Video data encoding using reference picture lists

An apparatus for encoding a video stream having a plurality of frames, comprising:

• a memory;
• a processor configured to execute instructions stored in the memory to:
• assign reference frames to reference picture buffers, the reference frames used to encode at least one of the plurality of frames;
• assign a respective picture number to respective ones of the reference frames;
• identify a reference picture list including picture numbers of the reference frames;
• rank the picture numbers included in the reference picture list in an order from smallest to largest or from largest to smallest;
• encode the reference picture list into the bitstream by encoding the picture numbers into the bitstream in the order determined by the ranking;
• generate a re-order picture list that arranges at least two of the reference frames in an order such that a first frame in the re-order picture list is used more often in a prediction process that other reference frames of the at least two of the reference frames;
• map the at least two of the reference frames to indexes of the reference picture list after the ranking;
• encode a total number of reference frames in the re-order picture list;
• and
• encode the indexes of the reference picture list.

An apparatus for encoding a video stream having a plurality of frames, comprising:

• a memory;
• a processor configured to execute instructions stored in the memory to:
• assign reference frames to reference picture buffers, the reference frames used to encode at least one of the plurality of frames;
• assign a respective picture number to respective ones of the reference frames;
• identify a reference picture list including picture numbers of the reference frames;
• reorder the reference picture list by assigning a shorter word length to a first picture number used more often in a prediction process than a second picture number;
• rank the picture numbers in an order from smallest to largest;
• encode a reorder list in the bitstream by encoding a number of pictures reordered and a list of indexes in the reference picture list for the first picture number and the second picture number;
• and
• encode the reference picture list into a bitstream by encoding the picture numbers according to the order, the picture numbers modified by subtracting an immediately preceding value of a picture number from current value of a picture number and subtracting one.