US 8,526,488 B2Granted

Video sequence encoding system and algorithms

AssigneeVanguard Software Solutions, Inc.

InventorsAlexander Zheludkov, Alexey Martemyanov, Nickolay Terterov, Ivan Minin, Michael Axenov

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Abstract

The video sequence encoding system with high compression efficiency is based on the H.264/AVC international video coding standard and is implementing proposed algorithms for: macroblock motion estimation; simplified rate-distortion optimization for transform size decision-making; acceleration of optimal macroblock type decision; modulation of quantization parameter with look-ahead refinement; and film-grain parameters calculation. The video encoding system comprises a motion estimation unit based on a measurement function for motion search of the matching texture block; a macroblock decision making unit; a pipeline processing module configured to accelerate complex transform; and a quantization parameter modulator configured to enhance the picture quality.

Claims18

Dependent claims

A video codec with high compression efficiency, the video codec comprising:

a macroblock encoding module configured to receive a digitized picture divided into macroblocks, encode at least some of the macroblocks of the picture and output a compressed stream of pixels;
and
a quantization parameter modulator operably coupled to the macroblock encoding module and configured to calculate quantization parameters for the macroblocks;
wherein the macroblock encoding module comprises:
a motion estimation unit configured to estimate macroblock motion based at least in part on a measurement function for motion search of a matching texture block;
and
a macroblock decision-making unit that is responsible to the motion estimation unit and that is configured to optimize selection of macroblock type and transform size;
the measurement function for motion search is calculated as:
W(I,R,M,N,QP,mvx,mvy)=C(I)·(SAD(I,R)+Cost(M,N,mvx,mvy,QP))+M·N·C(R),
where:
M, N—width and height of a current texture block;
I—two-dimensional M×N array of initial texture luminance component values corresponding to the current texture block with elements I(x, y),
where xε[0,M−1], yε[0,N−1];
R—two-dimensional M×N array of texture prediction luminance component values corresponding to a reference texture block with elements R(x, y),
where xε[0,M−1], yε[0,N−1];
QP—a quantization parameter used for video encoding;
mvx,mvy—components of difference between a current motion offset and a current motion vector prediction;
SAD(I, R)—is a Sum of Absolute Differences between corresponding elements of the arrays I and R;
Cost(M,N,mvx,mvy,QP)—a motion vector cost function;
and
C(A)—a complexity function for two-dimensional array A, A corresponding to arrays I or R, respectively:
C
⁡
(
A
)
=
∑
y
=
0
N
-
1
⁢
∑
x
=
0
M
-
1
⁢
F
⁡
(
A
,
x
,
y
,
B
H
⁡
(
x
)
,
B
V
⁡
(
y
)
)
;
where
F(A, x, y, dx, dy) is auxiliary function for a two-dimensional M×N array A;
and
BH(x), BV(y)—boundary indicator functions for first and second indices of the two-dimensional M×N array, which are equal to:
+1, if index equals a minimal value (zero);
−1, if the index equals a maximal value ((M−1) for BH(x) and (N−1) for BV(y));
and 0—otherwise.

71 more elements

A method of video encoding using a codec with high compression efficiency, the method comprising:

dividing an input picture into macroblocks of pixels;
calculating quantization parameters for at least some of the macroblocks;
performing motion estimation based on a measurement function for motion search of a matching texture block;
calculating an optimal macroblock type;
and
selecting an optimal transform size for corresponding macroblock transforms;
wherein the measurement function for motion estimation is calculated as:
W(I,R,M,N,QP,mvx,mvy)=C(I)·(SAD(I,R)+Cost(M,N,mvx,mvy,QP))+M·N·C(R),
where:
M, N—width and height of a current texture block;
I—two-dimensional M×N array of initial texture luminance component values corresponding to the current texture block with elements I(x, y), where xε[0,M−1], yε[0,N−1];
R—two-dimensional M×N array of texture prediction luminance component values corresponding to a reference texture block with elements R(x, y), where xε[0,M−1], yε[0,N−1];
QP—a quantization parameter used for video encoding;
mvx,mvy—components of difference between a current motion offset and a current motion vector prediction;
SAD(I,R)—is a Sum of Absolute Differences between corresponding elements of the arrays I and R;
Cost(M,N,mvx,mvy,QP)—a motion vector cost function;
and
C(A)—a complexity function for two-dimensional array A, A corresponding to arrays I or R, respectively:
C
⁡
(
A
)
=
∑
y
=
0
N
-
1
⁢
∑
x
=
0
M
-
1
⁢
F
⁡
(
A
,
x
,
y
,
B
H
⁡
(
x
)
,
B
V
⁡
(
y
)
)
;
where
F(A, x, y, dx, dy) is auxiliary function for a two-dimensional M×N array A;
and
BH(x), BV(y)—boundary indicator functions for first and second indices of the two-dimensional M×N array, which are equal to:
+1, if index equals a minimal value (zero);
−1, if the index equals a maximal value ((M−1) for BH(x) and (N−1) for BV(y));
and 0—otherwise.

68 more elements

A method of accelerating selection of optimal macroblock type in a video sequence encoder with high compression efficiency, comprising:

defining a two-dimensional 16×16 array of picture luma component values corresponding to a current macroblock MB;
choosing a best mode of Intra 16×16 prediction;
choosing best motion vectors and reference frames of Inter prediction;
calculating two-dimensional 16×16 arrays of texture prediction for luma component values corresponding to current macroblock for Intra 16×16 macroblock type PINTRA—16×16 and for Inter macroblock type PINTER;
calculating two dimensional arrays of differences RINTRA—16×16 between MB and PINTRA—16×16;
calculating two dimensional arrays of differences RINTER between MB and PINTER;
calculating a sum of absolute values SAD(RINTER);
calculating a sum of absolute values SAD(RINTRA—16×16);
calculating an auxiliary complexity function C(MB) as:
C
⁡
(
MB
)
=
∑
k
=
0
N
2
-
1
⁢
∑
j
=
0
N
2
-
1
⁢

MB
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(
2
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j
+
1
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2
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k
+
1
)
-
MB
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2
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j
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2
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k
+
1
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+
MB
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2
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j
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2
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k
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+
MB
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(
2
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j
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1
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2
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k
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+
MB
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min
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N
-
1
,
2
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j
+
2
)
,
2
⁢
k
)
4

where
MB(x,y)—elements of 16×16 two-dimensional macroblock texture array with horizontal coordinate x and vertical coordinate y;
N=16;
and
min (a,b) is the minimum value of a and b;
wherein no testing of Intra 4×4 macroblock type is required, when the following conditions are satisfied:
SAD(RINTER)<M(QP)·log2(C(MB));
and
SAD(RINTRA—16×16)>max(K·SAD(RINTER)+S(QP),T(QP)),
where:
QP is a quantization parameter for the current macroblock;
and
K, M(QP), S(QP), T(QP) are parameters selected based on the encoder compression efficiency and acceleration of decision-making procedure.

123 more elements

Dependencies are inferred from the claim text.

Facts

Application: 13/024,117Filed 9 Feb 2011 · us provisional application
Priority: 9 Feb 2010
Published: US 2011/0194615 A111 Aug 2011
Granted: 3 Sep 2013
Term ends: Not estimatedThe source records don’t support an estimate.

Classification12 codes

H04N 19/85
Methods or arrangements for coding, decoding, compressing or decompressing digital video signals: using pre-processing or post-processing…
H04N 19/107
Selection of coding mode or of prediction mode: between spatial and temporal predictive coding, e.g. picture refresh
H04N 19/122
Selection from among a plurality of transforms or standards, e.g. selection between discrete cosine transform [DCT] and sub-band transform or…:…
H04N 19/124
Characterised by the element, parameter or selection affected or controlled by the adaptive coding: quantisation