EP1047198A2
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EP
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Encoder with optimally selected codebook
Assignee: Panasonic Corp
•
Filing: 2000-04-19
•
Granted: —
•
Expires: 2020-04-19
Abstract
Abstract An encoder of the present invention includes: a number G of storage sections (G is an integer equal to or greater than 1) for storing a number G of groups of data; a Huffman codebook selection section for selecting one of a number H of Huffman codebooks (H is an integer equal to or greater than 1) for each of the groups of data stored in the respective storage sections, each of the Huffman codebooks having a codebook number; a number G of Huffman encoding sections, each of the Huffman encoding sections Huffman-encoding a corresponding one of the G groups of data by using one of the Huffman codebooks which is selected by the Huffman codebook selection section for the one group of data; and a codebook number encoding section for encoding the codebook number of each Huffman codebook selected by the Huffman codebook selection section. The Huffman codebook selection section includes a code length calculation section for calculating a code length which would result from a Huffman encoding operation of each of the G groups of data using each Huffman codebook, and a control section for selecting one of the Huffman codebooks which is suitable for the group of data based on the code length calculated by the code length calculation section. When the Huffman codebook selected is an unsigned codebook, a number of bits required for sign information has previously been added to the code length calculated by the code length calculation section.
Inventors
- 👤 Shuji Miyasaka
- 👤 Takeshi Norimatsu
- 👤 Mineo Tsushima
- 👤 Tomokazu Ishikawa
- 👤 Yoshiaki Sawada
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-01 21:59
CPC Classifications
H; H03; H03M; H03M7/00; H03M7/30; H03M7/40; H03M7/42
Claims Analysis
Total Claims: 36
Claim 1
Independent Claim
243 words
An encoder, comprising: a number G of storage sections (G is an integer equal
to or greater than 1) for storing a number G of groups of
data; a Huffman codebook selection section for selecting
one of a number H of Huffman codebooks (H is an integer equal
to or greater than 1) for each of the groups of data stored
in the respective storage sections, each of the Huffman
codebooks having a codebook number; a number G of Huffman encoding sections, each of the
Huffman encoding sections Huffman-encoding a corresponding
one of the G groups of data by using one of the Huffman
codebooks which is selected by the Huffman codebook
selection section for the one group of data; and a codebook number encoding section for encoding the
codebook number of each Huffman codebook selected by the
Huffman codebook selection section, wherein: the Huffman codebook selection section includes a
code length calculation section for calculating a code
length which would result from a Huffman encoding operation
of each of the G groups of data using each Huffman codebook,
and a control section for selecting one of the Huffman
codebooks which is suitable for the group of data based on
the code length calculated by the code length calculation
section; and when the Huffman codebook selected is an unsigned
codebook, a number of bits required for sign information
has previously been added to the code length calculated by
the code length calculation section.
Claim 2
Dependent Claim
27 words
An encoder according to claim 1, wherein the code length
calculation section has a table of data including a code
length previously calculated for each Huffman codebook.
Claim 3
Dependent Claim
228 words
An encoder, comprising: a number G of storage sections (G is an integer equal
to or greater than 1) storing a number G of groups of data; a Huffman codebook selection section for selecting
one of a number H of Huffman codebooks (H is an integer equal
to or greater than 1) for each of the groups of data stored
in the respective storage sections, each of the Huffman
codebooks having a codebook number; a number G of Huffman encoding sections, each of the
Huffman encoding sections Huffman-encoding a corresponding
one of the G groups of data by using one of the Huffman
codebooks which is selected by the Huffman codebook
selection section for the one group of data; and a codebook number encoding section for encoding the
codebook number of each Huffman codebook selected by the
Huffman codebook selection section, wherein: the Huffman codebook selection section includes a
code length calculation section for calculating a code
length which would result from a Huffman encoding operation
of each of the G groups of data using each Huffman codebook,
and a control section for selecting one of the Huffman
codebooks which is suitable for the group of data based on
the code length calculated by the code length calculation
section; and the code length calculation section is capable of
simultaneously obtaining code lengths for a plurality of
Huffman codebooks.
Claim 4
Dependent Claim
62 words
An encoder according to claim 3, wherein: the code length calculation section is adapted to
output respective code lengths which would result from
Huffman encoding operations of the one group of data, for
a plurality of Huffman codebooks; and the control section selects one of the Huffman
codebooks for which a smallest code length is output from
the code length calculation section.
Claim 5
Dependent Claim
75 words
An encoder according to claim 3, wherein: the code length calculation section is adapted to
output respective code lengths which would result from
Huffman encoding operations of the one group of data, for
a plurality of Huffman codebooks; and the control section selects one of the Huffman
codebooks based on the code length of the Huffman codebook
output from the code length calculation section and in view
of the codebook number of the Huffman codebook.
Claim 6
Dependent Claim
145 words
An encoder according to claim 5, wherein the control
section selects one of the Huffman codebooks for a (g+1) th group of data (g is an integer such that 1≤g≤G-1) by first
obtaining a code length Bmin and another code length Bg,
the code length Bmin being a code length which would result
from a Huffman encoding operation of the (g+1) th group of
data using a Huffman codebook Hmin for which a smallest code
length is output from the code length calculation section,
and the code length Bg being a code length which would result
from a Huffman encoding operation of a g th group of data using
a Huffman codebook Hg which has been selected for the g th group of data, and then selecting the Huffman codebook Hmin
if Bmin<(Bg-A) (A is a predetermined integer) or the Huffman
codebook Hg if Bmin≥(Bg-A).
Claim 7
Dependent Claim
40 words
An encoder according to claim 6, wherein the control
section selects one of the Huffman codebooks for which a
smallest code length is output from the code length
calculation section as a Huffman codebook for a first group
of data.
Claim 8
Dependent Claim
145 words
An encoder according to claim 5, wherein the control
section selects one of the Huffman codebooks for a (g-1) th group of data (g is an integer such that 2≤g≤G) by first
obtaining a code length Bmin and another code length Bg,
the code length Bmin being a code length which would result
from a Huffman encoding operation of the (g-1) th group of
data using a Huffman codebook Hmin for which a smallest code
length is output from the code length calculation section,
and the code length Bg being a code length which would result
from a Huffman encoding operation of a g th group of data using
a Huffman codebook Hg which has been selected for the g th group of data, and then selecting the Huffman codebook Hmin
if Bmin<(Bg-A) (A is a predetermined integer) or the Huffman
codebook Hg if Bmin≥(Bg-A).
Claim 9
Dependent Claim
41 words
An encoder according to claim 8, wherein the control
section selects one of the Huffman codebooks for which a
smallest code length is output from the code length
calculation section as a Huffman codebook for a G th group
of data.
Claim 10
Dependent Claim
55 words
An encoder according to claim 6, wherein when a same
Huffman codebook is selected for two or more contiguous
groups of data, the codebook number encoding section encodes
the codebook number of the Huffman codebook and the number
of the contiguous groups of data with a number of bits equal
to the predetermined integer A.
Claim 11
Dependent Claim
27 words
An encoder according to claim 3, wherein the H Huffman
codebooks are eleven Huffman codebooks used for Huffman-encoding
of spectral data as defined in the MPEG2-AAC
standard.
Claim 12
Dependent Claim
92 words
An encoder according to claim 11, wherein: the code length calculation section is adapted to
output respective code lengths which would result when
encoding data using Huffman codebooks 1-4 defined in the
MPEG2-AAC standard; and the code length calculation section has a first
table including respective code lengths which would result
when encoding data by using Huffman codebooks 1 and 2 for
a common index value and a second table including respective
code lengths which would result when encoding data by using
Huffman codebooks 3 and 4 for the common index value.
Claim 13
Dependent Claim
38 words
An encoder according to claim 12, wherein a number of
bits required for sign information has previously been added
to each of the code lengths for Huffman codebooks 3 and 4
which are included in the second table.
Claim 14
Dependent Claim
219 words
An encoder according to claim 13, wherein the first
table includes respective values of T1(F1(a, b, c, d)) and
T2(F1(a, b, c, d)) for i1, and the second table includes
respective values of T3(F2(a, b, c, d)) + nonz(a, b, c, d)
and T4(F2(a, b, c, d)) + nonz(a, b, c, d) for i2, where: nonz(w, x, y, z) is a function which gives the number
of non-zero values among w, x, y and z; F1(w, x, y, z) is a function defined as follows: F1(w,
x, y, z) = 27*(w+1) + 9*(x+1) + 3*(y+1) + (z+1) (where an
absolute value of each of w, x, y and z is 1 or less); F2(w, x, y, z) is a function defined as follows: F2(w, x, y, z) = 27*abs(w) + 9*abs(x) + 3*abs(y) + abs(z) (where
an absolute value of each of w, x, y and z is 2 or less); abs(x) is a function which gives an absolute value
of x; T1(index) to T4(index) are each a function which
gives a code length which would result when encoding data
by using Huffman codebooks 1 to 4, respectively; a, b, c and d are integers representing a group of
data; and i1 and i2 are index values calculated as a function
of the integers a, b, c and d.
Claim 15
Dependent Claim
54 words
An encoder according to claim 14, wherein: i1 = (X^3)*(a+1) + (X^2)*(b+1) + X*(c+1) + (d+1),
where X is a positive number equal to or greater than 3; i2 = (Y^3)*abs(a) + (Y^2)*abs(b) +Y*abs(c) +abs(d),
where Y is a positive number equal to or greater than 3;
and the symbol "^" denotes an exponentiation.
Claim 16
Dependent Claim
86 words
An encoder according to claim 14, wherein: the index value i1 is obtained through a bit connecting
operation of a, b, c and d each of which is represented
with X bits or more, where X is a positive number equal to
or greater than 2; and the index value i2 is obtained through a bit connecting
operation of abs(a), abs(b), abs(c) and abs(d) each
of which is represented with Y bits or more, where Y is a
positive number equal to or greater than 2.
Claim 17
Dependent Claim
67 words
An encoder according to claim 11, wherein: the code length calculation section is adapted to
output respective code lengths which would result when
encoding data using Huffman codebooks 1-4 defined in the
MPEG2-AAC standard; and the code length calculation section has a table of
data including respective code lengths which would result
when encoding data by using Huffman codebooks 1 to 4 for
a common index value.
Claim 18
Dependent Claim
37 words
An encoder according to claim 17, wherein a number of
bits required for sign information has previously been added
to each of the code lengths for Huffman codebooks 3 and 4
which are included in the table.
Claim 19
Dependent Claim
206 words
An encoder according to claim 18, wherein the table
includes respective values of T1(F1(a, b, c, d)), T2(F1(a,
b, c, d)), T3(F2(a, b, a, d)) + nonz(a, b, c, d) and T4(F2(a,
b, a, d)) + nonz(a, b, a, d) for j, where: nonz(w, x, y, z) is a function which gives the number
of non-zero values among w, x, y and z; F1(w, x, y, z) is a function defined as follows: F1(w,
x, y, z) = 27*(w+1) + 9*(x+1) + 3*(y+1) + (z+1) (where an
absolute value of each of w, x, y and z is 1 or less); F2(w, x, y, z) is a function defined as follows: F2(w,
x, y, z) = 27*abs(w) + 9*abs(x) + 3*abs(y) + abs(z) (where
an absolute value of each of w, x, y and z is 2 or less); abs(x) is a function which gives an absolute value
of x; T1(index) to T4(index) are each a function which
gives a code length which would result when encoding data
by using Huffman codebooks 1 to 4, respectively; a, b, c and d are integers representing a group of
data; and j is an index value calculated as a function of the
integers a, b, c and d.
Claim 20
Dependent Claim
46 words
An encoder according to claim 19, wherein the index
value j is obtained through a bit connecting operation of
a, b, c and d each of which is represented with Y bits or
more, where Y is a positive number equal to or greater than
2.
Claim 21
Dependent Claim
117 words
An encoder according to claim 11, wherein: the code length calculation section is adapted to
output respective code lengths which would result when
encoding data using Huffman codebooks 5-10 defined in the
MPEG2-AAC standard; and the code length calculation section has a first
table including respective code lengths which would result
when encoding data by using Huffman codebooks 5 and 6 for
a common index value, a second table including respective
code lengths which would result when encoding data by using
Huffman codebooks 7 and 8 for a common index value, and a
third table including respective code lengths which would
result when encoding data by using Huffman codebooks 9 and
10 for a common index value.
Claim 22
Dependent Claim
70 words
An encoder according to claim 21, wherein: a number of bits required for sign information has
previously been added to each of the code lengths for Huffman
codebooks 7 and 8 which are included in the second table;
and a number of bits required for sign information has
previously been added to each of the code lengths for Huffman
codebooks 9 and 10 which are included in the third table.
Claim 23
Dependent Claim
234 words
An encoder according to claim 22, wherein the first
table includes respective values of T5(F3(a, b)) and T6(F3(a,
b)) for i3, the second table includes respective values of
T7(F4(a, b)) + nonz(a, b) and T8(F4(a, b)) + nonz(a, b) for
i4, and the third table includes respective values of T9(F5(a,
b)) + nonz(a, b) and T10(F5(a, b)) + nonz(a, b) for i5, where: nonz(x, y) is a function which gives the number of
non-zero values among x and y; F3(x, y) is a function defined as follows: F3(x, y)
= 9*(x+4) + (y+4) (where an absolute value of each of x and
y is 4 or less); F4(x, y) is a function defined as follows: F4(x, y)
= 8*abs(x) + abs(y) (where an absolute value of each of x
and y is 7 or less); F5(x, y) is a function defined as follows: F5(x, y)
= 13*abs(x) + abs(y) (where an absolute value of each of
x and y is 12 or less); abs(x) is a function which gives an absolute value
of x; T5(index) to T10 (index) are each a function which
gives a code length which would result when encoding data
by using Huffman codebooks 5 to 10 defined in the MPEG2-AAC
standard, respectively; a and b are integers representing a group of data;
and i3, i4 and i5 are index values calculated as a
function of the integers a and b.
Claim 24
Dependent Claim
62 words
An encoder according to claim 23, wherein: i3 = X*(a+4) + (b+4) , where X is a positive number
equal to or greater than 9; i4 = Y*abs(a) + abs(b) , where Y is a positive number
equal to or greater than 8; and i5 = Z*abs(a) + abs(b) , where Z is a positive number
equal to or greater than 13.
Claim 25
Dependent Claim
119 words
An encoder according to claim 24, wherein: the index value i3 is obtained through a bit connecting
operation of a and b each of which is represented
with X bits or more, where X is a positive number equal to
or greater than 4; the index value i4 is obtained through a bit connecting
operation of a and b each of which is represented
with Y bits or more, where Y is a positive number equal to
or greater than 4; and the index value i5 is obtained through a bit connecting
operation of a and b each of which is represented
with Z bits or more, where Z is a positive number equal to
or greater than 5.
Claim 26
Dependent Claim
65 words
An encoder according to claim 11, wherein: the code length calculation section is adapted to
output respective code lengths which would result when
encoding data using Huffman codebooks 5-10 defined in the
MPEG2-AAC standard; and the code length calculation section has a table
including respective code lengths which would result when
encoding data by using Huffman codebooks 5 to 10 for a common
index value.
Claim 27
Dependent Claim
37 words
An encoder according to claim 26, wherein a number of
bits required for sign information has previously been added
to each of the code lengths for Huffman codebooks 7 to 10
which are included in the table.
Claim 28
Dependent Claim
209 words
An encoder according to claim 27, wherein the table
includes respective values of T5(F3(a, b)), T6(F3(a, b)),
T7(F4(a, b)) + nonz(a, b), T8(F4(a, b)) + nonz(a, b), T9(F5(a,
b)) + nonz(a, b) and T10(F5(a, b)) + nonz(a, b) for k, where: nonz(x, y) is a function which gives the number of
non-zero values among x and y; F3(x, y) is a function defined as follows: F3(x, y)
= 9*(x+4) + (y+4) (where an absolute value of each of x and
y is 4 or less); F4(x, y) is a function defined as follows: F4(x, y)
= 8*abs(x) + abs(y) (where an absolute value of each of x
and y is 7 or less); F5(x, y) is a function defined as follows: F5(x, y)
= 13*abs(x) + abs(y) (where an absolute value of each of
x and y is 12 or less); abs(x) is a function which gives an absolute value
of x; T5(index) to T10(index) are each a function which
gives a code length which would result when encoding data
by using Huffman codebooks 5 to 10 defined in the MPEG2-AAC
standard, respectively; a and b are integers representing a group of data;
and k is an index value calculated as a function of the
integers a and b.
Claim 29
Dependent Claim
44 words
An encoder according to claim 28, wherein the index
value k is obtained through a bit connecting operation of
a and b each of which is represented with Z bits or more,
where Z is a positive number equal to or greater than 5.
Claim 30
Dependent Claim
73 words
An encoder according to claim 3, wherein: the code length calculation section is adapted to
output an invalid signal which indicates that a Huffman
codebook is invalid when an input data value is outside a
variable range within which a code length can be calculated
using the Huffman codebook; and the control section is adapted not to select a
Huffman codebook when the control section receives an
invalid signal for the Huffman codebook.
Claim 31
Dependent Claim
145 words
An encoder according to claim 14, wherein: the value of the function T1(F1(a, b, c, d)) and the
value of the function T2(F1(a, b, c, d)) are stored
respectively on a MSB side and on a LSB side with respect
to the index value i1, with at least m1 bits of "0" (ml is
a positive integer) being inserted between the value of the
function T1 and the value of the function T2; and the value of the function T3(F2(a, b, c, d)) + nonz(a,
b, c, d) and the value of the function T4(F2(a, b, c, d))
+ nonz(a, b, c, d) are stored respectively on a MSB side
and on a LSB side with respect to the index value i2, with
at least m1 bits of "0" being inserted between the value
of the function T3 and the value of the function T4.
Claim 32
Dependent Claim
119 words
An encoder according to claim 19, wherein: the value of the function T1(F1(a, b. c, d)), the
value of the function T2(F1(a, b, c, d)), the value of the
function T3(F2(a, b, c, d)) + nonz(a, b, c, d) and the value
of the function T4(F2(a, b, c, d)) + nonz(a, b, c, d) are
stored in this order from a MSB side to a LSB side with respect
to the index value j, with at least m1 bits of "0" (m1 is
a positive integer) being inserted between the value of T1
and the value of T2, between the value of T2 and the value
of T3, and between the value of T3 and the value of T4.
Claim 33
Dependent Claim
59 words
An encoder according to claim 31, wherein the value of
m1 is an integer value obtained by rounding up a value of
the logarithm of 2 to the base of n1 (log 2 (n1)), where n1
is a value obtained by dividing a maximum number of data
included in each group among the G groups of data by 4.
Claim 34
Dependent Claim
196 words
An encoder according to claim 23, wherein: the value of the function T5(F3(a, b)) and the value
of the function T6(F3(a, b)) are stored respectively on a
MSB side and on a LSB side with respect to the index value i3,
with at least m2 bits of 0" (m2 is a positive integer) being
inserted between the value of the function T5 and the value
of the function T6; the value of the function T7(F4(a, b)) + nonz(a, b)
and the value of the function T8(F4(a, b)) + nonz(a, b) are
stored respectively on a MSB side and on a LSB side with
respect to the index value i4, with at least m2 bits of "0"
being inserted between the value of the function T7 and the
value of the function T8; and the value of the function T9(F5(a, b)) + nonz(a, b)
and the value of the function T10(F5(a, b)) + nonz(a, b)
are stored respectively on a MSB side and on a LSB side with
respect to the index value i5, with at least m2 bits of "0"
being inserted between the value of the function T9 and the
value of the function T10.
Claim 35
Dependent Claim
147 words
An encoder according to claim 28, wherein the value of
the function T5(F3(a, b)), the value of the function T6(F3(a,
b)), the value of the function T7(F4(a, b)) + nonz(a, b),
the value of the function T8(F4(a, b)) + nonz(a, b), the
value of the function T9(F5(a, b)) + nonz(a, b) and the value
of the function T10(F5(a, b)) + nonz(a, b) are stored in
this order from a MSB side to a LSB side with respect to
the index value k, with at least m2 bits of "0" (m2 is a
positive integer) being inserted between the value of T5
and the value of T6, between the value of T6 and the value
of T7, between the value of T7 and the value of T8, between
the value of T8 and the value of T9, and between the value
of T9 and the value of T10.
Claim 36
Dependent Claim
59 words
An encoder according to claim 34, wherein the value of
m2 is an integer value obtained by rounding up a value of
the logarithm of 2 to the base of n2 (log 2 (n2)), where n2
is a value obtained by dividing a maximum number of data
included in each group among the G groups of data by 2.
References Cited (Backward Citations)
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