Model parameter derivation of local illumination compensation in the luma mapping with chroma scaling-mapped domain in video coding

A device for decoding video data, the device comprising:

• memory configured to store the video data;
• and
• one or more processors implemented in circuitry and communicatively coupled to the memory, the one or more processors being configured to:
• reshape a pixel domain reference template block using a forward mapping function into a mapped domain reference template block, wherein the forward mapping function comprises:
• FwdMap(Y_pred)=((b2−b1)/(a2−a1))*(Y_pred−a1)+b1,
• where Y_pred is a luma prediction signal, i is a piece index, a1 is an input pivot point of i, a2 is an input pivot point of i+1, b1 is a mapped pivot point of i, and b2 is a mapped pivot point of i+1;
• derive local illumination compensation (LIC) model parameters from the mapped domain reference template block and a mapped domain neighboring reconstruction template block;
• apply the LIC model parameters to motion-compensated prediction signals;
• and
• decode the video data based on the application of the LIC model parameters.

A non-transitory computer readable storage medium having instructions stored thereon which, when executed, cause one or more processors to:

• reshape a pixel domain reference template block using a forward mapping function into a mapped domain reference template block, wherein the forward mapping function comprises:
• FwdMap(Y_pred)=((b2−b1)/(a2−a1))*(Y_pred−a1)+b1,
• where Y_pred is a luma prediction signal, i is a piece index, a1 is an input pivot point of i, a2 is an input pivot point of i+1, b1 is a mapped pivot point of i, and b2 is a mapped pivot point of i+1;
• derive local illumination compensation (LIC) model parameters from the mapped domain reference template block and a mapped domain neighboring reconstruction template block;
• apply the LIC model parameters to motion-compensated prediction signals;
• and
• decode the video data based on the application of the LIC model parameters.

A device for decoding video data, the device comprising:

• means for reshaping a pixel domain reference template block using a forward mapping function into a mapped domain reference template block, wherein the forward mapping function comprises:
• FwdMap(Y_pred)=((b2−b1)/(a2−a1))*(Y_pred−a1)+b1,
• where Y_pred is a luma prediction signal, i is a piece index, a1 is an input pivot point of i, a2 is an input pivot point of i+1, b1 is a mapped pivot point of i, and b2 is a mapped pivot point of i+1;
• means for deriving local illumination compensation (LIC) model parameters from the mapped domain reference template block and a mapped domain neighboring reconstruction template block;
• means for applying the LIC model parameters to motion-compensated prediction signals;
• and
• means for decoding the video data based on the application of the LIC model parameters.