JP2006025105A - Moving picture reproducing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize high-speed reproduction with which smooth motion of even moving picture data of a moving picture encoding system using in-frame and inter-frame correlation can be reproduced. <P>SOLUTION: The moving picture data are decoded by making a choice between a normal decoding means of performing decoding processing according to a normal moving picture encoding system and a simplified encoding means of performing simplified encoding processing of the moving picture encoding system according to a reproduction speed inputted to a reproduction speed input part 1 and the bit rate of the moving picture data. For example, when the reproduction speed is less than a specified threshold, a reconversion part 4, a filter processing part 7, and an inter-frame predictive image generation part 5 are selected as normal decoding means or when the reproduction speed is not less than the specified threshold, at least a simple reconversion part 11 for a low bit rate, at least a simple inter-frame predictive image generation part 12 for an intermediate bit rate, or at least a simple filter processing part 8 for a high bit rate is selected as the simple decoding means to perform decoding processing. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a moving image playback apparatus, and more particularly, to a moving image playback apparatus having a high-speed playback function for encoded moving images.

  Japanese Patent Publication No. 6-28446, “Reproduction Method of Compressed Recorded Image” of Japanese Patent Application Laid-Open No. 6-28446 discloses a conventional technique for realizing high-speed reproduction in a moving image encoding method using intra-frame and inter-frame correlation such as MPEG. There is technology. FIG. 8 shows a block configuration of a moving picture reproducing apparatus using the technique of Patent Document 1 as a conventional technique.

  8, 2 is a variable length code decoding unit that decodes encoded data, 3 is an inverse quantization unit that dequantizes the output of the variable length code decoding unit 2, and 4 is inverse quantization. Inverse conversion unit 5 that converts the output of unit 3 into a differential image, 5 performs inter-frame prediction based on the accumulated decoded moving image, and generates a predicted image, and 6 indicates decoding in the frame. An intra-frame prediction image generation unit that performs intra-frame prediction based on a completed image and generates a prediction image; and 7, a filter process for removing coding distortion such as block distortion on a composite image of the difference image and the prediction image 9 is a frame memory for accumulating the generated decoded image, 10a is an output selector switch for switching the output destination of the input data, and 13 is based on the reproduction speed information S designated from the outside. A decoding control unit for controlling the playback speed of the image reproducing apparatus 30.

The normal playback operation of the moving image playback device 30 using this technology is as follows.
(Step S10)
The encoded data to be reproduced is sequentially input to the variable length code decoding unit 2, and the variable length code is decoded.
(Step S20)
According to the designated reproduction speed information S, the decoding control unit 13 controls the variable length decoding control unit 2 as follows.
If the playback type is high-speed playback (S> 1) and the frame type decoded by the variable-length code decoding unit 2 is other than the I frame, the decoding control unit 2 Control to stop output.
In cases other than the above, that is, high-speed playback (S> 1) and the frame type is I frame, and normal playback that is not high-speed playback (S ≦ 1), the variable-length code decoding unit 2 The data decoded at is controlled so as to be output to the dequantization unit 3 and others for each type.
(Step S30)
The output changeover switch 10a is controlled according to the prediction mode decoded by the variable length code decoding unit 2. That is, when the prediction mode of the encoded data being decoded is inter-frame prediction, the prediction image is generated to the inter-frame prediction image generation unit 5, and when the prediction mode is intra-frame prediction, the prediction image is generated to the intra-frame prediction image generation unit 6. An image necessary for generation is supplied from the frame memory 9, and a predicted image is generated.
(Step S40)
Data relating to the difference image decoded by the variable length code decoding unit 2 is subjected to inverse quantization in the inverse quantization unit 3 and inverse transformation in the inverse transformation unit 4 to become a difference image.
(Step S50)
The prediction image and the difference image generated in steps S30 and S40 are combined, and the filter processing unit 7 performs filter processing for removing the coding distortion, thereby generating a decoded image.
(Step S60)
The generated decoded image is stored in the frame memory 9 and output as a reproduced image at a predetermined reproduction time.
As described above, in the technology, when performing high-speed reproduction, only high-speed reproduction is realized by selecting only I frames using only intra-frame correlation and performing intermittent reproduction.
Japanese Patent Publication No. 6-28446

  However, normally, I frames that use only intra-frame correlation are often encoded with a frequency of about one frame per ten frames. For example, double-speed reproduction is realized using the above-described technique as high-speed reproduction. In this case, only a few frames are displayed per second, and there is a problem that smooth motion cannot be reproduced.

  The present invention has been made to solve such a problem, and an object of the present invention is to make it possible to reproduce smooth motion even in high-speed playback.

A first technical means is a moving image reproducing apparatus for reproducing moving image data encoded using a predetermined moving image encoding method.
Two types of decoding: moving picture decoding means for decoding moving picture data in accordance with the predetermined moving picture encoding method and simplified moving picture decoding means for performing simple decoding processing that simplifies the predetermined moving picture encoding method And a playback speed control means for controlling the playback speed and selecting the decoding means based on the designated playback speed,
The playback speed control means selects the moving picture decoding means as the decoding means when the designated playback speed is less than a predetermined first threshold,
When the designated playback speed is equal to or higher than a predetermined first threshold, the simple video decoding means is selected as the decoding means,
The moving image data is decoded by the selected decoding means.

The second technical means is a moving image reproduction apparatus for reproducing moving image data encoded using a predetermined moving image encoding method.
Two types of decoding: moving picture decoding means for decoding moving picture data in accordance with the predetermined moving picture encoding method and simplified moving picture decoding means for performing simple decoding processing that simplifies the predetermined moving picture encoding method And a playback speed control means for controlling the playback speed and selecting the decoding means based on the specified playback speed and additional information related to the moving image data to be decoded.
The playback speed control means selects one of the moving picture decoding means and the simplified moving picture decoding means based on the additional information regarding the moving picture data to be decoded,
The moving image data is decoded by the selected decoding means.

A third technical means is the moving picture reproduction apparatus according to the second technical means,
The predetermined moving image coding method is a moving image coding method in which a frame is divided into a plurality of blocks and coding is performed for each block, and the additional information indicates a position in a frame of a block to be decoded. Information to show
The playback speed control means, based on the additional information, when the distance from the center of the frame to the block is less than a predetermined second threshold, selects the moving picture decoding means as the decoding means,
When the distance from the center of the frame to the block is equal to or greater than a predetermined second threshold, the simplified moving image decoding unit is selected as the decoding unit.

A fourth technical means is the moving picture reproducing apparatus according to the second technical means,
The predetermined video encoding scheme is a video encoding scheme using inter-frame prediction, and the additional information is a magnitude of a motion vector used for inter-frame prediction,
The playback speed control means selects the moving picture decoding means as the decoding means when the magnitude of the motion vector is equal to or greater than a predetermined third threshold based on the additional information,
When the magnitude of the motion vector is less than a predetermined third threshold, the simplified moving picture decoding means is selected as the decoding means.

A fifth technical means is the moving image reproduction apparatus according to the second technical means,
The predetermined moving image encoding method is a moving image encoding method using intra-frame prediction and inter-frame prediction, and the additional information is a prediction method applied to moving image data,
The playback speed control means selects the moving picture decoding means as the decoding means when the prediction method is intra-frame prediction based on the additional information,
When the prediction method is inter-frame prediction, the simple moving picture decoding means is selected as the decoding means.

Sixth technical means is the moving picture reproducing apparatus according to any one of the first to fifth technical means,
The decoding means includes a filtering process for removing coding distortion.

Seventh technical means is the moving picture reproducing apparatus according to any one of the first to fifth technical means,
The decoding means includes an inverse transformation process for generating a difference image.

The eighth technical means is the moving picture reproducing apparatus according to any one of the first to fifth technical means,
The decoding means includes an inter-frame prediction image generation process.

According to a ninth technical means, in the moving image reproduction apparatus for reproducing moving image data encoded using a predetermined moving image encoding method,
Decoding means for decoding moving image data, reproduction speed control means for controlling the reproduction speed and selecting the decoding means based on the designated reproduction speed and the bit rate of the moving image data to be decoded; With
As the decoding means, filter processing means for removing coding distortion in accordance with the predetermined moving picture coding system;
Simple filter processing means for performing coding distortion removal simplified than the filter processing means;
Inverse transform processing means for generating a difference image according to the predetermined moving image encoding method;
Simple inverse transformation processing means for performing an inverse transformation simplified than the inverse transformation processing means,
The reproduction speed control means selects the filter processing means and the inverse conversion means as the decoding means when the designated reproduction speed is less than a predetermined fourth threshold,
When the designated playback speed is equal to or higher than the predetermined fourth threshold and the bit rate of the moving image data to be decoded is lower than the predetermined fifth threshold, at least the decoding means Select the simple reverse conversion means instead of the reverse conversion means,
When the designated playback speed is equal to or higher than the predetermined fourth threshold and the bit rate of the moving image data to be decoded is equal to or higher than the predetermined fifth threshold, Select the simple filter processing means instead of the filter processing means,
The moving image data is decoded by the selected decoding means.

A tenth technical means is a moving picture reproducing apparatus for reproducing moving picture data encoded by using a predetermined moving picture encoding method.
Decoding means for decoding moving image data, reproduction speed control means for controlling the reproduction speed and selecting the decoding means based on the designated reproduction speed and the bit rate of the moving image data to be decoded; With
As the decoding means, filter processing means for removing coding distortion in accordance with the predetermined moving picture coding system;
Simple filter processing means for performing coding distortion removal simplified than the filter processing means;
Inverse transform processing means for generating a difference image according to the predetermined moving image encoding method;
Simple inverse transformation processing means for performing inverse transformation more simplified than the inverse transformation processing means;
An inter-frame prediction image generating means for generating an inter-frame prediction image according to the predetermined moving image encoding method;
Simple inter-frame prediction image generation means for performing inter-frame prediction more simplified than the inter-frame prediction image generation means,
The playback speed control means selects the filter processing means, the inverse transform means, and the inter-frame predicted image generation means as the decoding means when the designated playback speed is less than a predetermined sixth threshold. ,
When the designated playback speed is equal to or higher than a predetermined sixth threshold and the bit rate of the moving image data to be decoded is lower than the predetermined seventh threshold, at least the decoding means Select the simple reverse conversion means instead of the reverse conversion means,
When the designated playback speed is equal to or higher than a predetermined sixth threshold, and the bit rate of the moving image data to be decoded is equal to or higher than the predetermined seventh threshold and lower than the predetermined eighth threshold For the decoding unit, at least the inter-frame prediction image generation unit is selected instead of the inter-frame prediction image generation unit,
When the designated playback speed is equal to or higher than a predetermined sixth threshold and the bit rate of the moving image data to be decoded is equal to or higher than the predetermined eighth threshold, Select the simple filter processing means instead of the filter processing means,
The moving image data is decoded by the selected decoding means.

The eleventh technical means is a moving image reproducing apparatus for reproducing moving image data encoded using a predetermined moving image encoding method.
Decoding means for performing decoding processing of moving image data, playback speed control and decoding based on a designated reproduction speed, a bit rate of moving image data to be decoded, and a size of a motion vector used for inter-frame prediction Replay speed control means for selecting the means,
As the decoding means, filter processing means for removing coding distortion in accordance with the predetermined moving picture coding system;
Simple filter processing means for performing coding distortion removal simplified than the filter processing means;
Inverse transform processing means for generating a difference image according to the predetermined moving image encoding method;
Simple inverse transformation processing means for performing inverse transformation more simplified than the inverse transformation processing means;
An inter-frame prediction image generating means for generating an inter-frame prediction image according to the predetermined moving image encoding method;
Simple inter-frame prediction image generation means for performing inter-frame prediction more simplified than the inter-frame prediction image generation means,
The playback speed control means selects the filter processing means, the inverse transform means, and the inter-frame predicted image generation means as the decoding means when the designated playback speed is less than a predetermined ninth threshold. ,
When the designated playback speed is equal to or higher than a predetermined ninth threshold and the magnitude of the motion vector used for inter-frame prediction is less than the predetermined tenth threshold, at least as the decoding means, Select the simplified inter-frame prediction image generation means instead of the inter-frame prediction image generation means,
When the designated playback speed is equal to or greater than a predetermined ninth threshold, the magnitude of the motion vector used for inter-frame prediction is equal to or greater than the predetermined tenth threshold, and the moving image data to be decoded is If the bit rate is less than a predetermined eleventh threshold value, at least the simple inverse conversion means instead of the inverse conversion means is selected as the decoding means,
When the designated playback speed is equal to or greater than a predetermined ninth threshold, the magnitude of the motion vector used for inter-frame prediction is equal to or greater than the predetermined tenth threshold, and the moving image data to be decoded is If the bit rate is greater than or equal to a predetermined eleventh threshold, select at least the simple filter processing means instead of the filter processing means as the decoding means,
The moving image data is decoded by the selected decoding means.

  According to the moving picture reproducing apparatus according to the present invention constituted by each technical means as described above, a high-speed smooth movement is possible regardless of the encoding frequency of the I frame using only the inter-frame correlation during the high-speed reproduction. Reproduction can be realized.

(Embodiment 1)
Embodiments of a moving image playback apparatus according to the present invention will be described below with reference to the drawings.
FIG. 1 is a block diagram of a moving image reproducing apparatus according to Embodiment 1 of the present invention. In the moving picture reproduction apparatus 20 shown in FIG. 1, reference numeral 1 denotes a reproduction speed control unit that performs control for the main moving picture reproduction apparatus 20 to operate at a predetermined reproduction speed based on reproduction speed information S designated from the outside. A variable length code decoding unit that decodes encoded data, 3 is an inverse quantization unit that inversely quantizes the output of the variable length code decoding unit 2, and 4 is an inverse conversion unit that converts the output of the inverse quantization unit 3 into a differential image. 5 performs inter-frame prediction based on the accumulated decoded moving image and generates a predicted image, and 6 performs intra-frame prediction based on the decoded image in the frame. An intra-frame predicted image generating unit that generates an image, 7 is a filter processing unit that performs a filter process for removing coding distortion such as block distortion on a composite image of the difference image and the predicted image, and 8 is a filter processing unit 7 Is different A simple filter processing unit that performs filter processing for removing coding distortion by an easy method, 9 is a frame memory for storing the generated decoded image, and 10a and 10b are output changeover switches for switching the output destination of input data. is there.

In the moving picture reproduction apparatus 20 of FIG. 1, an image from which coding distortion has been removed by the filter processing unit 7 or the simple filter processing unit 8 is stored in the frame memory 9 and used for subsequent inter-frame prediction. However, as shown in the moving image reproducing apparatus 21 in FIG. 2, an image before encoding distortion removal, that is, a composite image of the difference image and the predicted image is stored in the frame memory 9 by the moving image encoding method to be handled. However, at the time of reproduction output, the filter processing unit 7 or the simple filter processing unit 8 may remove the encoding distortion and reproduce. FIG. 2 is a block diagram of a moving picture reproducing apparatus according to another embodiment of the first embodiment of the present invention.
Further, the inverse quantization unit 3, the inverse transform unit 4, the inter-frame prediction image generation unit 5, and the intra-frame prediction image generation unit 6 may also be omitted depending on the moving image encoding method to be handled.

  Next, the operation of the moving image playback apparatus 20 in the present embodiment shown in FIG. 1 will be described using the operation flowchart of FIG. FIG. 7 is an operation flowchart for explaining the operation of the moving image reproduction apparatus 20 according to the first embodiment of the present invention. In the following description, it is assumed that the limit values of the reproduction speed that can be processed by the filter processing unit 7 and the simple filter processing unit 8 are Smax and S′max, respectively, and Smax <S′max. That is, the process in the simple filter processing unit 8 can be performed at a higher speed than the process in the filter processing unit 7.

The operation will be described below with reference to the operation flow diagram of FIG.
(Step S1)
The reproduction speed control means 1 controls the output changeover switch 10b based on the inputted reproduction speed information S. The switching determination of the output changeover switch 10b for switching between the filter processing unit 7 and the simple filter processing unit 8 is performed as follows using a predetermined threshold TH (≦ Smax) according to the designated reproduction speed information S.
When S <TH, the filter processing unit 7 is selected as the output destination (step S1-a).
When S ≧ TH, the simple filter processing unit 8 is selected as the output destination (step S1-b).

(Step S2)
The encoded data to be reproduced is sequentially input to the variable length code decoding unit 2, and the variable length code is decoded. The decoded data is output to the inverse quantization unit 3 and others for each type.
(Step S3)
The output changeover switch 10a is controlled according to the prediction mode decoded by the variable length code decoding unit 2. That is, when the prediction mode of the encoded data being decoded is inter-frame prediction, the prediction image is generated to the inter-frame prediction image generation unit 5, and when the prediction mode is intra-frame prediction, the prediction image is generated to the intra-frame prediction image generation unit 6. An image necessary for generation is supplied from the frame memory 9, and a predicted image is generated.

(Step S4)
Data relating to the difference image decoded by the variable length code decoding unit 2 is subjected to inverse quantization in the inverse quantization unit 3 and inverse transformation in the inverse transformation unit 4 to become a difference image.
(Step S5)
The prediction image and the difference image respectively generated in step S3 and step S4 are combined, and filter processing for removing the coding distortion is performed in either the filter processing unit 7 or the simple filter processing unit 8 selected in step S1. And a decoded image is generated.
(Step S6)
The generated decoded image is temporarily stored in the frame memory 9 and output as a reproduction image at a predetermined reproduction time.
(Step S7)
The operations from step S1 to step S6 are repeated until decoding / reproduction output of the final frame is completed.

  With the operation as described above, the moving image playback apparatus 20 according to the present embodiment performs the filtering process at a filtering speed compatible with the playback speed information S. Therefore, all the normal playback and high speed playback are performed. Frame playback is realized according to the specified playback speed. Accordingly, since all frames are decoded even during high-speed playback, playback with smooth motion is possible. In the case of high-speed reproduction exceeding the predetermined threshold value TH described above, instead of the predetermined filter process of the moving image encoding method by the filter processing unit 7, a simple filter process with a small amount of calculation is performed for high-speed processing. Since the processing is switched to the simple filter processing unit 8 that performs the above, image degradation occurs.

  In addition, the moving image coding apparatus 20 according to the present embodiment, when the moving image coding method handles, the filter processing for removing the coding distortion requires an enormous amount of calculation compared to other decoding processing. Is particularly effective.

  Note that the switching control of the filter processing unit 7 / simple filter processing unit 8 in step S1 is not limited to the method described above, and is configured to switch according to the additional information N from the variable-length code decoding unit 2. It doesn't matter.

For example, when handling reproduction of moving images having different image sizes, the above Smax and S′max depend on the image size. That is, when the image size is N,
Smax = f (N)
S′max = f ′ (N)
And a function of N.
Note that f (N) and f ′ (N) are functions obtained by experiments.
f (N) = αN + β
f ′ (N) = α′N + β ′
Represented as: Here, α, β, α ′ and β ′ are constants.

So, for example,
TH = Smax = αN + β
As described above, if the switching control in step S1 is performed, the switching control can be performed at an optimum reproduction speed according to the image size to be handled by a simple process.
As a result, it is possible to avoid image quality deterioration at a relatively low playback speed. In the above description, the case where the image size is used as the additional information N has been described. However, for example, when playing back a moving image having a different frame rate, the same control may be performed with the frame rate as the additional information N. Is possible.

  Further, when the above-described image size is used, steps S1 to S6 are not repeated as shown in FIG. 7, but steps S2 to S6 are repeated depending on the moving picture encoding method to be handled. However, as a configuration in which the switching control of the filter processing unit 7 / simple filter processing unit 8 in step S1 is switched on a frame-by-frame basis, of course, a configuration in which steps S1 to S6 are repeated may be used.

As a different application example in the case where the switching control of the filter processing unit 7 / simple filter processing unit 8 is switched in frame units, the additional information N is not the image size but the frame number being decoded by the variable length code decoding unit 2 as the additional information N. A case where the additional information N is input to the reproduction speed control unit 1 and used will be described.
For example, when Smax = 1 and S′max = 3 as the limit values of the reproduction speed that can be processed by the filter processing unit 7 and the simple filter processing unit 8, respectively,
TH = 1.5 + (N mod2)
Then, according to the even number / odd number of the frame number of the additional information N, the threshold value TH alternately changes to 1.5, 2.5, 1.5, 2.5,. 9

  Therefore, when the playback speed information S designated from the outside is normal playback (S = 1), the filter processing unit 7 is always selected, and when the playback speed information S is double speed playback (S = 2), it is alternately displayed every frame. In addition, the filter processing unit 7 and the simple filter processing unit 8 are selected, and the simple filter selection unit 8 is always selected in the case of triple speed reproduction (S = 3).

  By adopting such a configuration, it becomes possible to switch the filter processing step by step according to the reproduction speed information S. As a result, it is possible to minimize image quality degradation at a relatively low playback speed.

Further, when decoding processing is performed in units of rectangular blocks each composed of H pixels and V pixels in the horizontal and vertical directions, the switching control in step S1 may be configured to switch in units of blocks.
In this case, an identifier indicating the block position being decoded is input from the variable length code decoding unit 2 to the playback speed control unit 1 as additional information N. For example, by setting the threshold value TH to be large in an area at the center of the screen that is likely to attract attention during video playback, and setting the threshold value TH to be small in other areas, the filter processing unit 7 is always selected in the center of the screen, and always in other areas. The simple filter processing unit 8 is selected, and high-speed reproduction is possible while suppressing subjective image quality degradation of the user.

  Alternatively, if the magnitude of the motion vector used in inter-frame prediction is used as the additional information N, the threshold value TH is set to be large in a region with a large amount of attention gathered during video reproduction, and the threshold value TH is set to be small in other regions. The filter processing unit 7 is always selected in a region where the motion is large, and the simple filter processing unit 8 is always selected in the region where the motion is small, and similarly, high-speed reproduction is possible while suppressing the subjective image quality degradation of the user.

  Alternatively, the prediction mode is used as the additional information N, and the threshold TH is set large in the region using the intraframe prediction, and the threshold TH is set small in the region using the interframe prediction. The filter processing unit 7 is always selected, and the simple filter processing unit 8 is always selected in an area using inter-frame prediction, so that it is possible to suppress image quality deterioration in an area where intra-frame prediction that has a large influence on image quality is performed.

Next, the simple filter processing unit 8 will be described. In general, in the filter processing unit 7, when the pixel value P _fin (x, y) of the input image and the pixel value P _fout (x, y) of the output image at coordinates (x, y) are used, the following equation (1) ) Is performed.

Here, W _f (x, y, i, j) and m, n are filter coefficients and constants determined by the moving picture encoding method to be used.
Similarly, the simplified filter processing unit 8 performs simplified filter processing represented by the following equation (2) when the pixel value P ′ _fout (x, y) of the output image is used.

Here, m ′ and n ′ are constants that satisfy m ′ ≦ m and n ′ ≦ n. For example, when m = n = 3 and m ′ = n ′ = 1, the filter processing unit 7 requires 49 multiplications and 48 additions per pixel, but the simple filter processing unit 8 Each pixel can be processed with 9 multiplications and 8 additions.
Further, the filter coefficient W ′ _f (x, y, i, j) is a coefficient close to the characteristics of the filter processing in the filter processing unit 7 in advance by simulation or the like.

When m ′ = n ′ = 0 and W ′ _f (x, y, i, j) = 1,
P ′ _fout (x, y) = P _fin (x, y)
It becomes. In this case, the simple filter processing unit 8 may be omitted.

  As described above, in the moving image reproduction device 20 of the present embodiment, the amount of calculation required for decoding is reduced by switching between the filter processing unit 7 and the simple filter processing unit 8, and high-speed reproduction with smooth motion is achieved. Is possible. Note that the moving image playback device 21 shown in FIG. 2 is exactly the same as the moving image playback device 20 shown in FIG.

(Embodiment 2)
FIG. 3 is a block diagram of a moving image playback apparatus in Embodiment 2 of the present invention. In the moving image reproduction device 22 shown in FIG. 3, 11 is a simple inverse transform unit that generates a difference image by a simple method with a small amount of calculation different from the inverse transform unit 4, and 10c is an output for switching the output destination of input data. It is a changeover switch. The other elements are the same as those in the moving image reproduction apparatus 20 of the first embodiment shown in FIG. 1, and the same reference numerals as those in FIG. In the moving image reproduction device 22 shown in FIG. 3, the simple filter processing unit 8 and the output changeover switch 10b of the moving image reproduction device 20 of the first embodiment shown in FIG. The unit 11 and the output changeover switch 10c are provided.

  Next, the operation of the moving image playback device 22 in this embodiment shown in FIG. 3 will be described. The operation of the moving image reproduction device 22 of the present embodiment is the reverse of the switching control of the filter processing unit 7 / simple filter processing unit 8 in (Step S1) in the description of the operation of the moving image reproduction device 20 of the first embodiment. Except for the point that it is replaced with the switching control of the conversion unit 3 / simple reverse conversion unit 11, the operation is the same as that of the moving image reproduction apparatus 20 of the first embodiment, and detailed description thereof is omitted. Further, the switching control of the inverse transform unit 3 and the simple inverse transform unit 11 can be configured in units of frames or blocks, which is the same as that of the moving image reproduction apparatus 20 of the first embodiment.

  Note that the moving image reproduction device 22 of the present embodiment is particularly effective when the difference image generation processing by inverse transformation requires a huge amount of calculation compared to other decoding processing in the moving image encoding method to be handled. It is.

  Next, the simple inverse transform unit 11 will be described. In general, the inverse transform unit 3 performs inverse discrete cosine transform (IDCT) represented by the following equation (3) in the case of a moving image coding method such as MPEG.

P _diff (x, y) is a pixel value of a difference image generated by inverse transformation, F (i, j) is a DCT coefficient, and C (i, j) is a predetermined constant.
The simple inverse transform unit 11 performs simplification by using a human visual characteristic and considering the DCT coefficient of a high frequency component that is difficult to recognize image quality deterioration as 0. For example,
F (i, j) = 0: i ≧ 4, j ≧ 4
Then, the inverse transformation in the simple inverse transformation unit 11 is expressed by the following equation (4).

Note that P ′ _diff (x, y) is a pixel value of a difference image generated by inverse transformation.
By performing the simplification as described above, it is possible to perform simple reverse conversion with a reduced amount of calculation. In the above description, the case where the predetermined inverse transform is IDCT has been described as the moving image coding method, but the same method can be applied to other orthogonal transforms such as discrete Fourier transform, Haar transform, Hadamard transform, and the like. Is possible.

  As described above, in the moving image playback device 22 of the present embodiment, high-speed playback with smooth motion is achieved by reducing the amount of computation required for decoding by switching between the inverse transform unit 4 and the simple inverse transform unit 11. Is possible.

(Embodiment 3)
FIG. 4 is a block diagram of a moving image playback apparatus in Embodiment 3 of the present invention. In the moving image reproduction device 23 shown in FIG. 4, 12 is a simple inter-frame prediction image generation unit that generates an inter-frame prediction image by a simple method with a small amount of calculation different from the inter-frame prediction image generation unit 5. This is an output changeover switch for changing the output destination of input data. The other elements are the same as those in the moving image reproduction apparatus 20 of the first embodiment shown in FIG. 1, and the same reference numerals as those in FIG. In the moving picture reproduction device 23 shown in FIG. 4, the simple filter processing unit 8 and the output changeover switch 10b of the moving picture reproduction device 20 of the first embodiment shown in FIG. The prediction image generation unit 12 and the output changeover switch 10d are provided.

  Next, the operation of the moving image playback device 23 in the present embodiment shown in FIG. 4 will be described. Note that the operation of the moving image playback device 23 of the present embodiment is the same as the operation of the moving image playback device 20 of the first embodiment except that the switching control of the filter processing unit 7 / simple filter processing unit 8 in (Step S1) The operation is the same as that of the moving image playback apparatus 20 of the first embodiment except that it is replaced by switching control between the inter prediction image generation unit 5 and the simple inter frame prediction image generation unit 12, and detailed description thereof is omitted. In addition, the switching control of the inter-frame prediction image generation unit 5 and the simple inter-frame prediction image generation unit 12 can be configured in units of frames or blocks as in the moving image reproduction device 20 of the first embodiment. It is.

  Note that the moving image playback device 23 of the present embodiment is particularly effective when the inter-frame prediction image generation process requires a large amount of computation compared to other decoding processes in the moving image encoding method to be handled. It is.

Next, the simple inter-frame prediction image generation unit 12 will be described. In general, the relationship between the predicted image P _pred (x, y) at the coordinates (x, y) and the reference image P _ref (x ′, y ′) used for prediction is expressed by the following equation (5).

Here, (x ′, y ′) represents a non-integer precision coordinate value, and P _ref (x ′, y ′) is an interpolation using pixel values of neighboring pixels in the inter-frame predicted image generation unit 5. Thus, the following equation (6) is obtained.

here,
x ′ = X + x ₀ , y ′ = Y + y ₀
age,
X and Y are integer parts of x ′ and y ′,
x ₀ and y ₀ represent non-integer parts of x ′ and y ′, respectively.
W _I (x ₀ , y ₀ , i, j) and m, n are weighting factors and constants determined by the moving picture coding method to be used.

Similarly, in the simplified inter-frame prediction image generation unit 12, an interpolated image P ′ _ref (x ′, y ′) is obtained as the following equation (7).

Here, m ′ and n ′ are constants that satisfy m ′ ≦ m and n ′ ≦ n. For example, when m = n = 3 and m ′ = n ′ = 1, the inter-frame prediction image generation unit 5 requires 36 multiplications and 35 additions per pixel for calculation of the interpolation image. However, the simplified inter-frame prediction image generation unit 12 can perform processing by four multiplications and three additions per pixel. Further, the weighting factor W ′ _I (x ₀ , y ₀ , i, j) is determined in advance by a simulation or the like that is close to the interpolation characteristic in the inter-frame predicted image generation unit 4.
For example, when m ′ = n ′ = 1, as shown in the following equation (8):

Then, a predicted image is generated from the interpolated image P ′ _ref (x ′, y ′) obtained by linear interpolation of four neighboring pixels.

  As described above, in the moving image reproduction device 23 of the present embodiment, the motion amount is reduced by reducing the amount of calculation necessary for decoding by switching between the inter-frame predicted image generation unit 5 and the simple inter-frame prediction image generation unit 12. Smooth high-speed playback is possible.

(Embodiment 4)
FIG. 5 is a block diagram of a moving image playback apparatus in Embodiment 4 of the present invention. The moving image reproduction device 24 shown in FIG. 5 includes all the components of the moving image reproduction device 20 of the first embodiment and the moving image reproduction device 22 of the second embodiment.
In the moving image reproducing apparatuses 20 and 22 in the first and second embodiments, the characteristics of image quality deterioration during high-speed reproduction are different. In the moving image playback device 20 of the first embodiment, image quality degradation in a low bit rate moving image that is highly effective in removing the coding distortion by the filter processing occurs, and in the moving image playback device 22 of the second embodiment, high frequency components are generated. There is a tendency for image quality deterioration in high-frequency moving images with high frequency to be remarkable.

  On the other hand, in the moving image reproduction device 24 of the present embodiment, the switching between the filter processing unit 7 / simple filter processing unit 8 and the inverse transform unit 4 / simple inverse transform unit 11 is input encoded by the output selector switches 10b and 10c. It is characterized by suppressing deterioration in image quality during high-speed playback by performing adaptively according to data characteristics.

  Next, the operation of the moving image playback device 24 of this embodiment will be described. The basic operation is the same as that of the moving image playback apparatuses 20 and 22 of the first and second embodiments, and only the control operation of the playback speed control unit 1 will be described. In the following description, as in the case of the first embodiment, the predetermined threshold TH for the input reproduction speed information S is used, the bit rate of the encoded data is set as additional information N, and the predetermined threshold THr for additional information N is used. Is used. Note that the threshold value THr is determined in advance as an optimal value by simulation or the like.

(1) When S <TH The filter processing unit 7 and the inverse conversion unit 4 are selected as output destinations.
(2) When S ≧ TH (2.1) When N <THr The filter processing unit 7 and the simple inverse transform unit 11 are selected as output destinations, respectively.
(2.2) When N ≧ THr The simple filter processing unit 8 and the inverse conversion unit 4 are selected as output destinations.

By performing the control as described above, it is possible to suppress deterioration in image quality during high-speed playback.
In the above description, only one of the simple filter processing unit 8 and the simple inverse transform unit 11 is used. However, in the cases (2.1) and (2.2), at least, When the simple inverse conversion unit 11 is used instead of the inverse conversion unit 4 and the simple filter processing unit 8 is used instead of the filter processing unit 7 and high-speed reproduction is performed at a high reproduction speed that cannot be handled only by using one of them. Alternatively, both the simple filter processing unit 8 and the simple inverse transform unit 11 may be used at the same time.

  6 may be added to the simplified inter-frame prediction image generation unit 12 described in the third embodiment. FIG. 6 is a block diagram of a moving image reproducing apparatus according to another embodiment of the fourth embodiment of the present invention. In the case of the moving image reproducing device 25 shown in FIG. 6, for example, according to the bit rate N, the simplified inverse transform unit 11 is used for encoded data at a low bit rate, and between simplified frames is used for encoded data at a medium bit rate. The prediction image generation unit 12 can be configured to perform high-speed reproduction using the simple filter processing unit 8 with high-bit-rate encoded data.

  That is, as in the case of the moving image playback device 24 of FIG. 5, a predetermined threshold TH for the input playback speed information S is used, the bit rate of the encoded data is set as additional information N, and a predetermined threshold for the additional information N is set. Threshold values THr and THr ′ are used. The threshold values THr and THr ′ are determined in advance by simulation or the like.

(1) When S <TH The filter processing unit 7, the inverse transform unit 4, and the inter-frame predicted image generation unit 5 are selected as output destinations.
(2) When S ≧ TH (2.1) When N <THr The filter processing unit 7, the simple inverse transform unit 11, and the inter-frame predicted image generation unit 5 are selected as output destinations.
(2.2) When THr ≦ N <THr ′ The filter processing unit 8, the inverse transform unit 4, and the simple inter-frame prediction image generation unit 12 are selected as output destinations.
(2.3) When N ≧ THr ′ The simple filter processing unit 8, the inverse transform unit 4, and the inter-frame prediction image generation unit 5 are selected as output destinations.

  In the above description, only one of the simple filter processing unit 8, the simple inverse conversion unit 11, and the simple inter-frame prediction image generation unit 12 is used. However, the above (2.1), (2. 2.1) and (2.2.2), at least the simple inverse transform unit 11 instead of the inverse transform unit 4 and the simple inter-frame predicted image generation unit 12 instead of the inter-frame predicted image generation unit 5, respectively. If the simple filter processing unit 8 is used instead of the filter processing unit 7 and high-speed reproduction is performed at a high reproduction speed that cannot be dealt with only by using one of them, the simple filter processing unit 8 A plurality of the conversion unit 11 and the simplified inter-frame prediction image generation unit 12 may be used at the same time.

  Alternatively, the simplified inter-frame prediction image generation unit 12 is used in a region where the motion is small, the simple inverse transform unit 11 is used in the case of a low bit rate, and the simple inverse conversion unit 11 is used in a case of a high bit rate. The simple filter processing unit 8 may be configured to perform high-speed reproduction using each.

  That is, as in the case of the moving image playback device 24 of FIG. 5, a predetermined threshold TH for the input playback speed information S is used, the bit rate of the encoded data is set as additional information N, and a predetermined threshold for the additional information N is set. The threshold THr is used, and the magnitude of a motion vector used in inter-frame prediction is set as additional information N1, and a predetermined threshold THr1 for the additional information N1 is used. Note that optimum values for the thresholds THr and THr1 are determined in advance by simulation or the like.

(1) When S <TH The filter processing unit 7, the inverse transform unit 4, and the inter-frame predicted image generation unit 5 are selected as output destinations.
(2) When S ≧ TH (2.1) When N1 <THr1 The filter processing unit 7, the inverse transform unit 4, and the simplified inter-frame prediction image generation unit 12 are selected as output destinations.
(2.2) In the case of N1 ≧ THr1 (2.2.1) In the case of N <THr The filter processing unit 7, the simple inverse transformation unit 11, and the inter-frame prediction image generation unit 5 are selected as output destinations, respectively. .
(2.2.2) When N ≧ THr The simple filter processing unit 8, the inverse transform unit 4, and the inter-frame predicted image generation unit 5 are selected as output destinations.

  In the above description, only one of the simple filter processing unit 8, the simple inverse conversion unit 11, and the simple inter-frame prediction image generation unit 12 is used. However, the above (2.1), (2. 2.1) and (2.2.2), at least the inter-frame prediction image generation unit 12 instead of the inter-frame prediction image generation unit 5, and the simple inverse conversion unit 11 instead of the inverse conversion unit 4. If the simple filter processing unit 8 is used instead of the filter processing unit 7 and high-speed reproduction is performed at a high reproduction speed that cannot be dealt with only by using one of them, the simple filter processing unit 8 A plurality of the conversion unit 11 and the simplified inter-frame prediction image generation unit 12 may be used at the same time.

  As described above, in the moving image reproduction devices 24 and 25 of the present embodiment, it is possible to suppress image quality deterioration during high-speed reproduction by performing control according to the characteristics of the input encoded data.

It is a block diagram of the moving image reproducing device in Embodiment 1 of the present invention. It is a block diagram of the moving image reproducing device of another form of Embodiment 1 of this invention. It is a block diagram of the moving image reproducing device in Embodiment 2 of the present invention. It is a block diagram of the moving image reproducing device in Embodiment 3 of the present invention. It is a block diagram of the moving image reproducing device in Embodiment 4 of the present invention. It is a block diagram of the moving image reproducing device of another form of Embodiment 4 of this invention. It is an operation | movement flowchart for demonstrating operation | movement of the moving image reproducing device in Embodiment 1 of this invention. It is a block diagram of the moving image reproducing | regenerating apparatus in a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Playback speed control part, 2 ... Variable length code decoding part, 3 ... Inverse quantization part, 4 ... Inverse transformation part, 5 ... Inter-frame prediction image generation part, 6 ... Intra-frame prediction image generation part, 7 ... Filter process 8 is a simple filter processing unit, 9 is a frame memory, 10a, 10b, 10c, and 10d are output changeover switches, 11 is a simple inverse conversion unit, 12 is a simple inter-frame prediction image generation unit, and 13 is a decoding control unit. , 21, 22, 23, 24, 25, 30...

Claims (11)

In a moving image reproducing apparatus for reproducing moving image data encoded using a predetermined moving image encoding method,
Two types of decoding: moving picture decoding means for decoding moving picture data in accordance with the predetermined moving picture encoding method and simplified moving picture decoding means for performing simple decoding processing that simplifies the predetermined moving picture encoding method And a playback speed control means for controlling the playback speed and selecting the decoding means based on the designated playback speed,
The playback speed control means selects the moving picture decoding means as the decoding means when the designated playback speed is less than a predetermined first threshold,
When the designated playback speed is equal to or higher than a predetermined first threshold, the simple video decoding means is selected as the decoding means,
A moving picture reproducing apparatus, wherein a decoding process of moving picture data is performed by a selected decoding means. In a moving image reproducing apparatus for reproducing moving image data encoded using a predetermined moving image encoding method,
Two types of decoding: moving picture decoding means for decoding moving picture data in accordance with the predetermined moving picture encoding method and simplified moving picture decoding means for performing simple decoding processing that simplifies the predetermined moving picture encoding method And a playback speed control means for controlling the playback speed and selecting the decoding means based on the specified playback speed and additional information related to the moving image data to be decoded.
The playback speed control means selects one of the moving picture decoding means and the simplified moving picture decoding means based on the additional information regarding the moving picture data to be decoded,
A moving picture reproducing apparatus, wherein a decoding process of moving picture data is performed by a selected decoding means. The moving image reproducing apparatus according to claim 2,
The predetermined moving image coding method is a moving image coding method in which a frame is divided into a plurality of blocks and coding is performed for each block, and the additional information indicates a position in a frame of a block to be decoded. Information to show
The playback speed control means, based on the additional information, when the distance from the center of the frame to the block is less than a predetermined second threshold, selects the moving picture decoding means as the decoding means,
The moving picture reproducing apparatus, wherein the simple moving picture decoding means is selected as the decoding means when the distance from the center of the frame to the block is equal to or greater than a predetermined second threshold. The moving image reproducing apparatus according to claim 2,
The predetermined video encoding scheme is a video encoding scheme using inter-frame prediction, and the additional information is a magnitude of a motion vector used for inter-frame prediction,
The playback speed control means selects the moving picture decoding means as the decoding means when the magnitude of the motion vector is equal to or greater than a predetermined third threshold based on the additional information,
When the magnitude of a motion vector is less than a predetermined third threshold, the moving picture reproducing apparatus is characterized in that the simple moving picture decoding means is selected as the decoding means. The moving image reproducing apparatus according to claim 2,
The predetermined moving image encoding method is a moving image encoding method using intra-frame prediction and inter-frame prediction, and the additional information is a prediction method applied to moving image data,
The playback speed control means selects the moving picture decoding means as the decoding means when the prediction method is intra-frame prediction based on the additional information,
When the prediction method is inter-frame prediction, the simple video decoding unit is selected as the decoding unit. In the moving image reproducing device according to any one of claims 1 to 5,
The moving image reproducing apparatus according to claim 1, wherein the decoding means includes a filtering process for removing encoded distortion. In the moving image reproducing device according to any one of claims 1 to 5,
The moving picture reproducing apparatus, wherein the decoding means includes an inverse transformation process for generating a difference image. In the moving image reproducing device according to any one of claims 1 to 5,
The moving picture reproducing apparatus, wherein the decoding means includes a process for generating an inter-frame prediction image. In a moving image reproducing apparatus for reproducing moving image data encoded using a predetermined moving image encoding method,
Decoding means for decoding moving image data, reproduction speed control means for controlling the reproduction speed and selecting the decoding means based on the designated reproduction speed and the bit rate of the moving image data to be decoded; With
As the decoding means, filter processing means for removing coding distortion in accordance with the predetermined moving picture coding system;
Simple filter processing means for performing coding distortion removal simplified than the filter processing means;
Inverse transform processing means for generating a difference image according to the predetermined moving image encoding method;
Simple inverse transformation processing means for performing an inverse transformation simplified than the inverse transformation processing means,
The reproduction speed control means selects the filter processing means and the inverse conversion means as the decoding means when the designated reproduction speed is less than a predetermined fourth threshold,
When the designated playback speed is equal to or higher than the predetermined fourth threshold and the bit rate of the moving image data to be decoded is lower than the predetermined fifth threshold, at least the decoding means Select the simple reverse conversion means instead of the reverse conversion means,
When the designated playback speed is equal to or higher than the predetermined fourth threshold and the bit rate of the moving image data to be decoded is equal to or higher than the predetermined fifth threshold, Select the simple filter processing means instead of the filter processing means,
A moving picture reproducing apparatus, wherein a decoding process of moving picture data is performed by a selected decoding means. In a moving image reproducing apparatus for reproducing moving image data encoded using a predetermined moving image encoding method,
Decoding means for decoding moving image data, reproduction speed control means for controlling the reproduction speed and selecting the decoding means based on the designated reproduction speed and the bit rate of the moving image data to be decoded; With
As the decoding means, filter processing means for removing coding distortion in accordance with the predetermined moving picture coding system;
Simple filter processing means for performing coding distortion removal simplified than the filter processing means;
Inverse transform processing means for generating a difference image according to the predetermined moving image encoding method;
Simple inverse transformation processing means for performing inverse transformation more simplified than the inverse transformation processing means;
An inter-frame prediction image generating means for generating an inter-frame prediction image according to the predetermined moving image encoding method;
Simple inter-frame prediction image generation means for performing inter-frame prediction more simplified than the inter-frame prediction image generation means,
The playback speed control means selects the filter processing means, the inverse transform means, and the inter-frame predicted image generation means as the decoding means when the designated playback speed is less than a predetermined sixth threshold. ,
When the designated playback speed is equal to or higher than a predetermined sixth threshold and the bit rate of the moving image data to be decoded is lower than the predetermined seventh threshold, at least the decoding means Select the simple reverse conversion means instead of the reverse conversion means,
When the designated playback speed is equal to or higher than a predetermined sixth threshold, and the bit rate of the moving image data to be decoded is equal to or higher than the predetermined seventh threshold and lower than the predetermined eighth threshold For the decoding unit, at least the inter-frame prediction image generation unit is selected instead of the inter-frame prediction image generation unit,
When the designated playback speed is equal to or higher than a predetermined sixth threshold and the bit rate of the moving image data to be decoded is equal to or higher than the predetermined eighth threshold, Select the simple filter processing means instead of the filter processing means,
A moving picture reproducing apparatus, wherein a decoding process of moving picture data is performed by a selected decoding means. In a moving image reproducing apparatus for reproducing moving image data encoded using a predetermined moving image encoding method,
Decoding means for performing decoding processing of moving image data, playback speed control and decoding based on a designated reproduction speed, a bit rate of moving image data to be decoded, and a size of a motion vector used for inter-frame prediction Replay speed control means for selecting the means,
As the decoding means, filter processing means for removing coding distortion in accordance with the predetermined moving picture coding system;
Simple filter processing means for performing coding distortion removal simplified than the filter processing means;
Inverse transform processing means for generating a difference image according to the predetermined moving image encoding method;
Simple inverse transformation processing means for performing inverse transformation more simplified than the inverse transformation processing means;
An inter-frame prediction image generating means for generating an inter-frame prediction image according to the predetermined moving image encoding method;
Simple inter-frame prediction image generation means for performing inter-frame prediction more simplified than the inter-frame prediction image generation means,
The playback speed control means selects the filter processing means, the inverse transform means, and the inter-frame predicted image generation means as the decoding means when the designated playback speed is less than a predetermined ninth threshold. ,
When the designated playback speed is equal to or higher than a predetermined ninth threshold and the magnitude of the motion vector used for inter-frame prediction is less than the predetermined tenth threshold, at least as the decoding means, Select the simplified inter-frame prediction image generation means instead of the inter-frame prediction image generation means,
When the designated playback speed is equal to or greater than a predetermined ninth threshold, the magnitude of the motion vector used for inter-frame prediction is equal to or greater than the predetermined tenth threshold, and the moving image data to be decoded is If the bit rate is less than a predetermined eleventh threshold value, at least the simple inverse conversion means instead of the inverse conversion means is selected as the decoding means,
When the designated playback speed is equal to or greater than a predetermined ninth threshold, the magnitude of the motion vector used for inter-frame prediction is equal to or greater than the predetermined tenth threshold, and the moving image data to be decoded is If the bit rate is greater than or equal to a predetermined eleventh threshold, select at least the simple filter processing means instead of the filter processing means as the decoding means,
A moving picture reproducing apparatus, wherein a decoding process of moving picture data is performed by a selected decoding means.

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