Embedded codec circuitry for sub-block based entropy coding of quantized-transformed residual levels
An embedded codec (EBC) circuitry includes a memory to store a plurality of one dimensional (1D) sub-blocks of quantized-transformed residual levels for a 1D image block and encoder circuitry to allocate a set of signaling bits to each 1D sub-block of the plurality of 1D sub-blocks. The encoder circuitry selects an entropy coding scheme, from a set of entropy coding schemes, for each 1D sub-block of the plurality of 1D sub-blocks, based on the allocated set of signaling bits for each 1D sub-block. The encoder circuitry generates a bit-stream of encoded 1D image block by selective application of the entropy coding scheme on a DC quantized-transformed residual level, a plurality of AC quantized-transformed residual levels, or a combination of the DC quantized-transformed residual level and the plurality of AC quantized-transformed residual levels of each 1D sub-block of the plurality of 1D sub-blocks.
1. An embedded codec (EBC) circuitry, comprising:
a memory configured to store a one dimensional (1D) image block; and
encoder circuitry configured to:
partition the 1D image block into a plurality of 1D sub-blocks;
allocate a set of signaling bits to each 1D sub-block of the plurality of 1D sub-blocks, wherein,
the allocation is based on a maximum value of an alternating current (AC) quantized-transformed residual level from a plurality of AC quantized-transformed residual levels in each 1D sub-block of the plurality of 1D sub-blocks, and
each 1D sub-block of the plurality of 1D sub-blocks is classified into a sub-block category from a set of sub-block categories based on the allocated set of signaling bits;
select an entropy coding scheme, from a set of entropy coding schemes, for each 1D sub-block of the plurality of 1D sub-blocks, based on the allocated set of signaling bits for each 1D sub-block; and
generate a bit-stream of encoded 1D image block by selective application of the entropy coding scheme on one of a direct current (DC) quantized-transformed residual level, the plurality of AC quantized-transformed residual levels, or a combination of the DC quantized-transformed residual level and the plurality of AC quantized-transformed residual levels of each 1D sub-block of the plurality of 1D sub-blocks.
2. The EBC circuitry according to claim 1 , wherein the encoder circuitry is further configured to execute a sequential encoding scheme on the 1D image block to generate the bit-stream of encoded 1D image block.
3. The EBC circuitry according to claim 2 , wherein
the bit-stream of encoded 1D image block comprises header information that indicates the sequential encoding scheme applied to encode the 1D image block to obtain the bit-stream of encoded 1D image block, and
the sequential encoding scheme comprises a sequential application of a 1D transform, followed by quantization, a residual prediction, and the entropy coding scheme selected for each 1D sub-block of plurality of 1D sub-blocks.
4. The EBC circuitry according to claim 3 , wherein
a type of the 1D transform applied on the 1D image block is based on a size of each 1D sub-block of the plurality of 1D sub-blocks, and
the size of each 1D sub-block of the plurality of 1D sub-blocks is specified prior to encode of the 1D image block.
5. The EBC circuitry according to claim 1 , wherein
the encoder circuitry is further configured to compare the maximum value for each 1D sub-block of the plurality of 1D sub-blocks to a first reference value and a second reference value,
the maximum value is one of greater than or equal to 0, and
the comparison determines whether the maximum value for each 1D sub-block of the plurality of 1D sub-blocks is one of equal to the first reference value, equal to the second reference value, or greater than the second reference value.
6. The EBC circuitry according to claim 5 , wherein the first reference value is 0 and the second reference value is 1.
7. The EBC circuitry according to claim 5 , wherein
the set of sub-block categories comprises a first sub-block category, a second sub-block category, and a third sub-block category, and
each sub-block category of the set of sub-block categories indicates a different flatness level and a different complexity level for a corresponding 1D sub-block of the plurality of 1D sub-blocks.
8. The EBC circuitry according to claim 7 , wherein the allocated set of signaling bits represents the first sub-block category, for a 1D sub-block of the plurality of 1D sub-blocks, based on the maximum value of the plurality of AC quantized-transformed residual levels in the 1D sub-block that is equal to the first reference value.
9. The EBC circuitry according to claim 7 , wherein the allocated set of signaling bits represents the second sub-block category, for a 1D sub-block of the plurality of 1D sub-blocks, based on the maximum value of the plurality of AC quantized-transformed residual levels in the 1D sub-block that is equal to the second reference value.
10. The EBC circuitry according to claim 7 , wherein the allocated set of signaling bits represents the third sub-block category, for a 1D sub-block of the plurality of 1D sub-blocks, based on the maximum value of the plurality of AC quantized-transformed residual levels in the 1D sub-block that is greater than the second reference value.
11. The EBC circuitry according to claim 7 , wherein a number of signaling bits in the allocated set of signaling bits to represent the first sub-block category is 1.
12. The EBC circuitry according to claim 7 , wherein a number of signaling bits in the set of signaling bits to represent the second sub-block category and the third sub-block category is 2.
13. The EBC circuitry according to claim 1 , wherein the set of entropy coding schemes comprises one of a Huffman coding scheme, an exponential Golomb coding scheme, a progressive Golomb coding scheme, or a Golomb-Rice coding scheme, or a combination of the Huffman coding scheme and the exponential Golomb coding scheme.
14. The EBC circuitry according to claim 1 , wherein the encoder circuitry is further configured to encode the DC quantized-transformed residual level of each 1D sub-block of the plurality of 1D sub-blocks, in accordance with the selected entropy coding scheme.
15. The EBC circuitry according to claim 1 , wherein the plurality of AC quantized-transformed residual levels of a 1D sub-block associated with a first sub-block category are represented by the allocated set of signaling bits such that a set of bits for the plurality of AC quantized-transformed residual levels are directly decodable at a decoder circuitry using the allocated set of signaling bits.
16. The EBC circuitry according to claim 1 , wherein the set of signaling bits are allocated to each 1D sub-block of the plurality of 1D sub-blocks such that a number of bits in the generated bit-stream of encoded 1D image block is less than a bit budget specified for a specific compression ratio for the 1D image block.
17. The EBC circuitry according to claim 1 , wherein
the encoder circuitry is further configured to encode, using a single bit, an AC quantized-transformed residual level of the plurality of AC quantized-transformed residual levels of a 1D sub-block associated with a second sub-block category, and
the AC quantized-transformed residual level is encoded using the single bit based on the AC quantized-transformed residual level that is 0.
18. The EBC circuitry according to claim 1 , wherein
the encoder circuitry is further configured to encode, using a pair of bits, an AC quantized-transformed residual level of the plurality of AC quantized-transformed residual levels of a 1D sub-block associated with a second sub-block category, and
the AC quantized-transformed residual level is encoded by the pair of bits based on the AC quantized-transformed residual level that is one of unsigned 1 or signed 1.
19. The EBC circuitry according to claim 1 , wherein the encoder circuitry is further configured to encode the plurality of AC quantized-transformed residual levels of a 1D sub-block, associated with a third sub-block category, in accordance with the selected entropy coding scheme.
20. The EBC circuitry according to claim 1 , wherein a number of bits in the bit-stream of encoded 1D image block comprises a number of the allocated set of signaling bits for each 1D sub-block of the plurality of 1D sub-blocks.
21. A method comprising:
in an embedded codec (EBC) circuitry that comprises a memory and encoder circuitry:
partitioning, by the encoder circuitry, a one dimensional (1D) image block into a plurality of 1D sub-blocks;
storing, by the memory, the plurality of 1D sub-blocks;
allocating, by the encoder circuitry, a set of signaling bits to each 1D sub-block of the plurality of 1D sub-blocks, wherein,
the allocation based on a maximum value of an AC quantized-transformed residual level from a plurality of Alternating Current (AC) quantized-transformed residual levels in each 1D sub-block, and
each 1D sub-block of the plurality of 1D sub-blocks is classified into a sub-block category from a set of sub-block categories based on the allocated set of signaling bits;
selecting, by the encoder circuitry, an entropy coding scheme, from a set of entropy coding schemes, for each 1D sub-block of the plurality of 1D sub-blocks, based on the allocated set of signaling bits for each 1D sub-block; and
generating, by the encoder circuitry, a bit-stream of encoded 1D image block by selective application of the entropy coding scheme on one of a Direct Current (DC) quantized-transformed residual level, the plurality of AC quantized-transformed residual levels, or a combination of the DC quantized-transformed residual level and the plurality of AC quantized-transformed residual levels of each 1D sub-block of the plurality of 1D sub-blocks.