Methods and Systems for Residual Layer Scaling

• US 20080008247A1
• Filed: 03/31/2007
• Published: 01/10/2008
• Est. Priority Date: 07/10/2006
• Status: Active Grant

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Segall, Christopher A.
• Granted Patent: US 8,059,714 B2
• Time in Patent Office: Days
• US Class Current: 375/240.18
• CPC Class Codes: H04N 19/122 Selection of transform size, e.g. 8x8 or 2x4x8 DCT; Selection of sub-band transforms of varying structure or type
• CPC Class Codes: H04N 19/124 Quantisation
• CPC Class Codes: H04N 19/187 the unit being a scalable video layer
• CPC Class Codes: H04N 19/30 using hierarchical techniques, e.g. scalability H04N19/63 takes precedence
• CPC Class Codes: H04N 19/40 using video transcoding, i.e. partial or full decoding of a coded input stream followed by re-encoding of the decoded output stream
• CPC Class Codes: H04N 19/44 Decoders specially adapted therefor, e.g. video decoders which are asymmetric with respect to the encoder
• CPC Class Codes: H04N 19/61 in combination with predictive coding
• CPC Class Codes: H04N 19/70 characterised by syntax aspects related to video coding, e.g. related to compression standards

Abstract

Embodiments of the present invention comprise systems and methods for managing and combining layers in a multi-layer bitstream.

Claims

1. A method for scaling transform coefficients in a multi-layer bitstream, said method comprising:

determining a first-layer quantization parameter based on said multi-layer bitstream;

determining a second-layer quantization parameter based on said multi-layer bitstream; and

scaling a first-layer transform coefficient based on said first-layer quantization parameter and said second-layer quantization parameter.

2. A method as described in claim 1 wherein said scaling is performed according to the following relationship:

$T_{\mathrm{SecondLayer}}=T_{\mathrm{FirstLayer}}·<br><br>2^{\frac{\mathrm{Qp\_FirstLayer}-\mathrm{Qp\_SecondLayer}}{k}}$

wherein T_SecondLayer and T_FirstLayer denote the transform coefficients at the second layer and first layer, respectively;

k is an integer, and Qp_FirstLayer and Qp_SecondLayer are the quantization parameters for the first layer and second layer, respectively.

3. A method as described in claim 2 wherein said k=6.

4. A method as described in claim 1 wherein said scaling is performed according to the following relationship:

Qp_Diff = Qp_FirstLayer −

Qp_SecondLayer T_SecondLayer = ((T_FirstLayer <

<

QP_Diff //

     6) * ScaleMatrix[QP_Diff %6] + M /

     2) >

>

M

wherein // denotes integer division, % denotes the modulo operation;

M and ScaleMatrix are constants;

T_{SecondLayer and TFirstLayer} denote the transform coefficients at the second layer and first layer, respectively;

k is an integer and Qp_FirstLayer and Qp_SecondLayer are the quantization parameters for the first layer and second layer, respectively.

5. A method as described in claim 4 wherein Qp_Diff is reset to zero when Qp_Diff is found to be less than zero.

6. A method as described in claim 4 wherein said ScaleMatrix=[512 573 642 719 806 902] and said M=512.

7. A method as described in claim 4 wherein said ScaleMatrix=[8 9 10 11 13 14] and said M=8.

8. A method as described in claim 1 wherein said scaling is performed according to the following relationship:

Qp_Diff = Qp_FirstLayer −

Qp_SecondLayer T_SecondLayer = ((T_FirstLayer <

<

QP_Diff //

     6) * ScaleMatrix[QP_Diff %6 + 5] + M /

     2) >

>

M

wherein // denotes integer division, % denotes the modulo operation;

M and ScaleMatrix are constants;

T_SecondLayer and T_FirstLayer denote the transform coefficients at the second layer and first layer, respectively;

k is an integer and Qp_FirstLayer and Qp_SecondLayer are the quantization parameters for the first layer and second layer, respectively.

9. A method as described in claim 8 wherein Qp_Diff is reset to zero when Qp_Diff is found to be less than zero.

10. A method as described in claim 8 wherein said ScaleMatrix=[291 325 364 408 457 512 573 642 719 806 902] and said M=512.

11. A method as described in claim 1 further comprising combining said scaled first-layer transform coefficient with a second-layer transform coefficient thereby creating a combined coefficient.

12. A method as described in claim 11 further comprising generating a combined bitstream comprising said combined coefficient.

13. A method as described in claim 1 further comprising determining a first-layer transform-coefficient-dependent weighting factor, S_F, and a second-layer transform-coefficient-dependent weighting factor, S_S, wherein said scaling is performed according to the following relationship:

$T_{\mathrm{SecondLayer}}=T_{\mathrm{FirstLayer}}·<br><br>2^{\frac{S_F<br><br>\mathrm{Qp\_FirstLayer}-S_S<br><br>\mathrm{Qp\_SecondLayer}}{k}}$

wherein TSecondLayer and TFirstLayer denote a transform coefficient at the second layer and first layer, respectively;

k is an integer, and Qp_FirstLayer and Qp_SecondLayer are the quantization parameters for the first layer and second layer, respectively.

14. A method as described in claim 1 further comprising:

determining a first-layer transform-coefficient-dependent weighting factor, S_F;

determining a second-layer transform-coefficient-dependent weighting factor, S_S; and

wherein said scaling is performed according to the following relationship;

Qp_Diff = S_FQp_FirstLayer −

S_SQp_SecondLayer T_SecondLayer = ((T_FirstLayer <

<

QP_Diff //

     6) * ScaleMatrix[QP_Diff %6] + M /

     2) >

>

M

wherein // denotes integer division, % denotes the modulo operation;

M and ScaleMatrix are constants;

T_SecondLayer and T_FirstLayer denote the transform coefficients at the second layer and first layer, respectively;

k is an integer and Qp_FirstLayer and Qp_SecondLayer are the quantization parameters for the first layer and second layer, respectively.

15. A method as described in claim 14 wherein S_F and S_S are explicitly present in said multi-layer bitstream.

16. A method as described in claim 14 wherein S_F and S_S are derived from said multi-layer bitstream.

17. A method as described in claim 1 further comprising:

determining a multiplicative transform-coefficient-dependent weighting factor, W1;

determining an additive transform-coefficient-dependent weighting factor, W2; and

wherein said scaling is performed according to the following relationship;

Qp_Diff = W1(Qp_FirstLayer −

Qp_SecondLayer) + W2 T_SecondLayer = ((T_FirstLayer <

<

QP_Diff //

     6) * ScaleMatrix[QP_Diff %6] + M /

     2) >

>

M

wherein // denotes integer division, % denotes the modulo operation;

M and ScaleMatrix are constants;

T_SecondLayer and T_FirstLayer denote the transform coefficients at the second layer and first layer, respectively;

k is an integer and Qp_FirstLayer and Qp_SecondLayer are the quantization parameters for the first layer and second layer, respectively.

18. A method as described in claim 17 wherein W1 and W2 are explicitly present in said multi-layer bitstream.

19. A method as described in claim 17 wherein W1 and W2 are derived from said multi-layer bitstream.

20. A method as described in claim 11 further comprising inverse quantizing said combined coefficient thereby generating a de-quantized combined transform coefficient.

21. A method as described in claim 20 further comprising inverse transforming said de-quantized combined transform coefficient thereby generating a spatial-domain residual value.

22. A method as described in claim 20 further comprising combining said spatial-domain residual value with a spatial-domain prediction value.