JP3108283B2 - Partial stretching device and method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a partial decompression apparatus and method for decompressing (decompressing) only a part of compressed data. In particular, the present invention relates to a technique for decompressing only a part of JPEG compressed data recorded on a recording medium.

[0002]

2. Description of the Related Art Various compression encoding methods have been proposed to reduce the memory capacity used for recording. When such a part of the compressed data is decoded (expanded), decoding all the compressed data is a waste of time.

[0003] Japanese Patent Application Laid-Open No. 4-347781 (G06F15 / 66) discloses a technique for partially expanding and decompressing a necessary part of compressed data previously recorded on a recording medium. In this technique, all of the compressed data recorded on a recording medium is read, and a part of the read compressed data is partially decompressed.

[0004]

However, in this technique, since all the compressed data recorded on the recording medium is read, it takes time to read the compressed data, and a part of the compressed data having a large data amount is partially decompressed. In this case, there is a problem that the total processing speed is reduced. The present invention has been made in view of the above-described problem, and has as its object to provide a partial decompression device and method that can perform partial decompression at higher speed.

Another object of the present invention is to provide a partial decompression device and method adapted to a general recording medium. That is, a general recording medium can be accessed in sector units, and the minimum unit for partial reading is a sector unit.

[0006]

The present invention provides a recording medium (1)
In the partial decompression method of reading out compressed data from the compressed data and decompressing a part of the compressed data necessary for reproducing a specified part of the compressed data, reading out the compressed data from the recording medium (1) Is characterized in that partial data including the necessary partial compressed data is read.

Further, the present invention is characterized in that the reading of the compressed data is performed on a sector basis including the part of the compressed data. Further, according to the present invention, the compressed data is data compressed by the JPEG method, and the part of the compressed data necessary for reproducing the specified part is:
A restart marker including this specified part of the area
It is a region (extended region) defined by a code.

Further, according to the present invention, the compressed data is a JPE
A part of the compressed data necessary for reproducing the specified part is a restart marker code including the specified part of the area. Area (extended area) defined by the recording medium (1)
The compressed data read from the
It is characterized by being a sector including an area partitioned by a code.

A partial decompression device according to the present invention comprises a recording medium (1) on which compressed data is recorded and a decompression area specifying means (11) for specifying a part of the compressed data as a decompression area.
Read area specifying means (12) for specifying a sector block including the decompressed area specified by the decompressed area specifying means (11) as a read area; and It is characterized by comprising reproduction means (2) for reading from 1) and partial decompression means (4) for decompressing the data read by this reproduction means (2).

Further, the partial decompression device of the present invention is characterized in that the partial decompression means (4) decompresses data corresponding to the decompression area among the data read by the reproduction means (2). And The partial decompression device according to the present invention includes a recording medium (1) on which compressed data that has been compressed in units of blocks (for example, 8 × 8 pixels) is recorded, and a partial block area of the compressed data. Decompressed area specifying means (11) for specifying as decompressed area, and decompressed area specifying means (11)
A read area designating means (12) for designating a sector block including the decompressed area specified as a read area,
Reproducing means (2) for reading data of the sector block which is the read area from the recording medium (1);
A partial decompression means (4) for decompressing the data read in (2) in block units.

Further, in the partial decompression device according to the present invention, the partial decompression means (4) decompresses the data of the decompression area among the data read by the reproduction means (2) in block units. It is characterized by. Further, the partial decompression device of the present invention is characterized in that the read area specifying means (12) specifies a minimum sector block including the decompressed area as a read area.

Further, in the partial decompression device according to the present invention, the compressed data is obtained by compressing image data. Further, the partial extension device of the present invention is provided with a
A recording medium (1) on which JPEG compressed data in which a marker code (hereinafter referred to as RST) is inserted is recorded;
A decompression area that specifies a decompression area from the RST position indicating the decompression start position to the RST position indicating the decompression end position based on an RST table that holds all the RST positions inserted in the JPEG compressed data. Specifying means (11); read area specifying means (12) for specifying, as a read area, a sector block from a read start sector before the decompression start position to a read end sector after the decompression end position; Reproducing means (2) for reading data in a read area from the recording medium (1),
An unnecessary start data receiving means (5) for receiving data from the read start sector to the decompression start position among the data read by the reproducing means (2);
Of the data read in (2), partial decompression means (4) for decompressing data from the decompression start position to the decompression end position, and of the data read by the reproduction means (2),
An end-unnecessary data receiving means (5) for receiving data from the decompression end position to the read end sector is provided.

[0013] A partial decompression device according to the present invention comprises a recording medium (1) on which JPEG compressed data in which a restart marker code (hereinafter referred to as RST) is inserted is recorded; A decompression area specifying means (11) for specifying a decompression area based on the insertion position of the RST; and a readout for specifying a sector block of the recording medium (1) in which an area including the decompression area is recorded as a read area. Area designating means (12), reproducing means (2) for reading the data of the read area from the recording medium (1), and partial decompressing means (4) for decompressing the data read by the reproducing means (2) And characterized in that:

Further, the partial decompression device of the present invention provides a recording medium accessible in sector units for recording JPEG compressed data in which a restart marker code (hereinafter referred to as RST) is inserted. Based on (1) and an RST table holding all the positions of the RST inserted in the JPEG compressed data, a decompression area extends from the RST position indicating the decompression start position to the RST position indicating the decompression end position. Decompression area designation means (11), and a sector block from a read start sector before the decompression start position to a read end sector after the decompression end position,
Read area specifying means (12) for specifying as a read area
A reproducing unit (2) for reading data of the read area from the recording medium; and a partial decompressing unit for decompressing data from the decompression start position to the decompression end position among data read by the reproduction unit. (4).

Further, in the partial decompression device according to the present invention, the read area designation means (12) reads a sector block from a sector address immediately before the decompression start position to a sector address immediately after the decompression end position. It is characterized as being specified as an area. Further, the partial decompression device of the present invention comprises a recording medium accessible in a sector unit for recording JPEG compressed data in which a restart marker code (hereinafter referred to as RST) is inserted; RST indicating the decompression start position based on an RST table holding all the RST positions inserted in the data.
And an RST position indicating the decompression end position, from the decompression area specifying means for specifying the decompression start position several sectors before the decompression start position to the read end sector several sectors after the decompression end position. Reading means for reading the data from the recording medium, and partial decompression means for decompressing data from the decompression start position to the decompression end position among the data read from the reading means. It becomes.

Further, according to the present invention, when a part of compressed data recorded on a recording medium accessible in sector units is partially decompressed, all of the compressed data is read into a memory in advance and then the partial decompression is performed. The conventional device
Only the sector area containing the desired partially compressed data is read out from the recording medium and is partially decompressed.

[0017]

According to the present invention, there is provided a partial decompression method for reading compressed data from a recording medium (1) and decompressing a part of the compressed data necessary for reproducing a specified part of the compressed data. Partial data including some necessary compressed data is read from the recording medium (1).

In the present invention, this reading is performed in sector units. Further, the present invention can be applied to JPEG-compressed data. In the present invention, JPEG
R holding the position of the RST inserted in the compressed data
Based on the ST table, an RST position indicating an expansion start position and an RST position indicating an expansion end position are designated,
Data from a read start sector before the decompression start position to a read end sector after the decompression end position is read from the recording medium, and among the data, data from the decompression start position to the decompression end position is read out. Elongate.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. First, compressed data used in this embodiment will be briefly described. This compressed data is a well-known JPEG (J
oint Photographic Expert Group), and its compression algorithm is described in the magazine interface published by CQ Publishing Company, December 160, 1991, P160-P182, or Maruzen Co., Ltd., June 1991. It is shown in "International Standards for Multimedia Coding", edited by Hiroshi Yasuda, published on the 30th.

A restart marker code (hereinafter referred to as RST) is included in the compressed data compressed by this compression method.
You can insert any number of codes. This R
The ST is used to reset the predicted value of the DC coefficient in the DCT transform, thereby preventing the propagation of an error due to a transmission error of the compressed data.

That is, if a transmission error occurs in the compressed data having no RST, the error propagates to the entire image after the occurrence of the error. But R
If the ST is inserted in the compressed data, even if a transmission error occurs, the propagation of the error can be suppressed to the next RST. This indicates that the compressed data is separated by the RST, and the blocks separated by the RST become independent partial compressed data, which can be decompressed by itself.

Therefore, it is possible to partially decompress part of the compressed data using the RST. Next, this embodiment will be described. FIG. 1 is a diagram showing functional blocks of this embodiment. The recording medium 1 is, for example, an optical disk or a hard disk. Since this recording medium 1 is accessible in sector units, it can be read and written in sector units.

This recording medium 1 stores image data in JPE
G-compressed compressed data and index information including a recording start sector address of the compressed data on the recording medium 1, a data size of the compressed data, various flags, and the like are integrally recorded. Further, the recording medium 1 records the recording positions of all the RSTs inserted in the compressed data. That is, position information indicating the byte number of the RST from the head of the compressed data is recorded in a table format.

The reproducing means 2 is, for example, an optical disk drive or a hard disk drive. Kono regeneration means 2
Is for reproducing the recording medium 1 and reading out the recorded contents. The decompression buffer 3 is a buffer for temporarily storing the compressed data reproduced by the reproducing means 3.

The expansion means 4 expands the compressed data stored in the expansion buffer 3. Specifically, the decompression means 4 performs inverse Huffman coding, inverse quantization, inverse two-dimensional DC
Image data is generated by performing processing such as T conversion. The storage unit 5 records the image data output from the decompression unit 4. Further, data output from the reproducing means 2 is recorded. The image data is stored in the display area of the storage unit 5,
Data reproduced from the reproducing means 2 is stored in a non-display area of the storage means 5.

The video processing means 6 takes out data from the display area of the storage means 5 and converts it into a video signal. The monitor 7 displays a video signal output from the video processing means 6. The input means 8 is, for example, a keyboard or a mouse. The input means 8 receives an instruction from the operator for the device. For example, an area designation parameter indicating which part of the image is to be displayed and output, a partial expansion operation start instruction, and the like are input.

The control means 9 controls the entire apparatus. The control means 9 starts its control in response to a partial expansion operation start instruction input from the input means 8.
The data buffer 10 stores the index information and the RST table recorded on the recording medium 1. The decompressed area specifying means 11 starts the compression data from any RST position of the compressed data based on the area specifying parameter input from the input means 8 and the RST table stored in the data buffer 10. Of which RST position is to be partially extended, and an extended region is designated. Therefore, the decompression start position, which is the head of the decompression area, and the decompression end position, which is the end of the decompression area, are both positions where the RST of the compressed data is inserted.

The read-out area designating means 12 determines the extension area information (decompression start position and extension end position) output from the extension area designation means 11 and the index information stored in the data buffer 10. From which sector address of the compressed data to which sector address of the compressed data is read from the recording medium 1, a read area is designated.

At this time, the read area specifying means 12
The read start sector, which is the head of this read area, is
The read area is designated as the sector address immediately before the decompression start position, and the read end sector at the end of the read area as the sector address immediately after the decompression end position. Next, the position of the RST inserted into the compressed data will be described.

FIG. 2 shows the RS inserted in the compressed data.
It is a figure showing the insertion position of T. This figure is for image data before the compressed data is compressed. J
In PEG, image data is divided into unit blocks of 8 × 8 pixels and compressed. Therefore, if the size of the image data is, for example, 1040 pixels vertically × 1920 pixels horizontally, there are a total of 3200 unit blocks, 130 in the vertical direction and 240 in the horizontal direction.

These unit blocks are one block line in the horizontal direction from the unit block at the upper left of FIG.
After the (240) processing, the processing line is lowered by one unit block, and similarly, one block line is processed in the horizontal direction from the leftmost unit block in FIG. JPE in such a procedure
When G compression is performed, the RST can be inserted after an arbitrary unit block. As shown in FIG. 2, the compressed data in this embodiment is, as shown in FIG. It is assumed that RST is inserted and JPEG-compressed every time.

Therefore, for example, if the data from one RST position to the next RST position in the compressed data is extracted and partially decompressed, the decompressed data becomes the image data of one block line in the horizontal direction. That is, 8 vertical pixels × 1920 horizontal pixels. Next, the operation of the present embodiment will be described. FIG. 4 is a diagram showing a flowchart of this apparatus.

Hereinafter, description will be made with reference to the flowchart of FIG. First, an area designation parameter indicating which part of the image is to be partially expanded is input from the input unit 8, and further, an instruction to start a partial expansion operation is input (step S).
1). Specifically, a rectangular frame (not shown) is displayed on the monitor, and, for example, a coordinate area of an area indicated by oblique lines in FIG. 2 is input as an area designation parameter.

Next, when an area designation parameter and an operation start instruction are inputted from the input means 8, the control means 9 instructs the reproducing means 2 to read the index information recorded on the recording medium 1 and the index information. Read the RST table and
Instruct these to be stored in the data buffer 10
(Step S2). Therefore, the index information reproduced from the recording medium 1 and the RST table are stored in the data buffer 10.

Further, the control means 9 includes the extension area designating means 1
1 instructs to output the area specifying parameter and to specify the decompressed area indicating the decompressed portion of the compressed data corresponding to the area specifying parameter (Step S1).
3). The expansion area specifying means 11 specifies the area to be partially expanded based on the coordinate area of the hatched portion in FIG. 2 input as the area specification parameter and the RST table stored in the data buffer 10.

More specifically, in FIG. 2, a block area of eight continuous horizontal block lines from the unit block of the 80th vertical block and the first horizontal block to the unit block of the 87th vertical block and the 240th horizontal block is shown. Is an extension area. Then, the decompression area designating means 11 calculates the position information of the RST (RST 79) immediately before the unit block of the 80th vertical and the 1st horizontal and the unit of the 87th vertical and the 240th horizontal from the RST table. The position information of the RST (RST 87) immediately after the block is obtained.

Thus, the decompression area specifying means 11 specifies the number of bytes between the decompression start position indicating the head of the decompression area and the decompression end position indicating the end of the decompression area from the head of the compressed data. The decompression start position and the decompression end position are output to the readout area specifying means 12. The read area designating means 12 receives the decompression start position and the decompression end position from the decompression area designating means 11 and also receives the index information from the data buffer 10 to actually read the data portion to be read from the recording medium 1. An area is specified (step S4).

This will be described with reference to FIG. Generally, the relationship between the data size of compressed data obtained by compressing image data and the sector size of a recording medium is considerably larger in data size of compressed data, and is several tens to several hundred times or more of the sector size. . Therefore, when the compressed data is recorded on the recording medium 1, the compressed data is recorded over a plurality of sectors.

FIG. 3 is a diagram schematically showing a state of a sector in the vicinity of the decompression area in the compressed data continuously recorded on the recording medium 1. As shown in FIG. The shaded area in FIG. 3 is the extension area designated by the extension area designation means 11. In this figure, an extension start position exists in a sector sandwiched between a sector address (N) and a sector address (N + 1), and the sector address (N
+ K) and the sector address (N + K + 1), there is a decompression end position in the sector, and compressed data of the decompression area is continuously recorded between these two sectors.

The read area specifying means 12 obtains the index information from the data buffer 10 and obtains from which sector address of the recording medium 1 the compressed data is recorded. Further, the read area designation means 12 determines the decompression start position (the number of bytes from the head of the compressed data) and 1
Calculated from the number of bytes of the sector size, the sector address (N) immediately before the decompression start position, which is the head of the decompression area,
Get. This sector address (N) becomes the read start sector address.

Further, the read area designation means 12 calculates the decompression end position (the number of bytes from the head of the compressed data) and 1
Calculated from the number of bytes of the sector size, the sector address (N
+ K + 1). This sector address (N + K + 1) becomes the read end sector address. In this way,
The read area from the read start sector address to the read end sector address is specified.

That is, the read area designating means 12 is the smallest continuous sector block including the decompressed area (the area from the sector address (N) to the sector address (N + K + 1)).
Is designated as a read area. In other words, the read area specifying means 12 specifies the read area so that the read area that is a part of the compressed data includes the decompressed area.

When the read area is specified, the read area specifying means 12 outputs a read start sector address and a read end sector address to the control means 9. After inputting the read start sector address and the read end sector address, the control means 9 instructs the reproduction means 2 to reproduce the data in the read area from the recording medium 1 (step S5). Thus, the reproduction of the read area from the recording medium 1 by the reproducing means 2 is started.

The control means 9 instructs the reproduction of the read area, and stores data from the read start sector address which is the head of the read area to the decompression start position which is the head of the decompression area. Control the storage address of the storage means 5 so as to store it in the display area
(Step S6). Therefore, data read from the recording medium 1 is sequentially stored in the non-display area of the storage unit 5.

The data stored in this step is unnecessary data for partial decompression, and the unnecessary unnecessary start data is simply discarded in the storage means 5. The control means 9 suspends the reading operation of the reproduction means 2 when the storage of the unnecessary start data in the storage means 5 is completed. Next, the control means 9 restarts the read operation of the reproducing means 2 and stores data from the decompression start position, which is the head of the decompression area, to the decompression end position, which is the end of the decompression area, in the decompression buffer 3. The storage address of the decompression buffer 3 is controlled so as to be stored (step S7). As a result, the reading of the reproduction unit 2 that has been temporarily interrupted is resumed, and the read data of the decompressed area is stored in the decompression buffer 3.

When the storing of the data in the decompression area in the decompression buffer 3 is completed, the control means 9 temporarily suspends the read operation of the reproduction means 2 again. Further, the control means 9
Restarts the read operation of the reproducing means 2 and
The storage address of the storage means 5 is controlled so that data from the expansion end position, which is the end of the expansion area, to the read end sector address, which is the end of the read area, is stored in the non-display area of the storage means 5. (Step S
8).

As a result, the reading of the reproduction means 2 which has been temporarily interrupted is resumed, and the read data is stored in the storage means 5. The data stored in this step is unnecessary data for partial decompression, and the unnecessary unnecessary termination data is simply discarded in the storage means 5. Next, the control means 9 controls the extension means 4 to
An instruction is issued to expand the data in the expansion area stored in the expansion buffer 3 (step S9). Therefore, the data in the decompression area, which is a part of the compressed data, is partially decompressed.

Further, the control means 9 instructs the image data expanded by the expansion means 4 to be stored in the display area of the storage means 5. Therefore, the image data (partially decompressed image data, the image in the hatched portion in FIG. 2) is stored in the storage unit 5.
And is converted into a video signal by the video processing means 6.

When this video signal is output to the monitor 7,
The image of only the hatched portion in FIG. 2 is displayed on the monitor 7 (step S10). In the above-described embodiment, in FIG. 3, the smallest sector unit area (sector address (N) to sector address (N + K +
Although the area up to 1) is a readout area, the readout area intended in the present application is not necessarily limited to this.

For example, the read start sector address is
Any sector address may be used as long as it exists before the decompression start position and after the head sector address of the compressed data. Further, for example, if the read end sector address is a sector address that exists after the decompression end position and before the end sector address of the compressed data,
Any sector address may be used.

That is, the read area may be any area as long as it is a sector block including the decompressed area within a range in which all of the compressed data is not read in order to read the data of the decompressed area. Further, in the above-described embodiment, in FIG. 4, the unnecessary start data in step S6 and the unnecessary unnecessary data in step S8 are stored in the storage unit 5, but the present invention is not limited to this.

For example, the unnecessary start data and the unnecessary end data are not stored in the storage means 3 but the start unnecessary data and the unnecessary end data read by the reproducing means 2 can be output by the reproducing means 2. Needless to say, the configuration may be such that the start unnecessary data and the end unnecessary data are only received by handshaking with the reproducing means 2.

In the above-described embodiment, the steps S6 and S8 are described in FIG. 4, but the present invention is not necessarily limited to this. For example, when the read start sector address and the decompression start position have the same value (the start unnecessary data is 0 bytes), it goes without saying that step S6 may be omitted.

For example, when the decompression end position and the read end sector address have the same value (the end unnecessary data is 0 byte), it goes without saying that step S8 may be omitted. Further, in the above-described embodiment, the case where the decompressed area of the compressed data to be partially decompressed is physically continuous on the recording medium has been described.
The present invention can be applied to a case where the decompressed area of the compressed data that is partially decompressed is not physically continuous on the recording medium. This will be described below.

For example, compressed data obtained by JPEG-compressing image data of 1,040 pixels in length × 1,920 pixels in width is prepared by inserting RST into each unit block. This allows
2 for each horizontal block line (240 unit blocks)
This means that 40 RSTs have been inserted. With respect to such compressed data, the operator uses the input unit 8 to input, for example, a rectangular image having (vertical 400 pixels, horizontal 800 pixels) and (vertical 800 pixels, horizontal 1600 pixels) diagonal endpoints. It is assumed that a coordinate area is input as an area specification parameter. That is, it is assumed that the area of the central part of the image data (50 unit blocks vertically × 100 unit blocks horizontally) has been designated.

In this case, each horizontal block line (1 vertical unit block × 100 horizontal blocks) in the designated coordinate area is recorded on the storage medium 1 at positions physically separated from each other by several sectors. Will be. In other words, in one horizontal block line, data is physically continuously recorded on the recording medium, but one horizontal block line and another horizontal block line are
This means that the data is physically discontinuously recorded on the recording medium.

In such a case as well, first, the processing of the flowchart of FIG. 4 is performed on the first horizontal block line in the designated coordinate area to partially expand one horizontal block line. Next, the same processing is performed on the second horizontal block line to partially expand one horizontal block line. This is repeated until the last horizontal block line in the coordinate area is partially extended. That is, partial expansion is performed sequentially for each horizontal block line in the area.

In this way, the portion of the specified coordinate area in the compressed data is partially expanded. Further, in the above-described embodiment, the case where compressed data of a still image is described as the compressed data. However, the present invention is not limited to this. For example, compressed data of a moving image may be used.
Alternatively, the data may be compressed audio data.

Further, in the above-described embodiment, the case where the compressed data compressed by the JPEG system is partially decompressed has been described, but the present invention is not limited to this. For example, M
Compressed data compressed by the PEG method may be partially decompressed, and MMR used in facsimile machines, etc.
Needless to say, compressed data compressed by the MH method, the MH method, or the MR method may be partially decompressed.

Further, in the above-described embodiment, the recording medium 1
In the above, the case where the compressed data and the RST table are recorded has been described. However, the present invention is not limited to this. For example, the compressed data and the RST table may be recorded on different recording media. Needless to say. Further, the RST table need not be recorded. In this case, the compressed data may be reproduced to search the insertion position of the RST, and the RST table may be created.

In the above-described embodiment, the input means 8 sets an area designation parameter indicating which part of the image is to be displayed and output, and sets the R value necessary for reproducing this area.
The area delimited by ST is set as an expansion area and expansion processing is performed. For this reason, the display area and the extension area do not always match. Therefore, a means may be provided for displaying and outputting the area specified by the area specification parameter in the expanded area when the two areas do not match. Also, the above-described embodiment
It is only an illustration of the present invention, and various changes are possible as needed, and the present invention described in the claims encompasses all such changes.

The functional blocks of the above-described embodiment are as follows.
If necessary, it may be constituted by software or hardware, and it goes without saying that the present invention also includes some forms.

[0063]

According to the first to fourteenth aspects of the present invention, all the compressed data recorded on the recording medium are not read, and the data necessary for partial decompression is read. The total processing speed can be increased when a part of the compressed data is partially decompressed.

Further, according to claims 2, 4, 7, 8, 9,
According to 11, 12, 13, and 14, all the compressed data recorded on the recording medium is not read out, and the data of the readout area in sector units including the data of the area to be partially expanded is read out from the recording medium. Therefore, the reading time of the compressed data can be reduced, and the processing can be speeded up when partially expanding the compressed data.

Further, according to the third, fourth, eleventh and twelfth aspects of the present invention,
According to Jap. 13, 14, JPE recorded on a recording medium
A configuration in which data in a necessary area is read from the recording medium without reading out all the compressed data of the G method can be used to reduce the time required to read out the compressed data and to speed up the process when partially expanding the compressed data. .

[Brief description of the drawings]

FIG. 1 is a diagram showing functional blocks of an embodiment of the present invention.

FIG. 2 is a diagram for explaining JPEG data in which an RST is inserted for each line.

FIG. 3 is a diagram showing a state of a sector of the recording medium of this embodiment.

FIG. 4 is a diagram showing a flowchart of this embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Recording medium 2 Reproduction means 4 Decompression means 5 Storage means 11 Decompression area designation means 12 Read area designation means

────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ identification symbol FI H04N 7/24 H04N 7/13 Z (56) References JP-A-5-64149 (JP, A) JP-A-4-347781 ( JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H04N 5/91-5/956 G06T 9/00 G11B 20/10-20/12 H03M 7/30 H04N 1/41-1 / 419 H04N 7/24-7/68

Claims (14)

(57) [Claims] 1. A reads the compressed data from the recording medium (1), of the compressed data, the partial decompression process for decompressing the compressed data of a portion required to play a part designated, the required Record the recording unit including some compressed data
Reading from the medium (1);
Extracting the required part of the compressed data from the recording unit.
Tsu partial decompression method characterized by having a flop. 2. The partial decompression method according to claim 1, wherein the reading of the compressed data is performed on a sector basis including the part of the compressed data. 3. The compressed data is data compressed by the JPEG method, and the part of compressed data necessary for reproducing the specified part includes the specified part of the area. 2. The method according to claim 1, wherein the area is defined by a restart marker code. 4. The compressed data is data compressed by the JPEG system, and the part of the compressed data necessary for reproducing the specified part includes the specified part of the area. The compressed data read out from the recording medium (1) is an area defined by the restart marker code, and the area defined by the restart marker code is the area defined by the restart marker code. 2. The partial decompression method according to claim 1, wherein the sector is a sector including the sector. 5. A recording medium (1) on which compressed data is recorded, a decompressed area specifying means (11) for specifying a part of the compressed data as a decompressed area, and a decompressed area specified by the decompressed area specifying means (11). read area designating means for designating a region read encompassing sector block extension region (12), and reproduction means for reading the data of a sector block which is the read area from said recording medium (1) (2), the regeneration In the sector block read by the means
A partial decompression device, comprising: a decompression area extraction means (9) for extracting the decompression area from the data; and a partial decompression means (4) for decompressing the data extracted by the decompression area extraction means (2) . 6. The reproducing device according to claim 1, wherein
6. The partial decompression device according to claim 5, wherein, among the data read in (2), data corresponding to the decompression area is decompressed. 7. A recording medium (1) on which compressed data compressed in units of blocks is recorded, an expansion area specifying means (11) for specifying a partial block area of the compression data as an expansion area, A read area designating means (12) for designating, as a read area, a sector block including the decompressed area specified by the decompressed area designating means (11); A partial decompression device characterized by comprising a reproducing means (2) for reading data from the memory and a partial decompressing means (4) for decompressing data read by the reproducing means (2) in block units. 8. The reproduction device according to claim 8, wherein the partial decompression means (4) is
8. The partial decompression device according to claim 7, wherein, of the data read in (2), the data in the decompression area is decompressed in block units. 9. The part according to claim 5, wherein said read area designation means (12) designates a smallest sector block including said decompressed area as a read area. Stretching device. 10. The partial decompression device according to claim 5, wherein the compressed data is obtained by compressing image data. 11. A restart marker code (hereinafter referred to as "restart marker code").
(RST) based on a recording medium (1) in which JPEG compressed data inserted therein and an RST table holding all the positions of the RSTs inserted in the JPEG compressed data are determined. Extension area designating means (11) for designating an extension area from the RST position indicating the extension end position to the RST position indicating the extension end position; and reading from the read start sector before the extension start position and after the extension end position. A read area designating means (12) for designating a sector block up to the end sector as a read area; a reproducing means (2) for reading data of the read area from the recording medium (1); and a reproducing means (2). An unnecessary start data receiving means (5) for receiving data from the read start sector to the decompression start position in the read data; Of the data read in (2), a partial decompression means (4) for decompressing data from the decompression start position to the decompression end position, and of the data read by the reproduction means (2), A partial decompression device comprising: an end-unnecessary data receiving unit (5) for receiving data from the decompression end position to the read end sector. 12. A restart marker code (hereinafter referred to as "restart marker code").
A recording medium (1) in which JPEG compressed data with an embedded (RST) is inserted; an extension area designating means (11) for designating an extension area based on the insertion position of the RST; The recording medium in which the area including is recorded (1)
Read area designating means (12) for designating a sector block as a read area
A reproducing means (2) for reading the data in the read area from the recording medium (1); and a partial decompressing means (4) for decompressing the data read by the reproducing means (2). Characteristic partial extension device. 13. A restart marker code (hereinafter referred to as "restart marker code").
(RST) based on a recording medium (1) accessible in sector units for recording JPEG compressed data inserted therein, and an RST table holding all positions of the RST inserted in the JPEG compressed data. Extension area designation means (11) for designating an extension area from the RST position indicating the extension start position to the RST position indicating the extension end position; and reading the extension end from the read start sector preceding the extension start position. A read area designating means (12) for designating, as a read area, a sector block up to the read end sector after the position; a reproducing means (2) for reading data of the read area from the recording medium; And a partial decompression means (4) for decompressing data from the decompression start position to the decompression end position in the output data. A partial extension device characterized by the above-mentioned. 14. The read area designating means (12) designates a sector block from a sector address immediately before the decompression start position to a sector address immediately after the decompression end position as a read area. The partial extension device according to any one of claims 11 to 13.