Picture signal encoding method and apparatus and picture signal decoding method and apparatus

• US 5,663,763 A
• Filed: 10/18/1993
• Issued: 09/02/1997
• Est. Priority Date: 10/29/1992
• Status: Expired due to Term

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Yagasaki, Yoichi, Tahara, Katsumi, Wada, Tohru
• Primary Examiner(s): Chin, Tommy P.
• Assistant Examiner(s): LEE, RICHARD J
• Application Number:
  US08/137,257
• Time in Patent Office: 1,415 Days
• Field of Search: 348/405, 348/384, 348/409, 348/412, 348/408, 348/415, 348/419, 348/400, 348/411, 348/27
• US Class Current: 375/240.03
• CPC Class Codes: H04N 19/112 according to a given display mode, e.g. for interlaced or progressive display mode
• CPC Class Codes: H04N 19/124 Quantisation
• CPC Class Codes: H04N 19/126 Details of normalisation or weighting functions, e.g. normalisation matrices or variable uniform quantisers
• CPC Class Codes: H04N 19/13 Adaptive entropy coding, e.g. adaptive variable length coding [AVLC] or context adaptive binary arithmetic coding [CABAC]
• CPC Class Codes: H04N 19/577 Motion compensation with bidirectional frame interpolation, i.e. using B-pictures
• CPC Class Codes: H04N 19/60 using transform coding
• CPC Class Codes: H04N 19/61 in combination with predictive coding
• CPC Class Codes: H04N 19/85 using pre-processing or post-processing specially adapted for video compression
• CPC Class Codes: H04N 19/91 Entropy coding, e.g. variable length coding [VLC] or arithmetic coding

Abstract

An encoding and decoding apparatus and method which has the primary benefit over the prior art of not requiring storage of the nonlinear sequence of numbers representative of the quantization characteristics. The hardware required for quantization is reduced and inverse quantization may be achieved using shifting operations and a multiplier of up to half the scale compared to conventional encoding/decoding methods and encoding/decoding apparatus.

Claims

1. An encoding method for picture signals in which input picture signals are quantized and subsequently encoded, comprising setting a digital signal value representing a quantization information used for expressing an index of powers of 2 as a first quantization information among a set of quantization information, setting a digital signal value corresponding to a coefficient multiplied by the powers of 2 as representing a second quantization information among the set of quantization information, and quantizing the picture signals based on non-linear quantization characteristic signals (QUANT) obtained by using k as said first quantization information, k being a positive integer, and by using (i/2+j) as said second quantization information, j being a positive integer and i being 0 or 1, wherein said non-linear quantization characteristic signals (QUANT) are represented by an equation:

space="preserve" listing-type="equation">QUANT=(i/2+j)×

2.sup.k +2.sup.(k+2) -4

and used as a width of quantization to produce quantized picture signals.

2. The picture signal encoding method as claimed in claim 1 wherein said set of quantization information comprising said first quantization information and said second quantization information is represented by five bits.

3. The picture signal encoding method as claimed in claim 2 wherein the relation between k, i and j and the non-linear quantization characteristic signals are as shown in the following Table 1:

space="preserve" listing-type="tabular"> TABLE 1 ______________________________________ quantization quantization characteristics index information decimal binary number k j i expression expression ______________________________________ 0 00 00 0 inhibit inhibit 1 00 00 1 0.5 00000.1 2 00 01 0 1.0 00001.0 3 00 01 1 1.5 00001.1 4 00 10 0 2.0 00010.0 5 00 10 1 2.5 00010.1 6 00 11 0 3.0 00011.0 7 00 11 1 3.5 00011.1 8 01 00 0 4.0 000100. 9 01 00 1 5.0 000101. 10 01 01 0 6.0 000110. 11 01 01 1 7.0 000111. 12 01 10 0 8.0 001000. 13 01 10 1 9.0 001001. 14 01 11 0 10.0 001010. 15 01 11 1 11.0 001011. 16 10 00 0 12.0 001100. 17 10 00 1 14.0 001110. 18 10 01 0 16.0 010000. 19 10 01 1 18.0 010010. 20 10 10 0 20.0 010100. 21 10 10 1 22.0 010110. 22 10 11 0 24.0 011000. 23 10 11 1 26.0 011010. 24 11 00 0 28.0 011100. 25 11 00 1 32.0 100000. 26 11 01 0 36.0 100100. 27 11 01 1 40.0 101000. 28 11 10 0 44.0 101100. 29 11 10 1 48.0 110000. 30 11 11 0 52.0 110100. 31 11 11 1 56.0 111000. ______________________________________

4. The picture signal encoding method as claimed in claim 3 wherein, if said non-linear quantization characteristic signals (OUANT) are represented by a binary number, there exists at least one effective bit in four consecutive bits.

5. The picture signal encoding method as claimed in claim 2 wherein the relation between k, i, and j and the non-linear quantization characteristic signals are as shown in the following Table 2:

space="preserve" listing-type="tabular"> TABLE 2 ______________________________________ quantization quantization characteristics index information decimal binary number k j i expression expression ______________________________________ 0 00 00 0 inhibit inhibit 1 00 00 1 0.5 00000.1 2 00 01 0 1.0 00001.0 3 00 01 1 1.5 00001.1 4 00 10 0 2.0 00010.0 5 00 10 1 2.5 00010.1 6 00 11 0 3.0 00011.0 7 00 11 1 3.5 00011.1 8 01 00 0 4.0 000100. 9 01 00 1 5.0 000101. 10 01 01 0 6.0 000110. 11 01 01 1 7.0 000111. 12 01 10 0 8.0 001000. 13 01 10 1 9.0 001001. 14 01 11 0 10.0 001010. 15 01 11 1 11.0 001011. 16 10 00 0 12.0 001100. 17 10 00 1 14.0 001110. 18 10 01 0 16.0 010000. 19 10 01 1 18.0 010010. 20 10 10 0 20.0 010100. 21 10 10 1 22.0 010110. 22 10 11 0 24.0 011000. 23 10 11 1 26.0 011010. 24 11 00 0 28.0 011100. 25 11 00 1 36.0 100100. 26 11 01 0 44.0 101100. 27 11 01 1 52.0 110100. 28 11 10 0 60.0 111100. 29 11 10 1 68.0 1000100. 30 11 11 0 76.0 1001100. 31 11 11 1 84.0 1010100. ______________________________________

6. The picture signal encoding method as claimed in claim 5 wherein there exists at least one effective bit in four consecutive bits.

7. A picture signal decoding method in which transmitted encoded data is inverse-quantized and subsequently decoded for restoring a picture from the encoded data, comprising the steps of reproducing non-linear quantization characteristic signals (QUANT) at the time of inverse quantization by multiplying powers of 2 by a coefficient, using a digital signal value for expressing an index of the powers of 2 as representing a first quantization information among a set of quantization information and a digital signal value corresponding to said coefficient as representing a second quantization information, and inverse guantizing data based on the reproduced non-linear quantization characteristic signals (QUANT) obtained by using k as said first quantization information and by using (i/2+j) as said second quantization information, j and k being positive integers and i being 0 or 1, wherein said non-linear quantization characteristic signals (QUANT) are represented by an equation:

space="preserve" listing-type="equation">QUANT=(i/2+j)×

2.sup.k +2.sup.(k+2) -4

and used as a width of quantization to reproduce quantized picture signals.

8. The picture signal decoding method as claimed in claim 7 wherein said set of quantization information comprising said first quantization information and said second quantization information is represented by five bits.

9. The picture signal decoding method as claimed in claim 8 wherein the relation between k, i and j and the non-linear quantization characteristic signals are as shown in the following Table 5:

space="preserve" listing-type="tabular"> TABLE 5 ______________________________________ quantization quantization characteristics index information decimal binary number k j i expression expression ______________________________________ 0 00 00 0 inhibit inhibit 1 00 00 1 0.5 00000.1 2 00 01 0 1.0 00001.0 3 00 01 1 1.5 00001.1 4 00 10 0 2.0 00010.0 5 00 10 1 2.5 00010.1 6 00 11 0 3.0 00011.0 7 00 11 1 3.5 00011.1 8 01 00 0 4.0 000100. 9 01 00 1 5.0 000101. 10 01 01 0 6.0 000110. 11 01 01 1 7.0 000111. 12 01 10 0 8.0 001000. 13 01 10 1 9.0 001001. 14 01 11 0 10.0 001010. 15 01 11 1 11.0 001011. 16 10 00 0 12.0 001100. 17 10 00 1 14.0 001110. 18 10 01 0 16.0 010000. 19 10 01 1 18.0 010010. 20 10 10 0 20.0 010100. 21 10 10 1 22.0 010110. 22 10 11 0 24.0 011000. 23 10 11 1 26.0 011010. 24 11 00 0 28.0 011100. 25 11 00 1 36.0 100100. 26 11 01 0 44.0 101100. 27 11 01 1 52.0 110100. 28 11 10 0 60.0 111100. 29 11 10 1 68.0 1000100. 30 11 11 0 76.0 1001100. 31 11 11 1 84.0 1010100. ______________________________________

10. The picture signal decoding method as claimed in claim 8 wherein, in inverse-quantizing the encoded data, the encoded data is multiplied in a three stage adder and a resulting sum is shifted by a number of bits determined by said first quantization information.

11. The picture signal decoding method as claimed in claim 8 wherein the relation between information k, i and j and the non-linear quantization characteristic signals are set as shown in the following Table 4:

space="preserve" listing-type="tabular"> TABLE 4 ______________________________________ quantization quantization characteristics index information decimal binary number k j i expression expression ______________________________________ 0 00 00 0 inhibit inhibit 1 00 00 1 0.5 00000.1 2 00 01 0 1.0 00001.0 3 00 01 1 1.5 00001.1 4 00 10 0 2.0 00010.0 5 00 10 1 2.5 00010.1 6 00 11 0 3.0 00011.0 7 00 11 1 3.5 00011.1 8 01 00 0 4.0 000100. 9 01 00 1 5.0 000101. 10 01 01 0 6.0 000110. 11 01 01 1 7.0 000111. 12 01 10 0 8.0 001000. 13 01 10 1 9.0 001001. 14 01 11 0 10.0 001010. 15 01 11 1 11.0 001011. 16 10 00 0 12.0 001100. 17 10 00 1 14.0 001110. 18 10 01 0 16.0 010000. 19 10 01 1 18.0 010010. 20 10 10 0 20.0 010100. 21 10 10 1 22.0 010110. 22 10 11 0 24.0 011000. 23 10 11 1 26.0 011010. 24 11 00 0 28.0 011100. 25 11 00 1 32.0 100000. 26 11 01 0 36.0 100100. 27 11 01 1 40.0 101000. 28 11 10 0 44.0 101100. 29 11 10 1 48.0 110000. 30 11 11 0 52.0 110100. 31 11 11 1 56.0 111000. ______________________________________

12. An encoding apparatus for encoding picture signals in which input picture signals are quantized and subsequently encoded, comprising:

means for setting a digital signal value representing a quantization information used for expressing an index of powers of 2 as a first quantization information among a set of quantization information,

means for setting a digital signal value corresponding to a coefficient multiplied by the powers of 2 as representing a second quantization information among the set of quantization information, and

means for quantizing the picture signals based on non-linear quantization characteristic signals (QUANT) obtained by using k as said first quantization information, k being a positive integer, and by using (i/2+j) as said second quantization information, j being a positive integer and i being 0 or 1, wherein said non-linear quantization characteristic signals (QUANT) are represented by an equation;

space="preserve" listing-type="equation">QUANT=(i/2+j)×

2.sup.k +2.sup.(k+2) -4

and used as a width of quantization to produce quantized picture signals.

13. A picture signal decoding apparatus in which transmitted encoded data is inverse-quantized and subsequently decoded for restoring a picture from coded data, comprising:

means for reproducing non-linear quantization characteristic signals (QUANT) at the time of inverse quantization by multiplying powers of 2 by a coefficient, using a digital signal value for expressing an index of the powers of 2 as representing a first quantization information among a set of quantization information and a digital signal value corresponding to said coefficient as representing a second quantization information, and

means for inverse quantizing data based on the reproduced non-linear quantization characteristic signals (QUANT) obtained by using k as said first quantization information and by using (i/2+j) as said second quantization information, j and k being positive integers and i being 0 or 1, wherein said non-linear quantization characteristic signals (QUANT) are represented by an equation;

space="preserve" listing-type="equation">QUANT=(i/2+j)×

2.sup.k +2.sup.(k+2) -4

and used as a width of quantization to reproduce quantized picture signals.