[Technical Field]
[0001]
The present disclosure relates to a
compression/encoding apparatus and method, a decoding
apparatus and method, and a program, and more
particularly, to a compression/encoding apparatus and
method, a decoding apparatus and method, and a program
that allow for provision of a lossless compression
technology with higher compression ratio.
[Background Art]
[0002]
Recent years have seen the emergence of music
delivery using high resolution sound sources, audio data
that offer higher quality than music COs (CO-DAs).
Lossless compression technologies such as FLAC (Free
Lossless Audio Codec) are available for PCM (Pulse Code
Modulation) sound sources including 96 kHz/24 bit and
have found application for delivery.
[0003]
For a one-bit delta-sigma-modulated digital signal
(DSD (Direct Stream Digital) data) rather than a PCM
2 SP366661
digital signal, on the other hand, a lossless compression
technology called DST (Direct Stream Transfer) developed
by Philips is available and used to create a Super Audio
CD (SACD) disc.
[0004]
However, this technology is based on one-bit signal
processing and is not fit for software processing using a
CPU that is based on byte-by-byte processing. Therefore,
this technology is implemented in hardware (LSI) in SACD
players and so on. It is difficult for an ordinary
embedded CPU to handle processing using software due to a
heavy processing load.
[0005]
Therefore, in the case where audio signals are
delivered using DSD data, a lossless compression
technology is required that allows even an ordinary
embedded CPU to handle processing in consideration of
execution by a mobile terminal.
[0006]
The present applicant has proposed, as an audio
signal lossless compression technology using DSD data, a
technology for referring to past data, four bits by four
bits, and compressing current data into two bits in PTL 1.
[Citation List]
[Patent Literature]
[0007]
[ PTL 1]
3
Japanese Patent Laid-Open No. H9-74358
[Summary]
[Technical Problem]
[0008]
SP366661
However, the technique disclosed in PTL 1 does not
offer a particularly high data compression ratio, and a
lossless compression technology that offers a higher
compression ratio is required.
[0009]
The present disclosure has been made in the light
of such a situation, and is intended to provide a
lossless compression technology that offers a higher
compression ratio.
[Solution to Problem]
[0010]
A. compression/encoding apparatus of a first aspect
of the present disclosure includes a GOB data
configuration section, a table generation section, and an
encoding section. The GOB data configuration section
configures GOB data with a group of digital data that
includes a plurulity of blocks by treating a frame of
delta-sigma-modulated digital data as a block. The table
generation section generates a conversion table for
4 SP366661
encoding the GOB data. The encoding section compresses
and encodes the digital data of each block included rn
the GOB data by using the conversion table.
[0011]
A compression/encoding method of the first aspect
of the present disclosure includes a step in which a
compression/encoding apparatus configures GOB data with a
group of digital data that includes a plurality of blocks
by treating a frame of delta-sigma-modulated digital data
as a block, generates a conversion table for encoding the
GOB data, and compresses and encodes the digital data of
each block included in the GOB data by using the
conversion table.
[0012]
A program of the first aspect of the present
disclosure causes a computer to function as a GOB data
configuration section, a table generation section, and an
encoding section. The GOB data configuration section
configures GOB data with a group of digital data that
includes a plurality of blocks by treating a frame of
delta-sigma-modulated digital data as a block. The table
generation section generates a conversion table for
encoding the GOB data. The encoding section compresses
and encodes the digital data of each block included in
the GOB data by using the conversion table.
SP366661
[0013]
In the first aspect of the present disclosure, GOB
data are configured with a group of digital data that
includes a plurality of blocks by treating a frame of
delta-sigma-modulated digital data as a block, a
conversion table is generated for encoding the GOB data,
and the digital data of each block included in the GOB
data are compressed and encoded by using the conversion
table.
[0014]
A decoding apparatus of a second aspect of the
present disclosure includes a data acquisition section
and a decoding section. The data acquisition section
acquires compressed GOB data that include a conversion
table and compressed data or uncompressed data. The
conversion table has been used for encoding GOB data that
include a group of digital data including a plurality of
blocks by treating a frame of delta-sigma-modulated
digital data as a block. The compressed data have been
obtained by compressing and encoding the digital data in
each block of the GOB data by using the conversion table.
The decoding section decodes, in the case where the
digital data in each block of the compressed GOB data are
the compressed data, the compressed data by using the
conversion table.
-
6 SP366661
[0015]
A decoding method of the second aspect of the
present disclosure includes a step in which a decoding
apparatus acquires compressed GOB data that include a
conversion table and compressed data or uncompressed data.
The conversion table has been used for encoding GOB data
that include a group of digital data including a
plurality of blocks by treating a frame of delta-sigmamodulated
digital data as a block. The compressed data
have been obtained by compressing and encoding the
digital data in each block of the GOB data by using the
conversion table. The decoding method includes a step in
which the decoding apparatus decodes, in the case where
the digital data in each block of the compressed GOB data
are the compressed data, the compressed data by using the
conversion table.
[0016]
A program of the second aspect of the present
disclosure causes a computer to function as a data
acquisition section and a decoding section. The data
acquisition section acquires compressed GOB data that
include a conversion table and compressed data or
uncompressed data. The conversion table has been used for
encoding GOB data that include a group of digital data
including a plurality of blocks by treating a frame of
7 SP366661
delta~sigma-modulated digital data as a block. The
compressed data have been obtained by compressing and
encoding the digital data in each block of the GOB data
by using the conversion table. The decoding section
decodes, in the case where the digital data in each block
of the compressed GOB data are the compressed data, the
compressed data by using the conversion table.
[0017]
In the second aspect of the present disclosure,
compressed GOB data are acquired that includes a
conversion table and compressed data or uncompressed data.
The conversion table has been used for encoding GOB data
that include a group of digital data including a
plurality of blocks by treating a frame of delta-sigmamodulated
digital data as a block. The compressed data
have been obtained by compressing and encoding the
digital data in each block of the GOB data by using the
conversion table. The compressed data are decoded by
using the conversion table in the case where the digital
data in each block of the compressed GOB data are the
compressed data.
[0018]
It should be noted that a program can be provided
by transmitting it through a transmission medium or by
recording it on a recording medium.
8 SP366661
[0019]
The compression/encoding apparatus and the decoding
apparatus may be independent apparatuses or may be
internal blocks included in a single apparatus.
[Advantageous Effect of Invention]
[0020]
According to the first and second aspects of the
present disclosure, it is possible to provide a lossless
compression technology with higher compression ratio.
[0021]
It should be noted that the effects described
herein are not necessarily limited and may be any one of
the effects described in this disclosure.
[Brief Description of Drawings]
[0022]
[Fig. 1]
Fig. 1 is a block diagram illustrating a
configuration example of a compression/encoding apparatus
according to the present disclosure.
[Fig. 2]
Fig. 2 is a block diagram illustrating detailed
configurations of a DSD data generation section and a DSD
data encoding section.
[Fig. 3]
Fig. 3 is a diagram describing a preparation method
9 SP366661
of a data occurrence count table.
[Fig. 4]
Fig. 4 is a diagram describing a conversion table.
[Fig. S]
Fig. S is a block diagram illustrating a
configuration example of an encoding section.
[Fig. 6]
Fig. 6 is a flowchart describing a GOB data
compressron and encoding process.
[Fig. 7]
Fig. 7 is a diagram describing a configuration of a
DSD lossless payload.
[Fig. 8]
Fig. 8 is a diagram illustrating a syntax example
of DSD lossless_payload()
[Fig. 9]
Fig. 9 is a diagram illustrating a syntax example
of DSD lossless gob configuration()
[Fig. 10]
Fig. 10 is a diagram illustrating a syntax example
of DSD lossless gob().
[Fig. 11]
Fig. 11 is a diagram illustrating a syntax example
of DSD lossless gob header().
[Fig. 12]
10 SP366661
Fig. 12 is a diagram illustrating a syntax example
of DSD lossless gob data().
[Fig. 13]
Fig. 13 is a diagram illustrating a configuration
of each block.
[Fig. 14]
Fig. 14 is a diagram illustrating a syntax example
of DSD lossless_block().
[Fig. 15]
Fig. 15 is a diagram illustrating a syntax example
of DSD frame header().
[Fig. 16]
Fig. 16 is a flowchart describing a DSD data
transmission process.
[Fig. 17]
Fig. 17 is a block diagram illustrating a
configuration example of a decoding apparatus according
to the present disclosure.
[Fig. 18]
Fig. 18 is a block diagram illustrating a detailed
configuration of a DSD data decoding section.
[Fig. 19]
Fig. 19 is a flowchart describing a GOB data
decoding process.
[Fig. 20]
11 SP366661
Fig. 20 is a flowchart describing a DSD data
reception process.
[Fig. 21]
Fig. 21 is a block diagram illustrating a
configuration example of an embodiment of a computer to
which the present technology is applied.
[Description of Embodiment]
[0023]
A description will be given below of a mode for
carrying out the present technology (hereinafter referred
to as an embodiment). It should be noted that the
description will be given in the following order:
1. Compression/encoding apparatus (apparatus for
generating and compressing and encoding DSD data)
2. Decoding apparatus (apparatus for decoding DSD data
that have been compressed and encoded by the
compression/encoding apparatus)
3. Computer configuration example
[0024]
<1. Compression/Encoding Apparatus>

Fig. 1 is a block diagram illustrating a
configuration example of a compression/encoding apparatus
according to the present disclosure.
[0025]
- ---- ---
12 SP366661
A compression/encoding apparatus 100 illustrated in
Fig. 1 converts an analog audio signal into a digital
signal through sigma-delta modulation, compresses and
encodes the converted audio signal, and outputs the
compressed and encoded signal.
[0026]
The compression/encoding apparatus 100 includes a
DSD data generation section 121, a GOB data configuration
section 122, a DSD data encoding section 123, a payload
generation section 124, and a data transmission section
125.
[0027]
The DSD data generation section 121 generates DSD
data, a digital signal delta-sigma-modulated by a one-bit
signal, by digitizing (performing A/D conversion on} an
input analog audio signal through sigma-delta modulation,
and outputs DSD data to the GOB data configuration
section 122.
[0028]
The GOB data configuration section 122 treats a
frame of DSD data supplied from the DSD data generation
section 121 as a block and configures a group (GOB: Group
of Blocks} of DSD data using a plurality of blocks of DSD
data. Then, the GOB data configuration section 122
outputs a group of configured DSD data (hereinafter also
13 SP366661
referred to as GOB data) to the DSD data encoding section
123.
[0029]
Here, one frame is a unit that divides an audio
signal into given time intervals (time periods) and
regards each as a chunk. In the present embodiment,
131072 bits worth of data whose reproduction time is 46
milliseconds is one frame. Also, one-frame audio signal
includes R-channel and L-channel stereo (two-channel)
audio signal.
[0030]
The DSD data generation section 121 converts an
analog signal into a one-bit digital signal, for example,
at a sampling frequency (2.8 MHz) 64 times the CD
sampling frequency 44.1 kHz used for Super Audio CD
(SACD). The GOB data configuration section 122 divides
that 2.8 MHz DSD data into frame units, treats each unit
as a block, and puts together the blocks into units of 10
blocks each. Then, the GOB data configuration section 122
outputs GOB data including 10 blocks of DSD data to the
DSD data encoding section 123.
[0031]
The DSD data encoding section 123 compresses and
encodes the GOB data supplied from the GOB data
configuration section 122 and outputs compressed encoded
14 SP366661
data to the payload generation section 124. Although
compression and encoding performed by the DSD data
encoding section 123 will be described in detail later,
the DSD data encoding section 123 performs lossless
compression (reversible compression) of GOB data that
include 10 blocks of DSD data on a block-by-block basis.
[0032]
The payload generation section 124 generates a DSD
lossless payload from the compressed encoded data
supplied from the DSD data encoding section 123 and
outputs the DSD lossless payload to the data transmission
section 125. The DSD lossless payload includes compressed
data obtained by reversibly compressing each block of DSD
data, a conversion table tablel used for compression and
encoding thereof, and so on as will be described later.
[0033]
DSD lossless payloads obtained by compressing and
encoding a group (GOB) of DSD data are successively
supplied from the payload generation section 124. The
data transmission section 125 transmits a DSD lossless
stream including a plurality of DSD lossless payloads to
other apparatus (reception apparatus), for example, in a
stream delivery format compliant with the MPEG·-DASH
(Moving Picture Experts Group phase - Dynamic Adaptive
Streaming over HTTP) standard.
15 SP366661
[0034]

Fig. 2 is a block diagram illustrating detailed
configurations of the DSD data generation section 121 and
the DSD data encoding section 123. It should be noted
that Fig. 2 also illustrates the GOB data configuration
section 122.
[0035]
The DSD data generation section 121 includes an
adder 21, an integrator 22, a comparator 23, a one-sample
delay circuit 24, and a one-bit DAC 25.
[0036]
An input analog audio signal is supplied to the
adder 21. The adder 21 adds up a one-sample-period-old
analog audio signal supplied from the one-bit DAC 25 and
the input audio signal and outputs the resultant signal
to the integrator 22.
[0037]
The integrator 22 integrates the audio signal from
the adder 21 and outputs the resultant signal to the
comparator 23. The comparator 23 performs one-bit
quantization by comparing the integrated audio signal
with a midpoint of the input audio signal. As a sampling
period frequency (sampling frequency), a frequency 64 or
128 times 48 kHz or 44.1 kHz, a conventional frequency,
16 SP366661
is used. The comparator 23 outputs the one-bit quantized
audio signal to the GOB data configuration section 122
and supplies the one-bit quantized audio signal to the
one-sample delay circuit 24.
[0038]
The one-sample delay circuit 24 delays the audio
signal from the comparator 23 by one sample period and
outputs the delayed signal to the one-bit DAC 25. The
one-bit DAC 25 converts the digital signal from the onesample
delay circuit 24 into an analog signal and outputs
the analog signal to the adder 21.
[0039]
The DSD data generation section 121 configured as
described above converts the input audio signal into a
one-bit digital signal (performs A/D conversion) and
outputs the one-bit digital signal to the GOB data
configuration section 122. This A/D conversion through
sigma-delta modulation allows for a digital audio signal
with a wide dynamic range to be acquired even in the case
of a small bit count such as one bit by increasing the
sampling period frequency (sampling frequency) to a
sufficiently high level.
[0040]
In the present embodiment, a stereo (two-channel)
audio signal is input to the DSD data generation section
17 SP366661
121, and the DSD data generation section 121 performs A/D
conversion at a sampling frequency 64 times 44.1 kHz to
convert the audio signal into a one-bit signal (DSD data)
and outputs the resultant signal to the GOB data
configuration section 122.
[0041]
It should be noted that the quantization bit count
may be two bits or four bits in sigma-delta modulation.
[0042]
The GOB data configuration section 122 temporarily
accumulates the DSD data supplied from the DSD data
generation section 121 and supplies the DSD data, GOB by
GOB, to the DSD data encoding section 123 at the
subsequent stage. As described above, a GOB includes, for
example, 10 blocks, and one block is, for example, 131072
bits worth of data whose reproduction time is 46
milliseconds. It should be noted that, needless to say,
the number of blocks included in a GOB and the number of
bits of DSD data included in one block are not limited
thereto, and desired values can be specified.
[0043]
The DSD data encoding section 123 has a control
section 31, an encoding section 32, an encoded data
buffer 33, and a data volume comparison section 34.
[0044]
18 SP366661
The control section 31 controls the overall
operation of the DSD data encoding section 123. Also, the
control section 31 has a function to prepare the
conversion table table1 necessary for compression and
encoding handled by the encoding section 32 and supply
the conversion table to the encoding section 32.
[0045]
Specifically, the control section 31 prepares a
data occurrence count table pretable by using the GOB
data supplied from the GOB data configuration section 122
and further prepares the conversion table table1 from the
data occurrence count table pretable. The control section
31 supplies the prepared conversion table tablel to the
encoding section 32 and the payload generation section
124 at the subsequent stage. The conversion table table1
is prepared (updated), GOB by GOB, and supplied to the
encoding section 32 and the payload generation section
124.
[0046]
The encoding section 32 compresses and encodes,
four bits by four bits, each block of DSD data supplied
from the GOB data configuration section 122, by using the
conversion table table1 supplied from the control section
31. Therefore, GOB data (10 blocks of DSD data) are
supplied to the encoding section 32 from the GOB data
19 SP366661
configuration section 122 simultaneously with the supply
of GOB data to the control section 31. However, the
encoding section 32 does not proceed with compression and
encoding until the conversion table tablel is supplied
from the control section 31.
[0047]
Although compression and encoding will be described
in detail later with reference to Figs. 3 to 5, the
encoding section 32 encodes four-bit DSD data into twobit
data or six-bit data and outputs the encoded data to
the encoded data buffer 33.
[0048]
The encoded data buffer 33 temporarily buffers the
compressed data, DSD data compressed and encoded by the
encoding section 32 and supplies the data to the data
volume comparison section 34 and the payload generation
section 124.
[0049]
The data volume comparison section 34 compares,
block by block, the DSD data (hereinafter also referred
to as uncompressed data) supplied from the GOB data
configuration section 122 with the compressed data
supplied from the encoded data buffer 33 in terms of data
volume (degree of compression). The reason for this is
that because the encoding section 32 encodes four-bit DSD
20 SP366661
data into two-bit data or six-bit data as described above,
there is a possibility that a post-compression data
volume may exceeds a pre-compression data volume in an
algorithm. Therefore, the data volume comparison section
34 compares compressed data and uncompressed data in
terms of data volume, selects the one with a smaller data
volume, and supplies selection control data indicating
which has been selected to the payload generation section
124. It should be noted that in the case where the data
volume comparison section 34 supplies, to the payload
generation section 124, selection control data indicating
that uncompressed data have been selected, the data
volume comparison section 34 also supplies uncompressed
data to the payload generation section 124. It can be
said that selection control data are, as viewed from the
apparatus on the receiving side of transmission data, a
flag indicating whether or not audio data sent from the
payload generation section 124 is data compressed and
encoded by the encoding section 32.
[0050]
Data (compressed or uncompressed) of each of the 10
blocks included in the GOB, selection control data
indicating whether the data are compressed or
uncompressed, and the conversion table table1 used for
the 10 blocks included in the GOB are supplied to the
21 SP366661
payload generation section 124 from the DSD data encoding
section 123 configured as described above.
[0051]

A description will be given next of DSO data
compression and encoding handled by the OSO data encoding
section 123 with reference to Figs. 3 to 5.
[0052]

A description will be given first of the method by
which the control section 31 prepares the data occurrence
count table pretable.
[0053]
The control section 31 prepares the data occurrence
count table pretable for GOB-by-GOB OSO data and
expresses the GOB-by-GOB DSD data supplied from the GOB
data configuration section 122, four bits by four bits,
as depicted below .
... D4[n-3],04[n-2],04[n-
1], 04 [n], 04 [n+1], D4 [n+2], 04 [n+3]
where 04[n] represents four-bit continuous data and
will be hereinafter also referred to as 04 data (n>3).
[0054]
The control section 31 counts the number of
occurrences of 04 data following the past three pieces of
22 SP366661
04 data (past 12-bit data) and prepares a data occurrence
count table pretable[4096] [16] illustrated in Fig. 3.
Here, "[4096]u and "[l6]u in the data occurrence count
table pretable[4096] [16] indicate that the data
occurrence count table pretable is a table (matrix) with
4096 rows by 16 columns, and each of rows [0] to [4095]
corresponds to the value which can be taken on by the
past three pieces of 04 data (past bit pattern), and each
of columns [0] to [15] corresponds to the value which can
be taken on by the next D4 data.
[0055]
Specifically, pretable [0] [0] to [0] [15], the first
row of the data occurrence count table pretable,
indicates the number of occurrences of next data when
04[n-3], 04[n-2], and 04[n-l], the past three pieces of
D4 data, were "Ou={OOOO,OOOO,OOOO} and indicates that the
number of times the four bits following the past three
pieces of data having "Ou were "Ou was 369a (HEX
notation) and that there was no other data.
[0056]
pretable [ 1] [ 0] to [ 1] [ 15] , the second row of the
data occurrence count table pretable, indicates the
number of occurrences of next data when 04[n-3], D4[n-2],
and 04[n-l], the past three pieces of 04 data, were
"lu={OOOO,OOOO,OOOl}. The fact that all the elements in
23 SP366661
the second row of the data occurrence count table
pretable are "0" indicates that three pieces of D4 data
having "1" as past data did not exist in this one frame.
[0057]
Also, in Fig. 3, pretable[l17] [0] to [117] [15], the
118th row of the data occurrence count table pretable,
indicates the number of occurrences of next data when
D4[n-3], D4[n-2], and D4[n-1], the past three pieces of
D4 data, were "117"~(0000,0111,0101}. This data indicate
that the number of times the four bits following the past
three pieces of data having "117" were "0" was 0, that
the number of times the four bits were "1" was 1, that
the number of times the four bits were "2" was 10, that
the number of times the four bits were "3" was 18, that
the number of times the four bits were "4" was 20, that
the number of times the four bits were "5" was 31, that
the number of times the four bits were "6" was 11, that
the number of times the four bits were "7" was 0, that
the number of times the four bits were "8" was 4, that
the number of times the four bits were "9" was 12, that
the number of times the four bits were "10" was 5, and
that the number of times the four bits were one of "11"
to "15" was 0.
[0058]
The control section 31 counts the number of
24 SP366661
occurrences of 04 data following past three pieces of 04
data (past 12-bit data) for a frame of OSO data and
prepares the data occurrence count table pretable as
described above.
[0059]

A description will be given next of the method by
which the control section 31 prepares the conversion
table table1.
[0060]
The control section 31 prepares a conversion table
table1[4096] [3] with 4096 rows by three columns on the
basis of the data occurrence count table pretable
prepared earlier. Here, each of rows [0] to [4095] of the
conversion table table1[4096] [3] corresponds to the value
which can be taken on by the past three pieces of 04 data,
and columns [0] to [2] store, of the 16 values which can
be taken on by the next 04 data, the three most frequent
values. The first column [0] of the conversion table
table1[4096] [3] stores the most frequent value, the
second column [1] stores the second most frequent value,
and the third column (2] stores the third most frequent
value.
[0061]
Fig. 4 illustrates an example of the conversion
25 SP366661
table tablel[4096] [3] corresponding to the data
occurrence count table pretable illustrated in Fig. 3.
[0062]
tablel[117] [0] to [117] [2] in the 118th row of the
conversion table tablel [4096] [3] reads { 05, 04, 03). This
corresponds to the contents of pretable[ll7] [OJ to
[11 7J [ 15] in the 118th row of the data occurrence count
table pretable illustrated in Fig. 3.
[0063]
The most frequent value in pretable [117] [0] to
[117] [15] in the 118th row of the data28 SP366661
the three values at the addresses (rows) indicated by
04[n-3],04[n-2],04[n-1] of the conversion table
tablel [4096] [3], is the same as 04 [n], and
in the case where tablel [04 [n-3], 04 [n-2], 04 [n-1]] [0] is
the same, converts 04[n] into "Olb,~ two bits,
in the case where tablel[04[n-3],04[n-2],04[n-l]][l] is
the same, converts 04[n] into "lOb,~ two bits, and
in the case where tablel [04 [n-3], 04 [n-2], 04 [n-1]] [2] is
the same, converts 04[n] into "llb,~ two bits.
[0071]
On the other hand, in the case where none of the
three values at the addresses (rows) indicated by 04[n-
3],04[n-2],04[n-l] of the conversion table
tablel[4096] [3], is the same, the encoding section 32
converts 04[n] into six bits such as "00b+04[n]~ by
adding "OOb~ before D4 [n]. Here, 'b' in "Olb, ~ "lOb,"
"llb,~ and "00b+04[n]~ indicates that these are in binary
notation.
[0072]
As described above, the encoding section 32
converts 04[n], four-bit OSD data, into "Olb,~ "lOb,~ or
"llb,~ two-bit data, by using the conversion table tablel
or into "00b+D4[n],~ six-bit data, first, and then
outputs the resultant data to the encoded data buffer 33.
[0073]
29 SP366661

Fig. 5 is a diagram illustrating a configuration
example of the encoding section 32 that handles
compression and encoding described above.
[0074]
Four-bit DSD data (e.g., D4[n]) supplied from the
GOB data configuration section 122 is stored in a
register 51 that holds four bits. Also, an output of the
register 51 is connected to an input terminal 56a, one of
input terminals of a selector 55, and a register 52 that
holds 12 bits. The register 52 holds the past 12-bit data
(e.g., D4[n-3],D4[n-2],D4[n-1]) immediately previous to
the four-bit DSD data stored in the register 51.
[0075]
A cortversion table processing section 53 has the
conversion table table1 supplied from the control section
31.
[0076]
The conversion table processing section 53 makes a
search to determine whether or not the four-bit data
(e.g., D4[n]) held in the register 51 is included in
three values at the addresses indicated by 12-bit data
(e.g., D4[n··3LD4[n-2],D4[n-1]) held in the register 52:
table1 [D4 [n-3], D4 [n-2], D4 [n-1]] [0];
table1 [D4 [n-3], D4 [n-2], D4 [n-1]] [1]; and
30 SP366661
table1 [04 [n-3], 04 [n-2], 04 [n-1]] [2].
In the case where the four-bit data are included, the
conversion table processing section 53 stores the value
corresponding to the column where the same value is held,
i.e., "Olb," "lOb,u or "llb," in a two-bit register 54.
Data stored in the two-bit register 54 are supplied to an
input terminal 56c, one of input terminals of the
selector 55.
[0077]
On the other hand, in the case where the four-bit
data (e.g., D4[n]) held in the register 51 are not
included in any of the three values at the addresses
indicated by 12-bit data (e.g., D4[n-3],D4[n-2],D4[n-l])
held in the register 52, the conversion table processing
section 53 outputs, to the selector 55, a signal
indicating that no conversion will be performed (e.g.,
hereinafter referred to as a conversionless signal).
[0078]
The selector 55 selects one of three input
terminals 56a to 56c and outputs data acquired from the
selected input terminal 56 from an output terminal 57.
[0079]
The input terminal 56a is supplied, for example,
with four-bit DSD data (e.g., D4[n]) stored in the
register 51, and the input terminal 56b is supplied with
31 SP366661
"OOb,u and the input terminal 56c is supplied with twobit
converted data stored in the register 54.
[0080]
In the case where a conversionless signal
indicating that no conversion will be performed is
supplied from the conversion table processing section 53,
the selector 55 selects the input terminal 56b, outputs
"OObu from the output terminal 57, and then, selects the
input terminal 56a, and outputs the four-bit DSD data
(e.g., D4[n]) stored in the register 51 from the output
terminal 57. As a result, "00b+D4[n],u six bits output in
the case where none of the values in the conversion table
tablel is the same as D4[n], is output from the output
terminal 57.
[0081]
On the other hand, in the case where a
conversionless signal indicating that no conversion will
be performed is not supplied (in the case where a
conversion signal indicating that conversion has been
performed is supplied), the selector 55 selects the input
terminal 56c and outputs the two-bit converted data
supplied from the register 54 from the output terminal 57.
As a result, two bits that are output in the case where
the same data as D4[n] are included in the conversion
table tablel, i.e., one of "Olb," ''lOb," and ''llb," are
32 SP366661
output from the output terminal 57.
[0082]

A description will be given of a GOB data
compression/encoding process handled by the DSD data
encoding section 123 with reference to the flowchart
illustrated in Fig. 6.
[0083]
First, in step Sl, the control section 31 counts
the number of occurrences of D4 data following the past
three pieces of D4 data (past 12-bit data) for a group
(GOB) of DSD data and prepares a data occurrence count
table pretable.
[0084]
In step S2, the control section 31 prepares the
conversion table table1 with 4096 rows by three columns
on the basis of the data occurrence count table pretable
prepared. The control section 31 supplies the prepared
conversion table table1 to the encoding section 32 and
the payload generation section 124.
[0085]
In step S3, the encoding section 32 performs
compression and encoding on a block of DSD data by using
the conversion table table1. Specifically, the encoding
section 32 performs, on a block of DSD data, a process of
33 SP366661
converting D4[n], four-bit DSD data, into "Olb," "lOb,"
or "llb," two-bit data, or into "00b+D4[n]," six-bit data.
Compressed data obtained as a result of compression and
encoding are supplied to the encoded data buffer 33 and
the data volume comparison section 34.
[0086]
In step S4, the data volume comparison section 34
compares the block of uncompressed data supplied from the
GOB data configuration section 122 and the block of
compressed data supplied from the encoded data buffer 33
in terms of data volume and decides whether the data
volume has been reduced as compared to before the
compression.
[0087]
In the case where it is decided in step S4 that the
data volume has been reduced as compared to before the
compression, the process proceeds to step SS, and the
data volume comparison section 34 supplies, to the
payload generation section 124, selection control data
indicating that the compressed data have been selected.
[0088]
In step S6, the encoded data buffer 33 supplies, to
the payload generation section 124, compressed data
obtained by compressing and encoding a block of DSD data
by using the conversion table tablel.
34 SP366661
(0089]
On the other hand, in the case where it is decided
in step S4 that the data volume has not been reduced as
compared to before the compression, the process proceeds
to step S7, and the data volume comparison section 34
supplies, together with the uncompressed data to the
payload generation section 124, selection control data
indicating that the uncompressed data have been selected.
(0090]
In step SB, the control section 31 decides whether
a group (GOB) of DSD data has been compressed and encoded.
(0091]
In the case where it is decided in step SB that a
group of DSD data has yet to be compressed and encoded,
the process returns to step S3, and the above processes
in steps S3 to SB are repeated. That is, the next block
of DSD data included in the same GOB is compressed and
encoded by using the same conversion table table1.
(0092]
On the other hand, in the case where it is decided
in step SB that a group of DSD data has been compressed
and encoded, the DSD data encoding section 123 terminates
the compression/encoding process of GOB data.
(0093]

35 SP366661
A description will be given next of generation of a
DSD lossless payload handled by the payload generation
section 124.
[0094]
The payload generation section 124 generates a DSD
lossless payload for a group (GOB) of compressed data
following compression and encoding.
[0095]
Fig. 7 illustrates a configuration of a DSD
lossless payload.
[0096]
As illustrated at the top row in Fig. 7, a DSD
lossless stream corresponding to a piece of content
(music) includes a plurality of DSD lossless payloads
(DSD_lossless_payload()).
[0097]
Then, a DSD lossless payload includes a format
version, a GOB config, and a GOB as illustrated at the
second row in Fig. 7.
[0098]
Fig. 8 illustrates a syntax example of a DSD
lossless payload (DSD_lossless_payload())
[0099]
The version number of the DSD lossless payload is
held in the format version.
36 SP366661
[0100]
It should be noted that, in the syntax examples
illustrated in Fig. 8 and subsequent figures, the value
under "No. of bits" represents the bit count of that
variable, and 'uimsbf' under "Data format" represents
unsigned integer most significant bit first.
[0101]
DSD_lossless gob configuration() in Fig. 8
corresponds to the GOB config in Fig. 7.
[0102]
DSD_lossless gob(number of_audio data) in Fig. 8
corresponds to GOB in Fig. 7. number of audio_data, an
argument of DSD_lossless gob(number of audio data), is
known by DSD lossless gob() that is sent in advance.
[0103]
Fig. 9 illustrates a syntax example of GOB config
(DSD_lossless gob configuration()) in Fig. 7.
[0104]
channel configuration, number of blocks,
sampling frequency, comment flag, comment size,
comment byte, and so on are held in GOB config.
[0105]
The number of channels is defined by
channel configuration. In the present embodiment,
'channel configuration=2' is used.
37 SP366661
[0106]
The number of blocks included in a group is defined
by number of blocks. In the present embodiment, 'number
of blocks~lO' is used.
[0107]
The sampling frequency is defined by
sampling frequency. As a sampling frequency, 64 times
44.1 kHz (2822400 Hz), 128 times 44.1 kHz (5644800 Hz),
or 256 times 44.1 kHz (11289600 Hz) can be adopted. In
the present embodiment, for example,
'sampllng frequency~2822400(44.1Kx64)' is used.
[0108]
The presence or absence of a comment is defined by
comment flag. The comment size is defined by comment size.
The contenL of the comment is held in comment_byte.
[0109]
Next, as illustrated at the third row in Fig. 7,
GOB includes a GOB header, GOB data, and a plurality of
blocks (Blockl, Block2, Block3 and so on). In the present
embodiment, the number of blocks included in a group is
set to 10. Therefore, 10 blocks (Blockl to Block10) are
provided.
[0110]
Fig. 10 illustrates a syntax example of GOB
(DSD lossless gob(number of audio data)) in Fig. 7.
38 SP366661
[0111]
DSD lossless gob header() corresponds to GOB header
in Fig. 7.
[0112]
Fig. 7.
[0113]
DSD lossless gob data() corresponds to GOB data in
DSD lossless_block() corresponds to each block from
Blockl to BlocklO in Fig. 7.
[ 0 114]
Fig. 11 illustrates a syntax example of GOB header
(DSD lossless_gob_header()) in Fig. 7.
[0115]
Whether the DSD lossless stream (DSD lossless
stream) as a whole is compressed and encoded, for example,
is defined by DSD lossless block info.
[0116]
Fig. 12 illustrates a syntax example of GOB data
(DSD lossless gob data()) in Fig. 7.
[0117]
The number of bytes of gob_codebook is defined by
gob codebook length.
[0118]
Data of the conversion table table1 used for
compression and encoding of the 10 blocks included in the
39
group are held in gob codebook[i].
[0119]
SP366661
Fig. 13 illustrates a configuration of each block
from Blockl to BlocklO in Fig. 7.
[0120]
As illustrated in Fig. 13, one block holds as many
frame headers (frame_header) and pleces of frame data
(frame data) as the number of channels
(channel configuration) .
[0121]
A frame header (frame header) includes a sync word
(sync_word), a channel ID (channel id), a frame length
index (frame length index), and a compression flag
(comp flag)
[0122]
Fig. 14 illustrates a syntax example of each block
(DSD_lossless_block()) in Fig. 7.
[0123]
DSD frame header() corresponds to the frame header
(frame header) in Fig. 13.
[0124]
Fig. 15 illustrates a syntax example of the frame
header ( DSD frame header ()) in Fig. 13.
[0125]
sync word (sync_word) holds data representing the
40 SP366661
beginning of the frame header (frame header) and the
frame data (frame data).
[0126]
Channel ID (channel id) holds data representing the
channel number of the frame header (frame header) and the
frame data (frame data) .
[0127]
Frame length index (frame length index) holds the
number of bytes of the frame data (frame data). It should
be noted that the actual number of bytes is
(frame length index+l) bytes.
[0128]
Compression flag (camp flag) holds data
representing whether or not the frame data (frame data)
are compressed and encoded. When camp flag~"1," it
indicates that the frame data are compressed. When
camp flag~"O," it indicates that the frame data are
uncompressed. This flag corresponds to selection control
data described above.
[ 012 9 J
Referring back to Fig. 14, frame data[j] holds
compressed or uncompressed data.
[0130]
The DSD lossless payload is configured as follows:
[0131]
41 SP366661
That is, the DSD lossless payload holds the
conversion table table1, generated for a group (GOB) of
DSD data that includes a plurality of blocks (Block1 to
Block10) together with compressed or uncompressed data of
each block included in the group. Also, the DSD lossless
payload holds a compression flag (comp_flag) indicating
whether the data of each block are compressed data or
uncompressed data.
[0132]

A description will be given next cif a DSD data
transmission process, a process handled by the
compression/encoding apparatus 100 as a whole illustrated
in Fig. 1 with reference to the flowchart illustrated in
Fig. 16.
[0133]
First, in step S21, the DSD data generation section
121 generates DSD data, a digital signal delta-sigmamodulated
by a one-bit signal, by digitizing (performing
A/D conversion on) an input analog audio signal through
sigma-delta modulation, and outputs DSD data to the GOB
data configuration section 122.
[0134]
In step S22, the GOB data configuration section 122
treats a given unit of DSD data as a block and configures
42 SP366661
GOB data that include a plurality of blocks of DSD data.
In the present embodiment, 131072 bits worth of data
whose reproduction time is 46 milliseconds is treated as
a block, and GOB data (a group of DSD data) include 10
blocks.
[0135]
In step S23, the DSD data encoding section 123
performs a GOB data compression/encoding process that
compresses and encodes the GOB data supplied from the GOB
data configuration section 122. That is, the DSD data
encoding section 123 performs the process described with
reference to the flowchart illustrated in Fig. 6.
[0136]
In step S24, the payload generation section 124
generates a DSD lossless payload that holds the
compressed or uncompressed data supplied from the DSD
data encoding section 123 and outputs the DSD lossless
payload to the data transmission section 125. The DSD
lossless payload also includes a compression flag
(comp flag) indicating whether the data of each block are
compressed data or uncompressed data and the conversion
table tablel that was used for compression and encoding.
[0137]
In step S25, the data transmission section 125
transmits the DSD lossless payload generated in the
-
43 SP366661
payload generation section 124 to other apparatus
(reception apparatus), for example, in a given stream
delivery format such as MPEG-DASH.
[0138]
The above processes in steps S21 to S25 are
repeated until all the audio signals input to the
compression/encoding apparatus 100 are processed.
[0139]
As described above, the compression/encoding
apparatus 100 illustrated in Fig. 1 includes the GOB data
configuration section 122, the control section 31, and
the encoding section 32. The GOB data configuration
section 122 treats a frame of delta-sigma-modulated DSD
data (digital data) as a block and configures GOB data
using a group of DSD data that include a plurality of
blocks of DSD data. The control section 31 generates the
conversion table tablel for encoding GOB data as a table
generation section. The encoding section 32 compresses
and encodes each block of the DSD data included in the
GOB data by using the conversion table tablel.
(0140]
Also, the compression/encoding apparatus 100
includes the data volume comparison section 34 and the
payload generation section 124. The data volume
comparison section 34 decides, block by block, the degree
- -
44 SP366661
of compression of compressed data compressed and encoded
by the encoding section 32 as a compression decision
sectiur1. The payload generation section 124 generates
compressed GOB data that adopt DSD data that have yet to
be compressed and encoded for a block whose degree of
compression is greater than the DSD data before the
compressron and encoding and that adopt compressed data
that have been compressed and encoded for a block whose
degree of compression is equal to or smaller than the DSD
data before the compression and encoding.
[ 0 141]
Further, the compression/encoding apparatus 100
further includes the data transmission section 125 that
transmits the conversion table table1 and compressed GOB
data that use the conversion table table1.
[0142]
For example, in the case where DSD data of a piece
of content were compressed and encoded through the
compression/encoding scheme of the present disclosure
with the data size of a block of data that has yet to be
compressed and encoded set to 32768 bytes, the data size
of each block was approximately 24 kbytes, and the data
size of the conversion table table1 was 8 kbytes.
Therefore, 8 kbyte data of the conversion table table1
are inserted once every 10 transmissions of 24 kbyte
45 SP36666l
block data. It becomes easier to deal with load
fluctuations in the transmission channel by reducing the
packet size. Also, in the case where the size of
compressed data exceeds the size of original data, the
transmission capacity as a whole can be reduced by
sending the block of data in its original size of 32768
bytes without compressing and encoding the data.
[0143]
According to the compression/encoding apparatus 100
in Fig. 1, it is possible to generate and provide a DSD
lossless stream obtained by lossless compression/encoding
of DSD data with a higher compression ratio.
[0144]
<2. Decoding Apparatus>

Fig. 17 is a block diagram illustrating a
configuration example of a decoding apparatus according
to the present disclosure.
[0145]
A decoding apparatus 200 illustrated in Fig. 17 is
an apparatus that receives a DSD lossless stream received
from the compression/encoding apparatus 100 in Fig. 1 and
reversibly decodes the DSD lossless stream through a
decoding scheme corresponding to the compression/encoding
scheme of the compression/encoding apparatus 100.
46 SP366661
[01461
The decoding apparatus 200 includes a data
reception section 221, a payload analysis section 222, a
DSD data decoding section 223, and an output section 224.
[0147]
The data reception section 221 receives a DSD
lossless stream transmitted from the compression/encoding
apparatus 100 via a network such as the internet, a
telephone line network, a satellite communication network,
a LAN (Local Area Network), or a WAN (Wide Area Network).
The DSD lossless stream is transmitted, for example, in a
format compliant with the MPEG-DASH standard.
[0148]
In MPEG-DASH, a plurality of pieces of encoded data
representing the same piece of content with different
bitrates are held in a content server so that client
apparatuses can receive desired encoded data through
streaming from among the plurality of pieces of encoded
data to match the network communication capacity.
[0149]
For this reason, the data reception section 221 may
request the content server holding the DSD lossless
stream with the plurality of bitrates generated by the
compression/encoding apparatus 100 to transmit (deliver)
the DSD lossless stream with a given bitrate, and in
47 SP366661
response to the request, the content server may recej.ve
the given DSD lossless stream from the content server.
[0150]
The data reception section 221 acquires DSD
lossless payloads included in the DSD lossless stream and
outputs the DSD lossless payloads to the payload analysis
section 222.
[0151]
The payload analysis section 222 analyzes the DSD
lossless payloads supplied from the data reception
section 221 and outputs the extracted data to the DSD
data decoding section 223. More specifically, the payload
analysis section 222 detects the number of channels of
the DSD data included in the DSD lossless payload, the
sampling frequency, the number of blocks, and so on,
extracts the data in each block from Block1 to Block10,
the data of the conversion table table1 used for
compression .and encoding thereof, and so on, and outputs
these pieces of data to the DSD data decoding section 223.
[0152]
The DSD data decoding section 223 decodes the data
rn each block from Block1 to Block10 supplied from the
payload analysis section 222 through a decoding scheme
corresponding to the compression/encoding scheme of the
compression/encoding apparatus 100, thereby restoring the
48 SP366661
DSD data. More specifically, in the case where the data
in each block from Blockl to BlocklO are compressed data,
the DSD data decoding section 223 decodes the data by
using the conversion table tablel. In the case where the
data in each block from Blockl to BlocklO are
uncompressed data, the DSD data decoding section 223
outputs the block data in an 'as-is' manner.
[0153]
The output section 224 includes, for example, an
LPF (low pass filter), a power amplifier, a speaker, and
so on, performs a given filtering process such as LPFbased
filtering on the decoded data supplied from the DSD
data decoding section 223, amplifies the data, and then
outputs the data as a sound.
[0154]

Fig. 18 is a block diagram illustrating a detailed
configuration of the DSD data decoding section 223.
[0155]
The DSD data decoding section 223 includes an
encoded data buffer 71, a decoding section 72, a table
storage section 73, and an output buffer 74.
[0156]
The compressed data in each block from Blockl to
BlocklO extracted by the payload analysis section 222 are
49 SP366661
supplied to the encoded data buffer 71. Uncompressed data
and selection control data are supplied to the output
buffer 74. The data of the conversion table tablel are
supplied to the table storage section 73.
[0157]
The table storage section 73 stores the conversion
table tablel supplied from the payload analysis section
222 and supplies the table to the decoding section 72 as
necessary.
[0158]
The encoded data buffer 71 temporarily accumulates
the compressed data supplied from the payload analysis
section 222 and supplies the compressed data to the
decoding section 72 at the subsequent stage at a given
timing.
[0159]
The decoding section 72 decodes the compressed data
back to its original form before the compression
(reversibly decodes the data) and supplies the data to
the output buffer 74.
[0160]
A description will be given of the decoding method
used by the decoding section 72.
[0161]
A case will be described in which compressed data
50 SP366661
sent from the compression/encoding apparatus 100 after
compression and encoding are expressed, two bits by two
bits, as depicted below and in which E2[n] is decoded .
. . . E2 [n-3], E2 [n-2], E2 [n-
1], E2 [n], E2 [n+l], E2 [n+2], E2 [n+3],
where E2[n] represents two-bit continuous data and will
also be referred to as E2 data.
[0162]
The decoding section 72 decides the value of E2[n]
first.
[0163]
In the case where E2[n] is "OOb," this data are not
included in the received conversion table tablel[4096] [3].
Therefore, "E2[n+l]+E2[n+2]," the four-bit data following
E2[n] are the data to be decoded.
[0164]
On the other hand, in the case where E2[n] is "Olb,"
"lOb," or "llb," this data are included in the received
conversion table tablel[4096] [3]. Therefore, the decoding
section 72 makes a search to find the data to be decoded
by referring to the received conversion table
tablel [4096][3] by using 04 [n-3], 04 [n-2], 04 [n-1], the 12-
bit 04 data decoded immediately previously. The data to
be decoded are the data held in "tablel[04[n-3],04[n-
2], 04 [n-1]] [E2 [n]-1]."
51 SP366661
[0165]
As described above, the decoding section 72 can
decode the compressed data back to its original form
before the compression (reversibly decode the data).
[0166]
As illustrated in Fig. 18, the decoding section 72
includes a two-bit register 91, a 12-bit register 92, a
conversion table processing section 93, a four-bit
register 94, and a selector 95.
[0167]
Two-bit E2 data (e.g., E2[n]) supplied from the
encoded data buffer 71 are stored in the register 91.
[0168]
The output of the selector 95 is supplied to the
12-bit register 92, and the register 92 holds the 12-bit
data (e.g., D4[n-3],D4[n-2],D4[n-l]) that were decoded
immediately before the two-bit E2 data (e.g., E2[n]) that
are stored in the register 91.
[0169]
In the case where the two-bit E2 data (e.g., E2[n])
stored in the register 91 are "OOb," the selector 95
selects an input terminal 96a and outputs
"E2[n+1]+E2[n+2]," the four-bit data following E2[n], as
a decoding result from an output terminal 97.
[0170]
52 SP366661
The two-bit E2 data (e.g., E2[n]) stored in the
register 91 are ''Olb,'' "lOb,'' or ''llb,'' the conversion
table processing section 93 stores, in the register 94,
four-bit data held in "tablel[D4[n-3],D4[n-2],D4[n-
1]] [E2 [n]-1]" of the conversion table tablel supplied
from the table storage section 73. The selector 95
selects an input terminal 96b and outputs the data stored
in the register 94 as a decoding result from an output
terminal 97.
[0171]
The output buffer 74 selects either the
uncompressed data supplied from the payload analysis
section 222 or the decoded data supplied from the
decoding section 72 as appropriate on the basis of
selection control data and outputs the selected data to
the output section 224 at the subsequent stage.
[0172]

A description will be given of a GOB data decoding
process handled by the DSD data decoding section 223 with
reference to the flowchart illustrated in Fig. 19.
[0173]
First, in step S41, the table storage section 73
acquires the conversion table tablel supplied from the
payload analysis section 222 and stores the conversion
53 SP366661
table tablel. The stored conversion table tablel is
supplied to the decoding section 72 as necessary.
[0174]
In step S42, the output buffer 74 decides, on the
basis of the selection control data supplied from the
payload analysis section 222, whether a given block of
data supplied from the payload analysis section 222 is
compressed data that have been compressed and encoded.
[0175]
In the case where it is decided, ln step S42, that
the given block of data is compressed data, the process
proceeds to step S43, and the decoding section 72 decodes
the compressed data supplied from the encoded data buffer
71 by using the conversion table tablel and supplies the
decoded data to the output buffer 74. That is, the
decoding section 72 performs, on a block of data, a
process of supplying "E2[n+l]+E2[n+2]," the four-bit data
following E2[n], to the output buffer 74 as a decoding
result in the case where the two-bit E2 data (e.g.,
E2[n]) are "OOb" and supplying, to the output buffer 74,
the four-bit data held in "tablel[D4[n-3],D4[n-2],D4[nl]]
[E2[n]-l]" of the conversion table tablel as a
decoding result in the case where the two-bit E2 data
(e.g., E2[n]) are "Olb," "lOb," or "llb."
[0176]
--·-
54 SP366661
In step S44, the output buffer 74 acquires the
decoded DSD data supplied from the decoding section 72
and outputs the decoded DSD data to the output section
224 at the subsequent stage.
[0177]
On the other hand, in the case where it is decided
in step S42 that the given block of data is not
compressed data, the process proceeds to step S45, and
the output buffer 74 acquires uncompressed data
(uncompressed DSD data) supplied from the payload
analysis section 222 and outputs the uncompressed data to
the output section 224 at the subsequent stage.
[0178]
In step S46, the DSD data decoding section 223
decides whether all the block data of a group (GOB)
included in a DSD lossless payload have been decoded.
[0179]
In the case where it is decided in step S46 that
all the block data of the group (GOB) have yet to be
decoded, the process returns to step S42, and the above
processes in steps S42 to S46 are repeated. Steps S42 to
S45 are performed for each of the 10 blocks (Blockl to
BlocklO)
[0180]
On the other hand, in the case where it is decided
55 SP366661
in step S46 that all the block data of the group (GOB)
have been decoded, the DSD data decoding section 223
terminates the GOB data decoding process.
[0181]

A description will be given next of a DSD data
reception process, a process handled by the decoding
apparatus 200 as a whole illustrated in Fig. 17, with
reference to the flowchart illustrated in Fig. 20.
[0182]
In step S61, the data reception section 221
acquires DSD lossless payloads included in a DSD lossless
stream and outputs the DSD lossless payloads to the
payload analysis section 222.
[0183]
In step S62, the payload analysis section 222
analyzes the DSD lossless payloads supplied from the data
reception section 221 and outputs the extracted data to
the DSD data decoding section 223.
[0184]
In step S63, the DSD data decoding section 223
performs a GOB data decoding process of decoding the data
supplied from the payload analysis section 222 through a
decoding scheme corresponding to the compression/encoding
scheme of the compression/encoding apparatus 100. That is,
56 SP36666l
the DSD data decoding section 223 performs the processes
described with reference to the flowchart illustrated in
Fig. 19.
[0185]
In step S64, the output section 224 performs a
given filtering process such as LPF-based filtering on
the decoded data supplied from the DSD data decoding
section 223, amplifies the data, and then outputs the
data as a sound.
[0186]
The above processes in steps S61 to S64 are
repeated each time the decoding apparatus 200 receives
DSD lossless payloads.
[0187]
As described above, the decoding apparatus 200
illustrated in Fig. 17 includes the data reception
section 221 and the decoding section 72. The data
reception section 221 acquires, as a data acquisition
section, compressed GOB data that include the conversion
table tablel and compressed data or uncompressed data.
The conversion table tablel was used for encoding GOB
data that include a group of DSD data (digital data}
including a plurality of blocks by treating a frame of
delta-sigma-modulated digital data as a block. Compressed
data have been obtained by compressing and encoding the
57 SP366661
DSD data in each block of the GOB data by using the
conversion table table1. The decoding section 72 decodes,
in the case where the DSD data in each block of the
compressed GOB data are compressed data, the compressed
data by using the conversion table table1.
[0188]
Also, the compressed GOB data include selection
control data indicating whether the DSD data in each
block of the compressed GOB data are compressed or
uncompressed, and the decoding apparatus 200 further
includes the output buffer 74 that selects, as a
selection section and on the basis of selection control
data, the uncompressed data included in the compressed
GOB data or the DSD data decoded by the decoding section
72 and outputs the selected data.
[0189]
Further, the decoding apparatus 200 further
includes the payload analysis section 222 that extracts
the conversion table table1 and compressed data or
uncompressed data by analyzing the acquired compressed
GOB data as a data analysis section.
[0190]
According to the decoding apparatus 200 illustrated
in Fig. 17, it is possible to acquire, decode and output
a DSD lossless stream, which is provided by the
-
58 SP366661
compression/encoding apparatus 100, obtained by lossless
compression/encoding of DSD data with a higher
compresslon ratio.
[0191]
According to the compression/encoding apparatus 100
and the decoding apparatus 200, it is possible to reduce
the communication capacity and stably receive DSD signal
content through streaming.
[0192]
Also, it is possible to dynamically select and view
DSD signals of better quality to match with the
communication line capacity through transmission and
reception of content between the compression/encoding
apparatus 100 and the decoding apparatus 200 in a stream
delivery format compliant with the MPEG-DASH (Moving
Picture Experts Group phase - Dynamic Adaptive Streaming
over HTTP) standard.
[0193]
According to the OSD lossless stream format
described above, it is possible to deal with fading and
other problems and take remedies against errors because
of appropriate block-by-block communication.
[0194]
It should be noted that, in the embodiment
described above, a case was described in which
59 SP366661
compression and encoding of a digital signal (DSD data)
delta-sigma-modulated by the DSD data generation section
121 was achieved by converting four bits into a two-bit
code by using the data conversion table tablel based on
data occurrence frequency.
[0195]
However, the compression/encoding apparatus 100 can
achieve compression and encoding, for example, by
converting four bits into a one-bit code or eight bits
into a four-bit code. The decoding apparatus 200 can also
perform a decompression process (reversible decoding) on
a code that has been compressed and encoded by the
compression/encoding apparatus 100.
[0196]
For example, in the case where four bits are
converted into a one-bit code, the register 54 of the
encoding section 32 illustrated in Fig. 5 is changed to a
one-bit storage. Also, the register 91 of the decoding
section 72 illustrated in Fig. 18 is changed to a one-bit
storage.
[0197]
For example, in the case where eight bits are
converted into a four-bit code, the register 51 of the
encoding section 32 illustrated in Fig. 5 is changed to
an eight-bit storage, and the register 54 is changed to a
60 SP366661
four-bit storage. Also, the register 91 of the decoding
section 72 illustrated in Fig. 18 is changed to a fourbit
storage, and the register 94 is changed to an eightbit
storage.
[0198]
Therefore, the compression/encoding apparatus 100
can include the encoding section 32 that converts an Mbit
delta-sigma-modulated digital signal into N bits
(M>N) by referring to the conversion table table1. Here,
letting the number of N-bit bit patterns be denoted by P,
the conversion table table1 stores the upper (P-1) codes
in terms of occurrence frequency in the past bit patterns.
[0199]
Also, the decoding apparatus 200 can include the
decoding section 72 that converts and decodes N bits of
encoded data, obtained by compressing and encoding an Mbit
delta-sigma-modulated digital signal into N bits
(M>N), into M bits by referring to the conversion table
tablel.
[0200]
<3. Computer Configuration Example>
The series of processes described above may be
performed by hardware or software. The
compression/decompression method of the present
disclosure is low in terms of volume of software-based
61 SP366661
processing handled by the CPU (Central Processing Unit),
making the compression/decompression method immune to
whether equipment has high processing capability. This
ensures low dependence on models of mobile terminals and
stationary equipment.
[0201]
In the case where the series of processes described
above are performed by software, the program included in
the software is installed to a computer. Here, the
computer includes a computer incorporated in dedicated
hardware, a general-purpose personal computer capable of
performing various functions as a result of installation
of various programs, and so on.
[0202]
Fig. ~1 is a block diagram illustrating a hardware
configuration example of a computer that performs the
series of processes described above by using a program.
[0203]
In a computer 400 illustrated in Fig. 21, a CPU 401,
a ROM (Read Only Memory) 402, and a RAM (Random Access
Memory) 403 are connected to each other by a bus 404.
[0204]
An input/output interface 405 is further connected
to the bus 404. An input section 406, an output section
407, a storage section 408, a communication section 409,
62
and a drive 410 are connected to the input/output
interface 405.
[0205]
SP366661
The input section 406 includes a keyboard, a mouse,
a microphone, and so on. The output section 407 includes
a display, a speaker, and so on. The storage section 408
includes a hard disk, a non-volatile memory, and so on.
The communication section 409 includes a network
interface and so on. The drive 410 drives a removable
recording medium 411 such as magnetic disk, optical disc,
magneto-optical disk, or semiconductor memory.
[0206]
In the computer 400 configured as described above,
the CPU 401 performs the above series of processes, for
example, by loading the program stored in the storage
section 408 into the RAM 403 via the input/output
interface 405 and bus 404 for execution.
[0207]
In the computer 400, the program can be installed
to the storage section 408 via the input/output interface
405 by inserting the removable medium 411 into the drive
410. Also, the program can be received by the
communication section 409 via a wired or wireless
transmission medium such as a local area network, the
Internet, or digital satellite broadcasting and installed
63 SP366661
to the storage section 408. In addition to the above, the
program can be installed, ln advance, to the ROM 402 or
storage section 408.
[0208]
It should be noted that the program executed by the
computer 400 may perform the processes chronologically
according to the sequence described in the present
specification, or in parallel, or at a necessary time as
when the program is called.
[0209]
It should be noted that embodiments of the present
disclosure are not limited to those described above and
can be modified in various ways without departing from
the gist of the present disclosure.
[0210]
For example, an embodiment can be adopted in which
all or some of the plurality of embodiments described
above are combined.
[0211]
For example, the present disclosure can have a
cloud computing configuration in which one function is
processed by a plurality of apparatuses via a network in
a shared and cooperative manner.
[0212]
Also, each of the steps described in the above
64 SP366661
flowcharts can be performed not only by a single
apparatus but also by a plurality of apparatuses 1n a
shared manner.
(0213]
Further, in the case where one step includes a
plurality of processes, the plurality of processes
included in that step can be performed not only by a
single apparatus but also by a plurality of apparatuses
in a shared manner.
(0214]
It should be noted that the effects described in
the present specification are merely illustrative and are
not restrictive and that there may be effects other than
those described in the present specification.
(0215]
It should be noted that the present technology can
also have the following configurations:
( 1)
A compression/encoding apparatus including:
a GOB data configuration section adapted to
configure GOB data with a group of digital data that
includes a plurality of blocks by treating a frame of
delta-sigma-modulated digital data as a block;
a table generation section adapted to generate a
conversion table for encoding the GOB data; and
65 SP366661
an encoding section adapted to compress and encode
the digital data of each block included in the GOB data
by using the conversion table.
( 2)
The compression/encoding apparatus of feature (1)
further including:
a compression decision section adapted to decide,
block by block, the degree of compression of compressed
data compressed and encoded by the encoding section; and
a payload generation section adapted to generate
compressed GOB data that adopt the digital data that have
yet to be compressed and encoded for a block whose degree
of compression is greater than that of the digital data
before the compression and encoding and adopt the
compressed data that have been compressed and encoded for
a block whose degree of compression is equal to or
smaller than that of the digital data before the
compression and encoding.
(3)
The compression/encoding apparatus of feature (2)
further including:
a data transmission section adapted to transmit the
conversion table and the compressed GOB data applied the
conversion table.
( 4)
66 SP366661
The compression/encoding apparatus of any one of
features (1) to (3), in which
the encoding section converts M-bit delta-sigmamodulated
digital data into N bits (M>N) by referring to
the conversion table, and
letting the number of N-bit bit patterns be denoted
by P, the conversion table stores upper (P-1) codes ln
terms of occurrence frequency in past bit patterns.
( 5)
A compression/encoding method including:
a step in which a compression/encoding apparatus
configures GOB data with a group of digital data that
includes a plurality of blocks by treating a frame of
delta-sigma-modulated digital data as a block;
a step in which the compression/encoding apparatus
generates a conversion table for encoding the GOB data;
and
a step in which the compression/encoding apparatus
compresses and encodes the digital data of each block
included in the GOB data by using the conversion table.
( 6)
A program causing a computer to function as:
a GOB data configuration section adapted to
configure GOB data with a group of digital data that
includes a plurality of blocks by treating a frame of
67 SP366661
delta-sigma-modulated digital data as a block;
a table generation section adapted to generate a
conversion table for encoding the GOB data; and
an encoding section adapted to compress and encode
the digital data of each block included in the GOB data
by using the conversion table.
( 7)
A decoding apparatus including:
a data acquisition section adapted to acquire
compressed GOB data that include a conversion table and
compressed data or uncompressed data, the conversion
table having been used for encoding GOB data that include
a group of digital data including a plurality of blocks
by treating a frame of delta-sigma-modulated digital data
as a block, the compressed data having been obtained by
compressing and encoding the digital data in each block
of the GOB data by using the conversion table; and
a decoding section adapted to decode, in the case
where the digital data in each block of the compressed
GOB data are the compressed data, the compressed data by
using the conversion table.
( 8)
The decoding apparatus of feature (7), in which
the compressed GOB data include selection control
data indicating whether the digital data in each block of
68 SP366661
the GOB data are the compressed data or the uncompressed
data, the decoding apparatus further including:
a selection section adapted to select and output,
on the basis of the selection control data, the
uncompressed data included in the compressed GOB data or
the digital data obtained by decoding by the decoding
section.
( 9)
The decoding apparatus of feature (7) or (8)
further including:
a data analysis section adapted to extract the
conversion table and the compressed data or the
uncompressed data by analyzing the acquired compressed
GOB data.
( 10)
The decoding apparatus of any one of features (7)
to (9), in which
the decoding section converts N bits of the
compressed data, obtained by compressing and encoding Mbit
delta-sigma-modulated digital data into N bits (M>N),
into the M bits by referring to the conversion table, and
letting the number of N-bit bit patterns be denoted
by P, the conversion table stores upper (P-1) codes in
terms of occurrence frequency in past bit patterns.
( 11)
69 SP366661
A decoding method including:
a step in which a decoding apparatus acquires
compressed GOB data that include a conversion table and
compressed data or uncompressed data, the conversion
table having been used for encoding GOB data that include
a group of digital data including a plurality of blocks
by treating a frame of delta-sigma-modulated digital data
as a block, the compressed data having been obtained by
compressing and encoding the digital data in each block
of the GOB data by using the conversion table; and
a step in which the decoding apparatus decodes, rn
the case where the digital data in each block of the
compressed GOB data are the compressed data, the
compressed data by using the conversion table.
(12)
A program causing a computer to function as:
a data acquisition section adapted to acquire
compressed GOB data that include a conversion table and
compressed data or uncompressed data, the conversion
table having been used for encoding GOB data that include
a group of digital data including a plurality of blocks
by treating a frame of delta-sigma-modulated digital data
as a block, the compressed data having been obtained by
compressing and encoding the digital data in each block
of the GOB data by using the conversion table; and
70 SP366661
a decoding section adapted to decode, in the case
where the digital data in each block of the compressed
GOB data are the compressed data, the compressed data by
using the conversion table.
[Reference Signs List]
[0216]
31 Control section
32 Encoding section
31 Data volume comparison section
72 Decoding section
73 Table storage section
74 Output buffer
100 Compression/encoding apparatus
121 DSD data generation section
122 GOB data configuration section
123 DSD data encoding section
124 Payload generation section
125 Data transmission section
200 Decoding apparatus
221 Data reception section
222 Payload analysis section
223 DSD data decoding section
224 Output section
400 Computer
401 CPU
71 SP366661
402 ROM
403 RAM
406 Input section
407 Output section
408 Storage section
409 Communication section
410 Drive

We Claim:-
A compression/encoding apparatus comprising:
a GOB data configuration section adapted to
configure GOB data with a group of digital data that
includes a plurality of blocks by treating a frame of
delta-sigma-modulated digital data as a block;
a table generation section adapted to generate a
conversion table for encoding the GOB data; and
an encoding section adapted to compress and encode
the digital data of each block included in the GOB data
by using the conversion table.
[Claim 2]
The compression/encoding apparatus of claim 1,
furttler cunvrising:
a compression decision section adapted to decide,
block by block, a degree of compression of compressed
data compressed and encoded by the encoding section; and
a payload generation section adapted to generate
compressed GOB data that adopt the digital data that have
yet to be compressed and encoded for a block whose degree
of compression is greater than that of the digital data
before the compression and encoding and adopt the
compressed data that have been compressed and encoded for
a block whose degree of compression is equal to or
73
smaller than that of the digital data before the
compression and encoding.
[Claim 3]
SP366661
The compression/encoding apparatus of claim 2,
further comprising:
a data transmission section adapted to transmit the
conversion table and the compressed GOB data applied the
conversion table.
[Claim 4]
The compression/encoding apparatus of claim 1,
wherein
the encoding section converts M-bit delta-sigmamodulated
digital data into N bits (M>N) by referring to
the conversion table, and
letting the number of N-bit bit patterns be denoted
by P, the conversion table stores upper (P-1) codes rn
terms of occurrence frequency in past bit patterns.
[Claim 5]
A compression/encoding method comprising:
a step in which a compression/encoding apparatus
configures GOB data with a group of digital data that
includes a plurality of blocks by treating a frame of
delta-sigma-modulated digital data as a block;
a step in which the compression/encoding apparatus
generates a conversion table for encoding the GOB data;
------------- -
74 SP366661
and
a step in which the compression/encoding apparatus
compresses and encodes the digital data of each block
included in the GOB data by using the conversion table.
[Claim 6]
A program causing a computer to function as:
a GOB data configuration section adapted to
configure GOB data with a group of digital data that
includes a plurality of blocks by treating a frame of
delta-sigma-modulated digital data as a block;
a table generation section adapted to generate a
conversion table for encoding the GOB data; and
an encoding section adapted to compress and encode
the digital data of each block included in the GOB data
by using the conversion table.
[Claim 7]
A decoding apparatus comprising:
a data acquisition section adapted to acquire
compressed GOB data that include a conversion table and
compressed data or uncornpressed data, the conversion
table having been used for encoding GOB data that include
a group of digital data including a plurality of blocks
by treating a frame of delta-sigma-modulated digital data
as a block, the compressed data having been obtained by
compressing and encoding the digital data in each block
75 SP36666J
of the GOB data by using the conversion table; and
a decoding section adapted to decode, in a case
where the digital data in each block of the compressed
GOB data are the compressed data, the compressed data by
using the conversion table.
[Claim 8]
The decoding apparatus of claim 7, wherein
the compressed GOB data include selection control
data indicating whether the digital data in each block of
the GOB data are the compressed data or the uncompressed
data, the decoding apparatus further comprising:
a selection sectior1 adapted to select and output,
on a basis of the selection control data, the
uncompressed data included in the compressed GOB data or
the digital data obtained by decoding by the decoding
section.
[Claim 9]
The decoding apparatus of claim 7, further
comprising:
a data analysis section adapted to extract the
conversion table and the compressed data or the
uncompressed data by analyzing the acquired compressed
GOB data.
[Claim 10]
The decoding apparatus of claim 7, wherein
76 SP366661
the decoding section converts N bits of the
compressed data, obtained by compressing and encoding Mbit
delta-sigma-modulated digital data into N bits (M>N),
into the M bits by referring to the conversion table, and
letting the number of N-bit bit patterns be denoted
by P, the conversion table stores upper (P-1) codes in
terms of occurrence frequency in past bit patterns.
[Claim 11]
A decoding method comprising:
a step in which a decoding apparatus acquires
compressed GOB data that include a conversion table and
compressed data or uncompressed data, the conversion
table having been used for encoding GOB data that include
a group of digital data including a plurality of blocks
by treating a frame of delta-sigma-modulated digital data
as a block, the compressed data having been obtained by
compressing and encoding the digital data in each block
of the GOB data by using the conversion table; and
a step in which the decoding apparatus decodes, ln
a case where the digital data in each block of the
compressed GOB data are the compressed data, the
compressed data by using the conversion table.
[Claim 12]
A program causing a computer to function as:
a data acquisition section adapted to acquire
77 SP366661
.~ornpressed GOB data that include a conversion table and
compressed data or uncompressed data, the conversion
table having been used for encoding GOB data that include
a group of digital data including a plurality of blocks
by treating a frame of delta-sigma-modulated digital data
as a block, the · :ompressed data having been obtained by
compressing and encoding the digital data in each block
of the GOB data by using the conversion table; and
a decoding section adapted to decode, in a case
where the digital data in each block of the compressed
GOB data are the compressed data, the compressed data by
using the conversion table.