JP2004194297A - Method for encoding and decoding motion picture - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To appropriately and effectively utilize the maximum value of a reference index and a command also for field encoding in frame/field switching encoding in a macro block unit. <P>SOLUTION: In the motion picture encoding method for performing encoding by switching frame encoding to field encoding or vice versa in the block unit within a picture, the frame reference index designating a reference frame and a frame command serving as an offset to the number of a frame to be a reference are assigned to the reference frame (S11), and the number of field reference indexes is determined on the basis of the number of frame reference indexes. Within the range of the determined number, the field reference index designating the reference field is assigned to the field (S12, S13). <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

  The present invention relates to a moving picture coding method and a moving picture decoding method, and more particularly to a coding method and a decoding method for performing inter-picture prediction with reference to already coded pictures.

  In recent years, with the development of multimedia applications, it has become common to handle information of all kinds of media such as images, sounds, and texts in a unified manner. Since a digitized image has an enormous amount of data, an image information compression technique is indispensable for storage and transmission. For interoperability of compressed image data, standardization of compression technology is also important. Standards for image compression technology include H.264 of ITU-T (International Telecommunication Union Telecommunication Standardization Sector). 261, H .; H.263, MPEG-1, MPEG-2 and MPEG-4 of ISO (International Organization for Standardization). In addition, the ITU is currently using H.264 as the latest image coding standard. 26L is under standardization.

Generally, in coding of a moving image, the amount of information is compressed by reducing redundancy in the time direction and the space direction. Therefore, in the inter-picture prediction coding for the purpose of reducing temporal redundancy, motion detection and prediction image creation are performed in block units with reference to the forward or backward picture, and the obtained predicted image and the current Encoding is performed on the difference value from the picture.
Here, a picture is a term representing one image, which means a frame in a progressive image and a frame or a field in an interlaced image. Here, an interlaced image is an image in which one frame is composed of two fields at different times. In encoding and decoding of an interlaced image, one frame can be processed as a frame, processed as two fields, or processed as a frame structure or a field structure for each block in the frame. .

Note that the picture described below is described in terms of a frame in a progressive image, but the same can be applied to a frame or a field in an interlaced image.
FIG. 35 is a diagram for explaining types of pictures and their reference relationships.
A picture that does not have a reference picture and performs intra-picture prediction coding, such as picture I1, is called an I picture. A picture such as picture P10 that performs inter-picture predictive coding by referring to only one picture is called a P picture. A picture that can perform inter-picture predictive coding by simultaneously referring to two pictures is called a B picture. The B picture can refer to two pictures in arbitrary directions in time, such as pictures B6, B12, and B18. The reference picture can be specified for each block, which is a unit of motion detection. The reference picture described earlier in the encoded code sequence is referred to as the first reference picture, and the reference picture described later is referred to as the first reference picture. Distinguishing as two reference pictures. However, as a condition for encoding and decoding these pictures, the picture to be referred to must be already encoded and decoded. FIG. 36A and FIG. 36B are examples of the order when encoding and decoding a B picture. FIG. 36A shows the display order, and FIG. 36B shows the display order of FIG. 36A in the order of encoding and decoding. It can be seen that the pictures referred to by pictures B3 and B6 are all rearranged as if they were encoded and decoded first.

  Next, a reference index for designating a reference picture will be described with reference to FIGS. Here, for simplicity, a number for identifying an actual picture is called a picture number, and a number used when designating a picture to be referred to in inter prediction is called a reference index. At this time, the one indicating the first reference picture is set as the first reference index, and the one indicating the second reference picture is set as the second reference index. The reference index is assigned a default value as shown in FIG. 37 as an initial state, but the assignment can be changed by a command.

  FIG. 37 shows a result of initial assignment of two reference indices to a picture number in frame encoding, and FIG. 38 shows an updated reference index of FIG. 37 using a command. When there is a picture sequence arranged in the coding order as shown in the figure, the picture numbers are assigned to the pictures held in the memory in the coding order. A command for assigning a reference index to a picture number is described in a slice header, which is a coding unit obtained by further dividing a picture, and the assignment method can be updated each time one slice is encoded. An arbitrary number of commands can be encoded as a command sequence using a difference value between an original picture number and an updated picture number as the command. The first command in the command sequence is applied to the picture number of the picture to be encoded, and indicates the picture number corresponding to reference index number 0. The second command in the command sequence is applied to the picture number corresponding to reference index number 0, and indicates the picture number corresponding to reference index number 1. The third command is applied to a picture number corresponding to reference index number 1 and indicates a picture number corresponding to reference index number 2. The same applies to the fourth and subsequent commands. Using the example of the first reference index in FIG. 38, “−2” is given as a command first, so that the reference index number 0 is obtained by adding −2 to the picture number 13 of the picture to be coded. The number picture is assigned. Next, since "+1" is given as a command, the twelfth picture is assigned to the reference index number 1 by adding +1 to the number 11 of the picture corresponding to the reference index number 0. Thereafter, the same processing is performed to assign each picture number. The same applies to the case of the second reference index.

  FIG. 39 is a schematic diagram illustrating an example of a code string when the above-described coding is performed. As shown in the figure, the maximum number of reference indices Max_idx1 for the first reference index (ref1) and the maximum number of reference indices Max_idx2 for the first reference index (ref2) are described in the picture common information of the code string, and the slice header is described. Describes reference index assignment command strings idx_cmd1 and idx_cmd2 for ref1 and ref2.

Non-Patent Document 1 is a document relating to such prior art.
ITU-T Rec.H.264 | ISO / IEC 14496-10 AVC Joint Final Committee Draft of Joint Video Specification (2002-8-10) (P.54 8.3.6.3 Default index orders / P.56 8.3.6.4 Changing the default index orders)

  By the way, as a method of encoding an interlaced image, it is possible to switch between frame encoding and field encoding for each macroblock in one image. This is referred to as "macroblocks adaptive frame / field coding (MBAFF)". In this method, as shown in FIG. 40, two macroblocks arranged in the vertical direction can be set as one pair and switched for each pair. In the case of frame coding, both are coded in frames, and in the case of field coding, coding is performed separately for macroblocks consisting only of odd lines and macroblocks consisting only of even lines.

  In macroblock unit frame field switching coding, as shown in FIGS. 41A and 41B, a reference picture is switched to a frame structure and a field structure each time according to a coding method of a macroblock pair. Used for reference. When encoding a macroblock pair to be encoded as a frame as shown in FIG. 41A, a reference picture is referred to as a frame like P1 to P3. In the case of coding a macroblock pair to be coded as a field as shown in FIG. 41 (b), the reference picture is divided into a top field and a bottom field such as P1T to P3B and referred to as a field. . At this time, the number of reference pictures is twice as large as that of a frame when counted in fields.

  However, the maximum number of reference indices (max_idx1 and max_idx2, see FIG. 39) and the command sequence for updating the allocation (idx_cmd1 and idx_cmd2, see FIG. 39) used when assigning a reference index to each picture are frame and frame. Since both fields cannot be handled at the same time, there is a problem that the maximum number of reference indices and a command for allocation cannot be determined well when performing macroblock-based frame field switching coding.

  Therefore, the present invention provides an image encoding method and an image decoding method that appropriately utilize a reference index in any of frame encoding and field encoding in case of macroblock unit frame field switching encoding. Aim.

  In order to achieve this object, an encoding method according to the present invention is a video encoding method for performing encoding by switching between frame encoding and field encoding on a block basis in a picture. A field coding reference index that specifies a field to be referred to at the time of field coding is assigned to a field using a frame coding reference index that specifies a frame to be referred to at some time.

According to this configuration, the reference index for frame encoding can be used for assigning the reference index for field encoding. In other words, the frame coding reference index can be appropriately used not only for frame coding but also for field coding.
Here, the moving picture coding method includes a specifying step of specifying two fields forming a frame specified by the reference index for frame coding, and a coding target block among the two specified fields. For a field having the same parity, a value obtained by doubling the value of the reference index for frame encoding is assigned as a reference index for field encoding. Allocating a value obtained by doubling the value of the encoding reference index and adding 1 as a field encoding reference index.

According to this configuration, the field-encoding reference index is assigned to values twice and twice as large as the frame-encoding reference index according to the parity of the field. It is very easy to assign a field coding reference index.
Here, the moving picture coding method further includes a determining step of determining a maximum number of reference indexes for field coding to be twice the maximum number of reference indexes for frame coding; In the above, the configuration may be such that a frame encoding reference index is assigned within the determined maximum number.

According to this configuration, the number of reference indices for field encoding can be assigned twice as many as the maximum number of reference indices for frame encoding. Therefore, the reference indices for frame encoding can be used as effectively as possible.
Here, the moving picture coding method includes a specifying step of specifying two fields constituting a frame specified by a frame coding reference index, and a top field of the specified two fields. A value obtained by doubling the value of the reference index for frame coding is assigned as a reference index for field coding, and a value obtained by doubling the value of the reference index for frame coding and adding 1 to a field code is assigned to the bottom field. And allocating as a reference index for conversion.

  The moving picture coding method may further include a specifying step of specifying two fields constituting the frame specified by the frame coding reference index, and, of the two specified fields, the same parity as the coding target block. And assigning the same value as the frame encoding reference index as the field encoding reference index only to the field having

  Here, the video encoding method further generates a command sequence indicating a method of assigning a reference index for frame encoding, and a command sequence indicating a method of assigning a reference index for field encoding, respectively, It may be configured to include an additional step of encoding two sets of command strings and adding them to the encoded signal.

  The video encoding method further includes a command sequence indicating a method of assigning a reference index for frame encoding, a command sequence indicating a method of assigning a reference index for top field encoding, and a reference index for assigning a reference index for bottom field encoding. And a command sequence indicating a method of assigning the three sets of commands may be generated independently, and the three sets of command sequences may be encoded and added to an encoded signal.

  The moving picture coding method may further comprise: a determining step of determining a maximum number of reference indices for field coding; and a frame coding for designating a frame to be referred to during frame coding within a range of the determined maximum number. An assignment step of assigning a field-encoding reference index for designating a field to be referred to at the time of field encoding using the reference index to the field.

Here, in the determining step, the maximum number of reference indexes for field coding may be determined to be twice the maximum number of reference indexes for frame coding.
According to this configuration, the number of reference indices for field coding is within the range of twice the maximum number of reference indices for frame coding, and the maximum number of reference indices for frame coding can be effectively utilized.

Here, in the determining step, the maximum number of reference indexes for field coding may be determined to be the same value as the maximum number of reference indexes for frame coding.
According to this configuration, the field coding reference index can utilize the frame coding reference index as effectively as possible within the range of the maximum number of frame coding reference indexes.

Here, the video encoding method further comprises independently determining a maximum number of reference indices for frame encoding and a maximum number of reference indices for field encoding, and encoding and encoding the two maximum numbers. It may be configured to have an additional step of adding to a signal.
According to this configuration, the maximum number of reference indices for field coding can be independently determined without depending on the maximum number of reference indices for frame coding. The maximum number can be notified.

  Here, the moving picture coding method further determines the maximum number of reference indices for frame coding, the maximum number for the top field, and the maximum number for the bottom field independently, and codes the three maximum numbers. It may be configured to have an additional step of adding the encoded signal to the encoded signal.

As described above, according to the encoding method of the present invention, when performing macroblock unit frame field switching encoding, the frame reference index, the maximum number of the frame reference index, and the frame command are originally encoded by the frame encoding. In addition, it can be appropriately used for field coding.
Further, the moving picture decoding method, the moving picture coding apparatus, the moving picture decoding apparatus and the program according to the present invention have the same configuration, operation and effect as those described above.

(Embodiment 1)
<Overview of Encoder and Decoder>
First, an overview of an encoding device and a decoding device according to the present embodiment will be described.
The encoding device and the decoding device according to the present embodiment perform macroblock unit frame field switching encoding. At this time, the following (1.1) and (1.2) are used for the maximum number of reference indices and the command sequence. Handle as Here, reference indices and commands are the same as those shown in FIG. 38, and the maximum number of reference indices is the same as that shown in FIG.

  (1.1) Regarding the maximum number of reference indices The coding apparatus describes the maximum number of reference indices for a frame in a transmitted code when field coding and frame coding are mixed. In the case of frame encoding, the encoding apparatus treats the maximum number as the number of usable reference indices. On the other hand, in the case of field encoding, the double value indicated by the maximum number is regarded as the number of field reference indices. For example, when reference indices for a frame are assigned from 0 to 2, the maximum number of reference indices for a frame is three. In the case of frame coding, it means the frame itself. In the case of field coding, 6 which is twice the maximum number of reference indexes for frame coding is regarded as the maximum number of reference indexes for field coding. The same applies to the decoding device.

  (1.2) As for the command sequence, the encoding device describes a frame command in a transmitted code. The encoding device assigns a frame reference index as described with reference to FIG. 38 when encoding the frame. When the command sequence is not encoded, the reference index is associated with the default assignment method as described with reference to FIG.

Further, in the field encoding, the assignment of the reference index for field encoding is updated on the premise of the reference index for the assigned frame.
In other words, a value obtained by doubling the value of the reference index for the frame with respect to a field having the same parity as the macroblock to be coded is different from the macroblock to be coded among the two fields constituting one frame. A value obtained by doubling the value of the reference index and adding 1 to the parity field (2 times +1) is assigned as a field reference index (see FIG. 4). Here, parity refers to the evenness of a field (the distinction between a top field composed of odd lines and a bottom field composed of even lines).

  In other words, if the macroblock to be coded belongs to the top field, a value obtained by doubling the value of the reference index for the frame is assigned to the top field of the two fields, and (2x + 1) is assigned to the bottom field. If the macroblock to be coded belongs to the bottom field, a value obtained by doubling the value of the reference index for the frame is assigned to the bottom field of the two fields, and the top field of the two fields is assigned to the top field of the two fields. (2 + 1).

  On the other hand, the decoding device decodes the maximum number of reference indices and the allocation command for the frame included in the transmitted code, and uses them to allocate the reference picture and the reference index in exactly the same manner as the coding device. I do.

<Configuration of encoding device>
Next, the configuration of the encoding device will be described.
FIG. 1 is a block diagram illustrating a configuration of a moving picture encoding device according to Embodiment 1 of the present invention. A description will be given of (1) an outline of encoding, (2) a method of assigning a frame reference index and a command, and a field reference index with reference to FIG.

(1) Outline of Encoding Here, it is assumed that an encoding target is a picture meaning either a frame or a field, and an outline of encoding common to frame encoding and field encoding will be described.
A moving image to be encoded is input to the picture memory 101 in units of pictures in the order of display, and the pictures are rearranged in the order of encoding. FIGS. 36A and 36B are diagrams showing an example of rearrangement. FIG. 36A shows an example of pictures arranged in the order of display, and FIG. 36B shows an example of pictures rearranged in the order of encoding. Since B3 and B6 here refer to both the forward and backward temporally, it is necessary to encode the picture to be referenced before encoding these pictures. In 36 (b), P4 and P7 are rearranged so as to be coded first. Further, each picture is divided into blocks of, for example, 16 × 16 pixels, which are called macroblocks, and the subsequent processing is performed in block units.

  An input image signal read from the picture memory 101 is input to a difference calculation unit 110, and a difference image signal obtained by taking a difference from a prediction image signal output from the motion compensation encoding unit 107 is converted into a prediction residual code. Output to the conversion unit 102. The prediction residual encoding unit 102 performs image encoding processing such as frequency conversion and quantization, and outputs a residual encoded signal. The residual coded signal is input to the prediction residual decoding unit 104, and performs image decoding processing such as inverse quantization and inverse frequency transform to output a residual decoded signal. The addition operation unit 111 generates a reconstructed image signal by adding the residual decoded signal and the predicted image signal, and it is likely that the reconstructed image signal will be referred to in the subsequent inter-picture prediction in the obtained reconstructed image signal. A certain signal is stored in the picture memory 105.

  On the other hand, the input image signal in macroblock units read from the picture memory 101 is also input to the motion vector detection unit 106. Here, a reconstructed image signal stored in the picture memory 105 is set as a search target, and a motion vector indicating the position is determined by detecting an image area closest to the input image signal. The motion vector detection is performed for each block obtained by further dividing the macroblock, and the obtained motion vector is stored in the motion vector storage unit 108. At this time, the H.264 standard currently being standardized. In the 26L, since a plurality of pictures can be used as a reference target, an identification number for designating a picture to be referred to is required for each block. The identification number is called a reference index, and the reference index / picture number conversion unit 109 can specify a reference picture by associating with a picture number of a picture in the picture memory.

  The motion compensation encoding unit 107 extracts an optimal image area for a predicted image from the reconstructed image signal stored in the picture memory 105 using the motion vector and the reference index detected by the above processing. At this time, it is determined which of the method of performing prediction in units of frames and the method of performing prediction in units of fields is more efficient for each macroblock, and coding is performed using the selected method. The encoding apparatus outputs the encoded information such as the reference index, the motion vector, the residual encoded signal, and the like output by the above-described series of processing, by performing variable-length encoding in the encoded stream generation unit 103. A code sequence is obtained.

  The flow of the processing described above is the operation in the case where the inter-picture prediction coding is performed. However, the switch to the intra-picture prediction coding is performed by the switches 112 and 113. When performing intra-coding, a predicted image is not generated by motion compensation, but a differential image signal is generated by generating a predicted image of a coding target region from a coded region in the same image and taking a difference. . The difference image signal is converted into a residual coded signal in a prediction residual coder 102 and subjected to variable-length coding in a code sequence generator 103, as in the case of inter-picture prediction coding, and is output. Is obtained.

(2) Reference index allocation method <Reference index allocation example>
First, examples of assignment of a frame reference index and a field reference index are shown in FIGS.

  FIG. 2 shows an example of assignment of default reference indices when a block of a picture to be encoded performs frame encoding. Indices are assigned in ascending order of the picture number. Such assignment is always performed when the assignment command is not encoded. FIG. 3 shows an example in which the reference index is updated by the assignment command with respect to the default reference index shown in FIG. First, since "-2" is given as a command, a picture having a picture number of 11 is assigned to the reference index of 0 by adding -2 to the number 13 of the picture to be coded. Next, "+1" is given as a command, and the picture of picture number 12 is assigned to reference index number 1. Thereafter, the same processing is performed to assign each picture number. The same applies to the case of the second reference index. In the following, a description will be given based on FIG. 2 in which default assignment is performed. However, the case where the assignment is changed by a command can be handled in exactly the same manner. Note that the above command is an example, and the case where the index is updated by a command having another allocation method can be handled in exactly the same manner.

  FIG. 4 shows the first and second reference indices for the top and bottom fields for the first and second reference indices for the frame shown in FIG. 2 according to the above (1.1) and (1.2). FIG. 9 is an explanatory diagram showing a result of associating reference indices; In FIG. 4, a field of the same parity as the macroblock to be encoded is assigned a value twice as large as the reference index for the frame, and a field with a different parity is assigned a value of +1 times the value of the reference index for the frame. You can see that it is.

  In the present embodiment, when field coding and frame coding are mixed in one picture, when performing field coding, the maximum number of reference indices is set to twice the value when performing frame coding. For handling, the number of indexes is three in FIG. 2, but the number of indexes is six in FIG.

<Reference index allocation processing>
FIG. 5 is a flowchart illustrating a reference index assignment process in the reference index / picture number conversion unit of the encoding device.

  The reference index / picture number conversion unit 109 performs reference index assignment processing for each slice when performing macroblock unit frame field switching encoding. Here, the slice indicates each area when one picture is divided into one or a plurality of areas. If there is no change in the reference index (the default case), the reference index / picture number conversion unit 109 omits all the processes in FIG.

  As shown in the drawing, the reference index / picture number conversion unit 109 first performs a process of allocating a frame reference index and a command to a frame (S11). This process is the same as that of FIG. Next, the reference index / picture number conversion unit 109 determines whether frame encoding and field encoding are mixed in the slice (S12). If mixed, the field reference index assigning process is performed (S12). S13).

  FIG. 6 is a flowchart illustrating a process of assigning a field reference index to a frame reference index and assigning the field reference index to a field. In the figure, the variable j is j = 1, 2 for a B picture, j = 1 for a P picture, max_idxj is the maximum number of the j-th reference index for a frame, and idxj (i) is Represents the value of the i-th j-th reference index for a frame. Loop 2 is adapted to be commonly applicable to the case of a B picture and the case of a P picture. Loop 1 is a loop of the maximum number of frame reference indices (max_idxj) times, and two field reference indices are assigned each time.

  Hereinafter, a process of allocating two field reference indices for one loop of loop 1, that is, a reference index for one frame will be described. The reference index / picture number conversion unit 109 reads the value idxj (i) of the i-th j-th reference index for the frame allocated in S11 of FIG. 5 (S23), and sets the macroblock to be coded in the top field. It is determined whether or not they belong (S26).

  If it is determined that the frame belongs to the top field, a value (S27) obtained by doubling the reference index idxj (i) for the frame is assigned to the top field of the two fields specified in S25 (S28). The value obtained by doubling (i) and adding 1 (S29) is assigned to the bottom field of the two fields specified in S25 (S30).

  If it is determined that the frame is the bottom field, a value (S31) obtained by doubling the reference index idxj (i) for the frame is assigned to the bottom field of the two fields specified in S25 (S32). The value obtained by doubling (i) and adding 1 (S33) is assigned to the top field of the two fields specified in S25 (S34).

In this manner, the value twice (2 times +1) of the frame reference index is assigned to the field reference index. As a result, as shown in FIG. 4, the maximum number of field reference indices is twice the maximum number of frame reference indices (max_idxj).
When coding a macroblock, reference indices for fields used as reference fields in the field-coded macroblock are set in the code as ref1 and ref2 (see FIG. 39). On the other hand, the reference indices for the frames used as reference frames in the frame-coded macroblock are set in the code as ref1 and ref2 (see FIG. 39).

In the example of FIG. 2, the number of frame reference indices is three, and in the example of FIG. 4, the number of field reference indices is six.
Although FIG. 6 illustrates the process of assigning a field reference index to each of the pictures to be coded to be field-coded, a table may be created in advance. That is, a correspondence table between the reference index for the frame and the picture number of the frame is created according to the command, and reference indexes are assigned to the top field and the bottom field in the same manner as in FIG. And a correspondence table between the field reference and the picture number of the field, and a correspondence table between the reference index for the bottom and the picture number of the field. Also, if this table is created only once at the beginning when encoding and decoding a picture, thereafter, by referring to this table for a reference index, a reference picture can be determined.

<Configuration of decoding device>
FIG. 7 is a block diagram showing a configuration of the decoding device according to Embodiment 1 of the present invention. With reference to the figure, (1) an outline of decoding and (2) a reference index conversion process will be described in this order. Here, it is assumed that the code from the encoding device of FIG. 1 is transmitted to the present decoding device.
(1) Outline of Decoding First, the maximum number of reference indexes from the picture common information area, the reference index allocation command string from the slice header area, and the block coding information area , Various information such as a reference index, motion vector information, and a prediction residual coded signal are extracted.

The maximum number of reference indices and the reference index allocation command sequence extracted by the code sequence analysis unit 201 are stored in the reference index / picture number conversion unit 206, the reference index is stored in the motion compensation decoding unit 204, and the motion vector information is stored in the motion vector. The prediction residual coded signal is output to unit 205 and prediction residual decoding unit 202, respectively.
The prediction residual decoding unit 202 performs image decoding processing such as inverse quantization and inverse frequency transform on the input residual encoded signal, and outputs a residual decoded signal. The addition operation unit 207 performs addition of the residual decoded signal and the prediction image signal output from the motion compensation decoding unit 204 to generate a reconstructed image signal, and obtains the reconstructed image signal between subsequent screens. The image data is stored in the picture memory 203 for use in reference in prediction and output for display.

  The motion compensation decoding unit 204 uses the motion vector input from the motion vector storage unit 205 and the reference index input from the code sequence analysis unit 201 to calculate a prediction image from the reconstructed image signal stored in the picture memory 203. The optimal image area. At this time, the reference index / picture number conversion unit 206 specifies the reference picture in the picture memory 203 by associating the given reference index with the picture number. At this time, when field coding is mixed, the reference field is designated after converting the frame reference index into the field reference index.

Further, the motion compensation decoding unit 204 performs a pixel value conversion process such as an interpolation process using linear prediction on the obtained pixel values of the image region, thereby creating a final predicted image. The decoded image generated by the above series of processing is stored in the picture memory 203, and is output as a display image signal in accordance with the display timing.
The flow of the processing described above is the operation in the case where the inter-picture prediction decoding is performed. When performing intra-screen decoding, a predicted image is not generated by motion compensation, but a predicted image of a decoding target area is generated from a decoded area in the same screen and a decoded image is generated by performing addition. . The decoded image is stored in the picture memory 203 and output as a display image signal in accordance with the display timing, as in the case of the inter prediction decoding.

(2) Reference Index Conversion Processing The reference index / picture number conversion unit 206 allocates a picture number and a reference index using the input maximum number of reference indexes and a reference index allocation command. The assignment method is exactly the same as that of the encoding device. In the present embodiment, a value twice as large as the maximum number of reference indexes for frame encoding is set as the maximum number of reference indexes for field encoding. Therefore, when the assignment as shown in FIG. 2 is performed in the frame encoding, the field encoding becomes as shown in FIG.

  As described above, according to the encoding apparatus and the decoding apparatus in the present embodiment, when performing macroblock unit frame field switching encoding, the maximum number of reference indices and the allocation command are used for frame encoding. Only by encoding only, it can be appropriately applied to not only frame encoding but also field encoding. In addition, since the maximum number of reference indices for fields is twice as large as that for frames, all of the fields held in the memory can be effectively used at the time of encoding and decoding.

(Embodiment 2)
<Overview of Encoder and Decoder>
First, an overview of an encoding device and a decoding device according to the present embodiment will be described.
The encoding device and the decoding device according to the present embodiment perform macroblock unit frame field switching encoding. At this time, the following (2.1) and (2.2) are used for the maximum number of reference indices and the command sequence. Handle as
(2.1) The maximum number of reference indices is the same as (1.1) described at the beginning of the first embodiment, and a description thereof will be omitted.

  (2.2) With regard to the command sequence, the encoding device describes a frame command in a transmitted code. The encoding device assigns a frame reference index as described with reference to FIGS. 37 and 38 at the time of frame encoding. When the command sequence is not encoded, the reference index is associated with the default assignment method as described with reference to FIG.

Further, in the field encoding, the assignment of the reference index for field encoding is updated on the premise of the reference index for the assigned frame.
In the present embodiment, unlike Embodiment 1, regardless of whether the current macroblock is the top or the bottom, of the top field of the two fields forming one frame, The value obtained by doubling the value of the reference index for the field and the value obtained by doubling the value of the reference index for the bottom field and adding 1 to the bottom field are assigned as the field reference index (see FIG. 9). ).

<Configuration of encoding device>
FIG. 8 is a block diagram illustrating a configuration of an encoding device according to Embodiment 2 of the present invention. The encoding apparatus shown in the figure is different from FIG. 1 in that a reference index / picture number conversion unit 109a is provided instead of the reference index / picture number conversion unit 109. The description of the same points as in FIG. 1 will be omitted, and different points will be mainly described. The reference index / picture number conversion unit 109a differs from FIG. 1 only in that the mapping of (2.2) is performed instead of the mapping (reference index assignment) of (1.2).

<Example of reference index assignment>
FIG. 9 shows the correspondence between the first and second reference indices for the frame and the first and second reference indices for the field shown in FIG. 2 according to (2.1) and (2.2) above. It is a figure showing a result. As shown in FIG. 9, mapping by reference index / picture number conversion section 109a in the present embodiment does not allocate reference indices separately for the top field and for the bottom field, but uses a common reference for the top and bottom. An index is assigned.

  In the present embodiment, when field coding and frame coding are mixed in one picture, when performing field coding, the maximum number of reference indices is set to twice the value when performing frame coding. For handling, the number of indexes is three in FIG. 2, but the number of indexes is six in FIG.

<Reference index assignment processing>
FIG. 10 is a flowchart illustrating reference index assignment processing in the reference index / picture number conversion unit of the encoding device.
The same step numbers are given to the same processes as those in the flowchart of FIG. 6, and the points that S26 and S31 to S34 in FIG. In that step S27 is executed. Due to this difference, a reference index for a field that is twice the number of reference indices for a frame is assigned, and a reference index for a common field is assigned to a top field and a bottom field, as shown in FIG. I have.

<Configuration of decoding device>
FIG. 11 is a block diagram showing a configuration of a decoding device according to Embodiment 2 of the present invention. The decoding apparatus of FIG. 11 differs from FIG. 7 in that a reference index / picture number conversion unit 206a is provided instead of the reference index / picture number conversion unit 206. The reference index / picture number conversion unit 206a differs from FIG. 7 only in that reference index conversion processing corresponding to the mapping of (2.2) is performed instead of the mapping of (1.2).

<Reference index conversion processing>
The reference index / picture number conversion unit 206a allocates a picture number and a reference index using the input maximum number of reference indexes and a reference index allocation command. The assignment method is exactly the same as that of the encoding device. In the present embodiment, a value twice as large as the maximum number of reference indexes for frame encoding is set as the maximum number of reference indexes for field encoding. Therefore, when the assignment as shown in FIG. 2 is performed in the frame encoding, the field encoding becomes as shown in FIG.

(Embodiment 3)
<Overview of Encoder and Decoder>
First, an overview of an encoding device and a decoding device according to the present embodiment will be described.
The encoding device and the decoding device in the present embodiment perform macroblock unit frame field switching encoding. At this time, the following (3.1) and (3.2) are used for the maximum number of reference indices and the command sequence. Handle as

  (3.1) Regarding the maximum number of reference indices The coding apparatus describes the maximum number of reference indices for a frame in a transmitted code when field coding and frame coding are mixed. The encoding device treats the maximum number as the number of usable reference indices in the case of frame encoding, and treats the same number as the number of reference indices for field encoding in the case of field encoding. For example, if the maximum number of reference indices for a frame is 3, the maximum number of reference indices for a field is also treated as 3.

  (3.2) The command sequence is the same as (1.2) described at the beginning of the first embodiment, and thus the description is omitted. However, since the maximum number of reference indices given by (3.1) uses the same value for frame encoding and field encoding, only the same number as in FIG. 2 can be allocated in the case of field encoding. No (see FIG. 13).

<Configuration of encoding device>
FIG. 12 is a block diagram illustrating a configuration of an encoding device according to Embodiment 3 of the present invention. The encoding apparatus shown in FIG. 11 is different from FIG. 1 in that a reference index / picture number conversion unit 109b is provided instead of the reference index / picture number conversion unit 109. The reference index / picture number conversion unit 109b differs from FIG. 1 only in that the reference index / picture number conversion unit 109b handles the number of reference indices according to (3.1) instead of (1.1).

<Example of reference index assignment>
FIG. 13 shows that the first and second reference indices for the field are associated with the first and second reference indices for the frame shown in FIG. 2 according to the above (3.1) and (3.2). It is a figure showing a result. As shown in FIG. 13, mapping by reference index / picture number conversion section 109b according to the present embodiment assigns reference indices separately for the top field and the bottom field, as in the first embodiment. Is the same as the maximum number of reference indices for frames.

<Configuration of decoding device>
FIG. 14 is a block diagram showing a configuration of a decoding device according to Embodiment 3 of the present invention. The decoding apparatus of FIG. 11 is different from FIG. 7 in that a reference index / picture number conversion unit 206b is provided instead of the reference index / picture number conversion unit 206. The reference index / picture number conversion unit 206b differs from FIG. 7 only in that the reference index / picture number conversion unit 206b performs a reference index conversion process corresponding to the maximum number of (3.2) instead of the maximum number of (1.1).

(Embodiment 4)
<Overview of encoding device and decoding device>
First, an overview of an encoding device and a decoding device according to the present embodiment will be described.
The encoding device and the decoding device according to the present embodiment perform macroblock unit frame field switching encoding. At this time, the following (4.1) and (4.2) are used for the maximum number of reference indices and the command sequence. Handle as
(4.1) The maximum number of reference indices is the same as (3.1) described at the beginning of the third embodiment, and a description thereof will be omitted.
(4.2) The description is omitted because it is the same as (2.2) described in the beginning of the second embodiment. However, since the maximum number of reference indices given by (4.1) uses the same value for frame encoding and field encoding, only the same number as in FIG. 2 can be allocated even in the case of field encoding. No (see FIG. 16).

<Configuration of encoding device>
FIG. 15 is a block diagram illustrating a configuration of an encoding device according to Embodiment 4 of the present invention. The encoding apparatus of FIG. 11 differs from FIG. 8 in that a reference index / picture number conversion unit 109c is provided instead of the reference index / picture number conversion unit 109a. The reference index / picture number conversion unit 109c differs from FIG. 8 only in that it handles the maximum number of reference indices according to (4.1) instead of (2.1).

<Example of reference index assignment>
FIG. 16 shows that the first and second reference indices for the frame shown in FIG. 2 correspond to the first and second reference indices for the field according to the above (4.1) and (4.2). It is a figure showing a result. As shown in FIG. 16, mapping by reference index / picture number conversion section 109b in the present embodiment assigns a common reference index to the top and bottom of the current macroblock, as in Embodiment 2. The difference is that the maximum number of reference indices for fields is the same as the maximum number of reference indices for frames.

<Configuration of decoding device>
The decoding device according to the present embodiment may be the same as the decoding device according to the second embodiment. However, the only difference is that the maximum number of reference indices for the field is not the double of the maximum number for the frame, but is the same.

(Embodiment 5)
<Overview of Encoder and Decoder>
First, an overview of an encoding device and a decoding device according to the present embodiment will be described.
The encoding device and the decoding device according to the present embodiment perform macroblock unit frame field switching encoding. At this time, the following (5.1) and (5.2) are used for the maximum number of reference indices and the command sequence. Handle as
(5.1) The maximum number of reference indices is the same as (3.1) described at the beginning of the third embodiment, and a description thereof will be omitted.

  (5.2) As for the command sequence, the encoding device describes a frame command in a transmitted code. The encoding device assigns a frame reference index as described with reference to FIGS. 37 and 38 at the time of frame encoding. When the command sequence is not encoded, the reference index is associated with the default assignment method as described with reference to FIG.

Further, in the field encoding, the assignment of the reference index for field encoding is updated on the premise of the reference index for the assigned frame.
In the present embodiment, unlike the first embodiment, the value of the reference index for the frame is set to the field of the same parity as that of the macroblock to be encoded, of the two fields constituting one frame. It is allocated as it is as a reference index for use, and is not allocated to a field of a different parity (see FIG. 18).

  In other words, if the macroblock to be coded belongs to the top field, the value of the frame reference index is assigned to the top field of the two fields as the field reference index. If the macroblock to be coded belongs to the bottom field, the value of the frame reference index is assigned to the bottom field of the two fields as the field reference index.

  On the other hand, the decoding device decodes the maximum number of reference indices and the allocation command for the frame included in the transmitted code, and uses them to allocate the reference picture and the reference index in exactly the same manner as the coding device. I do.

<Configuration of encoding device>
FIG. 17 is a block diagram showing a configuration of an encoding device according to Embodiment 5 of the present invention. The difference is that the reference index / picture number conversion unit 109 in FIG. 1 is replaced with a reference index / picture number conversion unit 109d in order to support the above (5.1) and (5.2).

<Example of reference index assignment>
FIG. 18 shows that the first and second reference indices for the field are associated with the first and second reference indices for the frame shown in FIG. 2 according to the above (5.1) and (5.2). It is a figure showing a result. As shown in FIG. 18, the value of the frame reference index is assigned as a field reference index to a field having the same parity as the macroblock to be encoded, and is not assigned to a field having a different parity.

<Reference index assignment processing>
FIG. 19 is a flowchart illustrating reference index assignment processing in the reference index / picture number conversion unit of the encoding device. 6 is different from FIG. 6 in that S81 is provided instead of S27 to S30 in FIG. 6 and that S82 is provided in place of S31 to S34.

<Configuration of decoding device>
FIG. 20 is a block diagram showing a configuration of a decoding device according to Embodiment 5 of the present invention. 7 differs from FIG. 7 in that a reference index / picture number conversion unit 206d is provided instead of the reference index / picture number conversion unit 206.

  The reference index / picture number conversion unit 206d converts the field index into the top field only if the decoding target is the top, and only the bottom field if the decoding target is the bottom, by the same operation as the mapping in (5.2). Is mapped.

(Embodiment 6)
<Overview of Encoder and Decoder>
First, an overview of an encoding device and a decoding device according to the present embodiment will be described.
The encoding device and the decoding device according to the present embodiment perform macroblock unit frame field switching encoding. At this time, the following (6.1) and (6.2) are used for the maximum number of reference indices and the command sequence. Handle as Here, reference indices and commands are shown in FIG. 37, and the maximum number of reference indices is the same as that shown in FIG.

(6.1) Regarding the maximum number of reference indices, the coding apparatus only describes the maximum number of reference indices for a frame in a transmitted code when field coding and frame coding are mixed. Instead, the maximum number of reference indices for the top field and the maximum number of reference indices for the bottom field are also described.
The decoding device follows the maximum number of reference indices for the top field and the maximum number of reference indices for the bottom field described in the code.

  (6.2) The command sequence is the same as in (1.2), and a description thereof will not be repeated. However, the reference index for the top field is handled so as not to exceed the maximum number described in the code. The same applies to the reference index for the bottom field.

  On the other hand, the decoding device decodes the maximum number of reference indices and the allocation command for the frame and the top field and the bottom field included in the transmitted code, and uses them to perform the same method as the coding device. To assign reference pictures and reference indices.

<Configuration of Encoding Device and Decoding Device>
The encoding device and the decoding device according to the present embodiment may be the same as the encoding device and the decoding device according to the first embodiment. However, the maximum number of the reference indices for the top field and the maximum number of the reference indices for the bottom field are not twice as large as the reference indices for the frame, but are described in the code, and thus follow.

<Data structure>
FIG. 21 is a diagram illustrating a data configuration of a code string according to Embodiment 6 of the present invention. In the figure, Max_idx1 included in the picture common information corresponds to a first reference picture ref1, and the maximum number of reference indices for a frame (Max_idx_frm), the maximum number of reference indices for a top field (Max_idx_top), The maximum number of reference indices for the bottom field (Max_idx_btm) is described.

  FIG. 22 is a diagram illustrating an example in which first and second reference indices are assigned to the picture numbers of the fields when performing field coding. In the case of the figure, while Max_idx_top is 5, Max_idx_btm is described as 6. As described above, the encoding device and the decoding device according to the present embodiment can flexibly set the maximum number of reference fields at the top and the bottom.

Note that the maximum number of reference indices for the top field and the maximum number of reference indices for the bottom field are individually described in the code (see (6.1)). A configuration in which one is described with a common number may be used.
Further, in (6.2), as in (1.2), of the two fields constituting the reference frame specified by the frame reference index and the command, a field having the same parity as the macroblock to be encoded On the other hand, a value obtained by doubling the value of the reference index for the frame and doubling the value of the reference index and adding 1 to a field having a parity different from that of the encoding-target macroblock (double +1) Are respectively assigned as field reference indexes (see FIG. 4). Instead, as in (2.2), a value obtained by doubling the value of the frame reference index with respect to the top field among the two fields constituting the reference frame specified by the frame reference index and the command. May be assigned to the bottom field by doubling the value of the reference index and adding 1 to the bottom field (double +1) as the field reference index (see FIG. 9).

(Embodiment 7)
<Overview of Encoder and Decoder>
First, an overview of an encoding device and a decoding device according to the present embodiment will be described.
The encoding device and the decoding device according to the present embodiment perform macroblock unit frame field switching encoding. At this time, the following (7.1) and (7.2) are used for the maximum number of reference indices and the command sequence. Handle as Here, reference indices and commands are shown in FIG. 37, and the maximum number of reference indices is the same as that shown in FIG.
(7.1) The maximum number of reference indices is exactly the same as in (6.1), and a description thereof will be omitted.

  (7.2) With regard to the command sequence, the coding apparatus performs not only the reference index and command for the frame but also the reference index and command for the top field and the reference index and command for the bottom field in the transmitted code. Write it down. The encoding device assigns a frame reference index at the time of frame encoding, and assigns a top field reference index and a bottom field reference index at the time of field encoding.

  On the other hand, the decoding device decodes the maximum number of reference indices and the allocation command for the frame and the top field and the bottom field included in the transmitted code, and uses them to perform the same method as the coding device. To assign reference pictures and reference indices.

<Configuration of encoding device>
FIG. 23 is a block diagram illustrating a configuration of an encoding device according to Embodiment 7 of the present invention. This figure differs from FIG. 1 in that a reference index / picture number conversion unit 109e is provided instead of the reference index / picture number conversion unit 109.

  FIG. 24 is a diagram illustrating a data configuration example of a code string according to the present embodiment. In the figure, idx_cmd1 is a command group for the first reference picture ref1, and includes idx_cmd_frm, idx_cmd_top, and idx_cmd_btm. idx_cmd_frm is a command sequence for a reference index for a frame. idx_cmd_top is a command string for the reference index for the top field. idx_cmd_btm is a command string for the reference index for the bottom field.

FIG. 25 is an explanatory diagram showing an example in which first and second reference indices are assigned to the picture numbers of the fields when performing field coding. In the figure, a reference index for the top field and a reference index for the bottom field can be independently assigned to any field.
FIG. 26 is a diagram showing an example of the correspondence relationship between the reference index, the command, and the picture number of the field in the case of FIG.

  FIG. 27 is a flowchart showing reference index and command assignment processing in reference index / picture number conversion section 109e. As shown in the figure, the reference index / picture number conversion unit 109e assigns a frame reference index and a command (S11). If frames and fields are mixed (S12), the reference index for the top field is used. And a command (S93), and further assigns a reference index and a command for the bottom field (S94).

  In FIG. 27, when the reference index is used by default, no command is assigned in S11, S93, and S94 in FIG.

<Configuration of decoding device>
FIG. 28 is a block diagram showing a configuration of a decoding device according to Embodiment 7 of the present invention. 7 is different from FIG. 7 in that a reference index / picture number conversion unit 206e is provided instead of the reference index / picture number conversion unit 206. The reference index / picture number conversion unit 206e uses the index assignment commands for the frame, top field, and bottom field input from the code sequence analysis unit 201 to independently associate the picture number with the reference index. Make the attachment.

In the present embodiment, individual command strings are described in the code for the top field and the bottom field. However, a common command string may be used. FIG. 29 is a diagram showing the data structure of the code string in that case. In the figure, idx_fld is a common command sequence for the top field and the bottom field.
Note that the maximum number of field reference indices described in (7.1) may be common to the top and bottom instead of being separate for the top field and the bottom field.

Further, the reference index and the command for the field described in (7.2) may be common to the top and the bottom, instead of being separate for the top field and the bottom field.
In addition, the decoding apparatus according to each of the above embodiments creates a correspondence table between the field reference index and the field picture number before starting decoding the slice, and refers to the table when decoding the field-coded macroblock. You may do so.

(Embodiment 8)
Further, by recording a program for realizing the configuration of the image encoding method or the image decoding method described in each of the above embodiments on a storage medium such as a flexible disk, The illustrated processing can be easily performed in an independent computer system.

FIGS. 30 (a), 30 (b), and 30 (c) show a case where the present invention is implemented by a computer system using a flexible disk storing the image encoding method or the image decoding method according to the first to seventh embodiments. FIG.
FIG. 30B shows the appearance, cross-sectional structure, and flexible disk as viewed from the front of the flexible disk, and FIG. 30A shows an example of the physical format of the flexible disk which is the recording medium body. The flexible disk FD is built in the case F, and a plurality of tracks Tr are formed concentrically from the outer circumference toward the inner circumference on the surface of the disk, and each track is divided into 16 sectors Se in an angular direction. ing. Therefore, in the flexible disk storing the program, an image encoding method as the program is recorded in an area allocated on the flexible disk FD.

  FIG. 30C shows a configuration for recording and reproducing the program on the flexible disk FD. When the above program is recorded on the flexible disk FD, the image encoding method or the image decoding method as the above program is written from the computer system Cs via the flexible disk drive. When the image encoding method is constructed in a computer system using 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.

  In the above description, the description has been made using a flexible disk as a recording medium. However, the same description can be made using an optical disk. Further, the recording medium is not limited to this, and the present invention can be similarly implemented as long as the program can be recorded, such as an IC card or a ROM cassette.

(Embodiment 9)
FIGS. 31 to 34 are diagrams illustrating a device that performs the encoding process or the decoding process described in the above embodiment, and a system using the device.

FIG. 31 is a block diagram illustrating an overall configuration of a content supply system ex100 that realizes a content distribution service. A communication service providing area is divided into desired sizes, and base stations ex107 to ex110, which are fixed wireless stations, are installed in each cell.
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 via the Internet service provider ex102 and the telephone network ex104, and the base stations ex107 to ex110. Each device such as a mobile phone ex115 with a tag is connected.

However, the content supply system ex100 is not limited to the combination as shown in FIG. 31, and may be connected by combining any of them. 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.
The camera ex113 is a device capable of shooting moving images, such as a digital video camera. In addition, a mobile phone is a PDC (Personal Digital Communications) system, a CDMA (Code Division Multiple Access) system, a W-CDMA (Wideband-Code Division Multiple Access) system, or a GSM (Global System for Mobile Communications) system. Or PHS (Personal Handyphone System) or the like, and either may be used.

  The streaming server ex103 is connected from the camera ex113 to the base station ex109 and the telephone network ex104, and enables live distribution and the like based on the encoded data transmitted by the user using the camera ex113. The encoding process of the captured data may be performed by the camera ex113, or may be performed by a server or the like that performs the data transmission process. Also, moving image data captured by the camera 116 may be transmitted to the streaming server ex103 via the computer ex111. The camera ex116 is a device such as a digital camera capable of shooting still images and moving images. In this case, encoding of the moving image data may be performed by the camera ex116 or the computer ex111. The encoding process is performed by the LSI ex117 included in the computer ex111 and the camera ex116. The 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. Further, the moving image data may be transmitted by a mobile phone with camera ex115. The moving image data at this time is data that has been encoded by the LSI included in the mobile phone ex115.

  In the content supply system ex100, the content (for example, a video of a live music shot) captured by the user with the camera ex113, the camera ex116, or the like is encoded and transmitted to the streaming server ex103 in the same manner as in the above embodiment. On the other hand, the streaming server ex103 stream-distributes the content data to the requesting client. Examples of the client include a computer ex111, a PDA ex112, a camera ex113, a mobile phone ex114, and the like, which are capable of decoding the encoded data. In this way, the content providing system ex100 can receive and reproduce the encoded data on the client, and further, can receive, decode, and reproduce the encoded data on the client in real time, thereby realizing personal broadcasting. It is a system that becomes possible.

The encoding and decoding of each device constituting this system may be performed using the video encoding device or the video decoding device described in each of the above embodiments.
A mobile phone will be described as an example.
FIG. 32 is a diagram illustrating the mobile phone ex115 that uses the moving picture encoding method and the moving picture decoding method described in the above embodiments. The mobile phone ex115 includes an antenna ex201 for transmitting and receiving radio waves to and from the base station ex110, a video image of a CCD camera or the like, a camera unit ex203 capable of taking a still image, a video image captured by the camera unit ex203, and an antenna ex201. A display unit ex202 such as a liquid crystal display for displaying data obtained by decoding a received video or the like, a main unit including a group of operation keys ex204, an audio output unit ex208 such as a speaker for outputting audio, and audio input. Input unit ex205 such as a microphone for storing encoded or decoded data, such as data of captured moving images or still images, received mail data, moving image data or still image data, etc. Recording medium ex207, and a slot ex20 for allowing 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 which can be electrically rewritten and erased, in a plastic case such as an SD card.

  Further, the mobile phone ex115 will be described with reference to FIG. The mobile phone ex115 controls a power supply circuit unit ex310, an operation input control unit ex304, an image encoding unit, and a main control unit ex311 that integrally controls each unit of a main unit including a display unit ex202 and operation keys 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 synchronous bus ex313. Connected to each other.

The power supply circuit unit ex310 activates the camera-equipped digital mobile phone ex115 in an operable state by supplying power to each unit from the battery pack when the call end and the power key are turned on by a user operation. .
The mobile phone ex115 converts an audio signal collected by the audio input unit ex205 into digital audio data by the audio processing unit ex305 in the audio communication mode based on the control of the main control unit ex311 including a CPU, a ROM, a RAM, and the like. This is spread-spectrum processed by a modulation / demodulation circuit unit ex306, subjected to digital-analog conversion processing and frequency conversion processing by a transmission / reception circuit unit ex301, and then transmitted via an antenna ex201. The mobile phone ex115 amplifies the received signal received by the antenna ex201 in the voice call mode, performs frequency conversion processing and analog-to-digital conversion processing, performs spectrum despreading processing in the modulation / demodulation circuit unit ex306, and performs analog voice processing in the voice processing unit ex305. After being converted into a signal, the signal is output via the audio output unit ex208.

  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 on the transmission / reception circuit unit ex301, and transmits the text data to the base station ex110 via the antenna ex201.

  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 the 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.

  The image encoding unit ex312 includes the image encoding device described in the present invention, and uses the image data supplied from the camera unit ex203 in the encoding method used in the image encoding device described in the above embodiment. The image data is converted into encoded image data by compression encoding, and is transmitted to the demultiplexing unit ex308. Further, at this time, the mobile phone ex115 simultaneously transmits the voice collected by the voice input unit ex205 during imaging by the camera unit ex203 to the demultiplexing unit ex308 as digital voice data via the voice processing unit ex305.

  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 modulates and outputs the resulting multiplexed data. The signal is subjected to spread spectrum processing in ex306 and subjected to digital / analog conversion processing and frequency conversion processing in the transmission / reception circuit unit ex301, and then transmitted via the antenna ex201.

When data of a moving image file linked to a homepage or the like is received in the data communication mode, a received signal 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 multiplexed signal is obtained. The demultiplexed data is sent to the demultiplexing unit ex308.
To decode the multiplexed data received via the antenna ex201, the demultiplexing unit ex308 separates the multiplexed data into a coded bit stream of image data and a coded bit stream of audio data. And supplies the encoded image data to the image decoding unit ex309 and the audio data to the audio processing unit ex305 via the synchronous bus ex313.

  Next, the image decoding unit ex309 is configured to include the image decoding device described in the present invention, and converts a coded bit stream of image data into a decoding method corresponding to the coding method described in the above embodiment. To generate reproduced moving image data and supply it to the display unit ex202 via the LCD control unit ex302, whereby, for example, moving image data included in a moving image file linked to a homepage is displayed. . At this time, at the same time, the audio processing unit ex305 converts the audio data into an analog audio signal, and then supplies the analog audio signal to the audio output unit ex208, whereby, for example, the audio data included in the moving image file linked to the homepage is reproduced. You.

  It should be noted that the present invention is not limited to the example of the system described above, and digital broadcasting using satellites and terrestrial waves has recently become a hot topic. As shown in FIG. Any of the decoding devices can be incorporated. Specifically, at the broadcasting station ex409, the coded bit stream of the video information is transmitted to the communication or the broadcasting satellite ex410 via radio waves. The broadcasting satellite ex410 receiving this transmits a radio wave for broadcasting, receives this radio wave with a home antenna ex406 having satellite broadcasting receiving equipment, and outputs the radio wave to a television (receiver) ex401 or a set-top box (STB) ex407 or the like. The device decodes the encoded bit stream and reproduces it. In addition, the image decoding device described in the above embodiment can be mounted on a playback device ex403 that reads and decodes an encoded bit stream recorded on a storage medium ex402 such as a CD or DVD that is a recording medium. is there. In this case, the reproduced video signal is displayed on the monitor ex404. A configuration is also conceivable in which an image 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 of the television. At this time, the image decoding device may be incorporated in the television instead of the set-top box. In addition, a car ex412 having an antenna ex411 can receive a signal from the satellite ex410 or a base station ex107 or the like, and can reproduce a moving image on a display device such as a car navigation ex413 included in the car ex412.

  Further, an image signal can be encoded by the image encoding device described in the above embodiment and recorded on a recording medium. As a specific example, there is a recorder ex420 such as a DVD recorder for recording an image signal on a DVD disc ex421 or a disc recorder for recording on a hard disk. Furthermore, it can be recorded on the SD card ex422. If the recorder ex420 includes the image decoding device described 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.

The configuration of the car navigation ex413 can be, for example, a configuration excluding the camera unit ex203, the camera interface unit ex303, and the image encoding unit ex312 from the configuration illustrated in FIG. ) Ex401 and the like are also conceivable.
In addition, the terminal such as the above-mentioned mobile phone ex114 has three mounting formats, in addition to a transmitting / receiving terminal having both an encoder and a decoder, a transmitting terminal having only an encoder and a receiving terminal having only a decoder. Can be considered.

As described above, the moving picture coding method or the moving picture decoding method described in the above embodiment can be used for any of the devices and systems described above. The effect can be obtained.
Further, the present invention is not limited to the above embodiment, and various changes or modifications can be made without departing from the scope of the present invention.

  The present invention is suitable for an image encoding device and an image decoding device that perform encoding by switching between frame encoding and field encoding in a block unit in a picture, a web server that distributes moving images, and a network that receives the video server. It is suitable for a terminal, a digital camera capable of recording and reproducing moving images, a mobile phone with a camera, a DVD recorder / player, a PDA, a personal computer, and the like.

FIG. 3 is a block diagram illustrating a configuration of an encoding device according to Embodiment 1 of the present invention. FIG. 11 is an explanatory diagram illustrating an example of a correspondence relationship between a picture number and first and second reference indexes when an MB is frame-coded. FIG. 6 is a diagram illustrating an example of a correspondence relationship between first and second reference indices, a command, and a picture number. FIG. 11 is an explanatory diagram showing an example in which first and second reference indices are assigned to picture numbers of fields when MBs are field-encoded. FIG. 6 is a flowchart illustrating a reference index and command assignment process in a reference index / picture number conversion unit of the encoding device. It is a flowchart figure which shows the process which allocates the reference index for fields to a field. FIG. 2 is a block diagram illustrating a configuration of a decoding device according to Embodiment 1 of the present invention. FIG. 13 is a block diagram illustrating a configuration of an encoding device according to Embodiment 2 of the present invention. FIG. 11 is an explanatory diagram showing an example in which first and second reference indices are assigned to picture numbers of fields when MBs are field-encoded. FIG. 9 is a flowchart illustrating a reference index assignment process in a reference index / picture number conversion unit of the encoding device. FIG. 14 is a block diagram illustrating a configuration of a decoding device according to Embodiment 2 of the present invention. FIG. 14 is a block diagram illustrating a configuration of an encoding device according to Embodiment 3 of the present invention. FIG. 11 is an explanatory diagram showing an example in which first and second reference indices are assigned to picture numbers of fields when MBs are field-encoded. FIG. 15 is a block diagram illustrating a configuration of a decoding device according to Embodiment 3 of the present invention. FIG. 14 is a block diagram illustrating a configuration of an encoding device according to Embodiment 4 of the present invention. FIG. 11 is an explanatory diagram showing an example in which first and second reference indices are assigned to picture numbers of fields when MBs are field-encoded. FIG. 21 is a block diagram illustrating a configuration of an encoding device according to Embodiment 5 of the present invention. FIG. 11 is an explanatory diagram showing an example in which first and second reference indices are assigned to picture numbers of fields when MBs are field-encoded. FIG. 9 is a flowchart illustrating a reference index assignment process in a reference index / picture number conversion unit of the encoding device. FIG. 21 is a block diagram illustrating a configuration of a decoding device according to Embodiment 5 of the present invention. FIG. 21 is a diagram illustrating a data configuration of a code string according to the sixth embodiment of the present invention. FIG. 11 is an explanatory diagram showing an example in which first and second reference indices are assigned to picture numbers of fields when MBs are field-encoded. FIG. 21 is a block diagram illustrating a configuration of an encoding device according to Embodiment 7 of the present invention. It is a figure showing the example of data composition of a code sequence. FIG. 11 is an explanatory diagram showing an example in which first and second reference indices are assigned to picture numbers of fields when MBs are field-encoded. It is a figure which shows an example of the correspondence of the reference index of a top field and a bottom field in field encoding, the command, and the picture number of a field. It is a flowchart which shows the allocation process of a reference index and a command when a frame code and a field code are mixed. FIG. 21 is a block diagram illustrating a configuration of a decoding device according to Embodiment 7 of the present invention. It is a figure showing other examples of data composition of a code sequence. (A)-(c) It is explanatory drawing about the recording medium which stores the program for implementing the encoding method and decoding method of the moving image of each embodiment with a computer system. FIG. 1 is a block diagram illustrating an overall configuration of a content supply system. It is an external view of a mobile phone. FIG. 2 is a block diagram illustrating a configuration of a mobile phone. FIG. 1 is a diagram illustrating an example of a digital broadcasting system. FIG. 9 is a schematic diagram for explaining a reference relation of pictures in a conventional example. (A) (b) It is a schematic diagram for demonstrating the rearrangement of the picture of the conventional example. FIG. 11 is a schematic diagram for explaining a method of assigning a picture number to a reference index in a conventional example. FIG. 38 is a schematic diagram showing an example in which the assignment of FIG. 37 in the conventional example is updated using a command. FIG. 9 is a schematic diagram for explaining a configuration of a code string in a conventional example. FIG. 3 is an explanatory diagram of a macroblock pair in the case of frame encoding and field encoding. It is an explanatory view showing a reference frame in (a) and (b) frame coding, and a reference field in field coding.

Explanation of reference numerals

Reference Signs List 101 Picture memory 102 Prediction residual encoding unit 103 Code string generation unit 104 Prediction residual decoding unit 105 Picture memory 106 Vector detection unit 107 Compensation encoding unit 108 Vector storage unit 109 Reference index / picture number conversion unit 110 Difference operation unit 111 Addition operation unit 112 Switch 113 Switch 201 Code string analysis unit 202 Prediction residual decoding unit 203 Picture memory 204 Compensation decoding unit 205 Vector storage unit 206 Reference index / picture number conversion unit 207 Addition operation unit 208 Switch

Claims (28)

A moving picture coding method for coding a picture by switching between frame coding and field coding in block units,
A video encoding method comprising: assigning a field-encoding reference index that designates a field to be referred to during field encoding to a field using a frame-encoding reference index that designates a frame to be referred to during frame encoding. . The video encoding method includes:
A specifying step of specifying two fields forming a frame specified by the frame coding reference index;
Of the two specified fields, a field having the same parity as the block to be coded is assigned a value obtained by doubling the value of the frame coding reference index as a field coding reference index. Assigning a value obtained by doubling the value of the reference index for frame encoding and adding 1 to a field having a parity different from that of the target block as a reference index for field encoding. The moving picture coding method according to claim 1. The video encoding method further includes:
A determining step of determining the maximum number of reference indices for field encoding to be twice the maximum number of reference indices for frame encoding;
The moving picture coding method according to claim 2, wherein in the allocating step, a reference index for field coding is allocated within the determined maximum number. The video encoding method includes:
A specifying step of specifying two fields forming a frame specified by the frame coding reference index;
Of the two specified fields, a value obtained by doubling the value of the frame coding reference index is assigned to the top field as a field coding reference index, and the frame coding reference is assigned to the bottom field. Allocating a value obtained by doubling the value of the index and adding 1 as a reference index for field coding, the method comprising: The video encoding method includes:
A specifying step of specifying two fields forming a frame specified by the frame coding reference index;
Assigning the same value as the frame coding reference index as a field coding reference index only to a field having the same parity as the block to be coded among the two specified fields. The moving picture coding method according to claim 1, wherein The moving picture encoding method further includes:
A command sequence indicating a method of assigning a reference index for frame encoding and a command sequence indicating a method of assigning a reference index for field encoding are generated independently, and the two sets of command sequences are encoded and added to an encoded signal. The moving image encoding method according to claim 1, further comprising: The video encoding method further includes:
A command string indicating a method of assigning a reference index for frame coding, a command string indicating a method of assigning a reference index for coding a top field, and a command string indicating a method of assigning a reference index for coding a bottom field are respectively independent of each other. The moving image encoding method according to claim 1, further comprising an adding step of generating, encoding the three sets of command strings, and adding the encoded command strings to an encoded signal. The video encoding method includes:
A determining step of determining a maximum number of reference indices for field encoding;
Within the determined maximum number range, a field coding reference index that specifies a field to be referred to at the time of field coding is assigned to a field using a frame coding reference index that specifies a frame to be referred to at the time of frame coding. The moving image encoding method according to claim 1, further comprising: an assignment step. In the determining step,
The moving picture coding method according to claim 8, wherein the maximum number of field coding reference indices is determined to be twice the maximum number of frame coding reference indices. In the determining step,
The moving picture coding method according to claim 8, wherein the maximum number of the field coding reference indexes is determined to be the same value as the maximum number of the frame coding reference indexes. The video encoding method further includes:
An additional step of determining the maximum number of reference indices for frame encoding independently of the maximum number of reference indices for field encoding and encoding the two maximum numbers and adding the same to an encoded signal. The moving picture coding method according to claim 8, wherein The video encoding method further includes:
A maximum number of reference indexes for frame encoding, a maximum number for a top field, and a maximum number for a bottom field are independently determined, and an additional step of encoding the three maximum numbers and adding the same to an encoded signal is provided. 9. The moving picture coding method according to claim 8, wherein: A moving picture decoding method for decoding a picture by switching between frame decoding and field decoding in block units,
A video decoding method comprising: assigning, to a field, a field decoding reference index that specifies a field to be referred to at the time of field decoding, using the frame decoding reference index that specifies a frame to be referred to at the time of frame decoding. . The video decoding method includes:
A specifying step of specifying two fields constituting the frame specified by the frame decoding reference index;
Of the two specified fields, for a field having the same parity as the block to be decoded, a value obtained by doubling the value of the frame decoding reference index is assigned as a field coding reference index, and decoding is performed. And allocating a value obtained by doubling the value of the reference index for frame decoding and adding 1 to a field having a parity different from that of the target block as a reference index for field encoding. The moving picture decoding method according to claim 13. The video decoding method may further include:
Determining a maximum number of field decoding reference indices to be twice the maximum number of frame decoding reference indices;
15. The moving picture decoding method according to claim 14, wherein in the allocating step, a reference index for frame decoding is allocated within the determined maximum number. The video decoding method includes:
A specifying step of specifying two fields constituting the frame specified by the frame decoding reference index;
Of the two specified fields, a value obtained by doubling the value of the frame decoding reference index is assigned to the top field as a field coding reference index, and the frame decoding reference is assigned to the bottom field. 14. A moving image decoding method according to claim 13, further comprising: allocating a value obtained by doubling the value of the index and adding 1 as a reference index for field coding. The video decoding method includes:
A specifying step of specifying two fields constituting the frame specified by the frame decoding reference index;
Assigning the same value as the frame decoding reference index as a field coding reference index only to a field having the same parity as the block to be decoded among the two specified fields. The moving picture decoding method according to claim 13, wherein The video decoding method includes:
A command sequence indicating a method of assigning a reference index for frame decoding, and a command sequence decoding step of decoding an encoded signal including a command sequence indicating a method of assigning a reference index for field decoding,
14. A moving picture decoding method according to claim 13, further comprising: allocating a frame decoding reference index and a field decoding reference index in accordance with the two decoded command strings. . The video decoding method may further include:
Coding including a command string indicating a method of assigning a reference index for frame decoding, a command string indicating a method of assigning a reference index for decoding a top field, and a command string indicating a method of assigning a reference index for decoding a bottom field. A command sequence decoding step of decoding the signal;
Allocating a reference index for frame decoding, a reference index for top field decoding, and a reference index for bottom field decoding in accordance with the three command strings decoded. Item 14. The moving picture decoding method according to Item 13. The video decoding method includes:
A determining step of determining the maximum number of reference indices for field decoding;
Within the determined maximum number range, a field decoding reference index that specifies a field to be referenced during field decoding is assigned to a field using a frame decoding reference index that specifies a frame to be referenced during frame decoding. 14. The moving image coding / decoding method according to claim 13, further comprising an assignment step. In the determining step,
21. The moving picture decoding method according to claim 20, wherein the maximum number of reference indexes for field decoding is determined to be twice the maximum number of reference indexes for frame decoding. In the determining step,
The moving picture decoding method according to claim 20, wherein the maximum number of the field decoding reference indices is determined to be the same as the maximum number of the frame decoding reference indices. In the determining step,
21. The two maximum numbers are determined by decoding an encoded signal including a maximum number of frame decoding reference indexes and a maximum number of field decoding reference indexes. Video decoding method. In the determining step,
By decoding an encoded signal including the maximum number of reference indices for frame decoding, the maximum number of reference indices for top field decoding, and the maximum number of reference indices for bottom field decoding, the three maximum values are obtained. 21. The moving picture decoding method according to claim 20, wherein the number is determined. A moving picture coding apparatus that performs coding by switching between frame coding and field coding in block units within a picture,
A moving image, comprising: an assigning unit that assigns a field-encoding reference index that designates a field to be referred to at the time of field encoding to a field by using a frame-coding reference index that designates a frame to be referred to at the time of frame encoding. Image coding device. A moving picture decoding apparatus that performs decoding by switching between frame decoding and field decoding on a block basis within a picture,
Using a frame decoding reference index to specify a frame to be referred to during frame decoding, assigning means for assigning a field decoding reference index to a field to specify a field to be referred to during field decoding,
A moving picture decoding apparatus, comprising: decoding means for decoding a frame specified by the frame decoding reference index or a field specified by the field decoding reference index. A program that causes a computer to execute a moving image encoding method of performing encoding by switching between frame encoding and field encoding in block units within a picture,
The program is
Using a frame coding reference index to specify a frame to be referred to at the time of frame coding, causing the computer to execute assigning a field coding reference index to a field to specify a field to be referred to at the time of field coding. Program to do. A program that causes a computer to execute a moving image decoding method of performing decoding by switching between frame decoding and field decoding in blocks in a picture,
The program is
Using a frame decoding reference index to specify a frame to be referred to at the time of frame decoding, causing the computer to execute assigning a field decoding reference index to a field to specify a field to be referred to at the time of field decoding. Program to do.

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