Method of color palette coding applicable to electronic device and electronic device using the same

An electronic device comprising:

• a non-transitory computer readable storage medium configured for providing a digital image including a coding unit;
• and
• a processor coupled to the storage medium and is configured at least for:
• encoding a bit stream of the digital image to represent a single color of the coding unit, wherein the bit stream comprises:
• a binary bit representing a run flag;
• a N binary bit sequence with each of the possible values of the N binary bit sequence representing an unique major color index of 2N major color indices, wherein the 2N major color indices comprises 2N−1 major color indices referring to 2N−1 major colors and an index referring to 2M−1 extended colors;
• and
• a M binary bit sequence with each of the possible values of the M binary bit sequence representing an unique extended color index of 2M extended color indices, wherein the 2M extended color indices comprises 2M−1 extended color indices referring to the 2M−1 extended colors and an index referring to an escape color or a second set of extended colors, wherein the 2M−1 extended colors are not the major colors and appears less frequently than the major colors in the coding unit;
• and
• storing the bit stream in the storage medium to be decoded and displayed or transmitting the bit stream to a video driver to be decoded and displayed.

A method of color palette for representing a color applicable to an electronic device comprising a non-transitory computer readable storage medium and a processor coupled to the storage medium, the method comprising:

• retrieving, by the processor, a bit stream from the storage medium;
• and
• decoding, by the processor, a color based on the bit stream according to at least:
• decoding, from the bit stream, a N binary bit sequence to obtain a major color index which indicates an index referring to one of 2N major color indices comprising 2N−1 major color indices referring to 2N−1 major colors and an index referring to 2M−1 extended colors;
• decoding, from the bit stream, a M binary bit sequence to obtain an extended color index based on the major color index, wherein the extended color index indicates an index referring to one of 2M−1 extended colors or an index referring to an escape color;
• decoding the color based on the extended color index if the color is not the escape color;
• and
• decoding the color based on the extended color index which is a last index of the extended color indices if the color is the escape color.