Digital video compression system utilizing vector adaptive transform

An apparatus for encoding frames of digitized video information, wherein the frames are divided into blocks, and wherein numbers of bits available for encoding video information change over time so that the number of bits available for encoding a frame may differ from the number of bits available for encoding a subsequent frame, said apparatus comprising:

• means for performing a spatial domain to transform domain transformation of video information related to each block of a frame to obtain a corresponding block of transform coefficients;
• means for ascertaining the number of bits available for encoding said frame;
• means for allocating a number of bits to the encoding of each block of transform coefficients for all the blocks in said frame;
• and
• means for quantizing and coding each block of transform coefficients to generate variable length coding bits for each block, wherein the number of bits generated is a function of the number of bits allocated to the encoding of a different block of transform coefficients.

A method for encoding frames of pixel values of video information, wherein the frames are divided into blocks, said method comprising:

• performing a spatial domain to transform domain transformation of video information related to each block of a frame to obtain a corresponding block of transform coefficients;
• quantizing and coding each block of transform coefficients to generate variable length coding bits for each block, wherein the quantizing step is performed by reference to one index within a set of numerical indices indicating number of bits resulting from the quantizing step, and wherein said indices have values that vary directly with the number of bits resulting from the quantizing step;
• computing an average value of the indices by reference to which the blocks of a frame have been quantized and coded in the quantizing and coding step;
• comparing said average value to predetermined range values;
• and
• multiplying each pixel value by a selected matrix element when the average value is within predetermined range values.

A method for encoding frames of digitized video information, wherein the frames are divided into blocks, said method comprising:

• performing a spatial domain to transform domain transformation of video information related to each block of a frame to obtain a corresponding block of transform coefficients;
• quantizing and coding each block of transform coefficients to generate variable length coding bits for each block, wherein said coding step includes:
• first scanning at least some of the coefficients of each block along at least two different paths and counting the number of nonzero scanned coefficients along each path to obtain at least two numbers;
• comparing the numbers obtained to find the largest of the numbers;
• and
• scanning the coefficients of each block along the path that results in the largest number before coding each block of transform coefficients.

A method for encoding frames of digitized video information, wherein the frames are divided into blocks, said method comprising:

• performing a spatial domain to transform domain transformation of video information related to each block of a frame to obtain a corresponding block of transform coefficients;
• quantizing and coding each block of transform coefficients to generate variable length coding bits for each block;
• dividing each block into two or more sets of zones;
• and
• forming a scan vector of at least one zone and variable length coding of coefficients of said at least one zone.

A method for encoding frames of video information, said frames divided into blocks, wherein the frames are encoded sequentially in a time sequence, so that each block in a frame has a corresponding block in a different frame, said method comprising:

• performing a spatial domain to transform domain transformation of video information related to each block of a frame to obtain a corresponding block of transform coefficients;
• quantizing and coding each block of transform coefficients to generate variable length coding bits for each block;
• reconstructing each block from its variable length coding bits;
• storing said reconstructed block;
• storing a predetermined frame of video information as the background frame, said frame containing a background block corresponding to said reconstructed block;
• comparing a current block to be quantized and coded to said reconstructed block and to the background block to determine a prediction block;
• and
• using the prediction block to derive said video information related to each block that is transformed in said performing step.