Method and device for predicting and restoring a video signal using palette entry and palette escape mode

A method of encoding a video signal, the method comprising:

• obtaining at least one palette entry of a current block from a palette map of a previous block;
• constructing a palette map of the current block including the obtained palette entry;
• determining a palette index on a sample-by-sample basis of the current block by using palette index number information and information about palette index run related to the current block;
• and
• reconstructing the current block by using the palette map of the current block and the palette index,
• wherein the information about palette index run includes first index run information and second index run information,
• wherein the first index run information is used to determine a repeated number of times of same palette index in a predetermined scan order, and the second index run information is used to determine whether same palette index occurs from the current sample to the last sample in the predetermined scan order, and
• wherein the method further comprises
• determining whether an escape present flag is encoded, the escape present flag indicating whether an escape mode is applied to at least one sample in the current block, wherein the escape present flag is encoded when a number of the palette entries included in the palette map is one or more, and
• determining whether a value of the derived palette index for a current sample in the current block is equal to a maximum value of palette index while the determined escape present flag indicates the escape mode applied to the current block,
• encoding a palette escape value for the current sample in the current block, if the value of the derived palette index for the current sample is equal to the maximum value of palette index, and
• wherein the palette index is derived using at least one of an index mode and a copy mode, the index mode is a method of deriving a palette index based on information about palette index run, and the copy mode is a method of deriving a palette index of the current sample using a palette index of a neighboring sample,
• wherein when at least one sample of the current block uses the index mode, the palette index is derived using the information about palette index run indicating the number of consecutive sample locations with same palette index, and
• wherein a value of the palette index run was entropy encoded and selected from one of two encoded types based on a number of bits used,
• as a first encoded type, a value of the palette index run is derived from a single encoded element that represents the value of the palette index run as is,
• as a second encoded type, a value of the palette index run is derived from two encoded elements that represent a most significant bit (MSB) value as is and refinement bits as is of the value of the palette index run.