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US 9,069,713 B2Granted
4X4 transform for media coding
AssigneeQUALCOMM Incorporated
InventorYuriy Reznik
Life of this patent
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Abstract
In general, techniques are described that provide for 4×4 transforms for media coding. A number of different 4×4 transforms are described that adhere to these techniques. As one example, an apparatus includes a 4×4 discrete cosine transform (DCT) hardware unit. The DCT hardware unit implements an orthogonal 4×4 DCT having an odd portion that applies first and second internal factors (C, S) that are related to a scaled factor (ξ) such that the scaled factor equals a square root of a sum of a square of the first internal factor (C) plus a square of the second internal factor (S). The 4×4 DCT hardware unit applies the 4×4 DCT implementation to media data to transform the media data from a spatial domain to a frequency domain. As another example, an apparatus implements a non-orthogonal 4×4 DCT to improve coding gain.
Claims42
An apparatus for encoding media data comprising:
- a 4×4 inverse discrete cosine transform (IDCT) hardware unit that implements An IDCT of an orthogonal 4×4 DCT having an odd portion that applies first and second internal factors (C, S) that are related to a scaled factor (ξ) such that the scaled factor equals a square root of a sum of a square of the first internal factor (C) plus a square of the second internal factor (S), the first and second internal factors (C, S) are co-prime and greater than or equal to two,
- wherein the 4×4 IDCT hardware unit applies the 4×4 IDCT implementation to DCT coefficients representative of media data to transform the media data from a frequency domain to a spatial domain and to determine one or more IDCT coefficients, and
- wherein the 4×4 IDCT hardware unit includes a quantization unit that multiplies the inverse of the scaled factor (ξ) with one or more IDCT coefficients to determine quantized IDCT coefficients.
A method for encoding media data comprising:
- applying a 4×4 inverse discrete cosine transform (IDCT) of an orthogonal 4×4 DCT with a 4×4 IDCT hardware unit to DCT coefficients representative of media data to transform the media data from a frequency domain to a spatial domain and to determine one or more IDCT coefficients,
- wherein the orthogonal 4×4 DCT includes an odd portion that applies first and second internal factors (C, S) that are related to a scaled factor (ξ) such that the scaled factor equals a square root of a sum of a square of the first internal factor (C) plus a square of the second internal factor (S), the first and second internal factors (C, S) are co-prime and greater than or equal to two, and
- wherein the 4×4 IDCT hardware unit includes a quantization unit that multiplies the inverse of the scaled factor (ξ) with one or more IDCT coefficients to determine quantized IDCT coefficients.
An apparatus for encoding media data comprising:
- means for applying a 4×4 inverse discrete cosine transform (IDCT) of an orthogonal 4×4 DCT to DCT coefficients representative of media data to transform the media data from a frequency domain to a spatial domain and to determine one or more IDCT coefficients,
- wherein the orthogonal 4×4 DCT includes an odd portion that applies first and second internal factors (C, S) that are related to a scaled factor (ξ) such that the scaled factor equals a square root of a sum of a square of the first internal factor (C) plus a square of the second internal factor (S), the first and second internal factors (C, S) are co-prime and greater than or equal to two, and
- wherein the means for applying a 4×4 IDCT includes a means for quantization that multiplies the inverse of the scaled factor (ξ) with one or more IDCT coefficients to determine quantized IDCT coefficients.
A non-transitory computer-readable storage medium that stores instructions for encoding media data that, when executed by a processor, cause the processor to:
- apply a 4×4 inverse discrete cosine transform (IDCT) of an orthogonal 4×4 DCT with a 4×4 IDCT hardware unit to DCT coefficients representative of media data to transform the media data from a frequency domain to a spatial domain and to determine one or more IDCT coefficients,
- wherein the orthogonal 4×4 DCT includes an odd portion that applies first and second internal factors (C, S) that are related to a scaled factor (ξ) such that the scaled factor equals a square root of a sum of a square of the first internal factor (C) plus a square of the second internal factor (S), the first and second internal factors (C, S) are co-prime and greater than or equal to two, and
- wherein the 4×4 IDCT hardware unit includes a quantization unit that multiplies the inverse of the scaled factor (ξ) with one or more IDCT coefficients to determine quantized IDCT coefficients.
An apparatus for encoding media data comprising:
- a 4×4 inverse discrete cosine transform (IDCT) hardware unit, wherein the DCT hardware unit implements an inverse DCT of a non-orthogonal 4×4 DCT having an odd portion that applies first and second internal factors (C, S) that are related to a scaled factor (ξ) by the following equation:
- ξ
- =
- C
- +
- S
- ω
- +
- ψ
- ,
- wherein variables ω and ψ denote irrational internal transform factors and variables C and S denote dyadic rational internal transform factors used in place of variables ω and ψ in integer implementations of the non-orthogonal 4×4 DCT, the first and second internal factors (C, S) are co-prime and greater than or equal to two,
- wherein the 4×4 IDCT hardware unit applies the 4×4 IDCT implementation to DCT coefficients representative of media data to transform the media data from a frequency domain to a spatial domain and to determine one or more IDCT coefficients, and
- wherein the 4×4 IDCT hardware unit includes a quantization unit that multiplies the inverse of the scaled factor (ξ) with one or more IDCT coefficients to determine quantized IDCT coefficients.
10 more elements
A method for encoding media data comprising:
- applying a 4×4 inverse discrete cosine transform (IDCT) with a 4×4 IDCT hardware unit to DCT coefficients representative of media data to transform the media data from a frequency domain to a spatial domain and to determine one or more IDCT coefficients,
- wherein the 4×4 IDCT comprises an IDCT of a non-orthogonal 4×4 DCT having an odd portion that applies first and second internal factors (C, S) that are related to a scaled factor (ξ) by the following equation:
- ξ
- =
- C
- +
- S
- ω
- +
- ψ
- ,
- wherein variables ω and ψ denote irrational internal transform factors and variables C and S denote dyadic rational internal transform factors used in place of variables ω and ψ in integer implementations of the non-orthogonal 4×4 DCT, the first and second internal factors (C, S) are co-prime and greater than or equal to two, and
- wherein the 4×4 IDCT hardware unit includes a quantization unit that multiplies the inverse of the scaled factor (ξ) with one or more IDCT coefficients to determine quantized IDCT coefficients.
10 more elements
An apparatus for encoding media data comprising:
- means for applying a 4×4 inverse discrete cosine transform (IDCT) with a 4×4 IDCT hardware unit to DCT coefficients representative of media data to transform the media data from a frequency domain to a spatial domain and to determine one or more IDCT coefficients,
- wherein the 4×4 IDCT comprises an IDCT of a non-orthogonal 4×4 DCT having an odd portion that applies first and second internal factors (C, S) that are related to a scaled factor (ξ) by the following equation:
- ξ
- =
- C
- +
- S
- ω
- +
- ψ
- ,
- wherein variables ω and ψ denote irrational internal transform factors and variables C and S denote dyadic rational internal transform factors used in place of variables ω and ψ in integer implementations of the non-orthogonal 4×4 DCT, the first and second internal factors (C, S) are co-prime and greater than or equal to two, and
- wherein the means for applying a 4×4 IDCT includes a means for quantization that multiplies the inverse of the scaled factor (ξ) with one or more IDCT coefficients to determine quantized IDCT coefficients.
10 more elements
A non-transitory computer-readable storage medium that stores instructions for encoding media data that, when executed by a processor, cause the processor to:
- apply a 4×4 inverse discrete cosine transform (IDCT) with a 4×4 IDCT hardware unit to DCT coefficients representative of media data to transform the media data from a frequency domain to a spatial domain and to determine one or more IDCT coefficients,
- wherein the 4×4 IDCT comprises an IDCT of a non-orthogonal 4×4 DCT having an odd portion that applies first and second internal factors (C, S) that are related to a scaled factor (ξ) by the following equation:
- ξ
- =
- C
- +
- S
- ω
- +
- ψ
- ,
- wherein variables ω and ψ denote irrational internal transform factors and variables C and S denote dyadic rational internal transform factors used in place of variables ω and ψ in integer implementations of the non-orthogonal 4×4 DCT, the first and second internal factors (C, S) are co-prime and greater than or equal to two, and
- wherein the 4×4 IDCT hardware unit includes a quantization unit that multiplies the inverse of the scaled factor (ξ) with one or more IDCT coefficients to determine quantized IDCT coefficients.
10 more elements
An apparatus for encoding media data comprising,
- a 4×4 inverse discrete cosine transform (IDCT) hardware unit that implements an IDCT of a non-orthogonal 4×4 DCT having an odd portion that applies first and second internal factors (A, B) as a part of the 4×4 inverse DCT that are related to a scaled factor by the (ξ) following equation:
- ξ
- =
- A
- +
- B
- 1
- +
- 1
- /
- 2
- ,
- wherein the scaled factor (ξ) equals a sum of the first internal factor (A) plus the second internal factor (B) divided by one plus one divided by the square root of two, the first and second internal factors (A, B) are co-prime and greater than or equal to two,
- wherein the 4×4 IDCT hardware unit applies the 4×4 IDCT implementation to media data to transform the media data from a frequency domain to a spatial domain and to determine one or more IDCT coefficients, and
- wherein the 4×4 IDCT hardware unit includes a quantization unit that multiplies the inverse of the scaled factor (ξ) with one or more IDCT coefficients to determine quantized IDCT coefficients.
12 more elements
A method for encoding media data comprising:
- applying a 4×4 inverse discrete cosine transform (IDCT) with a 4×4 IDCT hardware unit to media data to transform the media data from a frequency domain to a spatial domain and to determine one or more IDCT coefficients,
- wherein the non-orthogonal 4×4 DCT includes an odd portion that applies first and second internal factors (A, B) that are related to a scaled factor (ξ) by the following equation:
- ξ
- =
- A
- +
- B
- 1
- +
- 1
- /
- 2
- ,
- wherein the scaled factor (ξ) equals a sum of the first internal factor (A) plus the second internal factor (B) divided by one plus one divided by the square root of two, the first and second internal factors (A, B) are co-prime and greater than or equal to two, and
- wherein the 4×4 IDCT hardware unit includes a quantization unit that multiplies the inverse of the scaled factor (ξ) with one or more IDCT coefficients to determine quantized IDCT coefficients.
12 more elements
An apparatus for encoding media data comprising:
- means for applying a 4×4 inverse discrete cosine transform (IDCT) with a 4×4 IDCT hardware unit to media data to transform the media data from a frequency domain to a spatial domain and to determine one or more IDCT coefficients,
- wherein the non-orthogonal 4×4 DCT includes an odd portion that applies first and second internal factors (A, B) that are related to a scaled factor (ξ) by the following equation:
- ξ
- =
- A
- +
- B
- 1
- +
- 1
- /
- 2
- ,
- wherein the scaled factor (ξ) equals a sum of the first internal factor (A) plus the second internal factor (B) divided by one plus one divided by the square root of two, the first and second internal factors (A, B) are co-prime and greater than or equal to two, and
- wherein the means for applying a 4×4 IDCT includes a means for quantization that multiplies the inverse of the scaled factor (ξ) with one or more IDCT coefficients to determine quantized IDCT coefficients.
12 more elements
A non-transitory computer-readable storage medium that stores instructions for encoding media data that, when executed by a processor, cause the processor to:
- apply a 4×4 inverse discrete cosine transform (IDCT) with a 4×4 IDCT hardware unit to media data to transform the media data from a frequency domain to a spatial domain and to determine one or more IDCT coefficients,
- wherein the non-orthogonal 4×4 DCT includes an odd portion that applies first and second internal factors (A, B) as a part of the 4×4 DCT that are related to a scaled factor (ξ) by the following equation:
- ξ
- =
- A
- +
- B
- 1
- +
- 1
- /
- 2
- ,
- wherein the scaled factor (ξ) equals a sum of the first internal factor (A) plus the second internal factor (B) divided by one plus one divided by the square root of two the first and second internal factors (A, B) are co-prime and greater than or equal to two, and
- wherein the 4×4 IDCT hardware unit includes a quantization unit that multiplies the inverse of the scaled factor (ξ) with one or more IDCT coefficients to determine quantized IDCT coefficients.
12 more elements
Dependencies are inferred from the claim text.