Method and Apparatus of Constrained Intra Block Copy for Coding Video

Abstract

A method and apparatus for IntraBC (Intra-block copy) coding for a coding region are disclosed. The method operates to receive input data associated with a current block in the coding region and determine a maximum memory size of a reconstructed sample memory for storing a constrained previous reconstructed region, wherein the constrained previous reconstructed region comprises a group of previous reconstructed samples processed before the current block. The method then derives an IntraBC predictor from a valid previous reconstructed region within the constrained previous reconstructed region stored in the reconstructed sample memory, and applies IntraBC encoding or decoding to the current block using the IntraBC predictor derived.

1 . A method of SCC (screen content coding) or video coding using an IntraBC mode (Intra-block copy mode) for a coding region, wherein the coding region is divided into multiple coding blocks, the method comprising:
 receiving input data associated with a current block in the coding region;   determining a maximum memory size of a reconstructed sample memory for storing a constrained previous reconstructed region, wherein the constrained previous reconstructed region comprises a group of previous reconstructed samples processed before the current block;   deriving an IntraBC predictor from a valid previous reconstructed region within the constrained previous reconstructed region stored in the reconstructed sample memory; and   applying IntraBC encoding or decoding to the current block using the IntraBC predictor derived.   
     
     
         2 . The method of  claim 1 , wherein the maximum memory size corresponds to N coding blocks to store N previous reconstructed blocks, where N is a positive integer. 
     
     
         3 . The method of  claim 1 , wherein the maximum memory size corresponds to a full row of previous reconstructed blocks. 
     
     
         4 . The method of  claim 1 , wherein the valid previous reconstructed region within the constrained previous reconstructed region corresponds to the constrained previous reconstructed region overlapped with a ladder-shaped previous reconstructed region related to wave-front parallel processing (WPP). 
     
     
         5 . The method of  claim 1 , wherein if the previous reconstructed samples correspond to Inter-coded video data, the previous reconstructed samples are not stored. 
     
     
         6 . The method of  claim 1 , wherein if the previous reconstructed samples correspond to Intra-coded video data, the previous reconstructed samples are stored. 
     
     
         7 . An apparatus for SCC (screen content coding) or video coding using an IntraBC mode (Intra-block copy mode) for a coding region, wherein the coding region is divided into multiple coding blocks, the apparatus comprising one or more electronic circuits configured to:
 receive input data associated with a current block in the coding region;   determine a maximum memory size of a reconstructed sample memory for storing a constrained previous reconstructed region, wherein the constrained previous reconstructed region comprises a group of previous reconstructed samples processed before the current block;   derive an IntraBC predictor from a valid previous reconstructed region within the constrained previous reconstructed region stored in the reconstructed sample memory; and   apply IntraBC encoding or decoding to the current block using the IntraBC predictor derived.