US 9,319,685 B2Granted

8-point inverse discrete cosine transform including odd and even portions for media data coding

AssigneeQUALCOMM Incorporated

InventorsYuriy Reznik, Rajan Laxman Joshi, Marta Karczewicz

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Abstract

In general, techniques are described for implementing an 8-point inverse discrete cosine transform (IDCT). An apparatus comprising an 8-point inverse discrete cosine transform (IDCT) hardware unit may implement these techniques to transform media data from a frequency domain to a spatial domain. The 8-point IDCT hardware unit includes an even portion comprising factors A, B that are related to a first scaled factor (μ) in accordance with a first relationship. The 8-point IDCT hardware unit also includes an odd portion comprising third, fourth, fifth and sixth internal factors (G, D, E, Z) that are related to a second scaled factor (η) in accordance with a second relationship. The first relationship relates the first scaled factor to the first and second internal factors. The second relationship relates the second scaled factor to the third, fourth, fifth and sixth internal factors.

Claims30

Dependent claims

A method comprising:

receiving coded media data with a coding device;
and
performing an 8-point inverse discrete cosine transform (IDCT) with an 8-point IDCT hardware unit of the coding device to transform the coded media data from a frequency domain to a spatial domain, wherein the 8-point IDCT hardware unit includes:
an even portion comprising first and second internal factors (A, B) that are related to a first scaled factor (μ) in accordance with a first relationship, wherein the first relationship is defined such that the first scaled factor equals a sum of the first internal factor plus the second internal factor divided by a sum of a first approximation (α) of a cosine of three times a constant pi (π) divided by eight plus a second approximation (β) of a sine of three times the constant pi (π) divided by eight;
and
an odd portion comprising third, fourth, fifth and sixth internal factors (G, D, E, Z) that are related to a second scaled factor (η) in accordance with a second relationship,
wherein the second relationship is defined such that the second scaled factor equals one of the following equations that results in a minimal error:
(1) a sum of the third internal factor (G) plus the fourth internal factor (D) divided by a sum of a third approximation (γ) of a cosine of the constant pi divided by sixteen plus a fourth approximation (δ) of a sine of the constant pi divided by sixteen;
(2) a sum of the third internal factor (G) plus the fifth internal factor (E) divided by a sum of the third approximation (γ) plus a fifth approximation (ε) of a cosine of three times the constant pi divided by 16;
(3) a sum of the third internal factor (G) plus the sixth internal factor (Z) divided by a sum of the third approximation (γ) plus a sixth approximation (ζ) of a sine of three times the constant pi divided by 16;
(4) a sum of the fourth internal factor (D) plus the fifth internal factor (E) divided by a sum of the fourth approximation (δ) plus the fifth approximation (ε);
(5) a sum of the fourth internal factor (D) plus the sixth internal factor (Z) divided by a sum of the fourth approximation (δ) plus the sixth approximation (ζ);
and
(6) a sum of the fifth internal factor (E) plus the sixth internal factor (Z) divided by a sum of the fifth approximation (ε) plus the sixth approximation (ζ).

11 more elements

An apparatus comprising:

an 8-point inverse discrete cosine transform (IDCT) hardware unit that transforms coded media data from a frequency domain to a spatial domain, wherein the 8-point IDCT hardware unit includes:
an even portion comprising first and second internal factors (A, B) that are related to a first scaled factor (μ) in accordance with a first relationship, wherein the first relationship is defined such that the first scaled factor equals a sum of the first internal factor plus the second internal factor divided by a sum of a first approximation (α) of a cosine of three times a constant pi (π) divided by eight plus a second approximation (β) of a sine of three times the constant pi (π) divided by eight;
and
an odd portion comprising third, fourth, fifth and sixth internal factors (G, D, E, Z) that are related to a second scaled factor (η) in accordance with a second relationship,
wherein the second relationship is defined such that the second scaled factor equals one of the following equations that results in a minimal error:
(1) a sum of the third internal factor (G) plus the fourth internal factor (D) divided by a sum of a third approximation (γ) of a cosine of the constant pi divided by sixteen plus a fourth approximation (δ) of a sine of the constant pi divided by sixteen;
(2) a sum of the third internal factor (G) plus the fifth internal factor (E) divided by a sum of the third approximation (γ) plus a fifth approximation (ε) of a cosine of three times the constant pi divided by 16;
(3) a sum of the third internal factor (G) plus the sixth internal factor (Z) divided by a sum of the third approximation (γ) plus a sixth approximation (ζ) of a sine of three times the constant pi divided by 16;
(4) a sum of the fourth internal factor (D) plus the fifth internal factor (E) divided by a sum of the fourth approximation (δ) plus the fifth approximation (ε);
(5) a sum of the fourth internal factor (D) plus the sixth internal factor (Z) divided by a sum of the fourth approximation (δ) plus the sixth approximation (ζ);
and
(6) a sum of the fifth internal factor (E) plus the sixth internal factor (Z) divided by a sum of the fifth approximation (ε) plus the sixth approximation (ζ).

9 more elements

An apparatus comprising:

means for receiving coded media data;
and
means for performing an 8-point inverse discrete cosine transform (IDCT) to transform the coded media data from a frequency domain to a spatial domain, wherein the means for performing the 8-point IDCT includes:
an even portion comprising first and second internal factors (A, B) that are related to a first scaled factor (μ) in accordance with a first relationship, wherein the first relationship is defined such that the first scaled factor equals a sum of the first internal factor plus the second internal factor divided by a sum of a first approximation (α) of a cosine of three times a constant pi (π) divided by eight plus a second approximation (β) of a sine of three times the constant pi (π) divided by eight;
and
an odd portion comprising third, fourth, fifth and sixth internal factors (G, D, E, Z) that are related to a second scaled factor (η) in accordance with a second relationship,
wherein the second relationship is defined such that the second scaled factor equals one of the following equations that results in a minimal error:
(1) a sum of the third internal factor (G) plus the fourth internal factor (D) divided by a sum of a third approximation (γ) of a cosine of the constant pi divided by sixteen plus a fourth approximation (δ) of a sine of the constant pi divided by sixteen;
(2) a sum of the third internal factor (G) plus the fifth internal factor (E) divided by a sum of the third approximation (γ) plus a fifth approximation (ε) of a cosine of three times the constant pi divided by 16;
(3) a sum of the third internal factor (G) plus the sixth internal factor (Z) divided by a sum of the third approximation (γ) plus a sixth approximation (ζ) of a sine of three times the constant pi divided by 16;
(4) a sum of the fourth internal factor (D) plus the fifth internal factor (E) divided by a sum of the fourth approximation (δ) plus the fifth approximation (ε);
(5) a sum of the fourth internal factor (D) plus the sixth internal factor (Z) divided by a sum of the fourth approximation (δ) plus the sixth approximation (ζ);
and
(6) a sum of the fifth internal factor (E) plus the sixth internal factor (Z) divided by a sum of the fifth approximation (ε) plus the sixth approximation (ζ).

11 more elements

A non-transitory computer-readable storage medium comprising instructions that cause a processor to:

receive coded media data;
and
perform an 8-point inverse discrete cosine transform (IDCT) with an 8-point IDCT hardware unit to transform the coded media data from a frequency domain to a spatial domain, wherein the 8-point IDCT hardware unit includes:
an even portion comprising first and second internal factors (A, B) that are related to a first scaled factor (μ) in accordance with a first relationship, wherein the first relationship is defined such that the first scaled factor equals a sum of the first internal factor plus the second internal factor divided by a sum of a first approximation (α) of a cosine of three times a constant pi (π) divided by eight plus a second approximation (β) of a sine of three times the constant pi (π) divided by eight;
and
an odd portion comprising third, fourth, fifth and sixth internal factors (G, D, E, Z) that are related to a second scaled factor (η) in accordance with a second relationship,
wherein the second relationship is defined such that the second scaled factor equals one of the following equations that results in a minimal error:
(1) a sum of the third internal factor (G) plus the fourth internal factor (D) divided by a sum of a third approximation (γ) of a cosine of the constant pi divided by sixteen plus a fourth approximation (δ) of a sine of the constant pi divided by sixteen;
(2) a sum of the third internal factor (G) plus the fifth internal factor (E) divided by a sum of the third approximation (γ) plus a fifth approximation (ε) of a cosine of three times the constant pi divided by 16;
(3) a sum of the third internal factor (G) plus the sixth internal factor (Z) divided by a sum of the third approximation (γ) plus a sixth approximation (ζ) of a sine of three times the constant pi divided by 16;
(4) a sum of the fourth internal factor (D) plus the fifth internal factor (E) divided by a sum of the fourth approximation (δ) plus the fifth approximation (ε);
(5) a sum of the fourth internal factor (D) plus the sixth internal factor (Z) divided by a sum of the fourth approximation (δ) plus the sixth approximation (ζ);
and
(6) a sum a sum of the fifth internal factor (E) plus the sixth internal factor (Z) divided by a sum of the fifth approximation (ε) plus the sixth approximation (ζ).

11 more elements

Dependencies are inferred from the claim text.

Facts

Application: 13/765,040Filed 12 Feb 2013 · division
Priority: 24 Jun 2009
Published: US 2013/0148718 A113 Jun 2013
Granted: 19 Apr 2016
Term ends: Not estimatedThe source records don’t support an estimate.

Classification5 codes

H04N 19/625
Using transform coding: using discrete cosine transform [DCT]
G06F 17/147
Fourier, Walsh or analogous domain transformations , e.g. Laplace, Hilbert, Karhunen-Loeve, transforms: discrete orthonormal transforms, e.g.…
H04N 19/60
Methods or arrangements for coding, decoding, compressing or decompressing digital video signals: using transform coding
H04N
Pictorial communication

Family

Application61/219,891Us provisional application · filed 24 Jun 2009
Application12/820,312Parent of this division · filed 22 Jun 2010
US 2013/0148718 A1Pre-grant publication · published 13 Jun 2013
US 2010/0329329 A1Published application
US 9,118,898 B2Related patent
US 9,319,685 B2This patent

From the US filing history. Foreign family members aren’t listed.