JP3824268B2 - Motion vector deriving method and motion vector deriving device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a motion vector deriving method for deriving a motion vector indicating motion in units of blocks between images, and a moving image that encodes a moving image by inter-picture predictive coding with motion compensation using the derived motion vector. The present invention relates to an encoding method and a moving image decoding method.
[0002]
[Prior art]
In recent years, with the development of multimedia applications, it has become common to handle all media information such as images, sounds and texts in a unified manner. At this time, the media can be handled uniformly by digitizing all the media. However, since a digitized image has an enormous amount of data, image information compression technology is indispensable for storage and transmission. On the other hand, in order to interoperate compressed image data, standardization of compression technology is also important. Image compression technology standards include ITU-T (International Telecommunication Union Telecommunication Standardization Sector) H.261, H.263, ISO (International Organization for Standardization) MPEG (Moving Picture Experts Group) -1, MPEG- 2, MPEG-4 and so on.
[0003]
Inter-picture prediction with motion compensation is a common technique for these video coding systems. In motion compensation of these moving image coding methods, each picture constituting an input image is divided into rectangles of a predetermined size (hereinafter referred to as blocks), and each block is coded from a motion vector indicating motion between pictures. And a prediction image to be referred to in decoding is generated.
[0004]
The motion vector is detected for each block or for each area obtained by dividing the block. An encoded picture that is positioned forward or backward (hereinafter simply referred to as forward or backward) in accordance with the display order of the images with respect to the picture to be encoded is referred to as a reference picture. In motion detection, a block (region) that can predict the encoding target block most appropriately is selected from the reference pictures, and the relative position of the block with respect to the encoding target block is set as an optimal motion vector. At the same time, a prediction mode, which is information for specifying a prediction method that can be most appropriately predicted from the pictures that can be referred to, is determined.
[0005]
As a prediction mode, for example, there is a direct mode in which inter-picture prediction encoding is performed with reference to a picture that is forward or backward in display time (see, for example, Non-Patent Document 1). In the direct mode, the motion vector is not explicitly encoded as encoded data, but is derived from an already encoded motion vector. That is, a motion vector of a block (hereinafter referred to as a reference block) at the same coordinate position (spatial position) in a block of the picture to be coded and a block of the picture to be coded in a coded picture adjacent to the picture to be coded. Is referred to, the motion vector of the encoding target block is calculated. Then, a predicted image (motion compensation data) is generated based on the calculated motion vector. In decoding, a direct mode motion vector is derived from a motion vector already decoded in the same manner.
[0006]
Here, the calculation of the motion vector in the direct mode will be specifically described. FIG. 17 is an explanatory diagram of motion vectors in the direct mode. In FIG. 17, a picture 1200, a picture 1201, a picture 1202, and a picture 1203 are arranged in the display order. A picture 1202 is a picture to be encoded, and a block MB1 is a block to be encoded. FIG. 17 illustrates a case where inter-picture prediction is performed on the block MB1 of the picture 1202 using the picture 1200 and the picture 1203 as reference pictures. In the following description, the picture 1203 is described as the rear of the picture 1202 and the picture 1200 is the front of the picture 1202 for simplicity of description. However, the picture 1203 and the picture 1200 are not necessarily arranged in this order.
[0007]
A picture 1203, which is a reference picture behind the picture 1202, has a motion vector that refers to the picture 1200 ahead. Therefore, the motion vector of the encoding target block MB1 is determined using the motion vector MV1 of the reference block MB2 of the picture 1203 located behind the encoding target picture 1202. The two motion vectors MVf and MVb to be obtained are calculated using the following equations 1 (a) and 1 (b).
[0008]
MVf = MV1 × TRf / TR1 Formula 1 (a)
MVb = −MV1 × TRb / TR1 Formula 1 (b)
Here, MVf is the forward motion vector of the encoding target block MB1, MVb is the backward motion vector of the encoding target block MB1, TR1 is the time interval between the picture 1200 and the picture 1203 (up to the reference picture of the motion vector MV1) TRf is the time interval between the picture 1200 and the picture 1202 (time interval from the motion vector MVf to the reference picture), and TRb is the time interval between the picture 1202 and the picture 1203 (the motion vector MVb Time interval to reference picture). Note that TR1, TRf, and TRb are not limited to the time interval between pictures. For example, data using the difference in picture numbers assigned to each picture, the display order of pictures (or the display order of pictures) are shown. Data that uses the difference in information), data that uses the number of pictures, and other data that can recognize the time interval in the display order between pictures and that serves as an index used in motion vector scaling (explicitly in the stream) Or data implicitly included or data associated with a stream).
[0009]
Next, the flow of processing for obtaining a motion vector will be described. FIG. 18 is a flowchart showing a flow of processing for obtaining a motion vector. First, information on a motion vector included in the reference block MB2 is acquired (step S1301). In the example of FIG. 17, information on the motion vector MV1 is acquired. Next, parameters for deriving the motion vector of the encoding target block MB1 are acquired (step S1302). The parameter for deriving the motion vector of the encoding target block MB1 is scaling coefficient data used when scaling the motion vector acquired in step S1301. Specifically, TR1, TRf, and TRb in Formula 1 (a) and Formula 1 (b) are applicable. Next, the motion vector obtained in step S1301 is scaled by multiplication and division using the above-described equations 1 (a) and 1 (b) by these parameters, and the motion vectors MVf and MVb of the encoding target block MB1 are scaled. Is derived (step S1303).
[0010]
[Non-Patent Document 1]
ISO / IEC MPEG and ITU-T VCEG
Working Draft Number 2, Revision 2
2002-03-15, P.64 7.4.2 Motion vectors in direct mode
[0011]
[Problems to be solved by the invention]
As shown in the above equations 1 (a) and 1 (b), division processing is required to derive the motion vector. However, as a first problem, the division process takes a lot of time for the calculation process compared to the calculation such as addition and multiplication. This is not preferable in view of the use of a computing device with low power consumption specifications and low computing power for devices such as mobile phones that require low power consumption.
[0012]
Therefore, in order to avoid division processing, it is conceivable to derive a motion vector by multiplication processing with reference to a multiplier parameter corresponding to the divisor. As a result, instead of division, calculation can be performed with multiplication with a small amount of calculation, and scaling calculation can be simplified.
[0013]
However, as a second problem, since various values are applied to the parameter for deriving the motion vector depending on the interval between the reference picture and the picture of the target block, there are many possible values for the parameter. That is, if multiplier parameters corresponding to all divisors are prepared, a huge number of parameters must be prepared, and a large amount of memory is required.
[0014]
Therefore, in order to solve the first and second problems, the present invention provides a motion vector deriving method, a moving image encoding method, and a moving image decoding method for deriving a motion vector with a small amount of calculation. The purpose is to do.
[0015]
[Means for Solving the Problems]
To achieve the above object, a motion vector deriving method according to the present invention is a motion vector deriving method for deriving a motion vector of a block constituting a picture, and a reference motion vector for deriving a motion vector of a target block A reference motion vector obtaining step for obtaining a first parameter, a first parameter obtaining step for obtaining a first parameter corresponding to an interval between a picture having the reference motion vector and a picture referenced by the reference motion vector, and the target block A second parameter acquisition step of acquiring at least one second parameter corresponding to an interval between a picture and a picture referred to by the target block; and determining whether the first parameter is included in a predetermined range set in advance And a result of the determination in the determination step, When the first parameter is not included in the predetermined range, the reference motion vector is scaled based on the first predetermined value and the second parameter to derive the motion vector of the target block, A motion vector deriving step of deriving a motion vector of the target block by scaling the reference motion vector based on the first parameter and the second parameter when a parameter is included in the predetermined range; To do.
[0016]
The motion vector deriving method according to the present invention is a motion vector deriving method for deriving a motion vector of a block constituting a picture, and is a reference motion vector for obtaining a reference motion vector for deriving a motion vector of a target block. An obtaining step; a first parameter obtaining step for obtaining a first parameter corresponding to an interval between a picture having the reference motion vector and a picture referred to by the reference motion vector; a picture including the target block; A second parameter acquisition step of acquiring at least one second parameter corresponding to an interval with a picture to be referred to; and a determination step of determining whether or not the first parameter is equal to or greater than a first predetermined value set in advance. As a result of the determination in the determination step, the first parameter If it is greater than or equal to the first predetermined value, the reference motion vector is scaled based on the first predetermined value and the second parameter to derive a motion vector of the target block, while the first parameter is the predetermined value And a motion vector deriving step of deriving a motion vector of the target block by scaling the reference motion vector based on the first parameter and the second parameter.
[0017]
Here, in the determination step, it is further determined whether or not the first parameter is equal to or less than a second predetermined value that is smaller than the first predetermined value set in advance, and in the motion vector derivation step, If the result of determination in the determining step is that the first parameter is less than or equal to the second predetermined value, the reference motion vector is scaled based on the second predetermined value and the second parameter, and the motion of the target block A vector may be derived.
[0018]
Further, the motion vector deriving method further refers to a multiplier parameter table indicating a relationship between the first parameter and a reciprocal value with respect to the first parameter, and converts the acquired first parameter into the reciprocal value. It is preferable to include a conversion step of converting and obtaining the obtained value as the third parameter.
[0019]
In the motion vector deriving step, when the reference motion vector is scaled based on the first parameter and the second parameter, the reference motion vector, the second parameter, and the third parameter are multiplied, and It is preferable to derive a motion vector of the target block.
[0020]
As a result, the division processing necessary for scaling the reference motion vector can be performed by multiplication processing, and the parameter value used for scaling the reference motion vector is limited to a predetermined range. Can be reduced. In addition, it is possible to prevent a mismatch of results due to an operation error between the encoding process and the decoding process.
[0021]
The motion vector deriving method according to the present invention is a motion vector deriving method for deriving a motion vector of a block constituting a picture, and is a reference motion vector for obtaining a reference motion vector for deriving a motion vector of a target block. An obtaining step; a first parameter obtaining step for obtaining a first parameter corresponding to an interval between a picture having the reference motion vector and a picture referred to by the reference motion vector; a picture including the target block; A second parameter acquisition step of acquiring at least one second parameter corresponding to an interval with a picture to be referred to; and a determination step of determining whether or not the first parameter is equal to or greater than a first predetermined value set in advance. As a result of the determination in the determination step, the first parameter If it is greater than or equal to the first predetermined value, the reference motion vector is derived as a motion vector of the target block, while if the first parameter is less than the predetermined value, the first parameter and the second parameter are And a motion vector deriving step of deriving a motion vector of the target block by scaling the reference motion vector based on the reference motion vector.
[0022]
Here, in the determination step, it is further determined whether or not the first parameter is equal to or less than a second predetermined value that is smaller than the first predetermined value set in advance, and in the motion vector derivation step, As a result of the determination in the determination step, if the first parameter is equal to or less than the second predetermined value, the reference motion vector may be derived as a motion vector of the target block.
[0023]
Thereby, when the interval between the picture referred to by the reference motion vector and the picture having the reference motion vector is outside the predetermined range, the derivation of the motion vector can be simplified.
[0024]
The moving picture coding method according to the present invention is a moving picture coding method for coding each picture constituting a moving picture in units of blocks, and the motion vector derived by the motion vector deriving method according to the present invention. And a motion compensation step of generating a motion compensated image of the encoding target block using the encoding, and an encoding step of encoding the encoding target block using the motion compensation image.
[0025]
The moving picture decoding method according to the present invention is a moving picture decoding method for decoding moving picture encoded data in which each picture constituting a moving picture is encoded in units of blocks. A motion compensation step of generating a motion compensated image of the decoding target block using the motion vector derived by the motion vector deriving method; and a decoding step of decoding the decoding target block using the motion compensated image. It is characterized by including.
[0026]
The present invention can be realized not only as such a motion vector deriving method, moving image encoding method and moving image decoding method, but also as such a motion vector deriving method, moving image encoding method and moving image. It can be realized as a motion vector deriving device, a moving image encoding device, and a moving image decoding device having the characteristic steps included in the decoding method as means, or as a program for causing a computer to execute these steps. it can. Needless to say, such a program can be distributed via a recording medium such as a CD-ROM or a transmission medium such as the Internet.
[0027]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0028]
(Embodiment 1)
FIG. 1 is a block diagram showing a configuration of a moving picture encoding apparatus according to the present embodiment. In the processing of FIG. 1, the terms already described with reference to FIG. 17 in the prior art will be described using the same reference numerals as those in FIG. 17. The difference between the present embodiment and the prior art is that the numerical value width of parameters used for deriving the motion vector of the encoding target picture 1202 is limited to a predetermined range.
[0029]
As shown in FIG. 1, the moving image encoding apparatus includes a motion vector encoding unit 10, a motion vector derivation unit 11, a memory 12, a subtractor 13, an orthogonal transformation unit 14, a quantization unit 15, an inverse quantization unit 16, and an inverse quantization unit. An orthogonal transform unit 17, an adder 18, and a variable length coding unit 19 are provided.
[0030]
The motion vector encoding unit 10 encodes a motion vector (such as MV1) of each picture and outputs it as a motion vector stream. The motion vector deriving unit 11 derives the motion vector MVscl (MVb and MVf) of the encoding target block MB1 using the motion vector MVtar (MV1) of the reference block MB2, the parameter TRtar and the parameter TR1. Here, the motion vector of the reference block MB2 is scaled based on the equations 1 (a) and 1 (b) already described. The parameter TRtar corresponds to TRb or TRf already described.
[0031]
The memory 12 stores the image data of the reference picture and the motion vector MVscl of the encoding target picture 1202 derived by the motion vector deriving unit 11. In the memory 12, motion compensation data is generated based on the image data of the reference picture and the motion vector MVscl of the encoding target picture 1202. The subtractor 13 calculates a difference between the input image data and the motion compensation data input from the memory 12 to obtain a difference value. The orthogonal transform unit 14 DCT-transforms the difference value and outputs a DCT coefficient. The quantization unit 15 quantizes the DCT coefficient using a quantization step. The inverse quantization unit 16 inversely quantizes the quantized DCT coefficient using a quantization step, and returns the original DCT coefficient to the original DCT coefficient. The inverse orthogonal transform unit 17 performs inverse orthogonal transform on the DCT coefficient and outputs difference image data (difference value).
[0032]
The adder 18 adds the difference image data (difference value) from the inverse orthogonal transform unit 17 and the image data of the reference picture stored in the memory 12, and inputs the input image data (original input) of the encoding target picture 1202. Decoded image data corresponding to (image data) is obtained. This decoded image data is stored in the memory 12 as image data to be referred to when encoding the encoding target picture encoded after the encoding target picture 1202. The variable length coding unit 19 performs variable length coding on the DCT coefficient quantized by the quantization unit 15.
[0033]
Next, an operation at the time of encoding in the direct mode in the moving image encoding apparatus configured as described above will be described with reference to FIG.
[0034]
The motion vector of each picture is encoded by the motion vector encoding unit 10 and output as a motion vector stream.
[0035]
The motion vector deriving unit 11 derives a motion vector of the encoding target block MB1 by scaling the motion vector MVtar (MV1) of the reference block MB2 with the parameters TRtar and TR1. The memory 12 extracts an image indicated by the motion vector derived by the motion vector deriving unit 11 from the stored image data of the reference picture and outputs it as motion compensation data.
[0036]
The subtracter 13 calculates the difference between the input image data and the motion compensation data output from the memory 12, and obtains difference image data that is a difference value. The difference value is orthogonally transformed by the orthogonal transformation unit 14 and converted into a DCT coefficient. The DCT coefficient is quantized by the quantizing unit 15, and dequantized and restored to the original DCT coefficient by the inverse quantizing unit 16. The DCT coefficient is restored by inverse orthogonal transform to difference image data (difference value) in the inverse orthogonal transform unit 17, and the difference image data (difference value) is added to the motion compensation data output from the memory 12 in the adder 18. The decoded image data corresponding to the original input image data is obtained by addition. The obtained input image data is stored in the memory 12 as image data for reference at the time of the next encoding target picture encoding.
[0037]
The DCT coefficient quantized by the quantizing unit 15 is variable-length encoded by the variable-length encoding unit 19 and output as a stream.
[0038]
Next, a configuration for scaling a motion vector by limiting the numerical value width (size) of a parameter to a predetermined range will be described with reference to FIG.
[0039]
FIG. 2 is a block diagram showing a configuration of the motion vector deriving unit 11 of FIG.
[0040]
As shown in FIG. 2, the motion vector deriving unit 11 includes a comparison unit 20, a switching unit 21, a multiplier parameter table (for multiplier) 22, multipliers 23 and 25, and a multiplier parameter table (for divisor) 24.
[0041]
The comparison unit 20 compares whether or not the parameter TR1 related to the motion vector MVtar (MV1) of the reference block MB2 exceeds a predetermined value. The switching unit 21 switches whether to select the maximum value of the parameter TR stored in advance or the parameter TR1 according to the comparison result of the comparison unit 20. The multiplier parameter table 22 shows the correspondence between the parameter TRtar (TRb or TRf) and the multiplier (multiplication value). The multiplier 23 multiplies the motion vector MVtar (MV1) of the reference block MB2 by the multiplier parameter output from the multiplier parameter table 22.
[0042]
The multiplier parameter table 24 shows the correspondence between the output value of the switching unit 21 and the multiplication value. The multiplier 25 multiplies the output value of the multiplier 23 by the parameter output from the multiplier parameter table 24.
[0043]
The operation will be described below with reference to FIG. The motion vector deriving unit 11A illustrated in FIG. 2 represents the motion vector deriving unit 11 in the block diagram of the video encoding device illustrated in FIG.
[0044]
The parameter TR1 related to the motion vector MVtar (MV1) of the reference block MB2 is compared by the comparison unit 20 to determine whether it exceeds a predetermined value. As a result, when the parameter TR1 does not exceed the predetermined value, the switching unit 21 selects the parameter TR1 as it is. On the other hand, when the parameter TR1 exceeds a predetermined value, the switching unit 21 selects a predetermined value (the maximum value of TR).
[0045]
The parameter TRtar (TRb or TRf) of the motion vector MVscl (MVb or MVf) of the block to be encoded is selected as a corresponding multiplier parameter in the multiplier parameter table 22, and the selected multiplier parameter is referred to by the multiplier 23 as a reference block MB2. Is multiplied by the motion vector MVtar.
[0046]
In the multiplier parameter table 24, a multiplier parameter corresponding to the parameter selected by the switching unit 21 is selected, and the selected multiplier parameter is multiplied by the output of the multiplier 23 by the multiplier 25.
[0047]
In this way, a value (scaled value) obtained by multiplying the motion vector MVtar of the reference block MB2 by the multiplication parameter by the multiplier 23 and the multiplier 25 is the motion vector MVscl of the encoding target picture 1202.
[0048]
FIG. 3 is a diagram showing an example of the multiplier parameter table. In this example, the multiplier parameter table corresponds to the multiplier parameter table 24 of FIG.
[0049]
The leftmost column shown in FIG. 3 represents a parameter TR1 (divisor) input to this table, and this parameter TR1 is limited to a predetermined range from “1” to “8”. The middle column shows the reciprocal of the parameter (1 / TR1). The rightmost column shows the multiplier parameter (Tscl), which is a value approximated to the reciprocal (1 / TR1) of the parameter shown in the middle column. In the actual calculation, the rightmost multiplication parameter (Tscl) is used as a value for deriving the motion vector MVscl of the encoding target picture 1202, and thus the calculation is simplified.
[0050]
That is, for example, the two motion vectors MVf and MVb of the encoding target block MB1 shown in FIG. 17 are calculated using the following equations 2 (a) and 2 (b).
[0051]
MVf = MV1 × TRf × Tscl Equation 2 (a)
MVb = −MV1 × TRb × Tscl Equation 2 (b)
Here, MVf is the forward motion vector of the encoding target block MB1, MVb is the backward motion vector of the encoding target block MB1, and Tscl is a multiplier parameter corresponding to the reciprocal of the interval between the picture 1200 and the picture 1203, that is, 1 / TR1. TRf is the interval between the picture 1200 and the picture 1702, and TRb is the interval between the picture 1202 and the picture 1203.
[0052]
Next, a process for obtaining the motion vector MVscl of the encoding target block MB1 will be described with reference to FIG.
[0053]
FIG. 4 is a flowchart showing a processing procedure for obtaining the motion vector MVscl. The motion vector deriving unit 11A acquires information on the motion vector MVtar included in the reference block MB2 (step S401). This motion vector MVtar corresponds to MV1 in equations 1 (a) and (b). Next, the motion vector deriving unit 11A acquires the parameter TRtar and the parameter TR1 for deriving the motion vector MVscl of the encoding target block MB1 (step S402). The parameter TRtar corresponds to TRf and TRb in the equations 1 (a) and (b).
[0054]
Next, the comparison unit 20 determines whether or not the parameter TR1 corresponding to the divisor is greater than or equal to a predetermined value (step S403). If the parameter TR1 is equal to or greater than the predetermined value as a result of the determination, the switching unit 21 selects a parameter corresponding to the maximum divisor (the maximum value “8” of TR1 in the example of FIG. 3). Accordingly, the motion vector deriving unit 11A uses the parameter corresponding to the maximum divisor to scale the motion vector MVtar acquired in step S401, and derives the motion vector MVscl of the encoding target block MB1 (step S405). On the other hand, if the acquired parameter TR1 is less than the predetermined value, the switching unit 21 selects a parameter corresponding to the divisor. Accordingly, the motion vector deriving unit 11A performs similar scaling using the parameter corresponding to the divisor, and derives the motion vector MVscl of the encoding target block MB1 (step S404).
[0055]
As described above, according to the present embodiment, the multiplier parameter table corresponding to the divisor stored in the memory is obtained by limiting the parameter value used when scaling the motion vector of the reference block to a predetermined value or less. In addition, there is an effect that it is possible to prevent a mismatch of results due to an operation error between the encoding process and the decoding process.
[0056]
In the present embodiment, it is determined whether or not the parameter TR1 is equal to or greater than a predetermined value in the above determination (step S403). However, the present invention is not limited to this, and the parameter TR1 is a predetermined value. It may be determined whether or not it is included in the range. For example, as shown in FIG. 5, when referring to a picture in which the motion vector MV1 included in the reference block MB2 is behind, the parameter TR1 (divisor) and the multiplier parameter Tscl corresponding to the parameter TR1 have a negative value as follows: Become. In FIG. 5, a picture 1500, a picture 1501, a picture 1502, and a picture 1503 are arranged in the display order. A picture 1501 is a picture to be encoded, and a block MB1 is a block to be encoded. FIG. 5 shows a case where bi-directional prediction of block MB1 of picture 1501 is performed using picture 1500 and picture 1503 as reference pictures.
[0057]
A picture 1500 that is a reference picture ahead of the picture 1501 has a motion vector that refers to the picture 1503 behind. Therefore, the motion vector of the encoding target block MB1 is determined using the motion vector MV1 of the reference block MB2 of the picture 1500 located in front of the encoding target picture 1501. The two motion vectors MVf and MVb to be obtained are calculated using the above equations 2 (a) and 2 (b). In this way, when the motion vector MV1 included in the reference block MB2 refers to a picture behind, the parameter TR1 (divisor) and the multiplier parameter Tscl corresponding to the parameter TR1 are negative values.
[0058]
Therefore, it is determined whether or not parameter TR1 is equal to or greater than a predetermined first predetermined value, and whether or not parameter TR1 is equal to or smaller than a predetermined second predetermined value. If the result of this determination is that the parameter TR1 is greater than or equal to the first predetermined value, the motion vector MVtar is scaled using the parameter corresponding to the maximum divisor to derive the motion vector MVscl of the encoding target block MB1. When the parameter TR1 is equal to or smaller than the second predetermined value, the motion vector MVtar is scaled using the parameter corresponding to the minimum divisor to derive the motion vector MVscl of the encoding target block MB1. Further, when the parameter TR1 is less than the first predetermined value and larger than the second predetermined value, the motion vector MVtar is scaled using the parameter TR1, and the motion vector MVscl of the encoding target block MB1 is derived.
[0059]
As described in the prior art, in the present embodiment, the interval between pictures of the parameters TR1 and TRtar is not limited to the time interval between pictures. For example, a difference in picture numbers assigned to each picture is calculated. The time interval in the display order between pictures can be recognized, such as the data used, the data using the difference in the display order of pictures (or information indicating the display order of pictures), and the data using the number of pictures between pictures. Any data can be used as long as it is an index used in vector scaling.
[0060]
Also, if the divisor is not limited to a predetermined range, the parameter of the multiplier corresponding to the divisor will be infinite, so the parameter table corresponding to the divisor cannot be realized, and the division is realized by multiplication It cannot be realized.
[0061]
As an example of determining whether or not the parameter TR1 falls within a predetermined range, whether or not the parameter TR1 is “predetermined value or more” as shown in FIG. 4 is described. It may be a condition such as “less than a predetermined value”.
[0062]
(Embodiment 2)
In the first embodiment, when the motion vector MVscl is derived by scaling the motion vector MVtar that is the motion vector to be referenced, the parameter TR1 is compared with the upper limit value of the divisor included in the multiplier parameter table, and TR1 is equal to or higher than the upper limit value. In this case, the value corresponding to the maximum divisor that the multiplier parameter table has is used as the multiplier parameter corresponding to the input parameter TR1. In the second embodiment, the parameter TR1 is compared with the upper limit value of the divisor included in the multiplier parameter table. When TR1 is equal to or higher than the upper limit value, the motion vector MVtar is not derived by scaling, and the input MVtar is directly used as the motion vector. Let it be MVscl. This simplifies the process of deriving the motion vector MVscl when the value is equal to or greater than the upper limit value. Embodiment 2 of the present invention will be described below with reference to the drawings.
[0063]
FIG. 6 is a block diagram showing the configuration of the motion vector deriving unit according to the second embodiment. The motion vector deriving unit 11B illustrated in FIG. 6 represents the motion vector deriving unit 11 in the block diagram of the image encoding device illustrated in FIG. The configuration other than the motion vector deriving unit 11 in the block diagram of the image encoding device shown in FIG. 1 is as described in the first embodiment. Therefore, the motion vector deriving unit 11B shown in FIG. 6 will be described with reference to FIGS.
[0064]
As shown in FIG. 6, the motion vector deriving unit 11B includes a multiplier parameter table (for multiplier) 50, a multiplier parameter table (for divisor) 51, a comparison unit 52, multipliers 53 and 54, and a switching unit 55.
[0065]
The motion vector deriving unit 11B uses the motion vector MVtar (MV1), the parameter TRtar (TRf and TRb), and the parameter TR1 of the reference block MB2 shown in FIG. 17 to calculate the motion vector (MVb and MVf) of the encoding target block MB1. To derive. Here, the motion vector MVtar of the reference block MB2 is scaled using the above-described equations 2 (a) and 2 (b). The parameter TRtar corresponds to TRb or TRf already described.
[0066]
The comparison unit 52 compares whether or not the parameter TR1 related to the motion vector MVtar of the reference block MB2 exceeds a predetermined value. Here, the predetermined value is “8” which is the maximum value of the divisor included in the multiplier parameter table shown in FIG. 3, for example. The switching unit 55 selects the output (processing 57) of the multiplier 54 or the input motion vector MVtar (processing 58) of the reference block MB2 according to the comparison result of the comparison unit 52.
[0067]
A multiplier parameter table (for multiplier) 50 indicates the correspondence between the parameter TRtar (TRb or TRf) and the multiplier (multiplier value). A multiplier parameter table (for divisor) 51 shows the correspondence between TR1 and multiplier (divisor). In the second embodiment, TRtar input to the multiplier parameter table 50 is directly input to the multiplier 53. However, the present invention is not limited to this, and the multiplier parameter table 50 performs arithmetic processing as necessary. May be.
[0068]
The multiplier 53 multiplies the multiplier parameter output from the multiplier parameter table (for multiplier) 50 by the motion vector MVtar (MV1) of the reference picture 1203. The multiplier 54 multiplies the output value of the multiplier 53 by the multiplier parameter output from the multiplier parameter table (for divisor) 51. Note that the order of multiplication processing of the multiplier 53 and the multiplier 54 may be reversed.
[0069]
Next, the operation of the motion vector deriving unit 11B shown in FIG. 6 will be described with reference to FIG. FIG. 7 is a flowchart showing a processing procedure for obtaining the motion vector MVscl.
[0070]
First, the motion vector MVtar of the reference block MB2 is acquired (step S601). Next, parameters (TR1 and TRtar) for deriving the motion vector MVscl of the encoding target block MB1 are acquired (step S602).
[0071]
Next, it is determined whether or not the parameter TR1 corresponding to the acquired divisor is greater than or equal to a predetermined value (step S603). As a result of the determination, if the parameter TR1 corresponding to the divisor is equal to or greater than a predetermined value, the switching unit 55 selects the process 58. On the other hand, if the parameter TR1 corresponding to the divisor is not equal to or greater than the predetermined value, the switching unit 55 selects the process 57.
[0072]
When the process 58 is selected by the switching unit 55, the motion vector MVtar to be referred to acquired in step 601 is directly used as the motion vector MVscl (step S605). On the other hand, when the process 57 is selected by the switching unit 55, the motion vector MVscl is derived using the parameter corresponding to the divisor (TR1) (step S604). That is, the result of the multiplication process of the multiplier 53 and the multiplier 54 is the motion vector MVscl.
[0073]
Since the encoding target picture 1202 shown in FIG. 17 has two motion vectors MVf and MVb before and after, the processing of FIG. 7 is performed for each of them. That is, in order to calculate the motion vector MVf as the motion vector MVscl, the parameter TRtar acquired in step S602 is the parameter TRf, and in order to calculate the motion vector MVb as the motion vector MVscl, the parameter TRtar acquired in step S602. Is the parameter TRb.
[0074]
As described above, according to the second embodiment, the parameter value used when scaling the motion vector of the reference block is limited to a predetermined range, and when the upper limit value is exceeded, the motion vector MVtar is scaled. First, by determining a certain processing procedure in which the input MVtar is used as the motion vector MVscl as it is, it is possible to prevent a mismatch of results due to an operation error between the encoding process and the decoding process. In addition, the processing amount for deriving the motion vector can be reduced. Further, the multiplier parameter table stored in the memory can be reduced.
[0075]
As described in the conventional technique, in the second embodiment, the parameters TR1 and TRtar are not limited to time data, but are data using a difference in picture numbers assigned to each picture (for example, the picture 1200 in FIG. 17). When the picture number is 1200 and the picture number of the picture 1203 is 1203, 3 is obtained by subtracting 1200 from 1203, and data using the number of pictures between the encoding target picture and the reference picture (for example, in the case of FIG. 17) The time interval in the display order between the pictures can be determined quantitatively, such as TR1 where the number of pictures between the picture 1200 and the picture 1203 is two, but the picture interval is 2 + 1 = 3). Any data is acceptable.
[0076]
In the second embodiment, the parameter TR1 is compared with the upper limit value of the divisor included in the multiplier parameter table, and when the TR1 does not exceed the upper limit value, the multiplier unit 54 performs the multiplication process using the multiplier parameter table 51. Although an example of performing is described, division processing may be performed by the divisor unit 94 using the divisor parameter table 91 as shown in FIG. A motion vector deriving unit 11C illustrated in FIG. 10 represents the motion vector deriving unit 11 in the configuration diagram of the image encoding device illustrated in FIG. The configuration other than the motion vector deriving unit 11 in the block diagram of the video encoding device shown in FIG. 1 is as described in the first embodiment. In FIG. 10, the same reference numerals as those used in FIG. 6 are used for the same components as those in FIG.
[0077]
In the first embodiment and the second embodiment, the case where the motion vector shown in FIG. 17 is derived using Expression 2 (a) and Expression 2 (b) has been described. However, the movement shown in FIG. 8 and FIG. Even when a vector is derived, the invention described in this specification can be used.
[0078]
First, a method for deriving a motion vector in the direct mode shown in FIG. 8 will be described. In FIG. 8, a picture 1700, a picture 1701, a picture 1702, and a picture 1703 are arranged in the display order, and a block MB1 is an encoding target block. FIG. 8 illustrates an example in which the current block MB1 is bidirectionally predicted using the picture 1700 and the picture 1703 as reference pictures.
[0079]
The motion vectors MVf and MVb of the encoding target block MB1 are obtained by using the motion vector MV1 included in the reference block MB2 located behind the encoding target block MB1 in display time, using the above equations 2 (a) and 2 (b ).
[0080]
Here, MVf is the forward motion vector of the encoding target block MB1, MVb is the backward motion vector of the encoding target block MB1, and Tscl is a multiplier parameter corresponding to the reciprocal of the interval between the picture 1700 and the picture 1703, that is, 1 / TR1. TRf is the interval between pictures 1701 and 1702, and TRb is the interval between pictures 1702 and 1703.
[0081]
For TR1, TRf, and TRb, any data can be used as long as the picture interval can be quantitatively determined as described above. The flow of processing for obtaining the motion vector MVf and the motion vector MVb is as described in FIG. 4 or FIG.
[0082]
Next, a method for deriving the motion vector shown in FIG. 9 will be described. In FIG. 9, a picture 1800, a picture 1801 and a picture 1802 are arranged in the display order, and a block MB1 is an encoding target block. In FIG. 9, the encoding target block MB1 is predicted using a picture 1800 and a picture 1801 as reference pictures, and has a motion vector MV1 and a motion vector MV2. The motion vector MV2 is predictively encoded using a motion vector MVscl obtained by scaling the motion vector MV1 as follows.
[0083]
First, a motion vector MVscl that is a vector to a picture 1800 referenced by the motion vector MV2 is derived from the current block MB1 using the following equation. Note that the encoded motion vector MV2 itself is derived by a predetermined method. Equations 3 (a) and 3 (b) can be applied to the case shown in Embodiment 1, and Equations 4 (a) and 4 (b) can be applied to the case shown in Embodiment 2.
[0084]
MVscl = MV1 × TR3 × Tscl (TR1 <upper limit value) Equation 3 (a)
MVscl = MV1 × TR3 × TsclMin (TR1 ≧ upper limit) Equation 3 (b)
MVscl = MV1 × TR3 × Tscl (TR1 <upper limit value) Equation 4 (a)
MVscl = MV1 (TR1 ≧ upper limit value) Equation 4 (b)
Here, Tscl is the reciprocal of TR1 when TR1 is the interval between pictures 1801 and 1802, and the upper limit is the maximum divisor (“8” in FIG. 3) in the multiplier parameter table 51 (for divisor), TsclMin Is a multiplier parameter corresponding to the maximum divisor (TR1) in the multiplier parameter table 51 (for divisor), TR3 is an interval between pictures 1800 and 1802, and TR1 is an interval between pictures 1801 and 1802.
[0085]
Next, in order to encode the motion vector MV2, the motion vector MV2 itself is not encoded, and the motion vector MVscl derived from any one of the equations 3 (a) to 4 (b) and a predetermined method are used. Only the difference (difference vector) from the motion vector MV2 derived in step S3 is encoded, and in the decoding process, the motion vector MV2 is derived using the encoded difference vector and the MVscl obtained by scaling the motion vector MV1. It will be.
[0086]
For TR1 and TR3, any data can be used as long as it can quantitatively determine the time interval in the display order between pictures as described above. Further, the flow of processing for obtaining the motion vector MVscl is as described in FIG. 4 or FIG. In the multiplier parameter table shown in FIG. 3, the upper limit value is “8”. However, the upper limit value is not limited to this, and may be “16” or “32”. However, since the reciprocal change corresponding to the divisor becomes smaller as the divisor becomes larger, the error of the motion vector derived using the multiplier parameter set with a larger upper limit value is considerably small.
[0087]
(Embodiment 3)
FIG. 11 is a block diagram showing a configuration of the video decoding apparatus according to the present embodiment.
[0088]
As shown in FIG. 11, the moving picture decoding apparatus includes a variable length decoding unit 1000, an inverse quantization unit 1001, an inverse orthogonal transform unit 1002, an addition operation unit 1003, a motion vector decoding unit 1004, and a motion vector derivation unit 1005. , And a memory 1006. Note that the configuration and operation of the motion vector deriving unit 1005 are the same as those in the first embodiment and the second embodiment, and a detailed description thereof will be omitted.
[0089]
The variable-length decoding unit 1000 performs variable-length decoding processing on the encoded data stream output from the video encoding device according to each of the above-described embodiments, and performs prediction error encoding on the inverse quantization unit 1001. In addition to outputting data, the motion vector derivation parameters TRtar and TR1 are output to the motion vector derivation unit 1005. The inverse quantization unit 1001 inversely quantizes the input prediction error encoded data. The inverse orthogonal transform unit 1002 performs inverse orthogonal transform on the inversely quantized prediction error encoded data, and outputs difference image data.
[0090]
The motion vector decoding unit 1004 decodes the input motion vector stream and extracts motion vector information. The motion vector deriving unit 1005 derives the motion vector MVscl (MVb and MVf) of the current block MB1 using the motion vector MVtar of the reference block MB2, the parameter TRtar, and the parameter TR1. The memory 1006 stores the image data of the reference picture and the motion vector MVscl of the current block MB1 derived by the motion vector deriving unit 1005. The memory 1006 generates motion compensation data based on the image data of the reference picture and the motion vector MVscl of the encoding target block MB1. The addition operation unit 1003 adds the input difference image data and motion compensation data, and generates and outputs a decoded image.
[0091]
Next, an operation at the time of decoding in the direct mode in the moving picture decoding apparatus configured as described above will be described.
[0092]
The encoded data stream output from the moving image encoding apparatus is input to the variable length decoding unit 1000. The variable length decoding unit 1000 performs variable length decoding processing on the encoded data stream and outputs differential encoded data to the inverse quantization unit 1001 and outputs the parameters TRtar and TR1 to the motion vector deriving unit 1005. To do. The differentially encoded data input to the inverse quantization unit 1001 is inversely quantized, then inversely orthogonally transformed by the inverse orthogonal transform unit 1002, and output to the addition operation unit 1003 as difference image data.
[0093]
Also, the motion vector stream input to the video decoding apparatus according to the present embodiment is input to the motion vector decoding unit 1004 to extract motion vector information. Specifically, the motion vector decoding unit 1004 decodes the motion vector stream and outputs a motion vector derivation parameter MVtar to the motion vector derivation unit 1005. Subsequently, the motion vector deriving unit 1005 derives the motion vector MVscl (MVb and MVf) of the current block using the motion vector MVtar and the parameters TRtar and TR1. Then, the memory 1006 extracts the image indicated by the motion vector derived by the motion vector deriving unit 1005 from the stored image data of the reference picture, and outputs it as motion compensation data. The addition operation unit 1003 adds the input difference image data and motion compensation data, generates decoded image data, and finally outputs it as a reproduced image.
[0094]
(Embodiment 4)
Furthermore, by recording a program for realizing the configuration of the moving picture encoding method or the moving picture decoding method shown in each of the above embodiments on a storage medium such as a flexible disk, The processing shown in the form can be easily performed in an independent computer system.
[0095]
FIG. 12 is an explanatory diagram of a storage medium for storing a program for realizing the moving picture coding method and the moving picture decoding method according to the first to third embodiments by a computer system.
[0096]
FIG. 12B shows an appearance, a cross-sectional structure, and a flexible disk as seen from the front of the flexible disk, and FIG. 12A shows an example of a physical format of the flexible disk that is a recording medium body. The flexible disk FD is built in the case F, and on the surface of the disk, a plurality of tracks Tr are formed concentrically from the outer periphery toward the inner periphery, and each track is divided into 16 sectors Se in the angular direction. ing. Therefore, in the flexible disk storing the program, a moving image encoding method as the program is recorded in an area allocated on the flexible disk FD.
[0097]
FIG. 12C shows a configuration for recording and reproducing the program on the flexible disk FD. When recording the program on the flexible disk FD, the moving picture encoding method or the moving picture decoding method as the program is written from the computer system Cs via the flexible disk drive FDD. Further, when the above moving image coding method is constructed in a computer system by a program in a flexible disk, the program is read from the flexible disk by a flexible disk drive and transferred to the computer system.
[0098]
In the above description, a flexible disk is used as the recording medium, but the same can be done using an optical disk. Further, the recording medium is not limited to this, and any recording medium such as an IC card or a ROM cassette capable of recording a program can be similarly implemented.
[0099]
Furthermore, application examples of the moving picture coding method and the moving picture decoding method shown in the above embodiment and a system using the same will be described.
[0100]
FIG. 13 is a block diagram showing an overall configuration of a content supply system ex100 that implements a content distribution service. The communication service providing area is divided into desired sizes, and base stations ex107 to ex110, which are fixed radio stations, are installed in each cell.
[0101]
The content supply system ex100 includes, for example, a computer ex111, a PDA (personal digital assistant) ex112, a camera ex113, a mobile phone ex114, a camera via the Internet ex101, the Internet service provider ex102, the telephone network ex104, and the base stations ex107 to ex110. Each device such as the attached mobile phone ex115 is connected.
[0102]
However, the content supply system ex100 is not limited to the combination as shown in FIG. 13, and any of the combinations may be connected. Further, each device may be directly connected to the telephone network ex104 without going through the base stations ex107 to ex110 which are fixed wireless stations.
[0103]
The camera ex113 is a device capable of shooting a moving image such as a digital video camera. The mobile phone is a PDC (Personal Digital Communications), CDMA (Code Division Multiple Access), W-CDMA (Wideband-Code Division Multiple Access), or GSM (Global System for Mobile Communications) mobile phone, Alternatively, PHS (Personal Handyphone System) or the like may be used.
[0104]
In addition, the streaming server ex103 is connected from the camera ex113 through the base station ex109 and the telephone network ex104, and live distribution or the like based on the encoded data transmitted by the user using the camera ex113 becomes possible. The encoded processing of the captured data may be performed by the camera ex113 or may be performed by a server or the like that performs data transmission processing. Further, the moving image data shot by the camera ex116 may be transmitted to the streaming server ex103 via the computer ex111. The camera ex116 is a device that can shoot still images and moving images, such as a digital camera. In this case, the encoding of the moving image data may be performed by the camera ex116 or the computer ex111. The encoding process is performed in the LSI ex117 included in the computer ex111 and the camera ex116. Note that moving image encoding / decoding software may be incorporated in any storage medium (CD-ROM, flexible disk, hard disk, or the like) that is a recording medium readable by the computer ex111 or the like. Furthermore, you may transmit moving image data with the mobile telephone ex115 with a camera. The moving image data at this time is data encoded by the LSI included in the mobile phone ex115.
[0105]
In this content supply system ex100, the content (for example, video shot of music live) captured by the user with the camera ex113, camera ex116, etc. is encoded and transmitted to the streaming server ex103 as in the above embodiment. On the other hand, the streaming server ex103 distributes the content data to the requested client. Examples of the client include a computer ex111, a PDA ex112, a camera ex113, a mobile phone ex114, and the like that can decode the encoded data. In this way, the content supply system ex100 can receive and reproduce the encoded data at the client, and also realize personal broadcasting by receiving, decoding, and reproducing in real time at the client. It is a system that becomes possible.
[0106]
For the encoding and decoding of each device constituting this system, the moving image encoding device or the moving image decoding device described in the above embodiments may be used.
[0107]
A mobile phone will be described as an example.
[0108]
FIG. 14 is a diagram illustrating the mobile phone ex115 that uses the moving picture coding method and the moving picture decoding method described in the above embodiment. The mobile phone ex115 includes an antenna ex201 for transmitting and receiving radio waves to and from the base station ex110, a camera such as a CCD camera, a camera unit ex203 capable of taking a still image, a video shot by the camera unit ex203, and an antenna ex201. A display unit ex202 such as a liquid crystal display that displays data obtained by decoding received video and the like, a main body unit composed of a group of operation keys ex204, an audio output unit ex208 such as a speaker for outputting audio, and a voice input To store encoded data or decoded data such as a voice input unit ex205 such as a microphone, captured video or still image data, received mail data, video data or still image data, etc. Recording medium ex207, and slot portion ex20 for enabling the recording medium ex207 to be attached to the mobile phone ex115 The it has. The recording medium ex207 stores a flash memory element, which is a kind of EEPROM (Electrically Erasable and Programmable Read Only Memory), which is a nonvolatile memory that can be electrically rewritten and erased, in a plastic case such as an SD card.
[0109]
Further, the cellular phone ex115 will be described with reference to FIG. The cellular phone ex115 controls the power supply circuit ex310, the operation input control unit ex304, and the image coding for the main control unit ex311 which is configured to control the respective units of the main body unit including the display unit ex202 and the operation key ex204. Unit ex312, camera interface unit ex303, LCD (Liquid Crystal Display) control unit ex302, image decoding unit ex309, demultiplexing unit ex308, recording / reproducing unit ex307, modulation / demodulation circuit unit ex306, and audio processing unit ex305 via a synchronization bus ex313 Are connected to each other.
[0110]
When the end call and power key are turned on by a user operation, the power supply circuit ex310 activates the camera-equipped digital mobile phone ex115 by supplying power from the battery pack to each unit. .
[0111]
The mobile phone ex115 converts the voice signal collected by the voice input unit ex205 in the voice call mode into digital voice data by the voice processing unit ex305 based on the control of the main control unit ex311 including a CPU, a ROM, a RAM, and the like. The modulation / demodulation circuit unit ex306 performs spread spectrum processing, and the transmission / reception circuit unit ex301 performs digital analog conversion processing and frequency conversion processing, and then transmits the result via the antenna ex201. In addition, the cellular phone ex115 amplifies the received data received by the antenna ex201 in the voice call mode, performs frequency conversion processing and analog-digital conversion processing, performs spectrum despreading processing by the modulation / demodulation circuit unit ex306, and analog audio by the voice processing unit ex305. After the data is converted, it is output via the audio output unit ex208.
[0112]
Further, when an e-mail is transmitted in the data communication mode, text data of the e-mail input by operating the operation key ex204 of the main body is sent to the main control unit ex311 via the operation input control unit ex304. The main control unit ex311 performs spread spectrum processing on the text data in the modulation / demodulation circuit unit ex306, performs digital analog conversion processing and frequency conversion processing in the transmission / reception circuit unit ex301, and then transmits the text data to the base station ex110 via the antenna ex201.
[0113]
When transmitting image data in the data communication mode, the image data captured by the camera unit ex203 is supplied to the image encoding unit ex312 via the camera interface unit ex303. When image data is not transmitted, the image data captured by the camera unit ex203 can be directly displayed on the display unit ex202 via the camera interface unit ex303 and the LCD control unit ex302.
[0114]
The image encoding unit ex312 is configured to include the moving image encoding device described in the present invention, and the image data supplied from the camera unit ex203 is a code used in the moving image encoding device described in the above embodiment. The encoded image data is converted into encoded image data by compression encoding using the encoding method, and is sent to the demultiplexing unit ex308. At the same time, the cellular phone ex115 sends the sound collected by the audio input unit ex205 during imaging by the camera unit ex203 to the demultiplexing unit ex308 as digital audio data via the audio processing unit ex305.
[0115]
The demultiplexing unit ex308 multiplexes the encoded image data supplied from the image encoding unit ex312 and the audio data supplied from the audio processing unit ex305 by a predetermined method, and the multiplexed data obtained as a result is a modulation / demodulation circuit unit A spectrum spread process is performed in ex306, a digital analog conversion process and a frequency conversion process are performed in the transmission / reception circuit unit ex301, and then the signal is transmitted through the antenna ex201.
[0116]
When data of a moving image file linked to a homepage or the like is received in the data communication mode, the received data received from the base station ex110 via the antenna ex201 is subjected to spectrum despreading processing by the modulation / demodulation circuit unit ex306, and the resulting multiplexing is obtained. Is sent to the demultiplexing unit ex308.
[0117]
In addition, in order to decode multiplexed data received via the antenna ex201, the demultiplexing unit ex308 separates the multiplexed data into a bit stream of image data and a bit stream of audio data, and synchronizes them. The encoded image data is supplied to the image decoding unit ex309 via the bus ex313, and the audio data is supplied to the audio processing unit ex305.
[0118]
Next, the image decoding unit ex309 is configured to include the moving image decoding apparatus described in the present invention, and a bit stream of image data is decoded by a decoding method corresponding to the encoding method described in the above embodiment. Reproduction moving image data is generated by decoding, and this is supplied to the display unit ex202 via the LCD control unit ex302, thereby displaying, for example, moving image data included in the moving image file linked to the homepage. . At the same time, the audio processing unit ex305 converts the audio data into analog audio data, and then supplies the analog audio data to the audio output unit ex208. Thus, for example, the audio data included in the moving image file linked to the home page is reproduced. The
[0119]
It should be noted that the present invention is not limited to the above system, and recently, digital broadcasting using satellites and terrestrial waves has become a hot topic. As shown in FIG. Any of the video decoding devices can be incorporated. Specifically, in the broadcasting station ex409, a bit stream of video information is transmitted to a communication or broadcasting satellite ex410 via radio waves. Receiving this, the broadcasting satellite ex410 transmits a radio wave for broadcasting, and receives the radio wave with a home antenna ex406 having a satellite broadcasting receiving facility, such as a television (receiver) ex401 or a set top box (STB) ex407. The device decodes the bitstream and reproduces it. In addition, the moving picture decoding apparatus described in the above embodiment can also be implemented in a playback apparatus ex403 that reads and decodes a bitstream recorded on a storage medium ex402 such as a CD or DVD as a recording medium. . In this case, the reproduced video signal is displayed on the monitor ex404. A configuration is also possible in which a video decoding device is mounted in a set-top box ex407 connected to a cable ex405 for cable television or an antenna ex406 for satellite / terrestrial broadcasting, and this is reproduced on a monitor ex408 on the television. At this time, the moving picture decoding apparatus may be incorporated in the television instead of the set top box. It is also possible to receive a signal from the satellite ex410 or the base station ex107 by the car ex412 having the antenna ex411 and reproduce a moving image on a display device such as the car navigation ex413 that the car ex412 has.
[0120]
Furthermore, the image signal can be encoded by the moving image encoding apparatus shown in the above embodiment and recorded on a recording medium. As a specific example, there is a recorder ex420 such as a DVD recorder that records an image signal on a DVD disk ex421 or a disk recorder that records on a hard disk. Further, it can be recorded on the SD card ex422. If the recorder ex420 includes the moving picture decoding apparatus shown in the above embodiment, the image signal recorded on the DVD disc ex421 or the SD card ex422 can be reproduced and displayed on the monitor ex408.
[0121]
For example, the configuration of the car navigation ex413 may be a configuration excluding the camera unit ex203, the camera interface unit ex303, and the image encoding unit ex312 in the configuration illustrated in FIG. ) Ex401 can also be considered.
[0122]
In addition to the transmission / reception type terminal having both the encoder and the decoder, the terminal such as the mobile phone ex114 has three mounting formats: a transmitting terminal having only an encoder and a receiving terminal having only a decoder. Can be considered.
[0123]
As described above, the moving picture encoding method or the moving picture decoding method described in the above embodiment can be used in any of the above-described devices and systems, and as a result, the above-described embodiment has been described. An effect can be obtained.
[0124]
In addition, the present invention is not limited to the above-described embodiment, and various changes and modifications can be made without departing from the scope of the present invention.
[0125]
【The invention's effect】
As is clear from the above description, according to the motion vector deriving method according to the present invention, the division process necessary for scaling the reference motion vector can be performed by the multiplication process. Can be derived. Further, by limiting the parameter value used when scaling the reference motion vector to a predetermined range, the multiplier parameter table stored in the memory can be reduced. Therefore, since the processing load when deriving the motion vector is small, even a device with low processing capability can be processed, and its practical value is great.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of a moving picture encoding apparatus according to the present invention.
FIG. 2 is a block diagram showing a configuration of a motion vector deriving unit according to the present invention.
FIG. 3 is a diagram showing a multiplier parameter table according to the present invention.
FIG. 4 is a flowchart showing a method of deriving a motion vector according to the present invention.
FIG. 5 is an explanatory diagram of motion vectors according to the present invention.
FIG. 6 is a block diagram illustrating a configuration of a motion vector deriving unit according to the present invention.
FIG. 7 is a flowchart showing a method of deriving a motion vector according to the present invention.
FIG. 8 is an explanatory diagram of motion vectors according to the present invention.
FIG. 9 is an explanatory diagram of motion vectors according to the present invention.
FIG. 10 is a block diagram illustrating a configuration of a motion vector deriving unit according to the present invention.
FIG. 11 is a block diagram showing a configuration of a moving picture decoding apparatus according to the present invention.
FIG. 12 is an explanatory diagram of a recording medium for storing a program for realizing the moving picture encoding method and the moving picture decoding method of each embodiment by a computer system, and (a) the recording medium main body; An explanatory diagram showing an example of a physical format of a flexible disk, (b) an external view from the front of the flexible disk, a cross-sectional structure, and an explanatory diagram showing the flexible disk, and (c) recording and reproducing the program on the flexible disk FD. It is explanatory drawing which showed the structure for performing.
FIG. 13 is a block diagram showing an overall configuration of a content supply system.
FIG. 14 is a schematic diagram illustrating an example of a mobile phone.
FIG. 15 is a block diagram illustrating a configuration of a mobile phone.
FIG. 16 is a diagram illustrating an example of a digital broadcasting system.
FIG. 17 is an explanatory diagram of motion vectors.
FIG. 18 is a flowchart showing a flow of processing for obtaining a conventional motion vector.
[Explanation of symbols]
10 Motion vector encoding unit
11 Motion vector deriving unit
12 memory
13 Subtractor
14 Orthogonal transformation unit
15 Quantizer
16 Inverse quantization part
17 Inverse orthogonal transform unit
18 Adder
19 Variable length coding unit
20 comparison part
21 switching part
22 Multiplier parameter table (for multiplier)
23, 25 multiplier
24 Multiplier parameter table (for divisor)
1000 Variable length decoding unit
1001 Inverse quantization unit
1002 Inverse orthogonal transform unit
1003 Addition calculation unit
1004 Decoding unit for motion vector
1005 Motion vector deriving unit
1006 memory

Claims (2)

A motion vector deriving method for deriving a motion vector of blocks constituting a picture,
Determining a reference motion vector for deriving a motion vector of the target block,
Determining a first parameter corresponding to the distance between the reference picture in which the reference motion vector and a motion compensated picture is referenced using the reference motion vector,
Determining a second parameter corresponding to a distance between the picture and the reference picture including the current block,
A determination step of determining whether or not the first parameter is included in a range having a predetermined value as an upper limit ;
If it is determined in decision step, when said first parameter is not included in the range of up to the predetermined value, the by scaling the reference motion vector based on the predetermined value and the second parameter target block On the other hand, when the first parameter is included in the range having the predetermined value as an upper limit, the reference motion vector is scaled based on the first parameter and the second parameter, and the target block A motion vector deriving method, comprising: a motion vector deriving step for deriving a motion vector of. A motion vector deriving device for deriving a motion vector of a block constituting a picture,
Means for obtaining a reference motion vector for deriving a motion vector of the target block;
Means for determining a first parameter corresponding to an interval between a picture motion-compensated using the reference motion vector and a reference picture referenced by the reference motion vector;
Means for obtaining a second parameter corresponding to an interval between the picture including the target block and the reference picture; and judgment means for determining whether or not the first parameter is included in a range having a predetermined value as an upper limit. When,
If it is determined in the determination unit, wherein when the first parameter is not included in the range of up to the predetermined value, the by scaling the reference motion vector based on the predetermined value and the second parameter target block On the other hand, when the first parameter is included in the range having the predetermined value as an upper limit, the reference motion vector is scaled based on the first parameter and the second parameter, and the target block A motion vector deriving device comprising: motion vector deriving means for deriving a motion vector of

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