Methods and Systems for Image Intra-Prediction Mode Management

A method for determining an estimated pixel intra-prediction mode to be used for efficient prediction mode communication between an encoder and a decoder, said method comprising:

• arranging a set of potential prediction modes in an order of decreasing probability of producing a lesser prediction error by associating a sequential numerical value with each prediction mode such that the lowest numerical value is associated with the prediction mode most probable to produce a lesser prediction error and the prediction mode that is least probable to produce a lesser prediction error is associated with the highest numerical value in the sequence;
• selecting a target block for prediction mode estimation;
• receiving a first prediction mode that has been used for encoding a first adjacent block, said first adjacent block being adjacent to said target block;
• receiving a second prediction mode that has been used for encoding a second adjacent block, said second adjacent block being adjacent to said target block;
• determining an estimated prediction mode among said first prediction mode and said second prediction mode, wherein said estimated prediction mode is the prediction mode associated with the lesser of said numerical values;
• and
• calculating an actual prediction mode based on at least one pixel value in said target block and comparing said actual prediction mode to said estimated prediction mode.

A method for communicating a spatial pixel prediction mode for a target block in an image, said method comprising:

• a. establishing an ordered set of pixel prediction modes, wherein said prediction modes are ordered in order of decreasing probability of producing a lesser prediction error and wherein said order is not based on characteristics of said image;
• b. determining a first adjacent mode for predicting a first adjacent block, which is adjacent to a target block, wherein said first adjacent mode is selected based on an actual prediction error and said first adjacent mode is in said ordered set;
• c. determining a second adjacent mode for predicting a second adjacent block, which is adjacent to said target block, wherein said second adjacent mode is selected based on an actual prediction error and said second adjacent mode is in said ordered set;
• d. selecting one of said first adjacent mode and said second adjacent mode as an estimated mode for said target block, wherein said selecting is based on the order of said ordered set;
• e. determining an actual prediction mode for said target block by determining which mode in said ordered set results in the least prediction error;
• f. sending an estimated mode signal indicating that said estimated mode is the actual mode used to predict said target block when said actual prediction mode is substantially similar to said estimated mode;
• g. eliminating said estimated mode from said ordered set thereby creating a reduced ordered set when said actual prediction mode is not substantially similar to said estimated mode;
• and
• h. sending a mode selection signal indicating which mode in said reduced ordered set corresponds to said actual prediction mode when said actual prediction mode is not substantially similar to said estimated mode.

A method for communicating a pixel prediction mode for a target block in an image, said method comprising:

• l. establishing an ordered set of pixel prediction modes, wherein said order is not based on characteristics of said image;
• m. determining a first adjacent mode for predicting a first adjacent block, which is adjacent to a target block, wherein said first adjacent mode is selected based on an actual prediction error and said first adjacent mode is in said ordered set;
• n. determining a second adjacent mode for predicting a second adjacent block, which is adjacent to said target block, wherein said second adjacent mode is selected based on an actual prediction error and said second adjacent mode is in said ordered set;
• o. selecting one of said first adjacent mode and said second adjacent mode as an estimated mode for said target block, wherein said selecting is based on the relative positions of said adjacent modes in said ordered set;
• p. modifying said ordered set by moving said estimated mode from its original position in said ordered set to a new position in said ordered set thereby creating a modified ordered set.

A method for determining a pixel prediction mode for a target block in an image, said determining occurring at a decoder, said method comprising:

• s. establishing an ordered set of pixel prediction modes, wherein said order is not based on characteristics of said image;
• t. determining a first adjacent mode used for predicting a first adjacent block, which is adjacent to a target block, wherein said first adjacent mode is in said ordered set;
• u. determining a second adjacent mode used for predicting a second adjacent block, which is adjacent to said target block, wherein said second adjacent mode is in said ordered set;
• v. selecting one of said first adjacent mode and said second adjacent mode as an estimated mode for said target block, wherein said selecting is based on said ordered set;
• w. using said estimated mode as a prediction mode in decoding said target block when an estimated mode signal is received;
• x. eliminating said estimated mode from said ordered set thereby creating a reduced ordered set when an estimated mode signal is not received;
• and
• y. using a prediction mode in said reduced ordered set, said prediction mode being indicated by a mode selection signal when a mode selection signal is received.