Systems and methods for liner model derivation

A method of encoding a video sequence into a bitstream, the method comprising:

• receiving the video sequence;
• signal an index associated with a coding unit, the index indicating a selection mode among at least four selection modes;
• determining whether a plurality of top neighboring samples and a plurality of the left neighboring samples are available;
• determining four samples based on the index;
• determining two parameters based on the four samples;
• determining predicted samples of the coding unit based on the two parameters;
• and
• encoding the coding unit based on the predicted samples;
• wherein determining the four samples based on the index further comprises:
• determining the four samples based on an availability of the plurality of the top neighboring samples and the plurality of the left neighboring samples;
• in response to both of the plurality of the top neighboring samples and the plurality of the left neighboring samples being available, determining two of the four samples among the plurality of top neighboring samples and other two of the four samples among the plurality of left neighboring samples;
• in response to the plurality of the top neighboring samples being not available and the plurality of the left neighboring samples being available, determining the four samples among the plurality of left neighboring samples;
• and
• in response to the plurality of the top neighboring samples being available and the plurality of the left neighboring samples being not available, determining the four samples among the plurality of top neighboring samples.

A non-transitory computer readable medium storing a bitstream of a video for processing according to a method comprising:

• decoding an index associated with a coding unit based on the bitstream, the index indicating a selection mode among at least four selection modes;
• determining whether a plurality of top neighboring samples and a plurality of left neighboring samples are available
• determining four samples based on the index;
• determining two parameters based on the four samples;
• determining predicted samples of the coding unit based on the two parameters;
• and
• decoding the coding unit based on the predicted samples;
• wherein determining four samples based on the index, the method further comprises:
• determining the four samples based on an availability of the plurality of the top neighboring samples and the plurality of the left neighboring samples;
• in response to both of the plurality of the top neighboring samples and the plurality of the left neighboring samples being available, determining two of the four samples among the plurality of top neighboring samples and other two of the four samples among the plurality of left neighboring samples;
• in response to the plurality of the top neighboring samples being not available and the plurality of the left neighboring samples being available, determining the four samples among the plurality of left neighboring samples;
• and
• in response to the plurality of the top neighboring samples being available and the plurality of the left neighboring samples being not available, determining the four samples among the plurality of top neighboring samples.