JP3338183B2 - 3D video decoding device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a three-dimensional video decoding apparatus for decoding a plurality of compressed image data.

[0002]

2. Description of the Related Art Various methods have been devised as methods for creating a stereoscopic image. The most common method is a method in which an image for a left eye and an image for a right eye are alternately displayed on an image output device such as a television, and shutter glasses such as a liquid crystal shutter are used. This method utilizes the binocular parallax of a human, and when creating a stereoscopic image using this method, two cameras are installed at the position of the human eye and each image is recorded. A method of alternately recording on a medium is adopted. As a display method of these, images of an image output device such as a television are interlaced, images are alternately displayed left and right for each field or frame, and set at the position of the human eye in accordance with the switching. This is realized by switching the left and right of the shutter.

In a three-dimensional image reproducing method called a lenticular lens method, an image is photographed from many directions and the photographed image is projected from the same arrangement as at the time of photographing. In addition, it is possible to provide a three-dimensional image without a sense of discomfort.

[0004] On the other hand, a coding system for digital moving pictures has been remarkably developed in recent years.
l MPEG (Moving Picture Image Coding Expe) standardized by the Standard Organization: International Organization for Standardization
(rts Group: ISO11172) compression technology is widely used in many fields. This adopts a predictive coding method, and for a digital moving image, first, one image unit (for example, one field) is compressed and encoded within a unit of several to more than ten fields or frames,
The other image to be compression-encoded is an encoding method of compressing by using difference and motion compensation with reference to the image data after decoding.

[0005] In the encoding method using the above-mentioned compression technique,
Intra-frame coded image (this image is called an I picture)
And an inter-frame prediction coded image (this image is called a P picture) and a bidirectional prediction coded image (this image is called a B picture). Can restore the original image data only with its own decoded data, but the rest of the P-pictures and B-pictures need a reference image in addition to their own decoded results to restore the original image data. Become.

Therefore, the decoding order of each picture and its display order are different. This is shown in FIG. As shown in FIG. 4, when the order in which encoded data is read from the recording medium and decoded is I ₂ , B ₀ , B ₁ , P ₅ , B ₃ , and B ₄ , the display order in which the reproduced image is output is B ₀ , B ₁ , I
₂ , B ₃ , B ₄ , and P ₅ . Here, the subscript number indicates the display order. This difference in order is due to the fact that P and B pictures require reference images for their restoration. In FIG. 4, arrows indicate which pictures are used as reference pictures. The image data of the P picture is restored by adding the decoding result of the P picture and the display image data of the preceding I picture. The image data of the B picture is restored by adding both the preceding I picture or P picture and the subsequent I picture or P picture to the decoding result of the B picture as a reference image. On the other hand, the I picture has no reference image, and can restore the display image data only by the decoding result of its own compression-encoded data.

[0007]

In a three-dimensional video decoding apparatus, if a data reading error or a calculation error due to a disturbance occurs and decoding of the compressed image data becomes impossible, the decoding of the image part is performed. Data becomes indeterminate,
It becomes impossible to continue the decoding process thereafter. In the three-dimensional moving image reproducing apparatus, when at least one image cannot be reproduced, the other remaining images are reproduced, but the three-dimensional image is destroyed. In particular, when the compressed image data is recorded alternately on the left and right on one track, there is a problem that it is difficult to deal with an undecodable state due to either error.

The present invention has been made in view of such circumstances, and can minimize damage when decoding becomes impossible and can continuously output a reproduced image. It is an object to provide a decoding device.

[0009]

According to a first aspect of the present invention, there is provided a three-dimensional video decoding apparatus for decoding a plurality of compressed image data and outputting a plurality of image data. Detecting means for detecting whether or not decoding of the compressed image data is possible, and when the detecting means detects that decoding is impossible, temporarily sets all output image data to predetermined image data and detects the inability to decode. And control means for controlling to output decoded image data of the compressed image data which can be decoded immediately after the decoding.

A stereoscopic video decoding apparatus according to a second aspect of the present invention is characterized in that, in the first aspect, the predictive encoding method is used for compressing the image data, and the immediately decodable compressed image data is It is a field or intra-frame coded compressed image data.

[0011]

According to the stereoscopic video decoding apparatus of the present invention, when at least one piece of compressed image data cannot be decoded, the output of all image data is temporarily set as an initialization image, and Immediately output the decodable image data.
Therefore, the effect of the inability to decode is given only for a short period immediately after the inability to decode, and thereafter the decoding operation is performed normally.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be specifically described with reference to the drawings showing the embodiments.

FIG. 1 is a block diagram showing a configuration of a three-dimensional moving image reproducing apparatus according to an embodiment of the present invention. In the following embodiments, in order to facilitate understanding of the contents of the present invention, a case of basic two-channel image data will be described. However, the present invention can be applied to a case of image data of three or more channels. Of course.

In FIG. 1, reference numeral 1 denotes a recording medium for recording data obtained by compressing and encoding a three-dimensional moving image. As the recording medium 1, any type of recording medium such as a disk, a tape, and a memory can be used. In the case where communication is used, this portion is not a recording medium but a data transmission from a communication path. It may be a receiving receiver. Reference numeral 2 denotes a reading device that reads out compressed image data (compression-coded data) recorded on the recording medium 1,
The reading device 2 outputs the read compressed image data to the system controller (CPU) 3. The system controller 3 divides the input compressed image data into right-eye and left-eye images, outputs the right-eye compressed image data to the right-eye decoding device 4R, and converts the left-eye compressed image data into the left-eye decoding device. Output to 4L. Each of the decoding devices 4R and 4L decodes the right-eye and left-eye compressed image data in response to a trigger from the system controller 3, and converts the decoded original image data into the corresponding right-eye image output circuit 5R and left-eye image output circuit 5R. To the image output circuit 5L. The decoding devices 4R and 4L temporarily store the compressed image data sent from the system controller 3 and temporarily store the decoded image data that has not been output to the image output circuits 5R and 5L. Buffer memories 6R and 6L are connected.

Next, the operation will be described. In FIG. 1, a solid line indicates a flow of image data, and a broken line indicates a flow of a control signal.

First, the normal operation will be described. The compressed image data recorded on the recording medium 1 is read by the reading device 2 and input to the system controller 3. In the system controller 3, the input compressed image data is divided into right-eye and left-eye compressed image data, and right-eye and left-eye compressed image data are output to the decoding devices 4R and 4L, respectively. The compressed image data input to each of the decoding devices 4R and 4L is temporarily stored in the buffer memories 6R and 6L. Each decryption device
In 4R and 4L, the compressed image data read from the buffer memories 6R and 6L is decoded. The decoded image data for display is sent to the image output circuits 5R and 5L and output to the outside.

Next, the operation when an error occurs during decoding in the decoding device 4R or 4L will be described. When an arithmetic error occurs during decoding, the decoding device 4R or 4L outputs a control signal aR or aL for notifying the system controller 3 of the occurrence of the error. The system controller 3 sends the control signal aR from one of the decoding devices 4R and 4L.
Or, when aL is input, decoding is interrupted, initialization of internal registers and buffer memories 6R and 6L, and image output circuit 5
Control signal b for instructing output of the initialization image to R and 5L
R and bL are output to each of the decoding devices 4R and 4L. The initialization image here is generally a blue background, a black background, or the like, but may be a still image prepared in the buffer memories 6R and 6L in advance. System controller 3
Keeps receiving the compressed image data from the reading device 2, but stops transferring the input compressed image data to the decoding devices 4R and 4L. And the system controller 3
Retrieves data that can be decoded again (I-picture compressed image data in the MPEG system) from the compressed image data input from the reading device 2 and transfers the compressed image data to the decoding devices 4R and 4L at the search timing. At the same time, control signals bR and bL for starting decoding are output.

An example of a program process performed by the system controller 3 for realizing the above process will be described. Also in the following description, the image data is assumed to be two for the right eye and the left eye, and the initial image is a blue back.

FIG. 2 is a flowchart showing a processing procedure of the compressed image data from the reading device 2. The system controller 3 analyzes the read information of the header area from the reading device 2 (step S1), and determines whether the compressed image data is left-eye data (step S2). If it is the left-eye compressed image data, it is determined whether or not an error flag to be set when a decoding error has occurred is 0 (step S3). If the error flag is 0, the left-eye compressed image data is transferred to the decoding device 4L (step S4) and the process returns. If the error flag is not 0, it is determined whether or not the image from the reading device 2 is an I picture (step S).
5). If the picture is an I picture, the L standby flag to be set when decoding of the left-eye compressed image data is resumed is set to 1 (step S6), and the process proceeds to step S4.
If it is not an I picture, the process returns.

If it is determined in step S2 that the image data is not compressed image data for the left eye, that is, if the image data is compressed image data for the right eye, it is determined whether or not the error flag is 0 (step S7). If the error flag is 0, the right-eye compressed image data is transferred to the decoding device 4R (step S8), and the process returns. If the error flag is not 0, it is determined whether or not the image from the reading device 2 is an I picture (step S9). If the picture is an I-picture, the R standby flag to be set when decoding of the right-eye compressed image data is restarted is set to 1 (step S10), and the process proceeds to step S8. If it is not an I picture, the process returns.

FIG. 3 is a flowchart showing a processing procedure when a control signal is generated from the decoding devices 4R and 4L to the system controller 3. First, it is determined whether a left-eye decoding error has occurred (step S11). If a left-eye decoding error has not occurred, it is determined whether a right-eye decoding error has occurred (step S12). Step S11,
If a decoding error has occurred in any of S12, the error flag is set to 1 and the L standby flag and the R standby flag are reset to 0 (step S13). Then, the system controller 3 instructs both decoding devices 4R and 4L to stop decoding, initialize internal registers, and output a blue screen to the image output circuits 5R and 5L (step S14), and return. .

If a decoding error has not occurred in any of steps S11 and S12, it is determined whether or not the error flag is 1 (step S15). If the error flag is 1, it is determined whether the L standby flag and the R standby flag are each 1 (steps S16 and S16).
17). If the error flag is not 1 in step S15, if the L standby flag is not 1 in step S16, and if the R standby flag is not 1 in step S17, the process returns as it is. If the error flag is 1 and both standby flags are 1, the system controller 3 instructs both decoding devices 4R and 4L to resume decoding (step S18). Then, the error flag and both standby flags are reset to 0 (step S19), and the process returns.

The operation of the above two flowcharts is summarized as follows. When no decoding error has occurred, the system controller 3 performs header analysis (step S1), and continues to transfer the compressed image data to each of the decoding devices 4R and 4L. However, if a decoding error occurs in any of the decoding devices 4R and 4L, an error flag is set and both L and R standby flags are cleared to 0 (step S13). And
Instruct both decoding devices 4R and 4L to stop decoding, initialize internal registers, and output blue-back (Step S
14).

If the error flag is set (steps S3 and S7: NO), while the I picture is not detected (steps S5 and S9: NO), the system controller 3 sends the signals to the decoding devices 4R and 4L. Do not transfer compressed image data. When the left-eye and right-eye I-pictures are detected (steps S5 and S9: YES), both L and R standby flags are set (steps S6 and S10) and the transfer of the compressed image data is resumed (steps S4 and S8). ). And
If the error flag and both L and R standby flags are set (steps S15, S16, S17: YES), an instruction to start decoding is issued to both decoding devices 4R, 4L (step S1).
8) Reset all flags (step S1)
9).

[0025]

As described above, in the stereoscopic video decoding apparatus according to the present invention, when at least one of the compressed image data cannot be decoded, all the output image data are temporarily set as the initialization image. Since the immediately decodable image data is immediately output, the present invention is excellent in that damage when decoding becomes impossible can be minimized and a reproduced image can be continuously output. It has the effect.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a playback device using a stereoscopic video decoding device of the present invention.

FIG. 2 is a flowchart illustrating an example of a program process for processing compressed image data in the stereoscopic video decoding device according to the present invention.

FIG. 3 is a flowchart showing an example of a program process for a process at the time of a decoding error in the stereoscopic video decoding device of the present invention.

FIG. 4 is a schematic diagram showing a decoding order and a display order of an image by a compression technique using a predictive coding method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Recording medium 2 Reading device 3 System controller (CPU) 4R, 4L Decoding device 5R, 5L Image output circuit 6R, 6L Buffer memory

Claims (2)

(57) [Claims] 1. A stereoscopic video decoding apparatus which decodes a plurality of compressed image data and outputs a plurality of image data, wherein a detecting means for detecting whether or not the compressed image data can be decoded, and a decoding unit which cannot decode the compressed image data. When the detection means detects, the output image data is temporarily set to predetermined image data, and the decoded image data obtained by decoding the decodable compressed image data immediately after the detection of undecoding is output. A stereoscopic video decoding device, comprising: 2. The method according to claim 1, wherein a predictive coding method is used for compressing the image data, and the immediately decodable compressed image data is field or intra-frame coded compressed image data. An apparatus for decoding a stereoscopic video according to any one of the preceding claims.