JP2864950B2 - Management method of compressed video data - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of managing moving picture data which has been compressed by predictive coding between images (frames or fields), and more particularly to reproduction as still images (still reproduction, slow reproduction, fast forward reproduction, etc.). (Special play) is provided.

[0002]

2. Description of the Related Art Recently, moving picture compression techniques have begun to be used not only for transmission means such as broadcasting and communication, but also for storage media (recording media and recording means) such as CDs and ROMs. Such reproduction of a recording medium requires not only normal reproduction as a moving image but also special reproduction such as still image reproduction (still reproduction, slow reproduction, and fast-forward reproduction). However, in the compression of a moving image, inter-picture (picture) predictive encoding is performed, which compresses a moving image based on the preceding and following images (frames, fields). For this reason, a moving image is simply considered as a collection of still images, and data cannot be managed and played back as a still image as in the related art. That is, since the amount of data of the compressed moving image data differs for each image, the change in the data amount of the recording medium (access point) is not simply proportional to the time code of the image. Further, in image data that has been subjected to inter-picture prediction coding, if there is no reference image serving as a reference, the image cannot be decompressed and decoded.

For this reason, conventionally, as shown in FIG. 6A, for an image (picture) that needs to be reproduced as a still image, the same image is duplicated as still image data separately from moving image data. Was held. When special playback such as fast-forward playback is required, as shown in FIG. 3B, only an independent image (intra-compressed image) I that has not been subjected to inter-picture prediction coding is fast-forwarded as a still image. I was playing.

[0004]

However, in a configuration in which the same image is double-stored as still image data separately from a moving image, the capacity of the recording medium may be wasted, or processing may be performed before recording. There is a need. Further, in a configuration in which fast-forward playback or still image playback is performed using only an independent image, a required image (timing) cannot be targeted for fast-forward playback or still image playback. Furthermore, since the amount of information of moving image data differs for each image, it is necessary to actually decompress and compress the compressed data (header) in order to grasp the position of the image (such as time code). It takes time to access a desired image, and operability is not good. Therefore, the present invention efficiently manages the compressed moving image data to reproduce as a still image (still reproduction,
It provides a management method that enables slow playback and fast forward playback.

[0005]

In order to solve the above-mentioned problems, for example, as shown in FIGS. 1 and 2, a method of managing moving image data which has been compressed by predictive coding between images (frames or fields) and compressed. And manages the moving image data in block units and configures a moving image before compression.
Of a plurality of images to be reproduced as a still image, management information indicating the position of the image data of the reference image and the position of the image data of the image in predictive encoding of the image (for example, the reference image A compressed video, wherein the position of the image data is indicated by a block position, and the position of the image data of the image is managed by providing management information indicating the difference in the number of frames from the reference image). The present invention provides a method for managing image data.

[0006]

According to the method for managing compressed moving image data as described above, images are not managed in units of images (frames or fields) having variable capacities as in the prior art, but have fixed capacities. It is managed in block units. Furthermore, a still image is included in a plurality of images constituting a moving image before compression.
For an image to be reproduced as , image data of a reference image (reference image) in predictive coding is managed, for example, at a block position. Therefore, the desired image data and the necessary reference image (reference image) data are directly accessed without decompressing and decoding the compressed data (header).

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a method for managing compressed moving image data according to the present invention will be described below in detail with reference to the drawings. FIG.
Is an example of a management format when the present invention is applied to a disk medium. FIG. 2 is a diagram illustrating an example of managing still images in a management format. On the disk medium 11, information is recorded and reproduced in a unit of information usually called a block (12). Recording and reproduction management is performed in units of this block. The moving image data is data that has been compressed by predictive coding between images (frames or fields), so that its capacity is not a fixed amount, and one image data may be composed of a plurality of blocks. May have a plurality of image data.

The disk medium 11 is divided into a management information area 13 and a data information area 14. Image data and audio data are recorded in the data information area 14. The management information area 13 is divided into smaller units of information called records (management records 16). The management record 16 includes a management information name 17, a corresponding information block number (address) 18, and an information size 1
9, additional information 20 accompanying the management information, a frame offset 21, and the like are stored. The image data is managed by the management record 16 in units of blocks. Therefore, the image data and the audio data are continuously read from the data information area 14 with reference to the block number 18 and reproduced as a moving image.

As shown in FIGS. 1C and 2,
For an image to be a still image, the block number (address) of the image data of the reference image in predictive coding of the image is indicated by the address 18 of the management record 16. Further, the frame offset 21
Is a value indicating the difference between the number of frames between the image data of the reference image and the image in the predictive coding of the image for the image to be a still image. Frame offset 2
Reference numeral 1 denotes a frame offset necessary for reconstructing a still image from a compressed moving image, that is, a difference in the number of frames up to a reference image serving as a reference of an image (inter-frame) prediction-encoded image.

Further, as shown in FIGS. 1C and 2,
Constructs a moving image before compression , which is the target image for still images
For an image that is to be reproduced as a still image among a plurality of images to be reproduced , the block number (address) of the image data of the reference image in the predictive encoding of the image is designated as the management record
The index is designated by the address 18 of FIG. further,
The frame offset 21 is a value indicating a difference between the number of frames between the image data of the reference image and the image in the predictive coding of the image for the image to be a still image. The frame offset 21 is a frame offset necessary for reconstructing a still image from a compressed moving image, that is, a difference in the number of frames up to a reference image serving as a reference of an inter-image (frame) predictive-coded image. It is.

FIG. 4 is a flowchart showing a procedure for creating and recording a management record. At the time of recording and editing, when there is an image to be a still image, for example, when a highlight scene of a moving image is selected in advance and demoted as a still image, the management information for the still image (the management record 16) Is created in advance and written in the management information area 13. That is, for a specific image of the original uncompressed moving image (this is a stage of collection of still images), an image to be reproduced as a still image at the time of reproduction after compression is marked (step 101), the management record 16 having the frame offset 21 is created as follows.

That is, at the time of compression by inter-picture prediction coding,
With respect to the marked image, the address (the number of blocks) of the reference image which is the reference of the inter-picture predictive coding is specified (Step 102). Further, the difference between the reference image and the frame of the image, for example, the image (the screen indicated by a circle P in FIG. 2) and the image three screens earlier in time (the screen indicated by a circle I in FIG. 2) are displayed. When inter prediction coding is used as a reference,
2 "," 3 "when the image is inter-picture predictive coded based on the image three screens later in time, and" 0 "when the image is an independent image (intra-image compressed image).
Is the value of the frame offset 21 (step 1
03). The management record 16 having the frame offset 21 and the number of blocks (position, block number 18) of the reference image of the image is recorded. (Step 104).
As described above, the moving image is inter-picture predictive coded, compressed, and recorded on the disk medium 11.

During normal playback, the disk medium 1
The image data and the audio data are sequentially read out from the data information area 14 corresponding to the designated number of blocks by referring to the management record in the management information area 13 of one, and are continuously reproduced as a moving image.

FIG. 5 is a flowchart showing a procedure of reproducing a still image using the management record 16. In particular, when reproducing as a still image, the management information area 15
The management record 16 (still image management record) is read out and interpreted (step 201), and reading is performed from the block indicated by the block number 18 of the information. First, a still image starting from the block number 18 (this is a reference image serving as a reference) is decompressed (step 20).
2). Then, when the frame offset (19) is designated (that is, when the image is not an independent image compressed in an image but an inter-picture predictive coded image), a block is further read and a difference value (frame With reference to (offset), the corresponding still image is decompressed and displayed (steps 203 and 204). In this way, a still image can be reproduced from moving image data with good operability using the management record 16. Then, by repeating this still image reproduction, special reproduction such as slow reproduction and fast forward reproduction is performed.

In the case where an image to be a still image occurs at the time of reproduction, not at the time of recording / editing, for example, when the end user wants to reproduce and use a specific scene as a still image for his / her own taste, the above-mentioned case is adopted. Similarly to the processing at the time of recording and editing, the management record 16 having the frame offset 21 and the like may be created and used together with the management record group in the management information area 13.

Further, a CD is used as the information source 1 instead of the VTR.
A CD-ROM using a ROM player and a hard disk or memory instead of the disk recording / reproducing device 3
The method of managing compressed moving image data described above may be used for file management of a normal personal computer system having a player.

In the above embodiment, the block number (address) of the image data of the reference image in the predictive coding of the image is indicated by the address 18 of the management record 16 for the image to be a still image. However, the image to be a still image may be indexed by the address 18 of the management record 16.

[0017]

As described above in detail, the method of managing compressed moving image data according to the present invention is a method of managing compressed moving image data that has been subjected to inter-picture (frame or field) predictive coding. In addition to managing the moving image data in block units, for an image to be a still image, the position of the image data of the reference image and the position of the image data of the image in the predictive coding of the image are indicated. Management information (for example, management information in which the position of image data of a reference image is indicated by a block position and the position of image data of the image is indicated by the difference in the number of frames from the reference image) is provided and managed Therefore, for an image to be a still image, image data of a reference image (reference image) in predictive coding is managed, for example, at a block position. Therefore, the desired image data and the necessary reference image (reference image) data are directly accessed without decompressing and decoding the compressed data, and the moving image data is efficiently managed. (Still playback, slow playback, fast forward playback) is possible.

[0018]

As described above in detail, the method of managing compressed moving image data according to the present invention is a method of managing compressed moving image data that has been subjected to inter-picture (frame or field) predictive coding. Te, the moving image data as well as managed in block units, a plurality of constituting a moving image before compression
For images that you want to play back as still images ,
Management information indicating the position of the image data of the reference image and the position of the image data of the image in predictive encoding of the image (for example, the position of the image data of the reference image is indicated by the block position, and the image data of the image (Management information indicating the number of frames from the reference image) is provided to manage the position of the still image, so that the still image target image is a reference image (reference image) in predictive coding.
Is managed, for example, at the position of a block.
Therefore, the desired image data and the necessary reference image (reference image) data are directly accessed without decompressing and decoding the compressed data, and the moving image data is efficiently managed. (Still playback, slow playback, fast forward playback) is possible.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining an embodiment of a method for managing compressed moving image data according to the present invention, and is an example of a management format when it is applied to a disk medium.

FIG. 2 is a diagram illustrating an example of managing still images in a management format.

FIG. 3 is a configuration diagram of a recording / reproducing system.

FIG. 4 is a flowchart illustrating a procedure for creating and recording a management record.

FIG. 5 is a flowchart showing a procedure of still image reproduction using a management record.

FIG. 6 is a diagram showing a conventional example of still image reproduction using moving image data.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 VTR (information source) 2 Computer 3 Disk recording / reproducing apparatus 11 Disk medium 12 Signal block 13 Management information recording area 14 Main information area 16 Management record 18 Address 20 Additional information 21 Frame offset 104 Management for frame offset Step of recording a record 202 Step of expanding and decoding a reference image 203 Step of expanding and decoding a still image with reference to a frame offset

Claims (2)

(57) [Claims] 1. A predicted inter-coded image, a compressed management method of the moving image data, the moving image data as well as managed in block units, pressure
As a still image among multiple images that compose a video before reduction
The image to be reproduced is compressed and provided by providing management information indicating the position of the image data of the reference image and the position of the image data of the image in the predictive coding of the image. Video data management method. 2. The method according to claim 1, wherein the position of the image data of the reference image is indicated by the block position, and the position of the image data of the image is indicated by the difference in the number of frames from the reference image. The method of managing the compressed moving image data described above.