Video coding apparatus, video coding method and storage medium containing video coding program

A video coding apparatus dividing each frame of a motion picture into a predetermined number m of groups of blocks for coding the motion picture while switching a coding mode between an INTER coding mode and an INTRA coding mode in units of block included in each group of blocks, comprising:

• coding quantity determination means for determining whether or not a coding quantity resulting from coding of each group of blocks during a lapse of a prescribed time T from a prescribed point is in excess of a predetermined threshold;
• whole-group refresh means for performing whole-group refresh, defined as an operation of INTRA-coding all blocks included in a group of blocks in a coding process for the same frame, on a group of blocks so determined by said coding quantity determination means that said coding quantity is in excess of said threshold;
• and
• dispersed refresh means for performing dispersed refresh, defined as an operation of INTRA-coding each block included in a group of blocks in a coding process for frames varying with the block while regarding groups of blocks being in the same position in respective frames as the same group of blocks among groups of blocks in the frames, on a group of blocks so determined by said coding quantity determination means that said coding quantity is less than said threshold.

A video coding apparatus, employed in a picture transmission system formed by a coding apparatus for coding motion picture and transmitting coded data of said motion picture and a decoding apparatus for receiving said transmitted coded data and decoding the same while performing detection of an error in said coded data to be decoded and transmitting error notice to said coding apparatus when an error is detected as said coding apparatus, for dividing each frame of said motion picture into a predetermined number m of groups of blocks and coding said motion picture while switching a coding mode between an INTER coding mode and an INTRA coding mode in units of block included in each group of blocks, comprising:

• error receiving means for receiving said error notice;
• refresh selection means for determining, when said error notice is received by said error receiving means, whether or not there is motion exceeding a predetermined threshold in an object in a region of each group of blocks in each frame coded up to a moment preceding a point of receiving of said error notice by a prescribed time RTmax and deciding performance of refresh by INTRA coding on a group of blocks of a region having motion exceeding said threshold;
• and
• whole-group refresh means for performing whole-group refresh, defined as an operation of INTRA-coding all blocks included in a group of blocks in a coding process for the same frame, on a group of blocks decided by said refresh selection means to be subjected to refresh.

A video coding method of dividing each frame of a motion picture into a predetermined number m of groups of blocks for coding the motion picture while switching a coding mode between an INTER coding mode and an INTRA coding mode in units of a block included in each group of blocks, comprising:

• a motion determination step of determining whether or not there is motion exceeding a predetermined threshold in an object in each region of said number m of groups of blocks in each frame during a lapse of a prescribed time T from a prescribed point;
• a whole-group refresh step of performing whole-group refresh, defined as an operation of INTRA-coding all blocks included in a group of blocks in a coding process for the same frame, on a group of blocks of a region determined in said motion determination step as having motion exceeding said threshold;
• and
• a dispersed refresh step of performing dispersed refresh, defined as an operation of INTRA-coding each block included in a group of blocks in a coding process for frames varying with the block while regarding groups of blocks being in the same position in respective frames among groups of blocks in the frames as the same group of blocks, on a group of blocks of a region determined in said motion determination step as having no motion exceeding said threshold.

A video coding method of dividing each frame of a motion picture into a predetermined number m of groups of blocks for coding the motion picture while switching a coding mode between an INTER coding mode and an INTRA coding mode in units of block included in each group of blocks, comprising:

• a coding quantity determination step of determining whether or not a coding quantity resulting from coding of each group of blocks during a lapse of a prescribed time T from a prescribed point is in excess of a predetermined threshold;
• a whole-group refresh step of performing whole-group refresh, defined as an operation of INTRA-coding all blocks included in a group of blocks in a coding process for the same frame, on a group of blocks so determined in said coding quantity determination step that said coding quantity is in excess of said threshold;
• and
• a dispersed refresh step of performing dispersed refresh, defined as an operation of INTRA-coding each block included in a group of blocks in a coding process for frames varying with the block while regarding groups of blocks being in the same position in respective frames among groups of blocks in the frames as the same groups of blocks, on a group of blocks so determined in said coding quantity determination step that said coding quantity is less than said threshold.

A video coding method, employed in a picture transmission system formed by a coding apparatus for coding a motion picture and transmitting coded data of said motion picture and a decoding apparatus for receiving said transmitted coded data and decoding the same while performing detection of an error in said coded data to be decoded and transmitting error notice to said coding apparatus when an error is detected, for dividing each frame of said motion picture into a predetermined number m of groups of blocks and coding said motion picture while switching a coding mode between an INTER coding mode and an INTRA coding mode in units of block included in each group of blocks, comprising:

• an error receiving step of receiving said error notice;
• a refresh selection step of determining, when said error notice is received, whether or not there is motion exceeding a predetermined threshold in an object in a region of each group of blocks in each frame coded up to a moment preceding a point of receiving of said error notice by a prescribed time RTmax and deciding performance of refresh by INTRA coding on a group of blocks of a region having motion exceeding said threshold;
• and
• a whole-group refresh step of performing whole-group refresh, defined as an operation of INTRA-coding all blocks included in a group of blocks in a coding process for the same frame, on a group of blocks decided in said refresh selection step to be subjected to refresh.

A storage medium containing a video coding program thereon for dividing each frame of a motion picture into a predetermined number m of groups of blocks and coding the motion picture while switching a coding mode between an INTER coding mode and an INTRA coding mode in units of block included in each group of blocks as a program executed in a computer unit, said storage medium containing said video coding program recorded thereon for implementing on said computer unit operating environment including:

• a motion determination step of determining whether or not there is motion exceeding a predetermined threshold in an object in each region of said number m of groups of blocks in each frame during a lapse of a prescribed time T from a prescribed point;
• a whole-group refresh step of performing whole-group refresh, defined as an operation of INTRA-coding all blocks included in a group of blocks in a coding process for the same frame, on a group of blocks of a region determined in said motion determination step as having motion exceeding said threshold;
• and
• a dispersed refresh step of performing dispersed refresh, defined as an operation of INTRA-coding each block included in a group of blocks while regarding groups of blocks being in the same position in respective frames among groups of blocks in the frames as the same group of blocks in a coding process for frames varying with the block, on a group of blocks of a region determined in said motion determination step as having no motion exceeding said threshold.

A storage medium containing a video coding program thereon for dividing each frame of a motion picture into a predetermined number m of groups of blocks and coding the motion picture while switching a coding mode between an INTER coding mode and an INTRA coding mode in units of block included in each group of blocks as a program executed in a computer unit, said storage medium containing said video coding program recorded thereon for implementing on said computer unit operating environment including:

• a coding quantity determination step of determining whether or not a coding quantity resulting from coding of each group of blocks during a lapse of a prescribed time T from a prescribed point is in excess of a predetermined threshold;
• a whole-group refresh step of performing whole-group refresh, defined as an operation of INTRA-coding all blocks included in a group of blocks in a coding process for the same frame, on a group of blocks so determined in said coding quantity determination step that said coding quantity is in excess of said threshold;
• and
• a dispersed refresh step of performing dispersed refresh, defined as an operation of INTRA-coding each block included in a group of blocks in a coding process for frames varying with the block while regarding groups of blocks being in the same position in respective frames among groups of blocks in the frames as the same group of blocks, on a group of blocks so determined in said coding quantity determination step that said coding quantity is less than said threshold.

A storage medium containing a video coding program thereon, employed in a picture transmission system formed by a coding apparatus for coding a motion picture and transmitting coded data of said motion picture and a decoding apparatus for receiving transmitted said coded data and decoding the same while performing detection of an error in said coded data to be decoded and transmitting error notice to said coding apparatus when an error is detected, for dividing each frame of said motion picture into a predetermined number m of groups of blocks and coding said motion picture while switching a coding mode between an INTER coding mode and an INTRA coding mode in units of block included in each group of blocks as a program executed on a computer unit, said storage medium containing said video coding program recorded thereon for implementing on said computer unit operating environment including:

• an error receiving step of receiving said error notice;
• a refresh selection step of determining, when said error notice is received, whether or not there is motion exceeding a predetermined threshold in an object in a region of each group of blocks in each frame coded up to a moment preceding a point of receiving of said error notice by a prescribed time RTmax and deciding performance of refresh by INTRA coding on a group of blocks of a region having motion exceeding said threshold;
• and
• a whole-group refresh step of performing whole-group refresh, defined as an operation of INTRA-coding all blocks included in a group of blocks in a coding process for the same frame, on a group of blocks decided in said refresh selection step to be subjected to refresh.