Codec

A non-transitory machine-readable medium having instructions that, when executed, cause a method for encoding a video stream to be performed, the method comprising:

• dividing the video stream into:
• a first Key frame, and
• subsequent chunks each comprising 2n frames, where n is an integer greater than one, each chunk including a Key frame and 2n−1 Delta (Dx) frames, where x is a positive integer from 1 to n, and denotes the level of the Delta frame, and where 2x−1 denotes the number of Delta frames at level x in the chunk;
• constructing Dx level frames from adjacent Earlier and Later Dy frames, where y<x and y is an integer from 0 to x−1, and where for y=0, Dy is a Key frame, for all frames in a chunk where x>0;
• wherein the constructing includes:
• dividing the frame into Motion Regions representing groups of pixels;
• determining a pixel group in an Earlier (E) Dy frame and in a later (L) Dy frame that is a best match for a pixel group in a Motion Region of a Current (C) Dx frame;
• determining motion vectors for the best matches for the Motion Regions;
• and
• building a bitstream wherein motion vector data is represented by a quantity of data in the bitstream,
• the method further comprising correcting inaccuracies by determining, for each neighborhood comprising a predetermined number of pixels, the difference in grey scale value of adjacent pixels in each direction, such that
• (i) if the difference is no greater than 1, or no greater than 2, or no greater than 3 grey scale values in three or four directions, no difference is permitted between predicted and actual pixel values, and any difference is corrected;
• (ii) if the difference is no greater than 1, or no greater than 2, or no greater than 3 grey scale values in 2 directions, a maximum value of difference is permitted between predicted and actual pixel values before a correction is applied, wherein said maximum can vary between 1 and 16 greyscales;
• and
• (iii) if the difference is no greater than 1, or no greater than 2, or no greater than 3 grey scale values in one or zero directions, a larger difference than in two directions is permitted before a correction is applied.

A device including a camera, a processor and a non-transitory machine-readable medium having instructions that, when executed by the processor, encode a video stream captured by the camera, wherein the video stream is divided into:

• a first Key frame, and
• subsequent chunks each comprising 2n frames, where n is an integer greater than one, each chunk including a Key frame and 2n−1 Delta (Dx) frames, where x is a positive integer from 1 to n, and denotes the level of the Delta frame, and where 2x−1 denotes the number of Delta frames at level x in the chunk;
• the instructions, when executed by the processor, constructing Dx level frames from adjacent Earlier and Later Dy frames, where y<x and y is an integer from 0 to x−1, and where for y=0, Dy is a Key frame, for all frames in a chunk where x>0;
• wherein the constructing includes:
• dividing the frame into Motion Regions representing groups of pixels;
• determining a pixel group in an Earlier (E) Dy frame and in a later (L) Dy frame that is a best match for a pixel group in a Motion Region of a Current (C) Dx frame;
• determining motion vectors for the best matches for the Motion Regions;
• and
• building a bitstream, wherein motion vector data is represented by a quantity of data in the bitstream,
• the non-transitory machine-readable medium having instructions that, when executed by the processor, correct inaccuracies by determining, for each neighborhood comprising a predetermined number of pixels, the difference in grey scale value of adjacent pixels in each direction, such that
• (i) if the difference is no greater than 1, or no greater than 2, or no greater than 3 grey scale values in three or four directions, no difference is permitted between predicted and actual pixel values, and any difference is corrected;
• (ii) if the difference is no greater than 1, or no greater than 2, or no greater than 3 grey scale values in 2 directions, a maximum value of difference is permitted between predicted and actual pixel values before a correction is applied, wherein said maximum can vary between 1 and 16 greyscales;
• and
• (iii) if the difference is no greater than 1, or no greater than 2, or no greater than 3 grey scale values in one or zero directions, a larger difference than in two directions is permitted before a correction is applied.