JP2005079815A - Method for encoding-decoding image information and disk device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an encoding-decoding method and a disk device by which efficient compression/extension can be performed while suppressing data size even in image information of one-pixel 8-bit expression or more by performing compression processing while discriminating a compressed area from a non-compressed areas by the continuation/non-continuation of runs. <P>SOLUTION: In the image information encoding method, image information is equally divided into the integer number of divided areas in each prescribed length, whether compression is to be performed or not is decided in accordance with the repeatability of image information in each divided area to generate compression/non-compression information indicating whether the compression is to be performed or not in each divided area, and as to an area for performing compression out of the divided areas, one unit of the image information to be repeated in the area is attached to the compression/non-compression information. As to an area in which compression is not performed, the image information of the area is attached as it is to compress the image information. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an image information encoding / decoding method, and more particularly, to an image information encoding / decoding method and a disc apparatus which are performed by distinguishing between a compressed area and an uncompressed area.

  In recent years, DVD video discs with high image quality and high functionality and DVD video players that play back such discs have become widespread, and the range of choices including peripheral devices that play back multi-channel audio has expanded, making home theaters already familiar. An environment where movies and animations can be freely viewed at home has been prepared.

  In recent years, with the improvement of image compression technology, aiming to achieve higher image quality, content producers have been increasingly required to record high-definition TV format high-quality content on DVD video discs. Yes.

Patent Document 1 discloses an encoding / decoding system that performs a run-length compression method of 1-pixel 2-bit representation (4 colors) used for, for example, a sub-picture of a DVD video disk. With this encoding / decoding method, for example, the sub-picture information can be reduced in the volume of information to be processed by compressing continuous image information such as a background image.
JP-A-8-242448

  In the above-described prior art, it is suitable for run-length compression of 1-pixel 2-bit representation (4 colors) of image information, but 1 pixel used as subtitles or menu information for high-definition TV high-quality content. It is inappropriate to encode / decode image information of 8-bit representation or more. That is, for example, when a DVD sub-picture or the like is used as one pixel 8-bit representation (256 colors) or more, if one pixel 8-bit representation is used, the probability of run continuation (for example, 01b → 01b) is It drops from 1/4 to 1/256, and the run length cannot be earned. Therefore, when the uniform compression processing is performed even on the area where the runs are not continuous as in the conventional technique described above, the data size is increased due to the influence of the counter data, and the compression efficiency is greatly reduced. There's a problem.

  The present invention distinguishes between compressed and non-compressed areas based on whether the run is continuous or non-contiguous, thereby enabling efficient compression / decompression while suppressing the data size even for image information of 8 bits per pixel or more. It is an object of the present invention to provide an encoding / decoding method and a disk device that enable the recording and decoding.

  The encoding method according to the present invention divides image information into an integer number of divided areas equally for each predetermined length, and performs compression according to repeatability of the image information in each area. A compressed uncompressed information indicating whether or not to perform compression for each of the divided areas, and for the area to be compressed among the divided areas, a unit of image information repeated in the area Is attached to the compressed non-compressed information, and for the area that is not compressed among the divided areas, the image information of the area is directly attached to the compressed uncompressed information, thereby compressing the image information and compressing the compressed image. An image information encoding method characterized by generating information.

  According to the encoding method described above, the image information is not uniformly compressed, but the image information is classified into a compression area where compression is performed and a non-compression area where compression is not performed, and compression is performed only in the compression area. As described above, unnecessary counter information or the like is provided in an area where compression is not possible, so that there is no inconvenience such as a reduction in compression efficiency and an increase in information capacity. Therefore, since only the compression region is efficiently compressed, the most efficient encoding / decoding method of image information as a whole can be provided.

  In addition, for image information for one screen, an integer number of divided areas are defined, and a compressed area and an uncompressed area are defined along the divided area, and the distribution of the compressed area and the uncompressed area is addressed. It is possible at least to define using information. Further, by attaching the compression type information defining the compression type, more efficient compression processing can be performed.

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

An image information encoding / decoding method and a disk apparatus using the same according to the present invention have the following characteristics as technical fields.
(1) Encoding method for compressing and encoding bitmap image data such as digitally recorded captions or simple animations (2) Decoding method for expanding and decoding the encoded data (3) Encoding Compression / decompression system combined with / decoding method (4) This refers to an information storage medium on which information is recorded based on the above encoding method.

In addition, this encoding / decoding method is
(1) Run-length compression / decompression technology (2) This is applied to a sub-picture decoder.

  Hereinafter, the present embodiment will be described with reference to the drawings. The present invention is mainly represented by the first embodiment and the second embodiment.

In the first embodiment, an image display area is equally divided into an integer number, and encoding / decoding is performed using a designation flag indicating a compression area / non-compression area.

In the second embodiment, encoding / decoding is performed using address information indicating the distribution of the compressed area and the uncompressed area in the image display area.

<Encoding / Decoding Method and Disc Device According to the Present Invention>
Hereinafter, the present invention will be described in detail with reference to the drawings. Here, a case where the encoding / decoding method according to the present invention is applied to encoding / decoding of sub-picture information of a DVD (Digital Versatile Disk) will be described as an example. Needless to say, it is a form.

  FIG. 1 is a schematic diagram of a data structure of an optical disc subjected to the encoding / decoding method according to the present invention, and FIG. 2 shows an example of a data structure of a VOB of the optical disc subjected to the encoding / decoding method according to the present invention. FIG. 3 is a diagram showing an example of another data structure of a VOB of an optical disc to which the encoding / decoding method according to the present invention is applied, and FIG. 4 is an optical disc apparatus to which the encoding / decoding method according to the present invention is applied. It is a block diagram which shows an example of the structure of.

  FIG. 1A shows the appearance of a disk-shaped information storage medium 1 described in this embodiment. As shown in FIG. 1B, the information storage medium 1 has a lead-in area 10, a volume / file structure information area 11, a data area 12, and a lead-out area 13 from the inner circumference side. .

  Among these, the data area 12 includes a general computer information recording area 20, a video / data recording area 21, and another data recording area 22, as shown in FIG.

  The video data recording area 21 includes a video management information recording area 30 for managing all information recorded on the information storage medium 1 and 1 for managing information for each title, as shown in FIG. And one or more video title sets #n recording area 100.

  In addition, as shown in FIG. 1E, the video management information recording area 30 includes a control data (HD_VMG.IFO file) area 31, a menu video object (HD_VMGM.VOB file) area 32, and a control data backup ( HD_VMG.BUP file) area 33.

  Further, the video title set #n recording area 100 includes a control data (HD_VTS.IFO file) area 101 and a menu video object (HD_VTSM.VOB file) area 102 as shown in FIG. , A title video object (HD_VTS.VOB file) area 103 and a control data backup (HD_VTS.BUP file) area 104 are provided.

  Here, FIG. 2 and FIG. 3A show one or more video objects (VOB) 300 stored in each of the video object areas 32, 102, and 103 described above.

  This video object 300 is composed of one or more video object units (VOBU) 301 as shown in FIG. 2 and FIG. The video object unit 301 is a minimum unit for reproduction.

  As shown in FIG. 2 and FIG. 3C, the video object unit 301 includes a head control pack 302, a plurality of main video packs 303, and selectable first and second audio packs 304a. , 304b and selectable first and second sub-picture packs 305a, 305b. In FIG. 3C, a highlight information pack 305c and the like are further included.

  Then, the selected first or second audio pack 304a, 304b and the selected first or second sub-picture pack 305a, 305b are synchronized with the main video pack 303 in the video object unit 301. Played.

  FIG. 4 shows that the compressed information stored in the disk-shaped information storage medium 1 is read out, decoded and reproduced, and the given video information is compressed by the encoding method according to the present invention. 2 shows a disk device for recording on a disk. That is, the information storage medium 1 is mounted on the disk drive unit 201. The disk drive unit 201 rotates the mounted information storage medium 1 and reads information stored in the information storage medium 1 using an optical pickup 201a.

  Information read by the disk drive unit 201 is supplied to the data processor unit 202, subjected to error correction processing, and then stored in the track buffer 202a. Of the information stored in the track buffer 202a, the management information of the control data areas 31 and 101 is recorded in the memory unit 210 and used for reproduction control and data management.

  Of the information stored in the track buffer 202a, the information of the video object areas 32, 102, 103 is transferred to the separation unit 203, and the main video pack 303, audio packs 304a, 304b, and sub-video pack 305a. , 305b.

  The information of the main video pack 303 is supplied to the video decoder unit 204, the information of the audio packs 304a and 304b is supplied to the audio decoder unit 206, and the information of the sub video packs 305a and 305b is supplied to the sub video decoder unit 205, respectively. A decoding process characteristic of the present invention is performed.

  The main video information decoded by the video decoder unit 204 and the sub-video information decoded by the sub-video decoder unit 205 are supplied to the video processor unit 207 and subjected to a superimposition process. Digital / analogue (analogue) converter 208 converts the signal into an analog signal and outputs it as a video signal to a video display device (not shown) (for example, CRT: Cathode Ray Tube).

  The audio information decoded by the audio decoder unit 206 is converted into an analog signal by the D / A conversion unit 209 and output as an audio signal to an audio reproduction device (for example, a speaker) (not shown).

  A series of reproduction operations for the information storage medium 1 as described above are controlled in an integrated manner by an MPU (Micro Processing Unit) unit 211. The MPU unit 211 receives operation information from the key input unit 219 and controls the units 201 to 206 based on a program stored in a ROM (Read Only Memory) unit 220. The present invention will be described in detail later. The characteristic decoding process is performed.

  Similarly, the disk apparatus shown in FIG. 4 includes an A / D conversion unit 220 that obtains video input from the outside, a video processor unit 222 that processes this video information, and a main video pack 303 processed by the video processor unit 222. Is encoded by the video encoder unit 223, the sub video pack 305 a is encoded by the sub video encoder unit 224, and the audio packs 304 a and 304 b are encoded by the audio encoder unit 225. In particular, the sub-picture pack is encoded by the sub-picture encoder unit 224 by an encoding method characteristic of the present invention as described in detail later.

  Thereafter, these encoded packs are synthesized by the synthesis unit 226. The synthesized information is recorded on the disc 1 via the disc drive 201 unit under the control of the data processor unit 202.

  Here, in the above-described encoding / decoding processing of the sub-picture pack, when an image of 1-pixel 8-bit representation or the like is compressed / decompressed by the method described above in the related art, similarly to the 1-pixel 2-bit representation pixel, Since the probability of consecutive (for example, 01b → 01b) decreases from 1/4 to 1/256, the run length cannot be earned and is not compressed frequently. For this reason, for example, run-length count information or the like is burdened in an area where no continuous image exists, and there is a problem in that the compression rate is reduced as a whole and the capacity may be larger than the initial sub-picture information.

<First Embodiment of Encoding / Decoding Method According to the Present Invention>
The encoding (decoding) method according to the first embodiment of the present invention divides an image display area into an integer number of equal areas, for example, 16 divisions, and defines a compressed uncompressed area in each area. This is a method of performing compression processing only on the compression area.

FIG. 5 is a diagram showing an example of run-length compression rules in the encoding method according to the first embodiment, and FIG. 6 is a diagram showing an example in which an image display area is divided into 16 parts to which the encoding method according to the present invention is applied. FIG. 7 is a diagram illustrating an example of compressed data after the line (a) is encoded by the encoding method according to the first embodiment, and FIG. 8 is a diagram according to the encoding method according to the first embodiment. FIG. 9 shows an example of compressed data after encoding line (b), FIG. 9 shows an example of compressed data after encoding line (a) by the encoding method according to the first embodiment, FIG. 10 is a diagram illustrating an example of compressed data after the line (b) is encoded by the encoding method according to the first embodiment, and FIG. 11 is according to the encoding method according to the first embodiment. Shows an example of a second run-length compression rules,
FIG. 12 is a diagram illustrating an example of a third run-length compression rule according to the encoding method according to the first embodiment, and FIG. 13 is a third run-length compression rule according to the encoding method according to the first embodiment. FIG. 14 is a second image diagram showing another example in which the image display area is divided into 16 parts, and FIG. 15 is an encoding according to the first embodiment. FIG. 16 is a diagram illustrating an example of compressed data after the line (a) is encoded according to the third run-length compression rule according to the method; FIG. 16 illustrates third run-length compression according to the encoding method according to the first embodiment; FIG. 17 shows an example of compressed data after the line (b) is encoded according to a rule. FIG. 17 shows a third run-length compression rule according to the encoding method according to the first embodiment. Ri is a diagram showing an example of the compressed data after encoding the line (c).

  First, FIG. 5 is a diagram illustrating an example of a run length compression rule in the encoding method according to the first embodiment. (A) shows whether the image display area used for this compression is 1920 × 1080, 1440 × 1080, or 1280 × 720. This is written in only the first line of data (b) is 4 bits for byte alignment for inserting 4 bit data when byte alignment is not performed at the end. (C) is 16 blocks of compressed and uncompressed information that indicates one-to-one whether the area is a compressed area or an uncompressed area when one line is divided into 16 areas. (D) is pixel data used in both the compression / non-compression areas. In the encoding (decoding) method according to the present invention, since compression processing is performed only on blocks that are being compressed using compressed uncompressed information, efficient compression is performed even on image information expressed in 8-bit per pixel. (Decompression) processing can be performed.

  The display system having an image display area of 1920 × 1080 shown in FIG. 6 has four buttons A, B, C, and D and changes in the background image (A and C are background changes, and B and D are buttons). In this case, it is considered that the same pixels continue in places other than the four areas for transmission that shows the main video. At this time, 1920 pixels are divided into 16 areas every 120 pixels. As an example, FIG. 7 shows compressed image information when one line of (a) is encoded, and FIG. 8 shows compressed image information when one line of (b) is encoded.

  In FIG. 7, the compressed image information of line (a) is shown. First, the display mode is selected at the beginning of the first line. In this case, since it is 1920 × 1080, it is “0000”. The first line other than the first line is 16 bits and indicates compression / non-compression for each area. If “1” is a compressed area and “0” is an uncompressed area, 16 areas are “1110001110011111”. In the subsequent data area, only one compressed 8-bit pixel data is written in the compression area. At this time, since it is considered that the same image is continuous in the compression area, the compression areas d0 to d2 collectively indicate one pixel data. The uncompressed area describes all the pixel data for 120 pixels.

  In the case of FIG. 8, the compressed image information of the line (b) is shown. Since all of the compressed area is from the beginning to the end of the line, compression / non-compression is indicated. All 16 bits are “1” for compression, and after that, only 8 bits are described as compressed pixel data, and the line ends.

  In the case of this example, a case of 1920 × 1080 is assumed, but even in the case of 1440 and 1280, conversion can be easily performed by considering 16 area units. In the case of 1440 pixels, the area is 90 pixels, and in the case of 1280 pixels, the area is 80 pixels. Also, it may be more efficient to divide the area into smaller areas. In this case, the compression ratio compression information of 16 blocks is increased to cope with it.

  9 and 10 similarly show the encoding method of the first embodiment. Unlike FIG. 8, there is no change in the pixel data in the compressed area, but the pixel data in each area does not change. This is when there is a change. At this time, pixel data corresponding to the compressed area of the 16-block compressed / uncompressed information is described on a one-to-one basis, and all pixel data for 120 pixels are described in the uncompressed area.

  FIG. 11 is a diagram illustrating an example of a second run-length compression rule by the encoding method according to the first embodiment, and illustrates a case where data other than the same pixel is mixed in one area of the compression area. ing. By using a counter indicating the number of continuous pixels as shown in FIG. 11E, compression and decompression are possible even when one area of the compression area is composed of several types of identical pixels. At this time, since data other than the pixels to be compressed are also mixed in the compression area, an 8-bit counter is attached to the data in the compression area. If pixel data changes due to a difference in background color even within the compression area, a counter can be provided to connect the pixel data.

  12 and 13 show an example of a third run-length compression rule by the encoding method according to the first embodiment. Here, the counter of the second run length compression rule is used, and a compression type determination flag for one line is used.

  This 1-line compression type determination flag uses 4 bits used for byte alignment in the run-length compression rule as a compression type flag. In the compression type for each line, (1) compression The areas are all managed by the same pixel, (2) the compressed area is all the same pixel, and (3) the area is also divided into three types with changing points, as shown in FIG. 15, FIG. 16, and FIG. Generate a compressed image.

  That is, FIG. 15 shows a case where the compression type flag is “0, 0, 0, 0”, and the compression regions are all the same pixels. FIG. 16 shows a case where the compression type flag is “0, 0, 0, 1”, and the compression region area is all the same pixel. FIG. 17 shows a case where the compression type flag is “0, 0, 1, 0”, and there is a change in the area. The counter indicating the number of continuous pixels and the compression type flag are used in the encoding process and the decoding process, thereby enabling efficient compression / decompression processes such as sub-picture information.

  As described above, in the encoding / decoding method according to the first embodiment of the present invention, the image display area is divided into 16 (12) divisions, and the compressed uncompressed information is defined in each divided area. Since only the area can be efficiently compressed, efficient encoding / decoding can be performed even for image information such as sub-pictures of 1-bit 8-bit representation (256 colors) or more whose run length is insufficient. . Furthermore, encoding / decoding can be performed more efficiently by using a counter indicating the number of continuous pixels, a flag indicating the compression type, and the like.

<Second Embodiment of Encoding / Decoding Method According to the Present Invention>
The encoding (decoding) method according to the second embodiment of the present invention is a method of defining address information indicating the distribution of the compression area and the non-compression area in the image display area and performing the compression process only on the compression area. FIG. 18 is a third image diagram showing an example in which an image display area is divided into twelve, to which the encoding method according to the present invention is applied, and FIG. 19 is a line (FIG. 18) by the encoding method according to the second embodiment. The figure which shows an example of the compressed data after encoding a),
FIG. 20 is a diagram illustrating an example of compressed data after the line (b) in FIG. 18 is encoded by the encoding method according to the second embodiment, and FIG. 21 is a diagram illustrating the encoding method according to the second embodiment. FIG. 22 is a diagram illustrating an example of compressed data after the line (a) in FIG. 18 is encoded by the second run-length compression rule. FIG. 22 illustrates the second run-length compression by the encoding method according to the second embodiment. FIG. 23 is a diagram showing an example of compressed data after the line (b) in FIG. 18 is encoded according to a rule. FIG. 23 is a diagram showing an example in which an image display area to which the encoding method according to the present invention is applied is divided into 12 parts. FIG. 24 is an image diagram, and FIG. 24 shows the compression when encoding is performed on line (a) in FIG. 23 by the third run length compression rule by the encoding method according to the second embodiment. FIG. 25 is a diagram showing an example of the data, and FIG. 25 shows an example of the compressed data when encoded by the line (b) in FIG. 23 according to the third run length compression rule by the encoding method according to the second embodiment. FIG. 26 and FIG. 26 are diagrams showing an example of compressed data when encoded by the line (c) in FIG. 23 according to the third run length compression rule by the encoding method according to the second embodiment.

  FIG. 18 shows a third image diagram showing an example in which an image display area is divided into twelve, to which the encoding method according to the present invention is applied. In this figure, a display system having an image display area of 1920 × 1080 has four buttons A, B, C, and D and background image changes (A and C are background changes, and B and D are buttons). In this case, it is considered that the same pixels continue in places other than the four regions for transmission showing the main video. At this time, 1920 pixels are divided into 12 areas every 160 pixels.

  FIG. 19 is a diagram showing an example of compressed data after the line (a) of FIG. 18 is encoded by the encoding method according to the second embodiment. In FIG. 19, first, at the beginning of the first line, the display Select the mode. In this case, since it is 1920 × 1080, it is “0000”. Next, since the line (a) is a compressed area from the head of the line to the area “2”, a compressed area header (d1 to d3) is set. As the end X coordinate area indicating the end area (d4 to d7), since the subsequent two areas are non-compressed areas, the non-compressed area header (d8 to d11) and the end X-coordinate area (d12 to d15) compressed area header ( d16 to d19), and after that, compression is performed up to 8 areas, so the end X coordinate area (d20 to d23), the uncompressed area header (d24 to d27), the end X coordinate area (d28 to d31), and the compressed area header (d32 to d32) d35) Since the compression area extends to the end of the line, the end X-coordinate area (d36 to d39) and the compressed / uncompressed data (d40 to) are shown.

  In the case of FIG. 20, since all of the line from the beginning to the end is the compression area, after using 4 bits for selection of the display mode, “1011” representing 11 which is the last area in the compression area header and end X coordinate area. And create units in the order of compressed data.

  In this example, the case of 1920 × 1080 is assumed, but as shown in FIG. 18, even in the case of 1440 × 1280, conversion can be easily performed by considering in units of 160 pixels. Also, it may be more efficient to divide the area into smaller areas. In this case, the compression ratio compression information of 16 blocks is increased to cope with it.

  The case of FIG. 21 is the encoding when the line (a) is encoded, and is an extension when data other than the same pixel is mixed in the compression area of the compression method according to the second embodiment. At this time, since data other than the pixels to be compressed are also mixed in the compression area, by defining the compression area data with an 8-bit counter attached, even if a plurality of pixels are mixed in one compression area. Can be identified. As described above, when the same pixel data changes and continues in the compressed area due to a difference in background color, the image information is specified and compressed / expanded by rewriting the compressed area header and the end X coordinate area. be able to.

  In the case of FIG. 22, the encoding of the line (b) is performed, and all the pixels on the line are the same, and therefore, it is defined by one end X coordinate area in the compression area header. Thereafter, the number of continuous pixels and the compressed image data follow.

  FIG. 23 further shows a fourth image diagram showing an example in which the image display area is divided into 12 parts to which the encoding method according to the present invention is applied. In this figure, a display system having an image display area of 1920 × 1080 has four buttons A, B, C, and D and background image changes (A and C are background changes, and B and D are buttons). In this case, it is considered that the same pixels continue in places other than the four regions for transmission showing the main video. At this time, 1920 pixels are divided into 12 areas every 160 pixels.

  In the embodiments described so far, the pixel data length is 8 bits, and the counter length when the counter is attached is 8 bits. From this, it can be seen that if the change point n of the pixel data is less than n = m / 2 (pieces) with respect to the pixel data m in the compression area, the compression efficiency increases.

  In addition, in the area where no counter is attached, if there is even one compression area, the data amount can be reduced as compared with the case where compression is not performed.

  In FIGS. 24 to 26, as shown in FIGS. 12 and 13, a one-line compression type determination flag is used. That is, in the compression type for each line, (1) the compression area is the same pixel, (2) the compression area is the same pixel, and (3) the area is also divided into three types with change points. As shown in FIGS. 24, 25, and 26, a compressed image is generated.

  FIG. 24 is a diagram showing an example of compressed data when encoded in line (a) of FIG. 23 by the third run length compression rule by the encoding method according to the second embodiment, and the compression type flag is “0010”, which indicates a case where there is a change point even in the area of the compression region. Furthermore, a plurality of compressed areas and non-compressed areas are defined by address information. Furthermore, pixel data is defined using the number of continuous pixels as a counter.

  FIG. 25 is a diagram showing an example of compressed data when encoded by line (b) in FIG. 23 according to the third run length compression rule by the encoding method according to the second embodiment. “0001”, and the area of the compression area is the same pixel. Furthermore, a plurality of compressed areas and non-compressed areas are defined by address information. Furthermore, pixel data is defined using the number of continuous pixels as a counter.

  FIG. 26 is a diagram showing an example of compressed data when encoded in line (c) of FIG. 23 by the third run-length compression rule by the encoding method according to the second embodiment, and the compression type flag is “0000” and the compressed area is the same pixel. Therefore, after that, one piece of compressed image data is shown, so that the image data can be specified.

  As described above, in the encoding / decoding method according to the second embodiment of the present invention, the compression area and the non-compression area in the image display area are defined by the address information, and only the compression area is efficiently compressed. Since it can be processed, it is possible to efficiently encode / decode even image information such as sub-pictures of 8-bit representation (256 colors) or more with a short run length. Furthermore, as in the first embodiment, encoding / decoding can be performed more efficiently by using a counter indicating the number of continuous pixels, a flag indicating the compression type, and the like.

<Description of Encoding / Decoding Method According to the Present Invention by Flowchart>
The above-described encoding / decoding method according to the present invention will be described in detail with reference to flowcharts. FIG. 27 is a flowchart showing an example of the basics of run-length compression by the encoding method according to the present invention, FIG. 28 is a flowchart showing an example of the details of run-length compression by the encoding method according to the present invention, and FIG. 30 is a flowchart showing an example of the details of run-length compression by the encoding method according to the present invention, FIG. 30 is a flowchart showing an example of the details of run-length compression by the encoding method according to the present invention, and FIG. 31 is a run by the decoding method according to the present invention. FIG. 32 is a flowchart showing an example of the details of run-length expansion by the decoding method according to the present invention. FIG. 33 is an example of details of run-length expansion by the decoding method according to the present invention. FIG. 34 is a flowchart showing the decoding according to the present invention. Is a flowchart illustrating an example of the details of the run-length decompression according to the method.

(Encoding process)
FIG. 27 shows a basic flowchart of encoding (compression) of the run-length compression rule according to the present invention. First, the display mode is acquired, the discrimination process is performed, and this data is generated (S1). Next, the number of areas is determined and this data is generated (S2). Further, the compression / non-compression area is determined, and the compression / non-compression area information is generated (S3). Finally, the pixel data of the compressed image information is determined and combined with the compressed / uncompressed area information, etc., and the compressed image information is completed (S4).

  FIG. 28 is a flowchart showing an example of details of run-length compression by the encoding method according to the present invention. In this figure, first, two unit work areas and one line work area are secured, and one line pixel is obtained. Is counted (S11). Further, the display mode is acquired and the number of areas is determined (S12). Here, it is determined whether or not to define compression / non-compression for each block according to the first embodiment (S13).

  If yes, compression / non-compression is defined, for example, every 16 blocks according to the first embodiment described above (S14). If no, the address information of the compression / non-compression area is generated according to the second embodiment described above (S15).

  Thereafter, the compression process of the image information is started. If the area is the compression area (S16), the area continuation area determination process is performed (S17), and the compression area process is performed (S19). Continue to the line end area (S18). Also in the non-compressed area (S16), the area continuation area determination process is performed (S20), the compressed area process is performed (S22), and this continues to the line end area (S21). When each reaches the line end area, the holding data is output (S23).

  Here, in the compressed area processing pattern (S19) of FIG. 29, the pixel counter is cleared to 0, and count processing for coefficient of the same pixel data is performed (S31). Then, this is continued as long as it is the same pixel (S32), and when the same pixel ends, the count value and the pixel data are held (S33). Further, the count value is cleared to 0 and the address is adjusted (S34). These processes are continued until the area ends (S35).

  Further, in the uncompressed area processing pattern (S22) of FIG. 30, the process of holding the pixel data is performed and continued until the area is completed (S37).

Here, an example of a more detailed encoding method will be described below. That is, the encoding method of the present invention is an encoding process in which a data block in which the same pixel data is continuous is compressed as one compression unit in an information aggregate formed by collecting a plurality of pixel data defined by a predetermined number of bits. is there. In the encoding process, a step of determining the number of pixels of one line by determining the number of pixels of one line in the information aggregate and determining the image display area;
An output step of outputting a header corresponding to the image display area determined by the confirmation step;
An area dividing step of dividing the image display area into an integer number of areas;
An area specifying step for determining a compressed area and an uncompressed area according to differences in highlight information and background color,
If it is a compression region in the compression region specifying step, the same pixel number counting step of counting the continuous number of the same pixel data,
A run continuous counter generating step for storing the number obtained by the counting step;
A counter output step for outputting the run continuous counter value generated by the run continuous counter generation step;
A pixel data output step for outputting the same pixel;
An area pixel number determining step for determining the number of pixels in the area by the area dividing step and the region specifying step;
A counter value coefficient step for coefficienting the run continuous counter value generated by the run continuous counter generation step;
A comparison step of comparing the values in the area pixel number determination step and the counter value coefficient step;
A transition process that moves to the next area if the values in the comparison process match,
If it is a non-compression region in the compression region specifying step, an output step for outputting only pixel data;
An output pixel number coefficient step for coefficient of the number of pixels output in the output step;
The number of pixels in the area that determines the number of pixels in the area by the area dividing step and the region specifying step;
A comparison step of comparing values in the output pixel number coefficient step and the in-area pixel number determination step;
A transition process that moves to the next area when the values match in the comparison process, and
It is what has.

  According to the encoding method of the present invention, an image display area is divided into an integer number of areas, and a flag is provided for each unit in an area where a lot of runs are expected by clearly defining a compression / non-compression area. Increase in the amount of data can be avoided. In an area where runs do not continue, an efficient compression method is possible by avoiding data overhead due to addition of a counter.

(Decoding process)
Next, a decoding process for decoding the image information compressed by the above encoding process will be described. FIG. 31 shows a basic flowchart of the decoding (decompression) of the run length compression rule of the present invention. First, the display mode and the discrimination method are acquired from the given compressed image information (S41). Next, the number of areas is acquired from the compressed image information (S42). Then, the distribution of the compressed area and the uncompressed area is acquired from the compressed uncompressed area information (S43). Finally, the compressed image information is decompressed based on the acquired data and the pixel information (pixel data) included in the compressed image information (S44).

  FIG. 32 is a flowchart showing an example of the details of run-length expansion by the decoding method according to the present invention, and obtain 4 bits (d1 to d3) of the display mode from the compressed image information (S51). Next, the number of areas is determined (S52). And if it is a compression area | region (S53), the process of a compression area | region will be performed to the line end (S55) (S55). If it is a non-compressed area (S53), the non-compressed area is processed (S56) up to the end of the line (S57).

  Thereafter, the held data is output (S58), and if byte alignment is necessary (S59), byte alignment is performed with 4-bit dummy data (S60).

  Here, in the compressed area processing pattern (S54) of FIG. 33, decoding (decompression processing) of the compressed area is performed as follows. That is, the 8-bit counter is acquired (S61), the count value and the pixel data are held, and the pixel data is repeatedly output according to the counter value (S62). Next, the address is adjusted to obtain data (S63), and this process is continued until the end of the area (S64).

  Here, in the non-compressed area processing pattern of FIG. 34, decoding (decompression processing) of the non-compressed area is performed as follows. That is, when the pixel data of the area is acquired (S71), the address for acquiring the next data is adjusted (S72), and the area pixel data is continuously acquired until the area is completed (S73). .

Next, an example of a more detailed decoding method will be described below. That is, the decoding method of the present invention decompresses a compressed bit string using a unit in which the same pixel data is continuous as one unit among information aggregates formed by collecting a plurality of pixel data defined by a predetermined number of bits. A pixel number confirmation step of discriminating one line according to a display mode for judging the number of pixels of one line drawn in the first 4 bits of the bit string in the information aggregate;
An area number determination step for determining how many areas the image display area is divided by the pixel number confirmation step;
An area confirmation process for determining whether the image display area divided into an integer number of areas by the area number determination process is a compressed area or an uncompressed area;
An information holding step for holding the information determined in the region checking step;
When the area confirmation process is a compression area by the repetition process and the retained information, the area confirmation process and the information holding process are repeated until the line end area is determined by the number of areas determined by the area number determining process. A counter unit that coefficient the pixel data, a step of extracting a counter value represented by the counter unit,
Outputting the same pixel data by the number of counter values based on the extracted counter value;
In-region coefficient process for coefficient of counter value for each unit;
A region pixel number determining step for determining the number of pixels in the region by the region coefficient step, the area number determining step and the region checking step;
A comparison step for comparing the region pixel number determination step and the region coefficient step;
The process of moving to the next unit when both match in the comparison process,
If the region confirmation step is an uncompressed region, the step of outputting the pixel data as it is,
A coefficient process for coefficient of the number of output pixel data;
An in-region pixel number determining step for determining the number of pixels in the region by the area number determining step and the region checking step;
A comparison step for comparing the number of pixels in the region and the coefficient-related step;
The process of moving to the next unit when both match in the comparison process,
This is an image information decoding method.

  As described above, according to the decoding method of the present invention, the image display area is divided into an integer number of areas, and the compression / non-compression area is clearly defined, so that a flag is set for each unit in an area where many runs are expected to continue. It is possible to avoid an increase in the amount of data due to the provision of. In an area where runs do not continue, efficient compression and expansion are provided by avoiding data overhead due to addition of a counter.

  With the various embodiments described above, those skilled in the art can realize the present invention. However, it is easy for those skilled in the art to come up with various modifications of these embodiments, and have the inventive ability. It is possible to apply to various embodiments at least. Therefore, the present invention covers a wide range consistent with the disclosed principle and novel features, and is not limited to the above-described embodiments.

  For example, the encoding / decoding method according to the present invention has been described by taking an example of compression / decompression of a sub-picture of a DVD handled by the optical disc apparatus. However, the present invention is not limited to this, and as an encoding / decoding method for a large amount of image information. It is possible to apply.

1 is a schematic diagram of a data structure of an optical disc to which an encoding / decoding method according to the present invention is applied. The figure which shows an example of the data structure of VOB of the optical disk with which the encoding / decoding method concerning this invention is performed. The figure which shows an example of the other data structure of VOB of the optical disk with which the encoding / decoding method concerning this invention is performed. 1 is a block diagram showing an example of the structure of an optical disc apparatus to which an encoding / decoding method according to the present invention is applied. FIG. 5 is a diagram illustrating an example of a run length compression rule in the encoding method according to the first embodiment. The 1st image figure which shows an example which divided the image display area | region into 16 with which the encoding method which concerns on this invention is performed. The figure which shows an example of the compressed data after encoding line (a) by the encoding method which is 1st Embodiment. The figure which shows an example of the compressed data after encoding line (b) by the encoding method which is 1st Embodiment. The figure which shows an example of the compressed data after encoding line (a) by the encoding method which is 1st Embodiment. The figure which shows an example of the compressed data after encoding line (b) by the encoding method which is 1st Embodiment. The figure which shows an example of the 2nd run length compression rule by the encoding method which is 1st Embodiment. The figure which shows an example of the 3rd run length compression rule by the encoding method which is 1st Embodiment. The figure which shows an example of the 3rd run length compression rule by the encoding method which is 1st Embodiment. The 2nd image figure which shows the other example which divided the image display area | region into 16 with which the encoding method which concerns on this invention is performed. The figure which shows an example of the compressed data after encoding line (a) by the 3rd run length compression rule by the encoding method which is 1st Embodiment. The figure which shows an example of the compression data after encoding line (b) by the 3rd run length compression rule by the encoding method which is 1st Embodiment. The figure which shows an example of the compressed data after encoding the line (c) by the 3rd run length compression rule by the encoding method which is 1st Embodiment. The 3rd image figure which shows an example which divided the image display area | region into 12 with which the encoding method which concerns on this invention is performed. The figure which shows an example of the compression data after encoding the line (a) of FIG. 18 with the encoding method which is 2nd Embodiment. The figure which shows an example of the compressed data after encoding the line (b) of FIG. 18 by the encoding method which is 2nd Embodiment. The figure which shows an example of the compressed data after encoding the line (a) of FIG. 18 by the 2nd run length compression rule with the encoding method which is 2nd Embodiment. The figure which shows an example of the compressed data after encoding the line (b) of FIG. 18 by the 2nd run length compression rule with the encoding method which is 2nd Embodiment. The 4th image figure which shows an example which divided into 12 the image display area where the encoding method based on this invention is performed. The figure which shows an example of the compression data at the time of encoding by the line (a) of FIG. 23 with the encoding method which is 2nd Embodiment by the 3rd run length compression rule. The figure which shows an example of the compression data at the time of encoding with the line (b) of FIG. 23 with the encoding method which is 2nd Embodiment by the 3rd run length compression rule. The figure which shows an example of the compression data at the time of encoding with the line (c) of FIG. 23 with the encoding method which is 2nd Embodiment by the 3rd run length compression rule. The flowchart which shows an example of the basics of run length compression by the encoding method which concerns on this invention. The flowchart which shows an example of the detail of the run length compression by the encoding method which concerns on this invention. The flowchart which shows an example of the detail of the run length compression by the encoding method which concerns on this invention. The flowchart which shows an example of the detail of the run length compression by the encoding method which concerns on this invention. The flowchart which shows an example of the basics of the run length expansion | extension by the decoding method concerning this invention. The flowchart which shows an example of the detail of the run length expansion | extension by the decoding method concerning this invention. The flowchart which shows an example of the detail of the run length expansion | extension by the decoding method concerning this invention. The flowchart which shows an example of the detail of the run length expansion | extension by the decoding method concerning this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Disc, 201 ... Disk drive, 202 ... Data processor, 203 ... Separation unit, 204 ... Video decoder unit, 205 ... Sub video decoder unit, 206 ... Audio decoder unit, 207 ... Video processor unit, 208 ... D / A conversion 220, A / D converter, 222, video processor, 223, video encoder, 224, sub-video encoder, 225, audio encoder, 226, synthesis unit.

Claims (20)

Divide the image information equally into integer number of divided areas for each predetermined length,
For each of the divided areas, determine whether to perform compression according to the repeatability of the image information of the area,
Generating compressed uncompressed information indicating whether or not to perform compression for each of the divided areas;
For the area to be compressed among the divided areas, a unit of image information repeated in the area is attached to the compressed uncompressed information,
For the area that is not compressed among the divided areas, by attaching the image information of the area as it is to the compressed uncompressed information, the image information is compressed to generate compressed image information.
An image information encoding method characterized by the above.   The compression type is compression when all of the image information of the predetermined length is repetition of one image information, compression when all of the divided areas are repetition of one image information, 2. The encoding method according to claim 1, further comprising: a compression type information indicating whether the compression is performed when a part of the divided area is a repetition of one piece of image information. For each predetermined length, the image information is determined to be classified into a compressed area where compression is performed and an uncompressed area where compression is not performed, according to the repeatability of the image information.
Generating address information indicating the distribution of the compressed area and the uncompressed area;
For the compressed area, a unit of image information repeated in the area is attached to the address information,
For the non-compressed area, the image information of the area is directly attached to the address information, thereby compressing the image information and generating compressed image information.
An image information encoding method characterized by the above.   The compression type is compression when all of the image information of the predetermined length is repetition of one image information, compression when all of the compression information is repetition of one image information, 4. The encoding method according to claim 3, wherein compression type information indicating whether the compression is performed when a part of the compression area is repetition of one image information is further attached to the address information. Receiving compressed image information, identifying this as an integer number of divided regions for each predetermined length,
Compressed uncompressed information indicating whether or not compression is performed for each divided area and subsequent image information are detected,
When the compressed uncompressed information indicates that the divided area is a compressed area, the image information corresponding to the divided area is detected, and this is output a predetermined number of times,
If the compressed uncompressed information indicates that the divided area is an uncompressed area, the image information corresponding to the divided area is detected and output as it is to compress the compressed image information into an uncompressed image. A method for decoding image information, characterized by decompressing the information. The compression type is compression when all of the image information of the predetermined length is repetition of one image information, compression when all of the divided areas are repetition of one image information, Further detecting from the compressed image information compression type information indicating whether compression is performed when a part of the divided area is a repetition of one image information;
6. The decoding method according to claim 5, wherein the image information of the compressed area is restored for each of the divided areas based on a compression type indicated by the compression type information. Receiving the compressed image information, detecting address information indicating the distribution of the compressed region and the non-compressed region from here, and identifying the compressed region and the non-compressed region based on this,
For the compressed area, image information corresponding to the compressed area is detected from the compressed image information, and this is repeated a predetermined number of times and output.
For the non-compressed area, the image information corresponding to the non-compressed area is detected from the compressed image information, and the compressed image information is expanded to the pre-compressed image information by outputting it as it is. Decoding method of image information. The compression type is compression when all of the image information of a predetermined length is repetition of one image information, compression when all of the compression information is repetition of one image information, or the compression Further detecting from the compressed image information compression type information indicating whether compression is performed when a part of the region is a repetition of one image information;
8. The decoding method according to claim 7, wherein image information is restored for each compression area based on a compression type indicated by the compression type information. For each divided area obtained by dividing the image information given from the outside into an integral number of equal parts for each predetermined length, it is determined whether or not to perform compression according to the repeatability of the image information in that area, and for each divided area To generate compressed uncompressed information indicating whether or not to perform compression,
For the area to be compressed among the divided areas, a unit of image information repeated in the area is attached to the compressed uncompressed information, and for the area not to be compressed among the divided areas, image information of the area is attached. Is attached to the compressed uncompressed information as it is, and an encoder unit that compresses the image information to generate compressed image information;
A recording unit for recording the compressed image information generated by the encoder unit on a disc;
A disk device comprising:   In the encoder unit, when the type of compression is compression when all of the image information of the predetermined length is repetition of one image information, or when all of the divided areas are repetition of one image information 10. The compression type information indicating whether the compression is performed when the image is compressed or when a part of the divided area is a repetition of one piece of image information is further attached to the compressed uncompressed information. Disk unit. The encoder unit is a sub-video encoder unit that converts a sub-video with respect to a main video of given video information into compressed image information,
A video encoder for encoding video information which is a main video of the given video information;
The disk device according to claim 9, wherein the recording unit records the encoded video information of the main video and the sub-video on the disk. The image information given from the outside is determined to be classified into a compressed area where compression is performed and a non-compressed area where compression is not performed according to the repeatability of the image information for each predetermined length. Generate address information indicating the distribution with the compressed area,
For the compressed area, a unit of image information repeated in the area is attached to the address information, and for the non-compressed area, the image information of the area is attached as it is to the address information. An encoder unit that generates compressed image information by compressing
A recording unit for recording the compressed image information generated by the encoder unit on a disc;
A disk device comprising:   In the encoder unit, the compression type is compression when all of the image information of the predetermined length is repetition of one image information, or when all of the compression information is repetition of one image information. 13. The disc according to claim 12, further comprising: compression type information attached to the address information indicating whether the compression is performed when the image is compressed or when a part of the compressed area is a repetition of one image information. apparatus. The encoder unit is a sub-video encoder unit that converts a sub-video with respect to a main video of given video information into compressed image information,
A video encoder for encoding video information which is a main video of the given video information;
13. The disk apparatus according to claim 12, wherein the recording unit records the encoded video information of the main video and the sub video on the disk. A reading unit for reading compressed image information recorded on the disc;
The compressed image information is received from the reading unit, is identified as an integer number of divided regions for each predetermined length, and compressed uncompressed information indicating whether or not compression is performed for each of the divided regions, followed by an image Detect information and
When the compressed uncompressed information indicates that the divided area is a compressed area, the image information corresponding to the divided area is detected and output by repeating the predetermined number of times. When the divided area is indicated as an uncompressed area, the image information corresponding to the divided area is detected and output as it is, so that the compressed image information is decompressed and output to the image information before compression. A decoder unit to
A disk device comprising:   In the decoder unit, the compression type is compression when all of the image information of the predetermined length is repetition of one image information, or when all of the divided areas are repetition of one image information. Or compression type information indicating whether compression is performed when a part of the divided area is a repetition of one piece of image information is further detected from the compressed image information, and the compression type indicated by the compression type information 16. The disk device according to claim 15, wherein the image information of the compressed area is restored for each of the divided areas based on the information. The decoder unit is a sub-picture decoder unit that encodes compressed image information of a sub-video with respect to a main video of video information among compressed image information read from the reading unit;
16. The disk device according to claim 15, further comprising a main video decoder unit for decoding and outputting the compressed image information of the main video of the video information among the compressed image information read from the reading unit. A reading unit for reading compressed image information recorded on the disc;
The compressed image information is received from the reading unit, and address information indicating the distribution of the compressed area and the non-compressed area is detected therefrom to identify the compressed area and the non-compressed area. Image information corresponding to a compressed area is detected from the compressed image information, and this is repeated a predetermined number of times, and the image information corresponding to the non-compressed area is extracted from the compressed image information for the non-compressed area. A decoder unit that detects and outputs the compressed image information as it is before being compressed by outputting the compressed image information;
A disk device comprising:   The decoder unit may compress the type of compression when image information of a predetermined length is a repetition of one piece of image information or when all of the compression information is repetition of one piece of image information. Compression type information indicating whether compression or compression when a part of the compression area is a repetition of one piece of image information is further detected from the compressed image information, and based on the compression type indicated by the compression type information 19. The disk device according to claim 18, wherein image information is restored for each compressed area. The decoder unit is a sub-picture decoder unit that encodes compressed image information of a sub-video with respect to a main video of video information among compressed image information read from the reading unit;
19. The disk device according to claim 18, further comprising a main video decoder unit for decoding and outputting compressed image information of the main video of the video information among the compressed image information read from the reading unit.

Images