Video signal coding method and coding device

Claim 2

A picture signal coding method comprising the steps of defining N continuous frames as one coding control unit, performing intraframe coding of a Kth frame of the coding control unit without using a difference between frames, coding an Nth frame using a difference between the Nth frame and the Kth frame, coding a first frame to a (K-1)th frame using both difference between the first to the (K-1)th frame and an Nth frame of the latest previous coding control unit and difference between the first to the (K-1)th frame and the Kth frame of the current coding control unit, and coding a (K +1)th frame to a (N-1)th frame using both difference between the (K+1)th to the (N-1)th frame and the Kth frame of the current coding control unit and difference between the (K+1)th to the (N-1)th frame and the Nth frame of the current coding control unit, wherein target code amounts of all frames of the current coding control unit are set considering the difference between the Nth frame and the Kth frame as an index.

Claim 3

A picture signal coding method comprising the steps of defining N continuous frames as one coding control unit, performing intraframe coding of a first frame of the coding control unit without using a difference between frames, coding an Nth frame using a difference between the Nth frame and the first frame, and coding a second frame to a (N-1)th frame using both difference between the second to the (N-1)th frame and the first frame and difference between the second to the (N-1)th frame and the Nth frame, wherein a scene change in the coding control unit is detected based on a motion amount of the Nth frame from the first frame and a motion amount of each of the second frame to the (N-1)th frame from the first frame, and target code amounts of ail frames of the coding control unit are set considering a result of the scene change detection as an index.

Claim 4

A picture signal coding method comprising the steps of defining N continuous frames as one coding control unit, performing intraframe coding of a Kth frame of the coding control unit without using a difference between frames, coding an Nth frame using a difference between the Nth frame and the Kth frame, coding a first frame to a (K-1)th frame using both difference between the first to the (K-1)th frame and an Nth frame of the latest previous coding control unit and difference between the first to the (K-1)th frame and the Kth frame of the current coding control unit, and coding a (K +1)th frame to a (N-1)th frame using both difference between the (K+1)th to the (N-1)th frame and the Kth frame of the current coding control unit and difference between the (K+1)th to the (N-1)th frame and the Nth frame of the current coding control unit, wherein a scene change in the coding control unit is detected based on a motion amount of the Nth frame from the Kth frame and a motion amount of each of the first frame to the (K-1)th frame and the (K+1)th frame to the (N-1)th frame from the Kth frame, and target code amounts of all frames of the coding control unit are set considering a result of the scene change detection as an index.

Claim 5

A picture signal coding method comprising the steps of defining N continuous frames as one coding control unit, performing intraframe coding of a first frame of the coding control unit without using a difference between frames, coding an Nth frame using a difference between the Nth frame and the first frame, and coding a second frame to a (N-1)th frame using both difference between the second to the (N-1)th frame and the first frame and difference between the second to the (N-1)th frame and the Nth frame, wherein a degree of difficulty of coding picture signals in the coding control unit is detected from an activity calculated with respect to the first frame, and target code amounts of all frames of the coding control unit are set considering the degree of difficulty and the difference between the Nth frame and the first frame as indices.

Claim 6

A picture signal coding method comprising the steps of defining N continuous frames as one coding control unit, performing intraframe coding of a Kth frame of the coding control unit without using a difference between frames, coding an Nth frame using a difference between the Nth frame and the Kth frame, coding a first frame to a (K-1)th frame using both difference between the first to the (K-1)th frame and an Nth frame of the latest previous coding control unit and difference between the first to the (K-1)th frame and the Kth frame of the current coding control unit, and coding a (K +1)th frame to a (N-1)th frame using both difference between the (K+1)th to the (N-1)th frame and the Kth frame of the current coding control unit and difference between the (K+1)th to the (N-1)th frame and the Nth frame of the current coding control unit, wherein a degree of difficulty of coding picture signals in the coding control unit is detected from an activity calculated with respect to the Kth frame, and target code amounts of all frames of the coding control unit are set considering the degree of difficulty and the difference between the Nth frame and the Kth frame as indices.

Claim 7

A picture signal coding device comprising: a unit division means for divining inputted pictures into coding control units comprising one or plurality of frames that are to be subjected to a process selected from the group consisting of an intraframe coding process, an interframe forward coding process, and an interframe bidirectionally predictive coding process; an activity calculation means for calculating a frame activity from each frame of the inputted pictures and calculating a unit activity for each unit from the frame activities of the frames that belong to the unit; a target code amount determination means for determining a target code amount of a coding frame based on a frame activity of the coding frame, a unit activity of a coding unit to which the coding frame belongs, and an average unit activity of previous units; and a coding means for coding the coding frame with the target code amount to generate encoded data.

Claim 8

The picture signal coding device according to claim 7, wherein the frame activity calculated for each frame is multiplied by one of three weighting constants predetermined according to whether the coding frame is an I, P or B picture, and a resulting value is used as the frame activity.

Claim 9

A picture signal coding device comprising: an activity function generation means for calculating an activity for each macro block in each frame of inputted pictures, generating an activity function indicating an accumulation of the activity for each macro block in a coding frame, and calculating a frame activity of the coding frame; a target code amount determination means for determining a target code amount of the coding frame by using at least one of a remaining code amount at the time of coding the coding frame, a generated code amount of previously encoded frames, an activity of the previously encoded frames, an occupancy of a buffer, and the activity of the coding frame; a reference scaling factor calculation means for calculating a reference scaling factor of the coding frame by using at least one of a scaling factor of the previously encoded frames, the generated code amount of the previously encoded frames, the frame activity of the previously encoded frames, the frame activity of the coding frame, and the target code amount; an importance calculation means for detecting a visual importance for each macro block; and a coding means for generating a prediction model based on the activity function and the target code amount, coding the coding frame macro block by macro block by using the prediction model, the reference scaling factor, and the importance, and generating encoded data.

Claim 10

A picture signal coding device comprising: an activity function generation means for calculating an activity for each macro block in each frame with respect to inputted pictures, generating an activity function indicating an accumulation of the activity for each macro block in a coding frame, and calculating a frame activity of the coding frame; a target code amount determination means for determining a target code amount of the coding frame by using at least one of a remaining code amount at the time of coding the coding frame, a generated code amount of previously encoded frames, an activity of the previously encoded frames, an occupancy of a buffer, and the activity of the coding frame; a reference scaling factor calculation means for calculating a reference scaling factor of the coding frame by using at least one of a scaling factor of the previously encoded frames, the generated code amount of the previously encoded frames, the frame activity of the previously encoded frames, the frame activity of the coding frame, and the target code amount; an importance calculation means for detecting a visual importance for each macro block; and a coding means for generating a prediction model based on the activity function and the target code amount, setting a region with a specific width with respect to the prediction model, coding the coding frame macro block by macro block by using the reference scaling factor and the importance, correcting at least one of the reference scaling factor, the prediction model, the target code amount, and the region according to a deviation amount when an accumulation of a generated code amount for each macro block deviates from the region, and generating encoded data.

Claim 11

The picture signal coding device according to claim 9 or 10, wherein the coding means sets a check point for each integer macro blocks and determines whether the accumulation of the generated code amount for each macro block deviates from the region at the check point or not.

Claim 12

The picture signal coding device according to claim 9 or 10, wherein the importance calculation means calculates the importance for each orthogonal transformation block, calculates a sum of absolute values of AC components in orthogonal transformation data of the orthogonal transformation block when a coding system of a coding block is an interframe coding system and when the coding frame is a B picture, and sets the importance of the orthogonal transformation block high if the sum of the absolute values is larger than a threshold.

Claim 13

The picture signal coding device according to claim 9 or 10, wherein the importance calculation means calculates the importance for each orthogonal transformation block, calculates a sum of absolute values of AC components in orthogonal transformation data of the orthogonal transformation block when a coding system of a coding block is an interframe coding system and when the coding frame is a B picture, and sets all orthogonal transformation data of the orthogonal transformation block to 0 if the sum of the absolute values is smaller than a threshold.

Claim 14

The picture signal coding device according to claim 9 or 10, wherein the importance calculation means calculates the importance for each orthogonal transformation block; calculates number of sampling values having a larger value than a threshold among sampling values of a Y-R component block in the orthogonal transformation block with respect to an inputted picture for which a differential operation for motion compensation is not performed, when a coding system of a coding block is an interframe coding system; and sets the importance of the orthogonal transformation block high if the number of the sampling values is larger than a predetermined value.

Claim 15

The picture signal coding device according to claim 9 or 10, wherein the importance calculation means calculates the importance for each orthogonal transformation block; calculates number of sampling values having a larger value than a threshold among sampling values of a Y-B component block in the orthogonal transformation block with respect to an inputted picture for which a differential operation for motion compensation is not performed, when a coding system of a coding block is an interframe coding system; and sets the importance of the orthogonal transformation block high if the number of the sampling values is larger than a predetermined value.

Claim 16

The picture signal coding device according to claim 9 or 10, wherein the importance calculation means calculates the importance for each orthogonal transformation block; calculates number of sampling values having a value in the range of a first threshold to a second threshold with respect to a Y component block in a coding macro block and defines the number of the sampling values as a first detected value, calculates number of sampling values having a value in the range of a third threshold to a fourth threshold with respect to a Y-R component block in the coding macro block and defines the number of the sampling values as a second detected value, and calculates number of sampling values having a value in the range of a fifth threshold to a six threshold with respect to a Y-B component block in the coding macro block and defines the number of the sampling values as a third detected value, with respect to an inputted picture for which a differential operation for motion compensation is not performed, when a coding system of a coding block is an interframe coding system; and sets the importance of the orthogonal transformation block high when the first detected value is larger than a first number, when the second detected value is larger than a second number, and when the third detected value is larger than a third number.

Claim 17

The picture signal coding device according to claim 9 or 10, wherein the importance calculation means calculates the importance for each orthogonal transformation block; calculates number of sampling values in which absolute value of a difference between a sampling value of a Y-R component block and a sampling value of a Y-B component block is larger than a threshold with respect to the Y-B component block and the Y-R component block in a coding macro block, with respect to an inputted picture for which a differential operation for motion compensation is not performed, when a coding system of a coding block is an interframe coding system; and sets the importance of the coding macro block high if the number of the sampling values is larger than a predetermined value.

Claim 18

The picture signal coding device according to claim 9 or 10, wherein the importance calculation means calculates the importance for each orthogonal transformation block; calculates an activity of the orthogonal transformation block with respect to an inputted picture for which a differential operation for motion compensation is not performed and calculates a sum of absolute values of AC components in the orthogonal transformation block with respect to a differential picture for which a differential operation for motion compensation is performed when a coding system of a coding block is an interframe coding system; and sets the importance of the orthogonal transformation block low when the activity is larger than a first threshold and the sum of the absolute values of the AC components is larger than a second threshold.

Claim 19

The picture signal coding device according to claim 9 or 10, wherein the importance calculation means calculates the importance for each macro block, and sets an importance of a coding macro block low when the coding macro block is located at one of an upper end, a lower end, a left end, and a right end of a screen.

Claim 20

The picture signal coding device according to claim 9 or 10, wherein the importance calculation means calculates the importance for each orthogonal transformation block; and sets an importance of a coding macro block high when a coding system of a coding block is an interframe coding system, when types of a motion vector of the coding macro block and motion vectors of macro blocks around the coding macro block are detected, and when the type of the motion vector of the coding macro block differs from the type of the motion vectors of the macro blocks around the coding macro block.

Claim 21

The picture signal coding device according to claim 9 or 10, wherein a motion vector detection portion properly switches a plurality of predictive operation methods with respect to an inputted picture, and wherein a code amount control means calculates the importance for each macro block, and sets an importance of a coding macro block high when a coding system of a coding block is an interframe coding system and when a type of a first motion vector detected for each macro block differs from a type of a second motion vector detected for each super block comprising a plurality of macro blocks.

Claim 22

The picture signal coding device according to claim 9 or 10, wherein the importance calculation means detects importances with respect to T orthogonal transformation blocks that belong to the macro block, and defines a highest importance among the detected T importances as an importance of the macro block.

Claim 23

The picture signal coding device according to claim 9 or 10, wherein the importance calculation means detects the importance for each orthogonal transformation block, and sets all data of the block after orthogonal transformation to 0 and sets an activity of the orthogonal transformation block to 0 when the block is determined as unimportant.