KR100226563B1 - Motion picture data decoding system - Google Patents

Abstract

According to the present invention, even in the case of a transmission error in which a code error cannot be corrected in the moving picture data decoding apparatus, the defective part of the picture can be smoothly corrected with respect to the surrounding picture.

By decoding a block in which a code error that cannot be corrected is replaced with a block image generated by a past motion vector determined based on a past frame image, the image due to a code error can be decoded regardless of whether there is a motion in decoding. The defect component can be smoothly corrected with respect to the surrounding image.

Description

Video data decoding device

1 is a block diagram showing the configuration of an embodiment of a moving picture data encoding apparatus of the present invention.

2 is a schematic diagram providing a description of its interframe motion prediction.

3 is a block diagram showing the configuration of an embodiment of a moving picture data decoding apparatus of the present invention.

4 is a schematic diagram for explaining the inter-frame motion prediction in the case where a block that cannot be miscorrected in the intra frame I1 is detected.

5 is a schematic diagram for providing a description of motion compensation by a motion vector.

6 is a schematic diagram for explaining the inter-frame motion prediction in the case where a block that cannot be miscorrected in the bidirectional frame B3 is detected.

Explanation of symbols for main parts of the drawings

DESCRIPTION OF SYMBOLS 1: Video data coding apparatus 20: Video data decoding apparatus

21: input terminal 22: buffer circuit

23: Code error detection / correction circuit 24: Demultiplexer circuit

25 variable length decoding circuit 26 inverse quantization circuit

27: discrete cosine inverse conversion circuit 28: frame data generation circuit

29: frame memory 30, 31, 33: switching circuit

32: motion vector memory 34: motion compensation circuit

The present invention is most suitable for the case of reproducing moving picture data in a recording medium such as a compact disc, so to speak, a DAT (Digital Audio Tape Recorder) cassette, or a hard disc.

Conventionally, since a large amount of information is required to digitally record a moving picture, a recording medium having a very high continuous transfer rate is required to record / reproduce it.

For example, in the case of digitally recording a video signal by NTSC, recording / reproducing is performed using a video disc, so to speak.

However, in order to record moving image data having a generated amount of information as in the case of a video disc for a long time in a smaller recording medium (i.e., having a small amount of recording information), the video signal is encoded with high efficiency and recorded, and the read signal thereof efficiently. Means for decryption are indispensable.

In order to meet such demands, a high efficiency coding method of an image signal has been proposed, and one of them has a moving picture expert group (MPEG) method.

The MPEG system first performs a discrete cosine transform (DCT) in order to reduce the redundancy in the time axis direction, and then take the difference between the images in order to reduce the redundancy in the spatial axis direction.

However, in such an MPEG system, if a decoding device is provided at the beginning of the decoding, but an error that cannot be corrected by the error code correction capability of the decoding device occurs, there is a partial defect of the image there, and the image is left as it is. If you mark it, you will not see it.

There, generally, a mistake is corrected by inserting a past frame image into the defective portion as a partial image positioned at the same position as the defective image portion.

This method is effective for an image part without motion, but when there is motion, it is not possible to connect the flaw part and the peripheral part smoothly, and the flaw is conspicuous, and a good result is not necessarily obtained.

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above points, and it is an object of the present invention to propose a moving picture data decoding apparatus capable of reproducing an image closer to the original image even when a transmission error in which the decoding side cannot correct a code error occurs.

In order to solve such a problem, according to the present invention, in the moving picture data decoding apparatus 20 which decodes sequentially inputted moving picture data S21, the code error of the moving picture data S21 is corrected to reproduce the reproduced digital signal S22. And error detection / correction means 23 for outputting a misdetection detection signal S23 when a code error that cannot be corrected in the moving image data S21 is detected, and the reproduction digital signal S22 is moved. Demultiplex means 24 for separating into vector data S30 and image data S24, and predictive image generation for generating predictive image data S28 based on a misdetection detection signal S23 and motion vector data S30. Means (31, 32, 33, 34) and image synthesizing means (28, 29) for combining image data (S24) and predictive image data (S28). 34 is a code that cannot be mistaken and corrected in the moving image data S21. When the organosilane is detected on the basis of the motion vector (S31) corresponding to the moving picture data (S21) and to generate a predictive picture data (S28).

When decoding a moving image data S21, if a code error that cannot be corrected by mistake is detected, the image is generated from the predicted image data S28 generated based on the motion vector S31 corresponding to the moving image data S21. By changing the defects of the defects, even if the motion of the decoded moving image data S21 is large, defects due to code errors can be corrected without notice.

With reference to the following drawings, one embodiment of the present invention is described in detail.

1 shows a moving image data encoding apparatus (encoder) as a whole, and inputs the input image data S1 formed by converting an analog moving image signal into digital data from the input terminal 2. As shown in FIG. have.

At this time, the input image data S1 is composed of an intra frame I, a predictive frame P, and a bidirectional frame B as shown in FIG.

In this case, the intra frame I (I0, I1 ...) is a frame that is transmitted by data compression only within the frame, and the predictive frame P (P0, P1 ...) has no movement in one direction. The frame is predicted, and the bidirectional frame B (B0, B1, B2, B3 ...) is a frame in which motion is predicted in both directions.

The difference data generation circuit 3 inputs the input image data S1 from the input terminal 2 and the front frame image data S2 of the preceding frame stored in the frame memory 4 from the frame memory 4. ).

Here, the difference data generation circuit 3 obtains the difference between the input image data S1 and the previous frame image data S2 and generates the difference data S3 to generate a discrete cosine transform DCT (discrete cosine transform) circuit ( Output to 5).

The discrete cosine transform circuit 5 performs discrete cosine transform of the difference data S3 in units of small blocks using the two-dimensional correlation of the image, and quantizes the transformed data S4 obtained as a result of the quantization circuit Q (quantizer). It outputs to (6).

The quantization circuit 6 quantizes the transform data S4 to a predetermined quantization step size, and as a result, outputs the quantization data S5 obtained at the output terminal to the variable length coded VLC (variable length code) circuit 7.

Here, the variable length coding circuit 7 outputs to the multiplexer 8 variable length coded data S6 formed by variable length coding the quantization titer S5.

When the multiplexer 8 multiplexes the motion vector data S7 input from the encoder 9 to the variable length coded data S6, the multiplexer 8 transmits the data as the transmission data S8 via the buffer circuit 10.

The moving picture data encoding apparatus 1 also has a local decoding circuit system 11, which locally decodes the quantized data S5 transmitted as the transmission data S8 and supplies it to the frame memory 4.

When the local decoding circuit system 11 inputs the quantization data S5 to the inverse quantization circuit Q-1 and 12, the local decoding circuit system 11 dequantizes the quantization data S5 to a representative value and converts the quantization data S5 into inverse quantization data S10. The decoded transform data is decoded and supplied to the discrete cosine inverse transform (DCT-1) circuit 13.

The discrete cosine inverse conversion circuit 13 converts the inverse quantization data S10 decoded by the inverse quantization circuit 12 into the decoded image data S11 by inverse conversion processing with the discrete cosine conversion circuit 5. The data is output to the frame data generation circuit 14.

The frame data generation circuit 14 adds the frame image data S2 fed back from the frame memory 4 and the decoded image data S11 to restore the image data output as the transfer data S8, The frame memory 4 is stored in order.

When the moving image data encoding apparatus 1 obtains the motion vector by inputting the input image data S1 into the motion vector calculating circuit 18, the moving image data encoding apparatus 1 provides the motion compensation circuit 19 and the encoder 9 as the motion data S15. It is supposed to supply.

Here, the motion compensation circuit 19 reads the decoded data S16 from the frame memory 4 and transfers the motion prediction data S17 for motion compensation to the decoded data S16 to the frame memory 4. It is supposed to output.

The encoder 9 encodes the motion data S15 obtained by the motion vector calculation circuit 18 and outputs the motion data S15 to the multiplexer 8 as the motion vector data S7.

On the other hand, in Fig. 3, reference numeral 20 denotes a moving image data decoding apparatus (decoder) as a whole, and the reproduction data S21 read from the recording medium is coded from the input terminal 21 via the buffer circuit 22. Input to the error detection / correction circuit 23 is made.

Here, the code error detection / correction circuit 23 detects and corrects an error included in the image data in the reproduction data S21 and outputs the corrected reproduction image data S22 to the demultiplexer circuit 24. .

In addition, the code error detection / correction circuit 23 outputs a switching signal S23 for controlling the switching of the output image data when detecting a block in which code error cannot be corrected.

The demultiplexer circuit 24 separates the motion vector data from the reproduced image data S22, supplies it to the variable length decoding circuit (VLC-1) 25 as the differential image information data S24, and supplies the variable length encoding circuit ( The decoded image data S25 before being encoded in 7) is decoded and supplied to the inverse quantization circuit (Q-1) 26.

When the inverse quantization circuit 26 inversely quantizes the decoded image data S25 to a representative value and converts the inverse quantized data S26, the inverse quantized circuit 26 converts the inverse quantized circuit to the discrete cosine transform circuit 5. Is converted to the decoded image data S27 by the conversion processing and outputted to the frame data generation circuit 28.

The frame data generation circuit 28 adds the decoded data S27 to the motion compensation data S28 read out from the frame memory 29 to decode the decoded image data S29 and passes through the switching circuit 30. It outputs from the frame memory 29. FIG.

Here, the switching circuit 30 is controlled on / off by the switching signal S23 supplied from the code error detection and correction circuit 23, and the code error detection and correction circuit 23 can correct the reproduction data S21. If no code error is detected, the coded image data S29 is not stored in the frame memory 29.

When the demultiplexer circuit 24 separates the vector data from the reproduced image data S22, the demultiplexer circuit 24 supplies the current motion vector data S30 to the motion vector memory 32 via the switching circuit 31 as the switching circuit S30. It is supposed to be.

Here, the switching circuit 31 is a motion vector memory that holds motion vectors for the past three frames when the code error detection / correction circuit 23 cannot detect correctable code errors in the reproduction data S21. The current motion vector data S30 is supplied to 32.

The switching circuit 33 is controlled to switch to the switching signal S23 supplied from the code error detection / correction circuit 23, and code error which cannot be corrected by the reproduction data S21 of the current frame is not detected. In this case, the current motion vector S30 is supplied to the motion compensation circuit 34, or in the case where an uncorrectable code error is detected, the previous motion vector data S31 held in the motion vector memory 32. Is supplied to the motion compensation circuit 34.

The motion compensation circuit 34 inputs the existing frame data S32 in the frame memory 29 to generate a predicted block image based on the current or previous motion vector S30 or S31, and as the predicted picture data S33. It is stored in the frame memory 29.

When uncorrectable code error occurs, the frame memory 29 replaces and stores the predictive image data S33 generated by the preceding motion vector S31 as the image data of the corresponding block portion. It outputs as output image data S34.

In the above configuration, the moving picture data decoding apparatus 30 reads the reproduction data S21 sequentially from the recording medium, and inputs it to the code error detection and correction circuit 23 via the buffer circuit 22.

Here, when the code error detection and correction circuit 23 can correct the code error of the reproduction data S21, the moving picture data decoding apparatus 20 corrects the corrected image data S22 based on the error detection and correction code. ) Is supplied to the frame data generation circuit 28 via the demultiplexer circuit 24, the variable length coding circuit 25, the inverse quantization circuit 26, and the discrete cosine inverse conversion circuit 27.

The frame data generation circuit 28 adds the motion compensation data S28, which is formed by compensating for the intra frame 10 stored as the reference frame in the frame memory 29, and the decoded data S27 to decode the decoded data S29. ) Is supplied to the frame memory 29 via the switching circuit 30 to decode the image data of the predictive frame P0 and the bidirectional frames B0, B1 ... in order, thereby decoding the decoded image data ( S34).

On the other hand, the moving image data decoding apparatus 20 converts the switching signal S23 to the switching circuit S23 when the code error detection correction circuit 23 detects a block that cannot correct the code error of the reproduction data S21. 30 and 31 are output, and writing of the decoded image data S29 and the current motion vector S30 to the frame memory 29 and the motion vector memory 32 is stopped.

Furthermore, the moving picture data decoding apparatus 20 outputs the switching signal S23 to the motion vector memory 32 and the switching circuit 33 to move in the corresponding block of the past frame stored in the motion vector memory 32. The vector is read and supplied to the motion compensation circuit 34, and the predicted image data S23 predicted from the past motion vector is sent to the frame memory 29.

In addition, when the moving picture data decoding apparatus 20 detects a code error that cannot be corrected and corrected in the intra frame I1 as shown in FIG. 4, for example, the moving picture data decoding apparatus 20 stores the first video stored in the motion vector memory 32. FIG. And using the motion vector V (P0P1) between the second prediction frames P0 and P1, the predictive image data S33 of the intra frame I1 in the second prediction frame P1 is used for inter-frame prediction. To generate (figure 5).

The frame memory 29 replaces blocks whose defects are caused by uncorrectable codes in the predictive image data S33 generated by the motion compensation circuit 34 and outputs them as decoded image data S34.

As a result, when code error occurs in the conventional intra frame I, when code error occurs up to another frame, deterioration of image quality, which code error might propagate to other frames, can be effectively avoided even in these frames. have.

Similarly, when the video data decoding apparatus 20 detects a code error that cannot be mistaken and corrected in the second prediction frame P1, the motion vector V between the intra frame I0 and the first prediction frame P0 ( I0P0 is used to predict and replace the predicted image data S33 of the second prediction frame P1 in the intra frame I0 by inter-frame prediction.

Similarly, if a code error that cannot be miscorrected is detected in the fourth bidirectional frame B3 predicted in both the first and second prediction frames P0 and P1, the moving picture data decoding apparatus 20 Is a motion vector V (O0B1) between the intra frame I0 and the second bidirectional frame B1 and a motion vector V (O1B1) between the first prediction frame P0 and the second bidirectional frame B1. Next, the fourth bidirectional frame B3 is predicted and replaced in both the first and second prediction frames P0 and P1 using FIG. 6 (FIG. 6).

According to the above arrangement, in the moving picture data decoding apparatus which decodes and reproduces the moving picture data in units of blocks, when code error that cannot be mistaken is detected in the reproduced moving picture data, it is based on the motion vector in the past frame. By changing the image of the corresponding block in the predictive image generated in the past frame, the image quality can be further improved as compared with the conventional case where a defect due to code error is noticeable even when a large-motion image is decoded. .

In the above-described embodiment, the case where the image is predicted in units of frames has been described above. However, the present invention is not limited to this, but can also be applied to a system of predicting motion in units of fields.

In the above-described embodiment, the case of applying to a system using discrete cosine transform (DCT) and inter-frame motion prediction has been described above. However, the present invention is not limited thereto, and the inter-frame prediction process is performed. It is most suitable for the moving picture data decoding apparatus to be executed.

In the above-described embodiment again, the sequence of the configuration shown in FIG. 2, i.e., I0, B0, B1, P0, B2, B3, P1, B4, B5, I1, ... has been described above. The present invention can be applied not only to the present invention but also to the sequence in various combinations of the intra frame I, the predirectory frame P, and the bidirectional frame B. FIG.

In the above-described embodiment, the case where the motion vector memory 32 stores the motion vector for the past three frames has been described above. However, the present invention is not limited to this, but the case where the motion vector of the past multiple frames is stored. Widely applicable to

In the above-described embodiment, the case where code error occurs in a single frame has been described above. However, the present invention is not limited to this, and can also be applied to the case where code error occurs continuously.

For example, if a code error that cannot be miscorrected occurs in the predictive frame P1 and the intraframe I1, the motion vector V (I0, P0) between the intraframe I0 and the predictive frame P0 It is good to use.

As described above, according to the present invention, by decoding the moving picture data having an uncorrectable code error by converting it into predictive picture data generated by a corresponding motion vector, regardless of whether there is motion in decoding or not, Defects in the image can be smoothly corrected with respect to the surrounding image.

Claims (1)

In a moving picture decoding apparatus for decoding moving picture data sequentially inputted, a code error of the moving picture data is corrected to output a reproduced digital signal, and a code error that cannot be mistaken and corrected in the moving picture data is detected and detected. Error detection / correction means for outputting a signal, demultiplexing means for separating the reproduced digital signal into motion vector data and image data, and predictive image generation means for generating predictive image data based on the error detection signal and the motion vector data. And image synthesizing means for synthesizing the image data and the predictive image data, wherein the predictive image generating means corresponds to the moving image data when a code error that cannot be error-corrected is detected in the moving image data. Generate predictive image data based on motion vectors And a moving picture data decoding apparatus.