JP2020145765A - Decoding device, encoding device, decoding method, and encoding method - Google Patents

Abstract

To suppress deterioration of image quality.SOLUTION: A decoding device 50 includes a decoding section 56 and a conversion section 60. The decoding section 56 decodes encoded data included in transmission information including encoded data and color difference conversion information including a first color difference format showing resolution of a color difference component of the encoded data, and specified information of a filter used when a color difference format of a decoded image obtained by decoding the encoded data is converted; and generates the decoded image of the first color difference format. The conversion section 60 subjects the decoded image of the first color difference format to the color difference format conversion by using the filter specified by the specified information.SELECTED DRAWING: Figure 24

Description

Embodiments of the present invention relate to a decoding device, a coding device, a decoding method, and a coding method.

An image containing a luminance component and a color difference component is encoded after converting the resolution of the color difference component. Further, at the time of decoding, the resolution of the color difference component is converted after decoding the encoded data. The resolution of the color difference component includes a color difference format such as a 4: 4: 4 format, a 4: 2: 2 format, and a 4: 2: 0 format.

Image quality deterioration occurs by repeating the conversion of the resolution of the color difference component. Therefore, conventionally, attempts have been made to suppress deterioration in image quality. Specifically, it is disclosed that a filter satisfying the condition of suppressing image quality deterioration is designed as a filter used for converting the resolution of a color difference component.

Japanese Unexamined Patent Publication No. 2005-123913 Japanese Unexamined Patent Publication No. 2009-246929

However, in the past, image quality may deteriorate depending on the resolution of the color difference component during reproduction.

An object to be solved by the present invention is to provide a decoding device and a coding device capable of suppressing image quality deterioration.

The decoding device of the embodiment includes coded data, filter information for specifying a filter used for color difference format conversion of a decoded image obtained by decoding the coded data, pixel bit length at the time of reproduction, and reproduction. The decoding unit that decodes the coded data included in the transmission information including the maximum value of the color difference component and the minimum value of the color difference component at the time of reproduction to generate the decoded image, and the down indicated by the filter information. A conversion unit that converts the decoded image into a color difference format using a sampling filter, the pixel bit length at the time of reproduction, the maximum value of the color difference component at the time of reproduction, and the minimum value of the color difference component at the time of reproduction are satisfied. It is provided with an output unit that clippings the decoded image converted into a color difference format and outputs the decoded image after the clipping processing as a reproduced image.

The figure which shows the functional configuration of a coding apparatus. The figure which shows the functional structure of the conversion part. The figure which shows the functional structure of the coding part. The figure which shows the functional structure of the generation part. The figure which shows an example of the syntax of the color difference conversion information. The figure which shows an example of the data structure of definition information. The figure which shows an example of the syntax of the color difference conversion information. The figure which shows an example of the syntax of the color difference conversion information. The figure which shows an example of the data structure of definition information. The figure which shows an example of the data structure of definition information. The figure which shows an example of the syntax which expresses the color difference conversion filter information. The figure which shows an example of the syntax of the color difference conversion information. The figure which shows an example of the syntax which expresses the color difference conversion filter information. The figure which shows an example of the data structure of definition information. The figure which shows an example of the syntax which expresses the color difference conversion filter information. The figure which shows an example of the data structure of definition information. The figure which shows an example of the syntax which expresses the color difference conversion filter information. A flowchart showing the procedure of the coding process. The figure which shows the functional configuration of a coding apparatus. The figure which shows the functional structure of the generation part. The figure which shows the functional structure of the conversion part. The figure which shows the functional structure of the generation part. The figure which shows the functional configuration of a coding apparatus. The figure which shows the functional configuration of a decoding apparatus. The figure which shows the functional structure of the decoding part. The figure which shows the functional structure of the decoding part. The figure which shows the functional structure of the conversion part. A flowchart showing the procedure of the decryption process. The figure which shows the functional structure of the decoding part. The figure which shows the functional structure of the conversion part. The figure which shows the hardware composition of the coding apparatus and the decoding apparatus.

(Embodiment 1)
FIG. 1 is a schematic diagram showing a functional configuration of the coding device 10 of the present embodiment.

The coding device 10 encodes after changing the resolution of the color difference component of the original image. The original image is an image including a luminance component and a color difference component. The resolution of the color difference component includes a color difference format such as a 4: 4: 4 format, a 4: 2: 2 format, and a 4: 2: 0 format. In the present embodiment, the original image of any of these color difference formats is input to the encoding device 10.

In the present embodiment, as an example, a case where an original image in a color difference format of 4: 4: 4 format is input to the encoding device 10 will be described, but the present embodiment is not limited to this embodiment.

The coding device 10 includes a conversion unit 12, a coding unit 14, a generation unit 16, a NAL unit generation unit 18, and a transmission information generation unit 20.

The conversion unit 12 converts the resolution of the color difference component of the original image by filtering the original image. The conversion unit 12 outputs the original image obtained by converting the resolution of the color difference component as a color difference conversion image. In the present embodiment, the conversion unit 12 describes a case where the resolution of the color difference component is enlarged (upsampled) with respect to the original image.

FIG. 2 is a schematic diagram showing a functional configuration of the conversion unit 12.

The conversion unit 12 includes one or a plurality of conversion units that convert the resolution of the color difference component of the original image input to the coding device 10. The conversion of the resolution of the color difference component by the conversion unit 12 may be referred to as a color difference format conversion. In the present embodiment, the conversion unit 12 includes a conversion unit 12A, a conversion unit 12B, and an output adjustment unit 12C.

The conversion unit 12A converts the original image in the 4: 4: 4 format into the image in the 4: 2: 2 format. Specifically, the conversion unit 12A performs a filter process using a filter that thins out the color difference components of the pixels constituting the original image in the 4: 4: 4 format by 1/2 in the horizontal direction. As a result, the conversion unit 12A performs downsampling by thinning out the color difference components of the pixels constituting the original image in the 4: 4: 4 format to 1/2 in the horizontal direction, and converts the image into the image in the 4: 2: 2 format. .. The conversion unit 12A outputs an image in the 4: 2: 2 format to the conversion unit 12B.

The conversion unit 12B receives an image in a 4: 2: 2 format from the conversion unit 12A. The conversion unit 12B converts the received 4: 2: 2 format image into a 4: 2: 0 format image. Specifically, the conversion unit 12B performs filter processing using a filter that thins out the color difference components of the pixels constituting the image in the 4: 2: 2 format by 1/2 in the vertical direction. As a result, the conversion unit 12B performs downsampling by thinning out the color difference components of the pixels constituting the image in the 4: 2: 2 format to 1/2 in the vertical direction, and converts the image into the image in the 4: 2: 0 format. The conversion unit 12B outputs an image in the 4: 2: 0 format to the output adjustment unit 12C.

The output adjustment unit 12C has a range in which each pixel value constituting the 4: 2: 0 format image received from the conversion unit 12B is equal to or more than the minimum value defined by the standard and is equal to or less than the maximum value defined by the standard. Clipping processing is performed so that Then, the image after the clipping process is output to the coding unit 14 as a color difference conversion image that has been color-difference-converted by the conversion unit 12. The color difference conversion image is an original image after the resolution of the color difference component is converted by the conversion unit 12.

Returning to FIG. 1, the conversion unit 12 outputs the color difference conversion image to the coding unit 14. Further, the conversion unit 12 outputs the color difference signal information to the generation unit 16.

The color difference signal information includes the filter information used for the filter processing by the conversion unit 12. In the present embodiment, the color difference signal information includes the original image in the 4: 4: 4 format received by the conversion unit 12A, the filter information used for the filter processing by the conversion unit 12A, and the 4: 2 received by the conversion unit 12B. : Includes images in two formats and filter information used for filtering by the conversion unit 12B.

The filter information used for the filter processing by the conversion unit 12A is the horizontal downsampling filter information in the present embodiment. Further, the filter information used for the filter processing by the conversion unit 12B is the vertical downsampling filter information in the present embodiment.

The coding unit 14 receives the color difference conversion image from the conversion unit 12. The coding unit 14 encodes the received color difference conversion image and generates coded data. In the present embodiment, the coding unit 14 divides one frame into slices composed of a plurality of pixel regions and encodes each slice.

FIG. 3 is a schematic diagram showing a functional configuration of the coding unit 14.

The coding unit 14 includes a subtraction unit 14A, a conversion / quantization unit 14B, an entropy coding unit 14C, an inverse quantization / inverse conversion unit 14D, an addition unit 14E, a frame memory 14F, a prediction image generation unit 14G, and a motion vector search. A unit 14H is provided.

The subtraction unit 14A receives the color difference conversion image from the conversion unit 12. The subtraction unit 14A obtains the difference between the color difference conversion image and the prediction image generated by the prediction image generation unit 14G, and generates an error image which is the difference.

The conversion / quantization unit 14B converts the error image to generate a conversion coefficient, and quantizes the conversion coefficient to generate a quantization coefficient. Examples of the error image conversion method include orthogonal transform using DCT (Discrete Cosine Transform: discrete cosine transform), wavelet transform, and independent component analysis. The conversion / quantization unit 14B converts the error image by using any of these conversion methods. Further, the conversion / quantization unit 14B quantizes the conversion coefficient using the preset quantization parameters.

The conversion / quantization unit 14B outputs the quantization coefficient to the entropy coding unit 14C and the inverse quantization / inverse conversion unit 14D.

The entropy coding unit 14C receives the quantization coefficient from the conversion / quantization unit 14B. Further, the entropy coding unit 14C receives motion vector information from the motion vector search unit 14H, which will be described later. The entropy coding unit 14C entropy-encodes the quantization coefficient and the motion vector information according to a predetermined syntax to generate the coded data. The syntax is a setting rule for encoded data.

The entropy coding unit 14C performs entropy coding using, for example, Huffman coding or arithmetic coding.

The entropy coding unit 14C outputs the generated coded data to the NAL unit generation unit 18.

The inverse quantization / inverse conversion unit 14D inversely quantizes the quantization coefficient and then inversely transforms it to generate an error image. That is, the inverse quantization / inverse conversion unit 14D performs the reverse processing of the conversion / quantization unit 14B on the quantization coefficient. Specifically, when the conversion / quantization unit 14B performs wavelet transformation and quantization, the inverse quantization / inverse transform unit 14D performs inverse quantization and inverse wavelet transformation.

The addition unit 14E receives an error image from the inverse quantization / inverse conversion unit 14D, and receives a prediction image from the prediction image generation unit 14G. Then, the addition unit 14E adds the error image and the prediction image to generate a decoded image. This decoded image is stored in the frame memory 14F.

The frame memory 14F filters the decoded image and stores it as a reference image. The frame memory 14F outputs the reference image to the prediction image generation unit 14G and the motion vector search unit 14H.

The motion vector search unit 14H generates motion vector information by using the color difference conversion image received from the conversion unit 12 and the reference image received from the frame memory 14F. The motion vector search unit 14H outputs the generated motion vector information to the prediction image generation unit 14G and the entropy coding unit 14C.

The prediction image generation unit 14G generates a prediction image by using the reference image and the motion vector information. Then, the predicted image generation unit 14G outputs the generated predicted image to the addition unit 14E and the subtraction unit 14A.

Here, the reference image generated by the frame memory 14F is an image having the same color difference format as the color difference conversion image. That is, in the present embodiment, the reference image is an image in the same 4: 2: 0 format as the color difference conversion image obtained by converting the resolution of the color difference component by the conversion unit 12. In the present embodiment, the frame memory 14F outputs the reference image in the 4: 2: 0 format to the generation unit 16.

Returning to FIG. 1, the generation unit 16 receives the color difference signal information from the conversion unit 12. Further, the generation unit 16 receives a reference image in the same color difference format (4: 2: 0 format) as the color difference conversion image from the coding unit 14. The generation unit 16 generates the color difference conversion information by using the color difference signal information and the reference image of the color difference format of the color difference conversion image.

The color difference conversion information includes a first color difference format and specific information of a filter used at the time of color difference format conversion of the decoded image obtained by decoding the coded data.

In the present embodiment, as an example, a case where the color difference conversion format includes a first color difference format, a second color difference format, and specific information will be described.

The first color difference format indicates the resolution of the color difference component of the coded data encoded by the coding unit 14, that is, the color difference format. In other words, the first color difference format is the color difference format of the color difference converted image. In the present embodiment, the first color difference format is a 4: 2: 0 format. In the following, the resolution of the color difference component may be described simply as a color difference format.

The second color difference format is a color difference format at the time of reproduction of the decoded image obtained by decoding the encoded data. The time of reproducing the decoded image is a color difference format used when reproducing the decoded image obtained by decoding the encoded data, and is determined by the form at the time of reproduction, the reproduction device, and the like. In the present embodiment, the second color difference format is preset in the generation unit 16. The second color difference format may be received by the coding apparatus 10 together with the original image. Further, the second color difference format may be received from an external device or the like via a communication unit (not shown).

The specific information is information for specifying a filter used at the time of color difference format conversion of the decoded image.

In the present embodiment, as an example, a case where the specific information is information for specifying a filter used when converting a decoded image of the first color difference format into the second color difference format will be described. In the present embodiment, the case where the specific information is the filter information used for converting the decoded image of the first color difference format into the second color difference format will be described. The filter information includes, for example, a filter coefficient.

The specific information may include reference information of the second color difference format. The reference information may be information such as a flag for specifying the second color difference format, or may be the second color difference format itself.

FIG. 4 is a schematic diagram showing the functional configuration of the generation unit 16.

The generation unit 16 receives the color difference signal information from the conversion unit 12. Further, the generation unit 16 receives a reference image in the same color difference format (4: 2: 0 format) as the color difference conversion image from the coding unit 14.

As described above, in the present embodiment, the color difference signal information includes the original image in the 4: 4: 4 format received by the conversion unit 12A, the filter information used for the filter processing by the conversion unit 12A, and the conversion unit 12B. The received 4: 2: 2 format image and the filter information used for the filter processing by the conversion unit 12B are included.

The generation unit 16 includes a vertical filter information generation unit 16A, a conversion unit 16B, a horizontal filter information generation unit 16C, and a generation unit 16D.

The vertical filter information generation unit 16A receives the 4: 2: 2 format image and the filter information (vertical downsampling filter information) used for the filter processing by the conversion unit 12B among the information included in the color difference signal information. Further, the vertical filter information generation unit 16A receives a reference image in the same color difference format (4: 2: 0 format) as the color difference conversion image from the coding unit 14.

The vertical filter information generation unit 16A is an image in a 4: 2: 2 format, vertical downsampling filter information used for filtering by the conversion unit 12B, and an image in a color difference format after conversion by the conversion unit 12B. 4: 2 Design the reference image in the: 0 format and the filter information used to convert the image in the 4: 2: 0 format to the 4: 2: 2 format.

That is, the vertical filter information generation unit 16A designs the filter information used to obtain the 4: 2: 2 format image by performing the vertical upsampling process on the reference image in the 4: 2: 0 format. .. Then, the vertical filter information generation unit 16A outputs the designed vertical filter information, which is the filter information, to the conversion unit 16B and the generation unit 16D.

The following equations (1) to (3) are used for designing the filter information.

Equations (1) to (3) are formulas for calculating a filter that minimizes the root mean square of the difference between the color difference component of the image before filtering and the color difference component of the image after filtering, that is, the Wiener filter. ..

In equation (1), F represents a filter coefficient. In the formula (1), (f _{1 to} f _n ) indicate the filter coefficient. In addition, n represents an integer of 1 or more.

In the formula (2), S represents the color difference component of the image after the filtering process. In equation (2), x indicates the position of the pixel. In equations (2) and (3), _SF (x) indicates the image signal after filtering. In formula (3), _Sorg represents the color difference component of the image before filtering.

The conversion unit 16B receives a reference image in the same color difference format (4: 2: 0 format) as the color difference conversion image from the coding unit 14. Further, the conversion unit 16B receives the vertical filter information from the vertical filter information generation unit 16A.

The conversion unit 16B performs a filter process using the received vertical filter information, and converts the color difference format of the reference image in the same color difference format (4: 2: 0 format) as the color difference conversion image into the 4: 2: 2 format. The conversion unit 16B outputs the image in the 4: 2: 2 format obtained by the conversion to the horizontal filter information generation unit 16C.

Of the information included in the color difference signal information, the horizontal filter information generation unit 16C includes the original image in the 4: 4: 4 format received by the conversion unit 12A and the filter information (horizontal downsampling) used for the filter processing by the conversion unit 12A. Filter information) and accept. Further, the horizontal filter information generation unit 16C receives an image in a 4: 2: 2 format from the conversion unit 16B.

The horizontal filter information generation unit 16C obtains a 4: 4: 2 format image from the 4: 4: 4 format original image, the horizontal downsampling filter information, and the 4: 2: 2 format image at 4: 4. : Design the filter information used to convert to 4 formats. The above equations (1) to (3) are used for designing the filter information.

That is, the horizontal filter information generation unit 16C designs the filter information used to obtain the original image in the 4: 4: 4 format by performing the horizontal upsampling process on the image in the 4: 2: 2 format. Then, the horizontal filter information generation unit 16C outputs the horizontal filter information, which is the designed filter information, to the generation unit 16D.

The generation unit 16D generates the color difference conversion information. Specifically, the generation unit 16D uses the color difference format (4: 2: 0 format) of the reference image received from the coding unit 14 as the first color difference format of the coded data encoded by the coding unit 14. Further, the generation unit 16D reads the second color difference format at the time of reproduction of the decoded image obtained by decoding the encoded data from a memory (not shown). Further, the generation unit 16D uses the vertical filter information received from the vertical filter information generation unit 16A and the horizontal filter information received from the horizontal filter information generation unit 16C as specific information. Then, the generation unit 16D generates the color difference conversion information including the first color difference format, the second color difference format, and the specific information.

The generation unit 16D generates the color difference conversion information according to a predetermined setting rule (syntax).

FIG. 5 is a diagram showing an example of the syntax of the color difference conversion information.

Chrominance conversion information includes, as shown in FIG. 5, coded_format_idc, coded_data_bit_depth, target_format_idc, target_bit_depth, max_value, min_value, progressive_flag, implicit_vertical_flag, tap_length_vertical_minus1, ver_filter_coeff, implicit_horizontal_flag, interpolation_horizontal_idc, tap_length_horizontal_minus1, and Hor_filter_coeff.

Coded_format_idc indicates a first color difference format.

For example, when the value of coded_format_idc is "0", the first color difference format is a monochrome format in which only the luminance is specified. When the value of coded_format_idc is "1", the first color difference format is the 4: 2: 0 format. When the value of coded_format_idc is "2", the first color difference format is the 4: 2: 2 format. When the value of coded_format_idc is "3", the first color difference format is the 4: 4: 4 format.

The code_data_bit_depth indicates the pixel bit length of the encoded data.

target_format_idc indicates a second color difference format which is a color difference format at the time of reproduction of the decoded image obtained by decoding the coded data. target_bit_depth indicates the pixel bit length at the time of reproduction. max_value indicates the maximum value of the color difference component at the time of reproduction. min_value indicates the minimum value of the color difference component at the time of reproduction.

The progressive_flag is a flag indicating whether or not the encoded data is a progressive signal. For example, when the value of progressive_flag is "0", the encoded data is an interlaced signal rather than a progressive signal. In this case, it indicates that the color difference conversion process needs to be performed in field units.

implicit_vertical_flag, interpolation_vertical_idc, tap_length_vertical_minus1, ver_filter_coeff, implicit_horizontal_flag, interpolation_horizontal_ident_horizontal_id

The implicit_vertical_flag is a flag indicating that the predefined vertical filter information is used. interpolation_vertical_idc is the identification information of the filter information in the vertical direction defined in advance. tap_length_vertical_minus1 indicates a value of the tap length minus 1 of the filter coefficient in the vertical direction.

ver_filter_coeff indicates the filter coefficient in the horizontal direction. The implicit_horizontal_flag is a flag indicating that a predetermined horizontal filter information is used. Interpolation_horizontal_idc is pre-defined horizontal filter information identification information. tap_length_horizontal_minus1 indicates a value of the tap length minus 1 of the horizontal filter coefficient. hor_filter_coeff indicates the filter coefficient in the horizontal direction.

For example, it is assumed that the value of code_format_idc is "1", that is, the first color difference format, which is the format of the encoded data, is the 4: 2: 0 format. Further, it is assumed that the value of target_format_idc is "1" or more, that is, the second color difference format, which is the color difference format at the time of reproducing the decoded image, is the 4: 2: 2 or 4: 4: 4 format. In this case, upsampling processing is required in the vertical direction. Therefore, in this case, the generation unit 16 generates the filter information in the vertical direction (vertical upsampling filter information) as specific information.

Further, it is assumed that the value of coded_from_idc is larger than "1", that is, the first color difference format, which is the format of the encoded data, is the 4: 2: 2 format or the 4: 4: 4 format. Further, it is assumed that the value of target_format_idc is "1", that is, the second color difference format which is the color difference format at the time of reproduction is the 4: 2: 0 format. In this case, the specific information is vertical filter information (vertical downsampling filter information).

Further, it is assumed that the value of coded_format_idc is "1" or "2", that is, the first color difference format is 4: 2: 0 format or 4: 2: 2 format. Further, it is assumed that the value of target_format_idc is "3", that is, the second color difference format is the 4: 4: 4 format. In this case, the specific information is horizontal filter information (horizontal upsampling filter information).

Further, it is assumed that the value of coded_format_idc is "3", that is, the first color difference format is the 4: 4: 4 format. Further, it is assumed that the value of target_format_idc is "1" or "2", that is, the second color difference format is 4: 2: 0 format or 4: 2: 2 format. In this case, the specific information is horizontal filter information (horizontal downsampling filter information).

In FIG. 5, u (n) represents an n-bit non-negative binary representation. n is an integer of 1 or more. se (v) represents a signed 0th-order Exp-Golomb code.

The coding apparatus 10 previously generates a definition table in which a predefined vertical filter information, a predetermined horizontal filter information, and an identification information for identifying the filter information are associated with each other. 16 is stored in a memory (not shown).

FIG. 6 is a schematic diagram showing an example of a data structure of definition information.

The definition information is a table in which Value, Tap dimensions, and Filter cohesions are associated with each other.

Value is identification information of filter information. Value corresponds to the value indicated by interpolation_vertical_idc or interpolation_horizontal_idc included in the color difference conversion information shown in FIG.

Tap length indicates the tap length of the filter coefficient corresponding to the value of Value which is the identification information of the filter information. Filter cofficients indicate the filter coefficient corresponding to the value of Value which is the identification information of the filter information.

The color difference conversion information may be in a form that does not include information obtained from coded data or standardized reproduction information.

FIG. 7 is a diagram showing an example of the syntax of the color difference conversion information when the information obtained from the coded data and the standardized reproduction information are not included.

Specifically, the color difference conversion information includes target_format_idc, progressive_flag, implicit_vertical_flag, tap_length_vertical_minus1, ver_filter_coeff, implicit_horizontal_flag, interpolation_horizontal_idc, tap_length_horizontal_minus1, and Hor_filter_coeff.

That is, in the example shown in FIG. 7, the color difference conversion information does not include the first color difference format, which is the color difference format of the coded data, and the pixel bit length. Further, in the example shown in FIG. 7, the color difference conversion information does not include the pixel bit length at the time of reproduction and the maximum value and the minimum value of the color difference component at the time of reproduction.

As described above, the color difference conversion information includes the first color difference format indicating the resolution of the color difference component of the coded data, and the specific information of the filter used at the time of color difference format conversion of the decoded image obtained by decoding the coded data. It may be information.

FIG. 8 is a schematic diagram showing an example of the syntax of the color difference conversion information. Note that FIG. 8 shows a case where the color difference conversion information includes the first color difference format, the pixel sample position of the color difference component of the coded data, and the specific information.

In the example shown in FIG. 8, the color difference conversion information includes chroma_loc_info_present_flag, chroma_sample_loc_type_top_field, chroma_sample_loc_type_bottom_field, and chromafelf.

The chroma_loc_info_present_flag is a flag indicating the pixel position of the color difference signal and whether or not the filter information regarding the color difference conversion exists. For example, when the value of chroma_loc_info_present_flag is "1", this flag indicates that the filter information regarding the pixel position and the color difference conversion of the color difference signal exists. Further, when the value of chroma_loc_info_present_flag is "0", this flag indicates that there is no filter information regarding the pixel position of the color difference signal and the color difference conversion.

Chroma_sample_loc_type_top_field indicates the pixel sample position (sampling target pixel position) of the color difference component of the top field when the coded data is the coded data encoded by using interlaced scanning. There are a total of six known combinations of pixel sample positions of the color difference component in the top field, depending on the combination with the pixel sample positions of the luminance component.

chroma_sample_loc_type_bottom_field indicates the pixel sample position (sampling target pixel position) of the color difference component in the bottom field when the coded data is coded data encoded by using interlaced scanning. As in the case of the top field, there are a total of six known combinations of pixel sample positions of the color difference component in the bottom field, depending on the combination with the pixel sample positions of the luminance component.

chroma_filter_info_present_flag is a flag indicating whether or not filter information regarding color difference conversion exists. When the value of chroma_filter_info_present_flag is "1", it indicates that the filter information regarding the color difference conversion exists. When the value of chroma_filter_info_present_flag is "0", it indicates that there is no filter information regarding the color difference conversion.

chroma_filter_info is identification information of color difference conversion filter information. The color difference conversion filter information corresponding to the identification information of the color difference conversion filter information is preset in the color difference conversion filter definition information.

FIG. 9 is a schematic diagram showing an example of the data structure of the color difference conversion filter definition information. The color difference conversion filter definition information is a table in which the identification information of the color difference conversion filter information (corresponding to “Value” in FIG. 9) and the color difference conversion filter information specified by the identification information are associated with each other.

In the example shown in FIG. 9, the color difference conversion filter information includes Tap dimension, Filter co-efficients, Divisor, Phase shift, and Purpose.

Tap length indicates the tap length of the filter coefficient. Filter cofficients indicate the filter coefficient. Divisor indicates the number of denominators when dividing in filtering. Phase shift indicates the phase information of the filter. Purpose indicates the type of filter. Specifically, Purpose indicates a downsampling filter or an upsampling filter for color difference format conversion.

FIG. 10 is a schematic diagram showing another example of the data structure of the color difference conversion filter definition information. Similar to FIG. 9, the color difference conversion filter definition information shown in FIG. 10 includes identification information of the color difference conversion filter information (corresponding to “Value” in FIG. 10), color difference conversion filter information specified by the identification information, and It is a table associated with.

In the example shown in FIG. 10, similarly to FIG. 9, the color difference conversion filter information includes Tap length, Filter cohesions, Divisor, Phase shift, and Purpose.

The color difference conversion filter definition information shown in FIG. 10 indicates that when the value of "Value", which is the identification information, is a specific value, the color difference conversion filter information is generated according to a predetermined syntax.

FIG. 11 is a diagram showing an example of the syntax of the color difference conversion filter information. For example, when the value of "Value", which is the identification information in the color difference conversion filter definition information shown in FIG. 10, is "1", the color difference conversion filter information of the syntax shown in FIG. 11 is associated in advance.

In this case, when the value of "Value", which is the identification information in the color difference conversion filter definition information, is "1", the generation unit 16 generates the color difference conversion filter information according to the color difference conversion filter information of the syntax shown in FIG. ..

The color difference conversion filter information shown in FIG. 11 includes target_format_idc, num_of_filter_minus1, tap_length_minus1, and filter_coeff.

target_format_idc is the same as above. num_of_filter_minus1 indicates the value of the number minus 1 of the color difference conversion filter. tap_length_minus1 indicates a value of the tap length minus 1 of the filter coefficient. filter_coeff indicates the filter coefficient.

FIG. 12 is a schematic diagram showing another example of the syntax of the color difference conversion information. Note that FIG. 12 is different from the color difference conversion information shown in FIG. 8 in that it does not include chroma_filter_info.

In the example shown in FIG. 12, the color difference conversion information includes chroma_loc_info_present_flag, chroma_sample_loc_type_top_field, chroma_sample_loc_type_bottom_field_file_file_file_file_file.

The chroma_filter_info_present_flag is a flag indicating whether or not filter information regarding the color difference conversion exists separately. When the value of chroma_filter_info_present_flag is "1", it indicates that the filter information regarding the color difference conversion exists. When the value of chroma_filter_info_present_flag is "0", it indicates that there is no filter information regarding the color difference conversion.

FIG. 13 is a diagram showing an example of the color difference conversion filter information existing when the value of chroma_filter_info_present_flag in the color difference conversion information shown in FIG. 12 is “1”.

The color difference conversion filter information shown in FIG. 13 includes num_of_filter_set_minus1, implicit_filter_set_flag, filter_set_idc, num_of_filter_minus1, implicit_filter_mig, filter_filler_file, and filter_idc.

num_of_filter_set_minus1 indicates the number of filter sets minus one. The implicit_filter_set_flag is a flag indicating that the information of the predetermined filter set is used. filter_set_idc is the identification information of the information of the preset filter set. num_of_filter_minus1 indicates the value of the number minus 1 of the color difference conversion filter. The implicit_filter_flag is a flag indicating that a predetermined filter information is used. filter_idc is the identification information of the filter information defined in advance. tap_length_minus1 indicates a value of the tap length minus 1 of the filter coefficient. filter_coeff indicates the filter coefficient.

FIG. 14 is a schematic diagram showing an example of the data structure of the color difference conversion filter definition information, and is a diagram showing an example different from FIG. In the example shown in FIG. 14, the color difference conversion filter definition information is a table in which filter_set_idc, filter_idc, Tap dimension, Filter cohesions, Divisor, Phase shift, and Purpose are associated with each other.

filter_set_idc is identification information of filter set information. The value of this filter_set_idc corresponds to the filter_set_idc shown in FIG.

filter_idc is identification information of filter information. The value of filter_idc corresponds to filter_idc shown in FIG.

Tap length indicates the tap length of the filter coefficient as described above. Filter cofficients indicate the filter coefficient. Divisor indicates the number of denominators when dividing in filtering. Phase shift indicates the phase information of the filter. Purpose indicates the purpose of the filter, and indicates for downsampling and upsampling when converting the color difference format.

FIG. 15 shows an example of the color difference conversion filter information that exists when the value of chroma_filter_info_present_flag in the color difference conversion filter definition information is “1”.

Chrominance conversion filter information shown in FIG. 15 includes target_format_idc, implicit_vertical_flag, vertical_filter_idc, tap_length_vertical_minus1, ver_filter_coeff, second_filter_flag, second_vertical_filter_idc, tap_length_second_vertical_minus1, second_ver_filter_coeff, implicit_horizontal_flag, horizontal_filter_idc, tap_length_horizontal_minus1, and Hor_filter_coeff.

target_format_idc indicates a second color difference format, as in FIG. In the color difference conversion filter information shown in FIG. 15, the meaning of the value of target_format_idc is different from that in FIG. Specifically, in the example shown in FIG. 15, when the value of target_format_idc is "0", it indicates that the second color difference format is a monochrome format in which only the brightness is defined. Further, when the value of target_format_idc is "1", it indicates that the second color difference format is the 4: 2: 0 format. Further, when the value of target_format_idc is "2", it indicates that the second color difference format is the 4: 2: 2 format. When the value of target_format_idc is "3", it indicates that the second color difference format is the 4: 4: 4 format.

In addition, chroma_format_idc is included in the coded data and indicates the first color difference format.

The implicit_vertical_flag is a flag indicating that the predefined vertical filter information is used. vertical_filter_idc is pre-defined vertical filter information identification information. tap_length_vertical_minus1 indicates a value of the tap length minus 1 of the filter coefficient in the vertical direction.

ver_filter_coeff indicates the filter coefficient in the vertical direction. second_filter_flag is a flag defined when the top field and bottom field use different filter sets in the vertical direction in the case of a field signal, and if the value of second_filter_flag is "1", the second vertical Filters can be defined.

second_vertical_filter_idc is the identification information of the second vertical filter information defined in advance. tap_length_second_vertical_minus1 indicates a value of tap length minus 1 of the second vertical filter coefficient. second_ver_filter_coeff indicates the second vertical filter coefficient.

The implicit_horizontal_flag is a flag indicating that a predetermined horizontal filter information is used.

horizontal_filter_idc is pre-defined horizontal filter information identification information. tap_length_horizontal_minus1 indicates a value of the tap length minus 1 of the horizontal filter coefficient. hor_filter_coeff indicates the filter coefficient in the horizontal direction.

For example, assume that the value of chroma_format_idc is "1", that is, the first color difference format, which is the format of the encoded data, is the 4: 2: 0 format. Further, it is assumed that the value of target_format_idc is "1" or more, that is, the second color difference format, which is the color difference format at the time of reproducing the decoded image, is the 4: 2: 2 or 4: 4: 4 format. In this case, upsampling processing is required in the vertical direction. Therefore, in this case, the generation unit 16 generates the filter information in the vertical direction (vertical upsampling filter information) as specific information.

Further, it is assumed that the value of chroma_from_idc is larger than "1", that is, the first color difference format, which is the format of the encoded data, is the 4: 2: 2 format or the 4: 4: 4 format. Further, it is assumed that the value of target_format_idc is "1", that is, the second color difference format which is the color difference format at the time of reproduction is the 4: 2: 0 format. In this case, the specific information is vertical filter information (vertical downsampling filter information).

Further, it is assumed that the value of chroma_format_idc is "1" or "2", that is, the first color difference format is 4: 2: 0 format or 4: 2: 2 format. Further, it is assumed that the value of target_format_idc is "3", that is, the second color difference format is the 4: 4: 4 format. In this case, the specific information is horizontal filter information (horizontal upsampling filter information).

Further, it is assumed that the value of chroma_format_idc is "3", that is, the first color difference format is the 4: 4: 4 format. Further, it is assumed that the value of target_format_idc is "1" or "2", that is, the second color difference format is 4: 2: 0 format or 4: 2: 2 format. In this case, the specific information is horizontal filter information (horizontal downsampling filter information).

FIG. 16 is a schematic diagram showing an example different from FIG. 14 in the data structure of the color difference conversion filter definition information.

The color difference conversion filter definition information shown in FIG. 16 is a table in which filter_idc, Tap dimension, Filter cohesions, Divisor, Phase shift, and Purpose are associated with each other.

In FIG. 16, filter_idc is identification information of filter set information. Corresponds to vertical_filter_idc, second_filter_idc, and horizontal_filter_idc included in the color difference conversion information shown in FIG.

Tap length indicates the tap length of the filter coefficient. Filter cofficients indicate the filter coefficient. Divisor indicates the number of denominators when dividing in filtering. Phase shift indicates the phase information of the filter. Purpose indicates the purpose of the filter, and indicates for downsampling and upsampling when converting the color difference format.

FIG. 17 shows an example of the color difference conversion filter information existing when the value of chroma_filter_info_present_flag in the color difference conversion information shown in FIGS. 8 and 12 is “1”.

The color difference conversion filter shown in FIG. 17 includes target_format_idc, tap_length_vertical_minus1, ver_filter_coeff, second_filter_flag, tap_length_second_vertical_minus1, second_verminus1, second_vert_vert_verff. The difference between the color difference conversion filter shown in FIG. 17 and the color difference conversion filter shown in FIG. 15 is that all the filter information is explicitly defined.

Returning to FIG. 1, the generation unit 16 outputs the generated color difference conversion information to the NAL unit generation unit 18.

The NAL unit generation unit 18 receives coded data from the coding unit 14. Further, the NAL unit generation unit 18 receives the color difference conversion information from the generation unit 16.

The NAL unit generation unit 18 includes NAL (Network) including coding data received from the coding unit 14, color difference conversion information received from the generation unit 16, header information, byte alignment information which is adjustment information at the time of writing / reading, and the like. Header Layer) Generates unit information. The NAL unit generation unit 18 outputs the generated NAL unit information to the transmission information generation unit 20.

The NAL unit information is information corresponding to high-level syntax included in the transmission information to be described later, which is output by the coding apparatus 10. The high-level syntax is a syntax higher than a slice in the structure (syntax) of transmission information, and includes parameters that affect the entire frame of transmission information. In the present embodiment, as described above, the NAL unit information includes coded data, color difference conversion information received from the generation unit 16, header information, byte alignment information which is adjustment information at the time of writing / reading, and the like.

The transmission information generation unit 20 receives NAL unit information from the NAL unit generation unit 18. The transmission information generation unit 20 converts the received NAL unit information into information of a system layer such as an MPEG-2 system or an ISO file format, and generates transmission information. The transmission information generation unit 20 outputs the generated transmission information.

Next, the coding process executed by the coding apparatus 10 will be described.

FIG. 18 is a flowchart showing a procedure of the coding process executed by the coding apparatus 10.

First, the conversion unit 12 executes a color difference conversion process for converting the resolution of the color difference component on the original image received by the coding device 10 (step S100). Then, the conversion unit 12 outputs the original image obtained by converting the resolution of the color difference component to the coding unit 14 as a color difference conversion image. Further, the conversion unit 12 outputs the color difference signal information to the generation unit 16.

Next, the coding unit 14 encodes the color difference conversion image received from the conversion unit 12 and generates coded data (step S102). The coding unit 14 outputs the coded data to the NAL unit generation unit 18. Further, the coding unit 14 outputs a reference image in the same color difference format (4: 2: 0 format) as the color difference converted image to the generation unit 16.

Next, the generation unit 16 generates the color difference conversion information by using the color difference signal information received from the conversion unit 12 and the color difference format reference image of the color difference conversion image received from the coding unit 14 (step). S104). The generation unit 16 outputs the generated color difference conversion information to the NAL unit generation unit 18.

Next, the NAL unit generation unit 18 includes the coding data received from the coding unit 14, the color difference conversion information received from the generation unit 16, the header information, the byte alignment information which is the adjustment information at the time of writing / reading, and the like. , NAL unit information is generated (step S106). The NAL unit generation unit 18 outputs the generated NAL unit information to the transmission information generation unit 20.

Next, the transmission information generation unit 20 converts the NAL unit information received from the NAL unit generation unit 18 into system layer information, and generates transmission information (step S108). The transmission information generation unit 20 outputs the generated transmission information.

As described above, according to the coding apparatus 10 of the present embodiment, the coding unit 14 encodes the color difference conversion image to generate the coded data. The generation unit 16 has a first color difference format indicating the resolution of the color difference component of the coded data, a second color difference format indicating the resolution of the color difference component at the time of reproduction of the decoded image obtained by decoding the coded data, and a first color difference format. The color difference conversion information including the specific information for specifying the filter used when converting the decoded image of the coded data into the second color difference format is generated.

Therefore, when reproducing the decoded image obtained by decoding the coded data encoded by the coding apparatus 10, the coded data in the first color difference format is subjected to the filter specified by the specific information included in the color difference conversion information. By converting the decoded image to the second color difference format, deterioration of image quality due to resolution conversion can be suppressed.

Therefore, the coding device 10 of the present embodiment can suppress deterioration of image quality.

(Modification example 1)
In the above embodiment, the case where the specific information is the filter information used for converting the decoded image of the first color difference format into the second color difference format has been described.

However, the specific information may be any information for specifying the filter used when converting the decoded image of the first color difference format into the second color difference format. For example, the specific information may be identification information for identifying the filter information used for converting the decoded image of the first color difference format into the second color difference format.

In this case, the definition information in which the filter information and the identification information of the filter information are associated with each other is stored in advance in the coding device 10 and a decoding device (decoding device or the like described later) for decoding the coded data. Just do it. Then, on the device side that decodes the coded data, the decoded image obtained by decoding the coded data is filtered using the filter information corresponding to the identification information included in the specific information, so that the color difference format of the decoded image is obtained. You just have to convert.

Further, the specific information may be the filter information used for the filter processing by the conversion unit 12.

In this case, the decoding device that decodes the coded data sets a filter to be used when converting the decoded image of the first color difference format into the second color difference format from the filter information included in the specific information. Then, the decoding device may convert the color difference format of the decoded image by using the set filter.

(Embodiment 2)
In this embodiment, a mode for generating color difference conversion information by a method different from that of the first embodiment will be described.

FIG. 19 is a schematic diagram showing a functional configuration of the coding device 10A of the present embodiment.

The coding device 10A includes a conversion unit 120, a coding unit 14, a generation unit 160, a NAL unit generation unit 18, and a transmission information generation unit 20.

The coding device 10A has the same configuration as the coding device 10 of the first embodiment except that the conversion unit 120 is replaced with the conversion unit 12 and the generation unit 160 is provided instead of the generation unit 16.

The conversion unit 120 has the same configuration as the conversion unit 12 except that the filter information used by the conversion unit 120 is output to the generation unit 160 as the color difference signal information. Specifically, the conversion unit 120 outputs the color difference signal information including the filter information used for the filter processing by the conversion unit 12A and the filter information used for the filter processing by the conversion unit 12B to the generation unit 160. In the present embodiment, as in the first embodiment, the filter information used by the conversion unit 12A is the horizontal downsampling filter information, and the filter information used by the conversion unit 12B is the vertical downsampling filter information. is there.

The generation unit 160 receives the color difference signal information from the conversion unit 120. The generation unit 160 generates the color difference conversion information by using the color difference signal information.

FIG. 20 is a schematic diagram showing a functional configuration of the generation unit 160.

The generation unit 160 includes a vertical filter information generation unit 160A, a horizontal filter information generation unit 160B, and a generation unit 160C.

The vertical filter information generation unit 160A receives the filter information (vertical downsampling filter information) used for the filter processing by the conversion unit 12B among the information included in the color difference signal information.

The vertical filter information generation unit 160A designs the filter information used to convert the image in the 4: 2: 0 format into the 4: 2: 2 format from the vertical downsampling filter information used in the conversion unit 12B. That is, the vertical filter information generation unit 160A designs the filter information used to obtain the image in the 4: 2: 2 format by performing the vertical upsampling process on the decoded image in the 4: 2: 0 format. .. The filter information is designed using the following equation (4). Then, the vertical filter information generation unit 160A outputs the designed vertical filter information, which is the filter information, to the generation unit 160C.

The horizontal filter information generation unit 160B uses the filter information (horizontal downsampling filter information) used for the filter processing by the conversion unit 12A among the information included in the color difference signal information to obtain an image in 4: 2: 2 format at 4: 4. : Design the filter information used to convert to the original image in 4 formats. That is, the horizontal filter information generation unit 160B designs the filter information used to obtain the original image in the 4: 4: 4 format by performing the horizontal upsampling process on the image in the 4: 2: 2 format. The filter information is designed using the following equation (4). Then, the horizontal filter information generation unit 160B outputs the horizontal filter information, which is the designed filter information, to the generation unit 160C.

Equation (4) is a filter calculation equation used by the vertical filter information generation unit 160A and the horizontal filter information generation unit 160B at the time of filter design.

Specifically, in the equation (4), the color difference component in each pixel is downsampled to 1/2 after the one-dimensional image and the color difference component in each pixel constituting the one-dimensional image are upsampled twice. This is an equation for designing the filter information so that the image quality is the same as that of the image.

In the equation (4), D is a vector indicating the downsampling filter coefficient, and d _{1 to} d _2n (n is an integer of 1 or more) indicates the filter coefficient of the downsampling filter. U and V is a vector indicating the up-sampling filter _{coefficients,} u 1 _~u n (n is an integer of 1 or more) represents a filter coefficient used for upsampling for the top _field, v 1 _{to v} n (n Is an integer greater than or equal to 1) indicates the filter coefficient used for upsampling for the bottom field.

Further, in the equation (4), X is a matrix of 2n rows (2n-1) having the upsampling filter coefficient as an element, and I is the number of elements 2n-1, the nth being 1 and the rest being 0. It is a vector.

Then, the filter information is designed by designing D, U, and V so as to satisfy DX = I.

By using the equation (4), the corresponding upsampling filter coefficient can be obtained from the downsampling filter coefficient. On the contrary, the corresponding downsampling filter coefficient can be obtained from the upsampling filter coefficient.

The generation unit 160C generates color difference conversion information. Specifically, the generation unit 160C uses the color difference format (4: 2: 0 format) of the reference image received from the coding unit 14 as the first color difference format of the coded data encoded by the coding unit 14. Further, the generation unit 160C reads the second color difference format from a memory (not shown). Further, the generation unit 160C uses the vertical filter information received from the vertical filter information generation unit 160A and the horizontal filter information received from the horizontal filter information generation unit 160B as specific information. The generation unit 160C generates the first color difference format, the second color difference format, and the color difference conversion information including the specific information, and outputs the color difference conversion information to the NAL unit generation unit 18.

As described above, in the coding apparatus 10A of the present embodiment, the generation unit 160 receives the filter information used by the conversion unit 120 as the color difference signal information. The generation unit 160 uses the received color difference signal information to generate color difference conversion information.

Therefore, when reproducing the decoded image obtained by decoding the coded data encoded by the coding apparatus 10A, the coded data in the first color difference format is used by using the filter information specified by the specific information included in the color difference conversion information. By converting the decoded image of the above to the second color difference format, deterioration of image quality due to resolution conversion can be suppressed.

Therefore, even when the color difference conversion information is generated by a method different from that of the first embodiment, the same effect as that of the first embodiment can be obtained.

Further, in addition to the effect of the coding device 10 in the first embodiment, the configuration of the generation unit 160 (generation unit 16) can be simplified.

(Modification 2)
In the above embodiment, the conversion unit 12 includes two conversion units (conversion unit 12A and conversion unit 12B), and describes a case where the resolution of the color difference component is converted a plurality of times for the original image. However, the conversion unit 12 may be a functional unit that performs one color difference conversion. Further, in the above embodiment, the case where the conversion unit 12 performs a filter process (downsampling) for reducing the resolution of the color difference component has been described. However, the conversion unit 12 may perform a filter process (upsampling) to expand the resolution of the color difference component.

In this case, as shown in FIG. 19, the coding apparatus 10A includes a conversion unit 122 in place of the conversion unit 120, and a generation unit 162 in place of the generation unit 160.

FIG. 21 is a schematic diagram showing a functional configuration of the conversion unit 122. The conversion unit 122 includes a conversion unit 122A and an output adjustment unit 122B.

For example, the conversion unit 122 accepts an original image in a 4: 2: 0 format as an original image. The conversion unit 122A converts the received original image in the 4: 2: 0 format into an image in the 4: 2: 2 format. The conversion unit 122A performs filter processing using filter information for performing pixel interpolation in the vertical direction with respect to the color difference component of the pixels constituting the original image in the 4: 2: 0 format. As a result, the conversion unit 122A performs upsampling that vertically interpolates the color difference components of the pixels constituting the image in the 4: 2: 0 format. That is, the conversion unit 122A converts the original image in the 4: 2: 0 format into the image in the 4: 2: 2 format. The conversion unit 122A outputs the converted 4: 2: 2 format image to the output adjustment unit 122B.

The output adjustment unit 122B has a range in which each pixel value constituting the 4: 2: 2 format image received from the conversion unit 122A is equal to or more than the minimum value defined by the standard and is equal to or less than the maximum value defined by the standard. Clipping processing is performed so that Then, the original image after the clipping process is output to the coding unit 14 as a color difference conversion image converted by the conversion unit 122.

Further, the output adjustment unit 122B outputs the color difference signal information including the filter information used for the filter processing by the conversion unit 122A to the generation unit 162.

Next, the generation unit 162 will be described.

FIG. 22 is a schematic diagram showing a functional configuration of the generation unit 162.

The generation unit 162 includes a horizontal filter information generation unit 162A and a generation unit 162B.

The horizontal filter information generation unit 162A receives the filter information (horizontal upsampling filter information) used for the filter processing by the conversion unit 122A as the color difference signal information.

The horizontal filter information generation unit 162A designs the filter information used to convert the image in the 4: 2: 2 format into the 4: 2: 0 format from the horizontal upsampling filter information used in the filter processing by the conversion unit 122A. .. That is, the horizontal filter information generation unit 162A designs the filter information used to obtain the image in the 4: 2: 0 format by performing the horizontal downsampling process on the image in the 4: 2: 2 format. Then, the horizontal filter information generation unit 162A outputs the horizontal filter information, which is the designed filter information, to the generation unit 162B.

The generation unit 162B generates the color difference conversion information. Specifically, the generation unit 162B uses the color difference format (4: 2: 2 format) of the reference image received from the coding unit 14 as the first color difference format of the coded data encoded by the coding unit 14. Further, the generation unit 162B reads the second color difference format from a memory (not shown). Further, the generation unit 162B uses the horizontal filter information received from the horizontal filter information generation unit 162A as the specific information.

The generation unit 162B generates color difference conversion information including these first color difference format, second color difference format, and specific information, and outputs the color difference conversion information to the NAL unit generation unit 18.

In this way, even when the conversion unit 122 performs the filter processing (upsampling) for expanding the resolution of the color difference component, the generation unit 162 can display the first color difference format, the second color difference format, and the specific information. Generate the color difference conversion information including.

Therefore, in this modification as well, the same effect as that of the first embodiment can be obtained.

(Modification 3)
In the above embodiment, the case where the color difference conversion is performed in the coding device 10 and the coding device 10A has been described, but the configuration does not include the conversion unit 12 (conversion unit 120, conversion unit 122) for performing the color difference conversion. There may be.

FIG. 23 is a schematic diagram showing a functional configuration of the coding device 10B.

The coding device 10B includes a coding unit 14, a NAL unit generation unit 18, a transmission information generation unit 20, and a generation unit 16.

The coding device 10B has the same configuration as the coding device 10 of the first embodiment, except that the coding device 10B does not include the conversion unit 12. In the present embodiment, the coding unit 14 of the coding device 10B receives the color difference conversion image from an external device or the like. Further, the generation unit 16 receives the color difference conversion information from an external device or the like.

As described above, the coding device 10B may be configured not to include the conversion unit 12.

(Embodiment 3)
In this embodiment, the decoding device will be described. The decoding device is a device that decodes the coded data included in the transmission information generated by the coding devices 10, 10A, and 10B.

FIG. 24 is a schematic diagram showing a functional configuration of the decoding device of the present embodiment. The decoding device 50 of the present embodiment includes a transmission information decoding unit 52, a NAL unit decoding unit 54, a decoding unit 56, a decoding unit 58, and a conversion unit 60.

The transmission information decoding unit 52 receives the transmission information. In the present embodiment, as an example, a case where transmission information is received from the coding device 10 of the first embodiment will be described. Further, in the present embodiment, a case where transmission information including the color difference conversion information shown in FIG. 5 is received from the coding device 10 will be described. The transmission information decoding unit 52 generates NAL unit information from the received transmission information.

The NAL unit decoding unit 54 receives and decodes the NAL unit information from the transmission information decoding unit 52. As a result, the NAL unit decoding unit 54 obtains coded data, color difference conversion information, byte alignment information, and the like.

The NAL unit decoding unit 54 outputs the coded data obtained from the NAL unit information to the decoding unit 56. Further, the NAL unit decoding unit 54 outputs the color difference conversion information obtained from the NAL unit information to the decoding unit 58.

The decoding unit 58 decodes the color difference conversion information and obtains the first color difference format, the second color difference format, and specific information. Then, it is output to the conversion unit 60.

FIG. 25 is a schematic diagram showing a functional configuration of the decoding unit 58.

As shown in FIG. 25, the decoding unit 58 includes a decoding unit 58A. The decoding unit 58A analyzes the color difference conversion information and reads the first color difference format, the second color difference format, and the specific information included in the color difference conversion information. Then, the read first color difference format, second color difference format, and color difference conversion information including specific information are output to the conversion unit 60.

If the specific information included in the color difference conversion information is the filter information used when converting the decoded image of the first color difference format into the second color difference format, the decoding unit 58A will perform the specific information. The information is output to the conversion unit 60 as it is.

On the other hand, when the specific information included in the color difference conversion information is the identification information of the filter information used when converting the decoded image of the first color difference format into the second color difference format, the decoding unit 58A corresponds to the identification information. The filter information to be used is read from the definition information stored in advance in a memory (not shown). Then, the read filter information is output to the conversion unit 60 as specific information.

Further, when the specific information included in the color difference conversion information is the filter information used for the filter processing in the conversion unit 12 of the coding apparatus 10, the decoding unit 58A decodes the first color difference format from this filter information. Design filter information to convert the image to the second color difference format. Then, the filter information of the designed filter is output to the conversion unit 60 as specific information.

Returning to FIG. 24, the decoding unit 56 decodes the encoded data to obtain a decoded image. The decoding unit 56 outputs the decoded image to the conversion unit 60.

FIG. 26 is a schematic diagram showing the functional configuration of the decoding unit 56.

As shown in FIG. 26, the decoding unit 56 includes an entropy decoding unit 56A, an inverse quantization / inverse conversion unit 56B, an addition unit 56C, a frame memory 56D, and a prediction image generation unit 56E.

The entropy decoding unit 56A receives the encoded data from the NAL unit decoding unit 54. The entropy decoding unit 56A entropy decodes the received encoded data according to a predetermined syntax. As a result, the entropy decoding unit 56A obtains the quantization coefficient and the motion vector information.

The entropy decoding unit 56A outputs the quantization coefficient to the inverse quantization / inverse conversion unit 56B, and outputs the motion vector information to the prediction image generation unit 56E.

The inverse quantization / inverse conversion unit 56B inversely quantizes the quantization coefficient and then inversely transforms it to generate an error image. The addition unit 56C receives an error image from the inverse quantization / inverse conversion unit 56B, and receives a prediction image from the prediction image generation unit 56E. Then, the addition unit 56C adds the error image and the prediction image to generate a decoded image. This decoded image is stored in the frame memory 56D and then output to the conversion unit 60 and the prediction image generation unit 56E.

The prediction image generation unit 56E generates a prediction image by using the decoded image and the motion vector information. Then, the prediction image generation unit 56E outputs the generated prediction image to the addition unit 56C.

Returning to FIG. 24, the conversion unit 60 receives the decoded image from the decoding unit 56. Further, the conversion unit 60 receives the color difference conversion information from the decoding unit 58. The conversion unit 60 reads the first color difference format, the second color difference format, and the specific information included in the color difference conversion information. Then, the conversion unit 60 converts the resolution of the color difference component of the decoded image of the first color difference format using the filter specified by the specific information, and converts it into the second color difference format. The conversion unit 60 outputs the reproduced image obtained by converting the resolution of the color difference component of the decoded image to a reproduction device or the like.

FIG. 27 is a schematic diagram showing the functional configuration of the conversion unit 60.

The conversion unit 60 includes a conversion unit 60A, a conversion unit 60B, and an output adjustment unit 60C.

The conversion unit 60A converts the decoded image in the 4: 2: 0 format into the 4: 2: 2 format. The conversion unit 60A reads the filter information used for the filter processing by the conversion unit 12B as specific information from the color difference conversion information received from the decoding unit 58. Then, a filter process is performed using the read filter information, and the decoded image in the 4: 2: 0 format is converted into the 4: 2: 2 format.

The conversion unit 60A outputs the decoded image in the 4: 2: 2 format obtained by the conversion to the conversion unit 60B. The conversion unit 60B reads the filter information used for the filter processing by the conversion unit 12A as specific information from the color difference conversion information received from the decoding unit 58. Then, a filter process is performed using the read filter information, and the decoded image in the 4: 2: 2 format is converted into the 4: 4: 4 format. The conversion unit 60B outputs the converted 4: 4: 4 format decoded image to the output adjustment unit 60C.

The output adjustment unit 60C reads the pixel bit length at the time of reproduction, the maximum value of the color difference component at the time of reproduction, and the minimum value of the color difference component at the time of reproduction, which are defined in the color difference conversion information, or a predetermined color difference format. The decoded image is clipped so as to satisfy these values with the pixel bit length, the maximum value, and the minimum value according to the specifications of. Then, the decoded image after the clipping process is output as a reproduced image.

Next, the decoding process executed by the decoding device 50 will be described.

FIG. 28 is a flowchart showing a procedure of the decoding process executed by the decoding device 50.

First, the transmission information decoding unit 52 decodes the transmission information received from the coding device 10 (step S200). NAL unit information is obtained by the process of step S200.

Next, the NAL unit decoding unit 54 decodes the NAL unit information obtained in step S200 (step S202). By the process of step S202, the NAL unit decoding unit 54 obtains coded data, color difference conversion information, byte alignment information, and the like.

Next, the decoding unit 56 decodes the encoded data received from the NAL unit decoding unit 54 to obtain a decoded image (step S204).

Next, the decoding unit 58 decodes the color difference conversion information (step S206). By the process of step S206, the decoding unit 58 reads the first color difference format, the second color difference format, and the specific information included in the color difference conversion information. Then, the read first color difference format, second color difference format, and color difference conversion information including specific information are output to the conversion unit 60.

Next, the conversion unit 60 performs color difference conversion of the decoded image received from the decoding unit 56 into the second color difference format defined in the color difference conversion information (step S208). The conversion unit 60 outputs the reproduced image obtained by color-difference converting the decoded image to a reproduction device or the like. Then, this routine is terminated.

As described above, the decoding device 50 receives transmission information including color difference conversion information and coded data. Then, the decoding device 50 converts the decoded image of the first color difference format obtained by decoding the encoded data into the second color difference format by using the filter specified by the specific information included in the color difference conversion information. .. Therefore, the decoding device 50 can suppress deterioration of image quality due to resolution conversion.

Therefore, the decoding device 50 of the present embodiment can suppress deterioration of image quality.

(Modification example 4)
Next, the operations of the decoding unit 58 and the decoding unit 58A (see FIG. 25) when the transmission information decoding unit 52 receives the transmission information including the color difference conversion information shown in FIG. 8 from the coding device 10 will be described.

In this case, the decoding unit 58A decodes the color difference conversion information according to the syntax shown in FIG.

As described above, the chroma_loc_info_present_flag in the color difference conversion information shown in FIG. 8 is a flag indicating whether or not there is filter information regarding the pixel position of the color difference signal and the color difference conversion. When the value of this chroma_loc_info_present_flag is "0", the decoding unit 58A considers that the pixel position of the color difference signal and the filter information regarding the color difference conversion do not exist, and skips the reading. On the other hand, when the value of chroma_loc_info_present_flag is "1", there is filter information regarding the pixel position of the color difference signal and the color difference conversion. Therefore, in this case, the decoding unit 58A identifies the pixel sample position of the color difference by the values indicated by each of the chroma_sample_loc_type_top_field and the chroma_sample_loc_type_bottom_field.

Further, as described above, chroma_filter_info_present_flag is a flag indicating whether or not filter information regarding color difference conversion exists. Therefore, when the value of chroma_filter_info_present_flag is "0", the decoding unit 58A skips it because there is no filter information related to the color difference conversion. On the other hand, when the value of chroma_filter_info_present_flag is "1", there is filter information regarding the color difference conversion. Therefore, in this case, the decoding unit 58A reads the identification information (Value) indicated by chroma_filter_info from the color difference conversion filter definition information shown in FIG. 9 or FIG.

Specifically, the decoding unit 58A has a filter coefficient corresponding to the identification information in the color difference conversion filter definition information shown in FIG. 9 or 10, the number of denominators (Divisor) in the case of performing the filter processing, and after the filter processing. The information corresponding to each of the sample position (Phase shift) of the color difference pixel, the use of the filter coefficient, and the information (Purpose) of the second color difference format is read.

In addition, as described above, the color difference conversion filter definition information shown in FIGS. 9 and 10 includes a pair of coding devices other than the filter coefficient for performing color difference conversion from the first color difference format to the second color difference format. The filter coefficient used on the side for color difference conversion from the second color difference format to the first color difference format is also included.

Specifically, when the value of chroma_filter_info in the color difference conversion filter definition information shown in FIG. 10 is "1", the decoding unit 58A performs color difference conversion with the second color difference format target_format_idc according to the syntax shown in FIG. The values of num_of_filter_minus1 indicating the number of filters minus 1 and filter_coeff indicating the filter coefficient are read.

Then, the decoding unit 58A outputs these read values to the conversion unit 60. The processing of the conversion unit 60 is the same as described above.

Similarly, when the transmission information including the color difference conversion information shown in FIG. 8 is received, the decoding device 50 similarly uses the filter specified by the specific information included in the color difference conversion information to convert the coded data. The decoded image of the first color difference format obtained by decoding is converted into the color difference format. Therefore, the decoding device 50 can suppress deterioration of image quality due to resolution conversion.

(Modification 5)
Next, the operations of the decoding unit 58 and the decoding unit 58A (see FIG. 25) when the transmission information decoding unit 52 receives the transmission information including the color difference conversion information shown in FIG. 12 from the coding device 10 will be described.

In this case, the decoding unit 58A decodes the color difference conversion information according to the syntax shown in FIG.

As described above, the chroma_loc_info_present_flag in the color difference conversion information shown in FIG. 12 is a flag indicating whether or not there is filter information regarding the pixel position of the color difference signal and the color difference conversion. When the value of chroma_loc_info_present_flag is "0", the decoding unit 58A skips the value of this flag because there is no filter information regarding the pixel position of the color difference signal and the color difference conversion.

On the other hand, when the value of chroma_loc_info_present_flag is "1", there is filter information regarding the pixel position of the color difference signal and the color difference conversion. Therefore, in this case, the decoding unit 58A specifies the pixel sample position of the color difference from each value of chroma_sample_loc_type_top_field and chroma_sample_loc_type_bottom_field.

chroma_filter_info_present_flag is a flag indicating whether or not filter information regarding color difference conversion exists. When the value of this chroma_filter_info_present_flag is "1", the decoding unit 58A performs decoding according to the syntax of the color difference conversion filter information of FIG. 13, FIG. 15, or FIG.

Hereinafter, a case where the decoding unit 58A performs decoding according to the syntax of the color difference conversion filter information shown in FIG. 13 will be described.

As described above, num_of_filter_set_minus1 is a value indicating the number of filter sets minus 1, and indicates that loop processing is performed by the number of filter sets. Further, the implicit_filter_set_flag is a flag indicating that the information of the predetermined filter set is used. When this flag is "1", the decoding unit 58A reads filter_set_idc which is the identification information of the information of the preset filter set. On the other hand, when impedance_filter_set_flag is "0", the decoding unit 58A reads num_of_filter_minus1 indicating a value of minus 1 of the number of color difference conversion filters, and loops the following number of color difference conversion filters.

As described above, implicit_filter_flag is a flag indicating that predetermined filter information is used. When the value of this flag is "1", the decoding unit 58A reads filter_idc which is the identification information of the filter information defined in advance. On the other hand, when the value of implicit_filter_flag is "0", the decoding unit 58A reads tap_length_minus1 indicating the value of the tap length minus 1 of the filter coefficient. Then, the decoding unit 58A loops by the read filter coefficient tap length, and reads filter_coeff representing the filter coefficient value.

Next, the decoding unit 58A has a tap length of the filter coefficient of the preset color difference conversion filter definition information corresponding to filter_set_idc and filter_idc, a filter coefficient (Filter coefficient), and a number of denominators when performing filter processing (Filter cofficient). (Divisor), the sample position (Phase shift) of the color difference pixel after the filter processing, the use of the filter coefficient, and the information (Purpose) of the second color difference format are read. In filter_set_idc, the filter coefficient in the filtering process on the coding side, which is paired with the filtering process on the decoding side, can also be defined.

Then, the decoding unit 58A outputs these read values to the conversion unit 60. The processing of the conversion unit 60 is the same as described above.

Similarly, when the transmission information including the color difference conversion information shown in FIG. 12 is received, the decoding device 50 similarly uses the filter specified by the specific information included in the color difference conversion information to obtain the coded data. The decoded image of the first color difference format obtained by decoding is converted into the color difference format. Therefore, the decoding device 50 can suppress deterioration of image quality due to resolution conversion.

(Modification 6)
Next, in the modified example 5, a case where the decoding unit 58A performs decoding according to the syntax of the color difference conversion filter information shown in FIG. 14 will be described.

As mentioned above, target_format_idc indicates a second color difference format. Further, chroma_format_idc indicates a first color difference format.

When the value of chroma_format_idc is "1" and the value of target_format_idc is larger than "1", or when the value of chroma_format_idc is larger than "1" and the value of target_format_idc is "1", the decoding unit 58A is vertical. Read the direction filter information.

As described above, implicit_vertical_flag is a flag indicating that the predefined vertical filter information is used. When the value of this flag is "1", the decoding unit 58A reads the virtual_filter_idc which is the identification information of the vertically defined filter information. On the other hand, when the value of implicit_vertical_flag is "0", the decoding unit 58A reads tap_length_vertical_minus1 indicating the value of the tap length minus 1 of the vertical filter coefficient, and reads the vertical filter coefficient ver_filter_coeff for the tap length.

Then, when the encoded data is a field signal, the decoding unit 58A reads second_filter_flag, which is a flag defined when different filter sets are used in the vertical direction in the top field and the bottom field. Then, when the value of this flag is "1", the value of chroma_format_idc is "1", and the value of target_format_idc is larger than "1", the second filter information exists.

On the other hand, when the value of implicit_vertical_flag is "1", the decoding unit 58A reads second_vertical_filter_idc, which is the identification information of the second vertical filter information defined in advance. When the value of implicit_vertical_flag is "0", the decoding unit 58A reads tap_length_second_vertical_minus1 indicating the value of the tap length minus 1 of the second vertical filter coefficient, and reads the vertical filter coefficient second_ver_filter_coeff for the tap length. ..

Further, when the value of horizontal_format_idc is "1" or "2" and the value of target_format_idc is "3", or the value of chroma_format_idc is "3" and the value of target_format_idc is "1" or ". In the case of "2", the decoding unit 58A reads the filter information in the horizontal direction.

The implicit_horizontal_flag is a flag indicating that the predefined horizontal filter information is used. When the value of this flag is "1", the decoding unit 58A reads the horizontal_filter_idc which is the identification information of the horizontally defined filter information. On the other hand, when the value of implicit_vertical_flag is "0", the decoding unit 58A reads tap_length_horizontal_minus1 indicating the value of the tap length minus 1 of the horizontal filter coefficient, and reads the horizontal filter coefficient ho_filter_coeff for the tap length.

Then, the decoding unit 58A identifies the filter_idc in FIG. 16, which corresponds to the vertical_filter_idc, second_vertical_filter_idc, or horizontal_filter_idc shown in FIG. 15. Then, the decoding unit 58A has a tap length (Taplength) of a filter coefficient of the color difference conversion filter definition information defined in advance corresponding to the specified filter_idc, a filter coefficient (Filter coefficients), and a number of denominators when performing filter processing ( (Divisor), the sample position (Phase shift) of the color difference pixel after the filter processing, the use of the filter coefficient, and the information (Purpose) of the second color difference format are obtained.

Then, the decoding unit 58A outputs these read values to the conversion unit 60. The processing of the conversion unit 60 is the same as described above.

In this way, even when decoding is performed according to the syntax of the color difference conversion filter information shown in FIG. 14, the decoding device 50 encodes using the filter specified by the specific information included in the color difference conversion information. The decoded image of the first color difference format obtained by decoding the data is converted into the color difference format. Therefore, the decoding device 50 can suppress deterioration of image quality due to resolution conversion.

(Modification 7)
Next, in the modified example 5, a case where the decoding unit 58A performs decoding according to the syntax of the color difference conversion filter information shown in FIG. 17 will be described.

When the value of chroma_format_idc is "1" and the value of target_format_idc is larger than "1", or when the value of chroma_format_idc is larger than "1" and the value of target_format_idc is "1", the decoding unit 58A is in the vertical direction. Read the filter information of.

Specifically, the decoding unit 58A reads tap_length_vertical_minus1 indicating a value of the tap length minus 1 of the filter coefficient in the vertical direction, and reads the vertical filter coefficient ver_filter_coeff corresponding to the tap length.

When the encoded data is a field signal, the decoding unit 58A reads second_filter_flag, which is a flag defined when different filter sets are used in the vertical direction in the top field and the bottom field. Then, when the value of this flag is "1", the value of chroma_format_idc is "1", and the value of target_format_idc is larger than "1", the second filter information exists.

Therefore, in this case, the decoding unit 58A reads tap_length_second_vertical_minus1 indicating the value of the tap length minus 1 of the second vertical filter coefficient, and reads the vertical filter coefficient second_ver_filter_coeff for the tap length.

On the other hand, if the value of chroma_format_idc is "1" or "2" and the value of target_format_idc is "3", or the value of chroma_format_idc is "3" and the value of target_format_idc is "1" or "1" or ". In the case of "2", the decoding unit 58A reads the filter information in the horizontal direction.

Tap_length_horizontal_minus1, which indicates the value of the tap length minus 1 of the horizontal filter coefficient, is read, and the horizontal filter coefficient ho_filter_coeff for the tap length is read.

Then, the decoding unit 58A outputs these read values to the conversion unit 60. The processing of the conversion unit 60 is the same as described above.

In this way, even when decoding is performed according to the syntax of the color difference conversion filter information shown in FIG. 17, the decoding device 50 encodes using the filter specified by the specific information included in the color difference conversion information. The decoded image of the first color difference format obtained by decoding the data is converted into the color difference format. Therefore, the decoding device 50 can suppress deterioration of image quality due to resolution conversion.

(Modification 8)
Next, a case where the decoding device 50 receives the transmission information including the filter information used for the filter processing in the conversion unit 12 of the coding device 10 as specific information will be specifically described.

In this case, the decoding device 50 shown in FIG. 24 may be configured to include a decoding unit 580 instead of the decoding unit 58.

FIG. 29 is a schematic diagram showing a functional configuration of the decoding unit 580. The decoding unit 580 includes a decoding unit 580A, a vertical filter information generation unit 580B, and a horizontal filter information generation unit 580C.

The decoding unit 580A analyzes the color difference conversion information and reads the first color difference format, the second color difference format, and the specific information included in the color difference conversion information. In this modification, the specific information is the filter information used for the filter processing in the conversion unit 12 of the coding apparatus 10. Further, in this modification, vertical downsampling filter information and horizontal downsampling filter information are included as specific information.

The vertical filter information generation unit 580B generates vertical upsampling filter information to be used in the filtering process by the conversion unit 60 of the decoding device 50 from the vertical downsampling filter information included in the specific information. The horizontal filter information generation unit 580C generates horizontal upsampling filter information used in the filtering process by the conversion unit 60 of the decoding device 50 from the horizontal downsampling filter information included in the specific information. Then, the decoding unit 580 includes the vertical upsampling filter information generated by the vertical filter information generation unit 580B, the horizontal upsampling filter information generated by the horizontal filter information generation unit 580C, the first color difference format, and the second color difference. The color difference conversion information including the format is output to the conversion unit 60.

The conversion unit 60 reads the first color difference format, the second color difference format, and the specific information included in the color difference conversion information in the same manner as in the above embodiment. Then, the conversion unit 60 converts the resolution of the color difference component of the decoded image of the first color difference format using the filter specified by the specific information, and converts it into the second color difference format. The conversion unit 60 outputs the reproduced image obtained by converting the resolution of the color difference component of the decoded image to a reproduction device or the like.

In this way, the decoding device 50 may generate filter information used for the filtering process of the conversion unit 60 of the decoding device 50.

It is assumed that the specific information included in the color difference conversion information generated by the decoding unit 58 or the decoding unit 580 includes the vertical downsampling filter information.

In this case, the decoding device 50 includes a conversion unit 600 instead of the conversion unit 60.

FIG. 30 is a schematic diagram showing the functional configuration of the conversion unit 600.

The conversion unit 600 includes a conversion unit 600A and an output adjustment unit 600B.

The conversion unit 600A receives the decoded image in the 4: 2: 2 format from the decoding unit 56. The conversion unit 600A uses the received 4: 2: 2 format decoded image by using the vertical downsampling filter information indicated by the specific information included in the color difference conversion information received from the decoding unit 58 or the decoding unit 580. Color difference conversion to 2: 0 format. That is, the conversion unit 600A performs downsampling by thinning out the color difference components of the pixels constituting the decoded image in the 4: 2: 2 format to 1/2 in the vertical direction by using the vertical downsampling filter information. The conversion unit 600A outputs the converted 4: 2: 0 format decoded image to the output adjustment unit 600B.

The output adjustment unit 600B reads the pixel bit length at the time of reproduction, the maximum value of the color difference component at the time of reproduction, and the minimum value of the color difference component at the time of reproduction, which are defined in the color difference conversion information, or a predetermined color difference format. The decoded image is clipped so as to satisfy these values with the pixel bit length, the maximum value, and the minimum value according to the specifications of. Then, the decoded image after the clipping process is output as a reproduction image to be reproduced.

(Embodiment 4)
Next, the hardware configurations of the coding devices 10, 10A, 10B, and the decoding device 50 will be described. FIG. 31 is a block diagram showing the hardware configurations of the coding devices 10, 10A, 10B, and the decoding device 50.

The coding devices 10, 10A, 10B, and decoding device 50 of the present embodiment include a communication interface (IF) 86, a CPU 80 (Central Processing Unit), a ROM (Read Only Memory) 82, and a RAM (Random Access Memory) 84. Etc. are connected to each other by a bus, and the hardware configuration uses a normal computer.

The CPU 80 is an arithmetic unit that controls the entire processing in each of the coding devices 10, 10A, 10B, and the decoding device 50. The RAM 84 stores data required for various processes by the CPU 80. The ROM 82 stores a program or the like that realizes various processes by the CPU 80. The communication interface (IF) 86 is an interface for connecting to an external device via a communication line and transmitting / receiving data to / from the connected external device.

The program for executing the coding process executed by the coding devices 10, 10A and 10B and the program for executing the decoding process executed by the decoding device 50 are provided in advance in the ROM 82 or the like. Program.

The program for executing the coding process executed by the coding devices 10, 10A and 10B and the program for executing the decoding process executed by the decoding device 50 are the coding devices 10, 10A and 10B. , And a file in a format that can be installed in the decoding device 50 or in an executable format, and is recorded on a computer-readable recording medium such as a CD-ROM, a flexible disk (FD), a CD-R, or a DVD (Digital Versaille Disk). May be configured to provide.

Further, a program for executing the coding process executed by the coding devices 10, 10A and 10B and a program for executing the decoding process executed by the decoding device 50 are connected to a network such as the Internet. It may be configured to be stored on a computer and provided by downloading via a network. Further, a program for executing the coding process executed by the coding devices 10, 10A and 10B and a program for executing the decoding process executed by the decoding device 50 are provided or provided via a network such as the Internet. It may be configured to be distributed.

The program for executing the coding process executed by the coding devices 10, 10A and 10B and the program for executing the decoding process executed by the decoding device 50 have a modular configuration including the above-mentioned parts. There is. As actual hardware, the CPU 80 reads various programs from the ROM 82 or the like and executes them, so that each of the above parts is loaded on the main storage device, and the above-mentioned functional configuration is generated on the main storage device. There is.

Although some embodiments and modifications of the present invention have been described above, these embodiments and modifications are presented as examples and are not intended to limit the scope of the invention. These novel embodiments and modifications can be implemented in various other embodiments, and various omissions, replacements, and conversions can be made without departing from the gist of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are also included in the scope of the invention described in the claims and the equivalent scope thereof.

10, 10A, 10B Encoding device 14 Encoding unit 16, 160, 162 Generation unit 50 Decoding device

Claims (4)

A first color difference format indicating the resolution of the coded data and the color difference component of the coded data, a second color difference format indicating the resolution of the color difference component used when reproducing the decoded image obtained by decoding the coded data, and a filter. Filter information to identify, and a reception unit that accepts transmission information including
A decoding unit that decodes the coded data and generates the decoded image,
A conversion unit that converts the decoded image into a color difference format using the filter indicated by the filter information, and
With
The first color difference format and the second color difference format indicate the resolutions of the color difference components of the 4: 4: 4 format, the 4: 2: 2 format, or the 4: 2: 0 format, respectively.
The filter information includes filter identification information.
Based on the identification information, the first color difference format, and the second color difference format, the conversion unit selects the filter including at least one of a horizontal sampling filter and a vertical sampling filter from a plurality of predetermined filters. select,
Decoding device. A coding unit that generates coded data and
A first color difference format indicating the resolution of the color difference component of the coded data, a second color difference format indicating the resolution of the color difference component used when reproducing the decoded image obtained by decoding the coded data, and a filter for specifying the filter. A generator that generates filter information, and
An output unit that outputs transmission information including the coded data, the first color difference format, the second color difference format, and the filter information.
With
The first color difference format and the second color difference format indicate the resolutions of the color difference components in the 4: 4: 4 format, the 4: 2: 2 format, or the 4: 2: 0 format, respectively.
Encoding device. A first color difference format indicating the resolution of the coded data and the color difference component of the coded data, a second color difference format indicating the resolution of the color difference component used when reproducing the decoded image obtained by decoding the coded data, and a filter. A reception step that accepts transmission information, including filter information, to identify
A decoding step of decoding the encoded data to generate the decoded image, and
A conversion step of converting the decoded image into a color difference format using the filter indicated by the filter information, and
Including
The first color difference format and the second color difference format indicate the resolutions of the color difference components of the 4: 4: 4 format, the 4: 2: 2 format, or the 4: 2: 0 format, respectively.
The filter information includes filter identification information.
In the conversion step, the filter including at least one of a horizontal sampling filter and a vertical sampling filter is selected from a plurality of predetermined filters based on the identification information, the first color difference format, and the second color difference format. select,
Decryption method. The coding steps to generate the coded data and
A first color difference format indicating the resolution of the color difference component of the coded data, a second color difference format indicating the resolution of the color difference component used when reproducing the decoded image obtained by decoding the coded data, and a filter for specifying the filter. Generate steps to generate filter information, and
An output step for outputting transmission information including the coded data, the first color difference format, the second color difference format, and the filter information.
Including
The first color difference format and the second color difference format indicate the resolutions of the color difference components in the 4: 4: 4 format, the 4: 2: 2 format, or the 4: 2: 0 format, respectively.
Coding method.

Images