation 15), (Equation 18) and (Equation 22)
G (n) is determined from the range that satisfies the condition (S22 in FIG. 2).
0).

If the value of S is 0 and the value of N is 2 or more, n
If the value of is 1, (Equation 16), (Equation 20) and (Equation 24)
G (n) is determined from the range that satisfies the condition (S22 in FIG. 2).
2).

When the value of n is 2 or more, the compression unit 2 in FIG.
Counting the size of the data output from g (n-
1) (S218 and S219 of FIG. 2).

If S is 1 and N and n are 2 or more, after passing through the step of S218 in FIG. 2, (Equation 15) and (Equation 1)
7) and g (n) are determined from the range satisfying (Equation 21) (S221 in FIG. 2).

If S is 0 and N and n are 2 or more, after the step of S219 in FIG.
9) and g (n) are determined from the range satisfying (Equation 23) (S223 in FIG. 2).

In the example, the value of S is 1, the value of N is 2, and n
2 is 1, the compression target value g (1) at the time of recompressing the data of F10 of FIG. 3 already decompressed in the step of S210 of FIG. 2 is determined in the step of S220 of FIG. It

Next, the data of F10 of FIG. 3 which has already been expanded in the step of S210 of FIG. 2 is converted into the compression unit 2 of FIG.
With g (1) as the target value, recompression is performed to a value equal to or close to g (1) (S2254 in FIG. 2).
Next, the value of n is counted up to 2 (S in FIG.
225). Next, it is determined whether n is larger than N (S226 in FIG. 2).

When n is N or less, the process proceeds to step S203 in FIG. 2, the next image unit (F11 in FIG. 3 in the example) is input, and the operation after S203 is performed. When n is larger than N, N consecutive recompression target images (F10 in the example)
And F11) mean that the recompression has been completed, and the process goes to step S227 in FIG. In the step S227 of FIG. 2, whether all the recompression target images used for editing have been recompressed (in the example, F10, F11, F14, F1).
5) F20, F21, F24, and F25, and whether the recompression process for each image unit is completed) is determined. If all the recompression target images have been recompressed, all the processes are terminated. If all the recompression target images have not been recompressed, the processes after S202 in FIG. 2 are repeated.

By repeating the above operation, in the example, the program B shown in FIG.
It is possible to obtain moving image compressed data such as.

In this way, some image units near the boundary of each scene are the same as the recompression target value g (n), or g
By recompressing to a value close to (n) and connecting, it is possible to create a new program without causing data overflow or underflow in the data buffer 5 of FIG. 6 when performing decompression.

It should be noted that the data occupancy in the data buffer 5 of FIG.
Since the recompression is performed by setting to, the data overflow or underflow does not occur in the data buffer 5 in FIG. 6 even if the order of scene 1 and scene 2 in FIG. There is an advantage that it is easy to redo.

The determination of g (n) and the recompression of each recompression target image may be performed before or after each successive recompression target image.

In the above description, the first and last two image units of each scene are recompressed as an example, but the number N of image units to be recompressed is not limited to this.

In the above example, the data amount of the recompressed unit data output from the compression unit 2 of FIG. 1 is counted by the compression target value calculation unit 3 and substituted into g (n-1). The substitution as described above does not necessarily have to be performed, and in that case, it is not necessary to input the recompressed unit data output from the compression unit 2 to the compression target value calculation unit 3.

Although the amount of data occupied in the data buffer 5 of FIG. 6 is set to the common value Bc in the connection portion of each scene in the above description and recompression is performed, the program B of FIG. If it is premised that scene 1 and scene 2 are connected in this order, for example, F14 and F1 in FIG.
The recompression may be performed with 5, F20 and F21 as a series.

In this case, it is not always necessary to set Bc, and (Equation 15), (Equation 17), (Equation 18) and (Equation 2)
Using only 1) and (Equation 22), (Equation 15) and (Equation 17)
And (Equation 18), (Equation 21) and (Equation 22) instead of Bc, the value of Bv (2) of FIG. 4 is used, and instead of Bv of (Equation 15), Bv (3) of FIG. The compression target value is calculated using the value of.

In the above, the case where the moving image compressed data is used is shown as an example, but it is not limited to the moving image, and the same can be applied to the case where the voice or text data is compressed.

In the above description, when the signal S is 1, for example, when recompressing one of the recompression target images in each scene that is temporally ahead of the non-recompression target image, the signal S is 0. In the case of, the case of re-compressing the one located backward in time is described, but the present invention is not limited to this.

[0081]

EFFECTS OF THE INVENTION Of the decompression unit group necessary for editing, some decompression units are decompressed to be decompressed unit data, an appropriate compression target value is determined, and the decompressed unit data is set as a compression target value. By recompressing to the same value or a value close to it, and switching and combining already recompressed compressed data and existing compressed data to form a new necessary decompression unit group,
As shown in FIG. 8, it is possible to generate compressed data in the data buffer 5 that avoids data overflow or underflow.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a compressed data editing device according to an embodiment of the present invention.

FIG. 2 is a flow chart of a process of editing compressed data for explaining the operation in the embodiment of the present invention.

FIG. 3 is a diagram showing a data occupation amount of a program A for explaining an embodiment of the present invention.

FIG. 4 is a diagram showing a data occupation amount of a program B for explaining an embodiment of the present invention.

FIG. 5 is a diagram showing a data occupation amount of an image to be recompressed for explaining an embodiment of the present invention.

FIG. 6 is a configuration diagram of an expander for explaining an embodiment of the present invention and a conventional example.

FIG. 7 is a diagram showing a data occupation amount of a program A for explaining a conventional example.

FIG. 8 is a diagram showing a data occupation amount of a program B for explaining a conventional example.

[Explanation of symbols]

 1 Expansion Unit 2 Compression Unit 3 Compression Target Calculation Unit 4A Changeover Switch 4B Changeover Switch 5 Data Buffer 6 Expansion Unit

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hitoshi Fujimoto 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Ikuji Shimizu, 1006, Kadoma, Kadoma City, Osaka

Claims (6)

[Claims] 1. A target data amount for compressing the decompressed unit data by decompressing at least one decompression unit among the compressed data composed of decompression units of which the data size is indefinite. Is set as the compression target value, the compression target value is calculated and determined, and at least one decompressed unit data is recompressed to the compression target value or a data amount close to the compression target value to be recompressed unit data, and the compressed data is switched. A compressed data editing method that combines while. 2. An average data amount of compressed data per unit time is R, and a maximum allowable amount is Bmax in a data buffer for temporarily storing a part or all of the compressed data for decompressing the compressed data. It is assumed that the input speed is the same value as the above R and the output of each decompression unit is performed every time t (i), and there is a necessary decompression unit group composed of decompression units required for editing in the compressed data. , Of the necessary decompression unit groups, the decompression unit group that is recompressed during editing is the recompression target unit group, and the decompression unit group that is not recompressed is the non-recompression target unit group and the recompression target unit group. The occupancy amount of data in the data buffer at the contact point with the non-recompression target unit group is Bv, the common target occupancy amount in the data buffer at the beginning and end of each required expansion unit group is Bc, and the required extension amount is Let S be a variable that indicates whether the recompression target unit group to be recompressed in the long unit group is temporally ahead or behind the non-recompression target unit group, and N is the number of decompression units to be recompressed
, N is an integer of 1 or more, the compression target value of the n-th expanded unit data is g (n), the data amount of the re-compressed unit data is H, N, Bv, and R Then, the compression target value g (n) is calculated and determined using the t (i), or when the S or the H is further used and the H is used, the value of the H is g (n-1). The compressed data editing method according to claim 1, wherein the compressed target value g (n) is calculated and determined, or the Bc is further calculated and determined. 3. When Bc is used in calculating the compression target value, [Equation 2] Bc is determined from the range satisfying both of the above, and the value of S indicates that the recompression target unit group to be recompressed in the necessary decompression unit group is temporally ahead of the non-recompression target unit group. In this case, when the value of N is 1, From the value satisfying only, when the value of N is 2 or more and the value of n is 1, (Equation 3) and (Equation 5) From the value satisfying, when N is 2 or more and n is 2 or more, (Equation 3) and (Equation 7) The compression target value g (n) is determined from the value satisfying the following, and the value of S is such that the recompression target unit group to be recompressed in the necessary decompression unit group is positioned behind the non-recompression target unit group in time. When the value of N is 1, From the value satisfying only, when the value of N is 2 or more and the value of n is 1, (Equation 8) and (Equation 10) From the value that satisfies the above, when the value of N is 2 or more and the value of n is 2 or more, (Equation 8) and (Equation 12) When the compression target value g (n) is determined from the value that satisfies the above and Bc is not used, only (Equation 3) (Equation 4) (Equation 5) (Equation 6) (Equation 7) is used, and (Equation 3 ) (Equation 4) (Equation 5) (Equation 6) (Equation 7) B
In place of c, the value of Bv in the front necessary extension unit group of the two necessary extension unit groups to be combined at the time of editing is used,
In (Equation 3), instead of Bv, the compression target value g (n) is determined using the value of Bv in the rear necessary extension unit group out of the two required extension unit groups to be combined at the time of editing. The compressed data editing method according to claim 2. 4. A decompression unit that decompresses at least one decompression unit to obtain decompressed unit data among compressed data composed of decompression units whose data size is indefinite, and when compressing the decompressed unit data. And a compression target value calculation unit that calculates and determines the compression target value, and a compression unit that recompresses at least one decompressed unit data into a compression target value or a data amount close to the compression target value. And a compressed data editing device having a data switching unit for combining compressed data. 5. An average data amount of compressed data per unit time is defined as R, and a maximum allowable amount is Bmax in a data buffer for temporarily storing a part or all of the compressed data to decompress the compressed data. It is assumed that the input speed is the same value as R and the output of each decompression unit is performed every time t (i), and there is a necessary decompression unit group composed of decompression units necessary for editing in the compressed data. , Of the necessary decompression unit groups, the decompression unit group that is recompressed during editing is the recompression target unit group, and the decompression unit group that is not recompressed is the non-recompression target unit group. The occupancy of data in the data buffer at the point of contact with the unit group to be recompressed is Bv, and the common target occupancy in the data buffer at the beginning and end of each required decompression unit group is Bc. group In S, a signal indicating whether the recompression target unit group to be recompressed is located ahead or behind the non-recompression target unit group in time is recompressed in each recompression target unit group. The number of extension units is N
, N is an integer of 1 or more, the compression target value of the nth expanded unit data is g (n), the data amount of the recompressed unit data is H, and , Bv, R, and t (i) are input, or S or H is further input, and when H is input, the value of H is stored as g (n-1). 5. The method further comprises means for calculating and determining the compression target value g (n), or further for calculating and determining the Bc.
The compressed data editing device described. 6. When using Bc in the compression target value calculation unit, Bc is determined from a range that satisfies both (Equation 1) and (Equation 2), and the value of S is within the necessary expansion unit group. When it is shown that the recompression target unit group to be recompressed is temporally located ahead of the non-recompression target unit group, when the value of N is 1, from the value satisfying only (Equation 3), When the value is 2 or more and the value of n is 1, from the values satisfying (Equation 3), (Equation 4) and (Equation 5), the value of N is 2 or more and the value of n is 2 or more. In this case, the compression target value g (n) is determined from the values satisfying (Equation 3), (Equation 6) and (Equation 7), and the value of S is the recompression target to be recompressed in the necessary decompression unit group. When the unit group indicates that it is temporally behind the non-recompression target unit group, when N is 1, only (Equation 8) is satisfied. If the value of N is 2 or more and the value of n is 1, the values satisfying (Equation 8), (Equation 9) and (Equation 10) When the value of is 2 or more, the compression target value g (n) is determined from the values that satisfy (Equation 8), (Equation 11) and (Equation 12), and when Bc is not used, (Equation 3) ( (4) (5)
Using only (Equation 6) and (Equation 7), in (Equation 3) (Equation 4) (Equation 5) (Equation 6) (Equation 7),
Instead of Bc, the value of Bv in the necessary necessary extension unit group of the two necessary necessary extension unit groups to be combined at the time of editing is used, and in (Equation 3), instead of Bv, the value is combined at the time of editing. 6. The compressed data according to claim 5, further comprising means for determining the compression target value g (n) by using the value of Bv in the rear necessary expansion unit group of the two necessary expansion unit groups to be processed. Editing device.