Breakpoint determining for hybrid variable length coding using relationship to neighboring blocks

An apparatus comprising a programmable processing system including one or more processors coupled to a memory, programmed to carry out a method comprising:

• (a) determining a breakpoint for hybrid variable length coding an ordered sequence of quantized transform coefficients of a block, or for hybrid variable length coding ordered sequences of a multi-block partition, the breakpoint determining using a relationship to properties of blocks that neighbor the block or multi-block partition,
• wherein the quantized transform coefficients have respective amplitudes of a set of amplitudes including a most likely-to-occur amplitude,
• wherein the hybrid variable length coding an ordered sequence of quantized transform coefficients of a block includes recognizing any event that includes a cluster of one or more quantized coefficients having amplitude other than the most likely-to-occur amplitude, encoding a first part of the sequence using a selected low-frequency coding method up to and including an ending event recognized by the selected low-frequency coding method, and encoding a second part of the sequence starting from immediately after the ending event using a selected high-frequency coding method,
• wherein the breakpoint indicates the location of the ending event in the sequence;
• (b) encoding the ordered sequence of quantized transform coefficients of the block, or the ordered sequences of the multi-block partition, using the hybrid variable length coding and the ending event indicated by the breakpoint determined in (a);
• and
• (c) in the case information additional to the properties of the neighboring blocks would be needed by a decoder or decoding process to determine the breakpoint determined in (a), encoding sufficient information about the relationship such that a decoder or decoding process can, prior to decoding the coded data of the block or multi-block partition use the sufficient information and the properties of the neighboring blocks to determine the breakpoint used to encode the coded data of the block or multi-block partition,
• such that the breakpoint may be variable among blocks of an image,
• wherein the properties and the neighboring blocks are such that in the decoding, the properties of the neighboring blocks are known or determinable prior to the decoding of the coded data of the block or multi-block partition.

A non-transitory computer-readable medium configured with instructions that when executed by one and more processors of a processing system, cause carrying out a method, the method comprising:

• (a) determining a breakpoint for hybrid variable length coding an ordered sequence of quantized transform coefficients of a block, or for hybrid variable length coding ordered sequences of a multi-block partition, the breakpoint determining using a relationship to properties of blocks that neighbor the block or multi-block partition,
• wherein the quantized transform coefficients have respective amplitudes of a set of amplitudes including a most likely-to-occur amplitude,
• wherein the hybrid variable length coding an ordered sequence of quantized transform coefficients of a block includes recognizing any event that includes a cluster of one or more consecutive quantized coefficients having amplitude other than the most likely-to-occur amplitude, encoding a first part of the sequence using a selected low-frequency coding method, the selected low-frequency coding method including recognizing an ending event, the encoding a first part being up to and including the recognized ending event, and encoding a second part of the sequence starting from immediately after the recognized ending event using a selected high-frequency coding method,
• wherein the breakpoint indicates the location of the ending event in the sequence;
• (b) encoding the ordered sequence of quantized transform coefficients of the block, or the ordered sequences of the multi-block partition, using the hybrid variable length coding and the recognized ending event;
• and
• (c) in the case information additional to the properties of the neighboring blocks would be needed by a decoder or decoding process to determine the breakpoint determined in (a), encoding sufficient information about the relationship such that a decoder or decoding process can, prior to decoding the coded data of the block or multi-block partition use the sufficient information and the properties of the neighboring blocks to determine the breakpoint used to encode the coded data of the block or multi-block partition,
• such that the breakpoint may be variable among blocks of an image,
• wherein the properties and the neighboring blocks are such that in the decoding, the properties of the neighboring blocks are known or determinable prior to the decoding of the coded data of the block or multi-block partition.

A method of decoding comprising:

• accepting a bitstream that includes codewords of a to-be-decoded block or multi-block partition of image data encoded by a coding method, the coding method including:
• (a) determining a breakpoint for hybrid variable length coding an ordered sequence of quantized transform coefficients of a block, or for hybrid variable length coding ordered sequences of a multi-block partition, the breakpoint determining using a relationship to properties of blocks that neighbor the block or multi-block partition,
• wherein the quantized transform coefficients have respective amplitudes of a set of amplitudes including a most likely-to-occur amplitude,
• wherein the hybrid variable length coding an ordered sequence of quantized transform coefficients of a block includes recognizing any event that includes a cluster of one or more consecutive quantized coefficients having amplitude other than the most likely-to-occur amplitude, encoding a first part of the sequence using a selected low-frequency coding method, the selected low-frequency coding method including recognizing an ending event, the encoding a first part being up to and including the recognized ending event, and encoding a second part of the sequence starting from immediately after the recognized ending event using a selected high-frequency coding method,
• wherein the breakpoint indicates the location of the ending event in the sequence;
• (b) encoding the ordered sequence of quantized transform coefficients of the block, or the ordered sequences of the multi-block partition, using the hybrid variable length coding and the recognized ending event;
• and
• (c) encoding any additional information about the relationship that together with the properties of the neighboring blocks is sufficient to determine the breakpoint used to encode the coded data of the to-be-decoded block or multi-block partition,
• such that the breakpoint may be variable among blocks of an image,
• decoding any such additional information for the to-be-decoded block or multi-block partition;
• determining the properties of blocks neighboring the to-be-decoded block or multi-block partition;
• determining the breakpoint used to encode the to-be-decoded block or multi-block partition using the determined properties of blocks neighboring the to-be-decoded block or multi-block partition;
• recognizing codewords in the bitstream;
• and
• decoding the recognized codewords to determine the sequence or sequences of the block or multi-block partition.

A non-transitory computer-readable medium configured with instructions that when executed by one or more processors of a processing system cause carrying out a method, the method comprising:

• accepting a bitstream that includes codewords of a to-be-decoded block or multi-block partition of image data encoded by a coding method, the coding method including:
• (a) determining a breakpoint for hybrid variable length coding an ordered sequence of quantized transform coefficients of a block, or for hybrid variable length coding ordered sequences of a multi-block partition, the breakpoint determining using a relationship to properties of blocks that neighbor the block or multi-block partition,
• wherein the quantized transform coefficients have respective amplitudes of a set of amplitudes including a most likely-to-occur amplitude,
• wherein the hybrid variable length coding an ordered sequence of quantized transform coefficients of a block includes recognizing any event that includes a cluster of one or more consecutive quantized coefficients having amplitude other than the most likely-to-occur amplitude, encoding a first part of the sequence using a selected low-frequency coding method, the selected low-frequency coding method including recognizing an ending event, the encoding a first part being up to and including the recognized ending event, and encoding a second part of the sequence starting from immediately after the recognized ending event using a selected high-frequency coding method,
• wherein the breakpoint indicates the location of the ending event in the sequence;
• (b) encoding the ordered sequence of quantized transform coefficients of the block, or the ordered sequences of the multi-block partition, using the hybrid variable length coding and the recognized ending event;
• and
• (c) encoding any additional information about the relationship that together with the properties of the neighboring blocks is sufficient to determine the breakpoint used to encode the coded data of the to-be-decoded block or multi-block partition,
• such that the breakpoint may be variable among blocks of an image,
• decoding any such additional information for the to-be-decoded block or multi-block partition;
• determining the properties of blocks neighboring the to-be-decoded block or multi-block partition;
• determining the breakpoint used to encode the to-be-decoded block or multi-block partition using the determined properties of blocks neighboring the to-be-decoded block or multi-block partition;
• recognizing codewords in the bitstream;
• and
• decoding the recognized codewords to determine the sequence or sequences of the block or multi-block partition.