Enhanced chroma coding using cross plane filtering

Abstract

Cross plane filtering may be used for enhanced chroma coding. An indication of a cross-plane filter associated with a current picture may be received. The current picture may include an intra-coded video block and a plurality of reference samples. The plurality of reference samples may be used to predict the intra-coded video block. A luma sample region may be determined in the current picture. The luma sample region may determined to enhance a corresponding chroma sample in the current picture. The cross-plane filter may be applied to a plurality of luma samples in the luma sample region to determine an offset. The cross-plane filter may be a high pass filter. The offset may be applied to the corresponding chroma sample to determine an enhanced chroma sample.

1 - 26 . (canceled) 
     
     
         27 . A method comprising:
 obtaining a cross-plane filter indication, wherein the cross-plane filter indication is configured to indicate that a chroma sample is to be predicted using an offset;   determining a luma region associated with predicting the chroma sample, wherein the luma region comprises a plurality of luma samples;   deriving the offset based on the plurality of luma samples in the determined luma region;   predicting the chroma sample using the derived offset; and   reconstructing a video block based on the predicted chroma sample.   
     
     
         28 . The method for  claim 27 , wherein the luma region is determined based on at least one of an intra prediction mode or an inter prediction mode. 
     
     
         29 . The method of  claim 27 , wherein the luma region is determined such that the luma region comprises at least one of a luma sample that neighbors a corresponding chroma sample or the luma sample that is collocated with the corresponding chroma sample. 
     
     
         30 . The method of  claim 27 , wherein the video block comprises the chroma sample. 
     
     
         31 . An apparatus comprising:
 a processor configured to:
 obtain a cross-plane filter indication, wherein the cross-plane filter indication is configured to indicate that a chroma sample is to be predicted using an offset 
 determine a luma region associated with predicting the chroma sample, the luma region comprising a plurality of luma samples; 
 derive the offset based on the plurality of luma samples in the determined luma region; 
 predict the chroma sample using the derived offset; and 
 reconstruct a video block based on the predicted chroma sample. 
   
     
     
         32 . The apparatus for  claim 31 , wherein the luma region is determined based on at least one of an intra prediction mode or an inter prediction mode. 
     
     
         33 . The apparatus for  claim 31 , wherein the luma region is determined such that the luma region comprises at least one of a luma sample that neighbors a corresponding chroma sample or the luma sample that is collocated with the corresponding chroma sample. 
     
     
         34 . The apparatus for  claim 31 , wherein the video block comprises the chroma sample. 
     
     
         35 . The apparatus of  claim 31 , wherein the apparatus further comprises a memory. 
     
     
         36 . A method comprising:
 determining a luma region associated with predicting a chroma sample, wherein the luma region comprises a plurality of luma samples;   deriving an offset based on the plurality of luma samples in the determined luma region;   generating a cross-plane filter indication, wherein the cross-plane filter indication is configured to indicate that the chroma sample is to be predicted using the derived offset; and   including the cross-plane filter indication in a bitstream that is representative of a video signal.   
     
     
         37 . The method for  claim 36 , wherein the luma region is determined based on at least one of an intra prediction mode or an inter prediction mode. 
     
     
         38 . The method for  claim 36 , wherein the luma region is determined such that the luma region comprises at least one of a luma sample that neighbors a corresponding chroma sample or the luma sample that is collocated with the corresponding chroma sample. 
     
     
         39 . The method of  claim 36 , wherein the method comprises:
 generating a cross-plane filter number indication, wherein the cross-plane filter number indication indicates a number of cross-plane filters to be signaled; and   including the cross-plane filter number indication in the bitstream.   
     
     
         40 . The method of  claim 36 , wherein the cross-plane filter indication is included in a slice level or a picture level. 
     
     
         41 . An apparatus comprising:
 a processor configured to:   determine a luma region associated with predicting a chroma sample, wherein the luma region comprises a plurality of luma samples;   derive an offset based on the plurality of luma samples in the determined luma region;   generate a cross-plane filter indication, wherein the cross-plane filter indication is configured to indicate that the chroma sample is to be predicted using the derived offset; and   include the cross-plane filter indication in a bitstream that is representative of a video signal.   
     
     
         42 . The apparatus for  claim 41 , wherein the luma region is determined based on at least one of an intra prediction mode or an inter prediction mode. 
     
     
         43 . The apparatus for  claim 41 , wherein the luma region is determined such that the luma region comprises at least one of a luma sample that neighbors a corresponding chroma sample or the luma sample that is collocated with the corresponding chroma sample. 
     
     
         44 . The apparatus for  claim 41 , wherein the processor is configured to:
 generate a cross-plane filter number indication, wherein the cross-plane filter number indication indicates a number of cross-plane filters to be signaled; and   include the cross-plane filter number indication in the bitstream.   
     
     
         45 . The apparatus for  claim 41 , wherein the cross-plane filter indication is included in a slice level or a picture level. 
     
     
         46 . The apparatus of  claim 41 , wherein the apparatus further comprises a memory.