JP2000242296A - Voice data recoding device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the capacity of a buffer memory which preserves decoded data temporarily in a decoding device of voice data which are constituted of plural channel groups. SOLUTION: In this voice data decoding device, a memory 01 stores voice data which are constituted of plural channel groups. A pointer 02 stores the position of data being read out in the memory 01. A pointer control part 03 controls the pointer 02. A FIFO memory 04 temporarily stores the data read out from the memory 01. A decode part 05 issues an instruction to the pointer control part 03 and also decodes the voice data. A buffer memory 06 temporarily stores the voice data decoded in the decode part 5. A voice output means 07 outputs the decoded voice data. A register part 08 stores the value of the pointer 02.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a device for decoding compressed audio data.

[0002]

2. Description of the Related Art One standard for audio data compression is a method called MPEG audio.

[0003] MPEG audio includes MPEG1 audio and M
There is PEG2 audio, MPEG1 audio supports 2-channel stereo, and MPEG2 audio supports 5.1
Multi-channel support.

[0004] Since MPEG2 audio has compatibility with MPEG1 audio, the compressed data is divided into a main channel section and an extension channel section.

[0005] An audio data decoding / reproducing apparatus having an audio data decoding apparatus capable of decoding MPEG2 audio data.
When decoding / reproducing MPEG2 audio data, both the main channel section and the extension channel section are decoded / reproduced, and the audio data decoding / reproducing apparatus including the audio data decoding apparatus capable of decoding MPEG2 audio data is used for decoding MPEG1 audio data. When decoding and reproducing data, only the main channel section is decoded and reproduced.

FIG. 8 shows an example of a conventional audio data decoding / reproducing apparatus equipped with a conventional audio data decoding apparatus capable of decoding MPEG2 audio data.

In FIG. 8, a conventional audio data decoding / reproducing apparatus having an audio data decoding apparatus capable of decoding MPEG2 audio data holds a memory 11 for storing MPEG2 audio data and a position of data read from the memory 11. Pointer 12, a pointer control unit 13 for controlling the pointer 12, a first-in first-out memory 14 for storing data read from the memory 11, and a decoding unit 15 for decoding data read from the memory 11, for synchronization between channels. And a buffer memory 16 for preventing underflow, and audio output means 17 for multiplexing and reproducing channels of audio data decoded by the decoding unit 15.

As described above, since the MPEG2 audio data is input to the memory in a structure divided into the main channel section and the extension channel section, the main channel and the extension channel are stored in the memory 11 in the header of the main channel section in frame units. 110, main channel data 11
1. The header 112 of the extension channel section and the data 113 of the extension channel section are separately stored in different areas.

An audio data decoding / reproducing apparatus having an audio data decoding apparatus capable of decoding MPEG2 audio data is provided.
When decoding / reproducing MPEG2 audio data, first, the pointer control unit 13 sets the pointer 12 according to the instruction of the decoding unit 15, and the header 110 of the main channel unit, the data 111 of the main channel unit, The header 112 of the extension channel section and the data 113 of the extension channel section are read from the memory 11 in this order.

The read data is stored in a first-in first-out memory 1
4 to the decoding unit 15 through which the main channel
Decode in the order of extension channels.

The decoded data is temporarily stored in the buffer memory 16 and then reproduced by multiplexing the channels by the audio output means 17.

[0012]

Therefore, in order to perform reproduction in synchronization with the main channel and the extension channel, the capacity of the buffer memory 16 is limited by the decoded main channel data for one frame and the decoding unit. A minimum capacity is required to hold the decoded data of the extension channel processed at one time. However, since the memory capacity cannot be increased unnecessarily, the capacity of the buffer memory is preferably as small as possible.

Accordingly, the present invention provides an audio data decoding / reproducing apparatus including an audio data decoding apparatus for decoding audio data composed of a plurality of channel groups such as MPEG2 audio data, and temporarily stores the decoded data. It is an object of the present invention to provide a memory reading method capable of reducing the capacity of a buffer memory for use in the present invention and an audio data decoding device provided with a memory reading means.

It is another object of the present invention to provide a pointer control method in which a writable area of a memory can be easily determined and a memory can be used effectively.

Further, in the memory read method, a memory control device capable of reducing invalid data transfer at the time of data transfer from the memory to the first-in first-out memory and eliminating underflow of the first-in first-out memory when switching a channel group to be read. The purpose is to provide.

[0016]

According to a first aspect of the present invention, there is provided an audio data decoding apparatus for decoding audio data composed of a plurality of channel groups, comprising: a memory for temporarily storing audio data; A pointer that holds the position, a pointer control unit that controls the pointer, a command that issues an instruction to move the position of the pointer to the pointer control unit, and a decoding unit that decodes the audio data, and temporarily holds the data read from the memory. A first-in first-out memory, and when reading audio data composed of a plurality of channel groups from the memory, the area of the plurality of channel groups in one frame unit is divided into 1 / N,
A memory read method for alternately reading regions of a plurality of channel groups for each divided region is provided.

According to a second aspect of the present invention, in the first aspect, a first pointer for reading data in the memory, a register for holding the position of the first pointer, and a register for valid data in the memory. A pointer control method including a second pointer for holding a head position is provided.

[0018] In a third aspect based on the first aspect, the same number of pointers as the number of channel groups of the plurality of channel groups for reading the area of each channel group of the plurality of channel groups; The memory control method includes a first-in first-out memory of the same number as the number of channel groups of the plurality of channel groups that hold the read data, and a multiplexer that selects data of the first-in first-out memory.

According to a fourth aspect, in the first aspect, the pointer control section includes condition holding means for holding a condition for switching a region of a channel group to be read by a pointer in the memory. The channel group is read with reference to the condition held in the condition holding means.

[0020]

Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 1 is a block diagram illustrating an audio data decoding apparatus according to a first embodiment of the present invention.

In FIG. 1, an audio data decoding apparatus according to the first embodiment includes a memory 01, a pointer 02,
And a pointer control unit 03 and a first-in first-out memory 04
, A decoding unit 05, and a register 08.
The audio data decoding / reproducing apparatus including the audio data decoding apparatus according to the embodiment includes a buffer memory 06 and an audio output unit 07.

In the audio data decoding / reproducing apparatus provided with the audio data decoding apparatus according to the first embodiment, audio data is composed of a first channel group and a second channel group, and the memory 01 In the example, the area holding the header 010 of the first channel group, the data 011 of the first channel group, the header 012 of the second channel group, and the data 013 of the second channel group is an example. Listed in Memory 0
When reading and decoding / reproducing audio data from 1, the pointer control unit 03 first sets the pointer 02 according to the instruction of the decoding unit 05.

Next, the region 011 of the first channel group
012 and the second channel group regions 013 and 0
14 is divided into 1 / N of one frame, and data is read out in divided data units.

FIG. 1 shows an example of four divisions. The first channel group region is divided into a region 0111, a region 0112, a region 0113, and a region 0114, and the second channel group region is divided into a region 0121. , An area 0122, an area 0123, and an area 0124, and data is read in units of the divided areas.

The order of reading from the memory 01 is to alternately read the first channel group area and the second channel group area as shown in the figure.

The register 08 holds the position of the next data to be read out of the area of the channel group that is not currently being read. When changing the area of the channel group to be read, the pointer control unit 03 receives an instruction from the decoding unit 05. Moves the pointer 02 to the position of the data to be read next to the area of the channel group to be read next, which is held in the register 08, and performs the read next to the area of the channel group to which the read has been performed. After the data position is held in the register 08, the data in the area of the channel group to be read next is read.

For example, in FIG. 1, when the data 0113 is being read, the register 08 holds the position of the first data of the data 0123.

The data read from the memory 01 is temporarily stored in the first-in first-out memory 04 and decoded by the decoding unit 05 in units of data. After temporarily storing the decoded data in the buffer memory 06, the audio output means 07 outputs the data in synchronization with the channels.

An example of the movement of the pointer 02 according to the first embodiment of the present invention will be described with reference to FIG. However, the same items as those in FIG. 1 have the same numbers.

In FIG. 5, a solid arrow indicates that data is read using the pointer 02, and a dotted arrow indicates that only the pointer 02 is moved without reading the data.

In FIG. 5, first, error detection is performed on the first channel group area and the second channel group area, and thereafter, the areas 0111, 0121, 0112, 0122, 0113, and 012 are performed.
3, the area 0114 and the area 0124 are read in this order.

As described above, the data of the first channel group and the data of the second channel group are divided into 1 / N of one frame, and decoding and reproduction are performed in units of the divided data, thereby obtaining the buffer memory 06. Capacity can be reduced. In FIG. 5, the buffer size is data 01
It is enough if there is a total size of 11 and data 0121.

In the above specific embodiment, the case where the number of channel groups is "2" and the division of the channel group area is "4" has been described as a condition. The application of the device is not limited to this. Under other conditions, the same effect can be obtained by controlling the pointer in the same manner as described above and reading data alternately from a plurality of channel groups.

(Embodiment 2) FIG. 2 is a block diagram illustrating an audio data decoding apparatus according to a second embodiment of the present invention. However, the same items as those in FIG. 1 have the same numbers.

In FIG. 2, a first pointer 021 is used to read data in the memory 01,
The second pointer 022 is used to hold the last position of the writable area in the memory 01, and
Reference numeral 14 denotes a writable area in the memory 01 before the second pointer 022.

The register 0211 is used to hold the position of the next data to be read in the area of the channel group that is not currently being read.
When the area 0114 is read by the first pointer 211, the next data to be read out of the area of the channel group that is not currently being read is the area 0124. Holds the position of the first data item.

The first pointer 02 for reading data from the memory 01 according to the second embodiment of the present invention.
An example of the movement of the first and second pointers 022 will be described with reference to FIG. However, the same items as those in FIG. 1 have the same numbers.

In FIG. 6, the solid arrow indicates the first pointer 02.
1 indicates that data reading is to be performed, and a dashed arrow indicates that the second pointer 022 is to be moved.
A dotted arrow indicates that the first pointer 021 is moved without reading data.

In FIG. 6, first, error detection is performed on the first channel group area and the second channel group using the first pointer 021, and further, the first channel group is detected using the first pointer 21. Region 0111 and the second channel group region 0121
Is read, the position held by the second pointer 022 is set to the head of the area 0112.

Next, by using the first pointer 211, the first pointer
After reading the region 0112 of the channel group region and the region 0122 of the second channel group,
The position held by the second pointer 022 is set to the head of the area 0113.

Next, using the first pointer 211, the first pointer
After reading the region 0113 of the channel group region and the region 0123 of the second channel group,
The position held by the second pointer 022 is set to the head of the area 0114.

Next, using the first pointer 211, the first pointer
After reading the region 0114 of the channel group region and the region 0124 of the second channel group,
The position held by the first pointer 021 and the second pointer 022 is set as the head of the next frame.

For example, in FIG. 6, after reading the area 0113 of the first channel group and the area 0133 of the second channel group, the register 0211 in FIG. 2 stores the area 011 of the first channel group.
4, the second pointer 022 is moved to the position of the first data of the first channel group area 0114, which is the position held by the register 0211 in FIG.

In this case, the area 014 before the second pointer 022 is the header 010 of the first channel group.
A region 0111 of a region of the first channel group;
A region 0112 of a region of the first channel group;
When data is alternately read from a plurality of channel groups as described above, the control of the first pointer 21 is complicated, but the data is not related to the position held by the first pointer 021. By referring to the second pointer 022, it can be easily determined that new data can be written in the area 014, and the memory 01 can be used efficiently.

In the above specific embodiment, the case where the number of channel groups is "2" and the division of the channel group area is "4" has been described as a condition. The application of the playback device is not limited to this, and under other conditions, the same effect can be obtained by controlling the first pointer and the second pointer in the same way as described above.

(Embodiment 3) FIG. 3 is a block diagram for explaining an audio data decoding apparatus according to a third embodiment of the present invention. However, the same items as those in FIG. 1 have the same numbers.

In FIG. 3, the first pointer 023 is used to read the area of the first channel group, and the second pointer 024 is used to read the area of the second channel group.

The first first-in first-out memory 041 is used to temporarily hold data read from the first channel group area, and the second first-in-first-out memory 042 is read from the second channel group area. The multiplexer 043 is used to temporarily hold the output data, and the multiplexer 043 is connected to the first first-in first-out memory 041 and the second
The data in the first-in first-out memory 042 is selected and transferred to the decoding unit 05.

In the third embodiment of the present invention, the first
An example of the movement of the pointer 023 and the second pointer 024 will be described with reference to FIG. However, the same items as those in FIG. 1 have the same numbers.

In FIG. 7, error detection in the first channel group area is performed using the first pointer 023, and the first channel group area 0111, the first channel group area 0112, The area 0113 of the area of the first channel group and the area 0114 of the area of the first channel group are read in this order, temporarily stored in the first first-in first-out memory 041 in FIG. The error detection of the channel group area is performed, and the area 0131 of the second channel group area and the area 0 of the second channel group area are detected.
132, a region 013 of the region of the second channel group
3, reading is performed in the order of the area 0134 of the area of the second channel group, and the second first-in first-out memory 0 shown in FIG.
42 temporarily. The 043 multiplexer selects the data held in the first-in first-out memory 041 and the first-in first-out memory 042 and transfers the data to the decoding unit 05.

As described above, for the first channel group and the second channel group, the first pointer 02
3, the first pointer 024, the first first-in first-out memory 041, and the second first-in first-out memory 042, when reading the area of the first channel group and the area of the second channel group alternately. , Invalid data transfer when writing new data to the first first-in first-out memory 041 and the second first-in-first-out memory 042 can be eliminated, the memory bandwidth can be reduced, and the first channel In the case where the area of the group and the area of the second channel group are alternately read, it is possible to eliminate the underflow of the first-in first-out memory when changing the channel group to be read.

In the above specific embodiment, the case where the number of channel groups is "2" and the division of the channel group area is "4" has been described as a condition. The application of the reproducing apparatus is not limited to this, and the same effect can be obtained under other conditions by controlling the pointer in the same way as described above.

(Embodiment 4) FIG. 4 is a block diagram for explaining an audio data decoding apparatus according to a fourth embodiment of the present invention. However, the same items as those in FIG. 1 have the same numbers.

In FIG. 4, the decoding unit 05 issues a condition to switch the channel group to be read when issuing an instruction to the pointer control unit 03, and the pointer control unit 03 stores the condition to switch the channel group to be read into the condition holding means 09.
To hold. The pointer control unit 03 refers to the condition for switching the channel group to be read held in the condition holding unit 09, controls the position held by the pointer 02, reads data from the memory 01, and transfers the data to the first-in first-out memory 04.

As described above, the pointer 02 can be efficiently controlled by referring to the condition for switching the channel group to be read held in the condition holding means 09, and the data is transferred from the memory 01 to the first-in first-out memory 04. Invalid data transfer at the time,
In addition, underflow of the first-in first-out memory 04 when switching the channel group to be read can be eliminated.

In the above specific embodiment, the case where the number of channel groups is "2" and the division of the area of the channel group is "4" is described as a condition. The application of the reproducing apparatus is not limited to this, and under other conditions, the same effect can be obtained by referring to the condition held in the condition holding means and controlling the pointer in the same way as described above.

[0058]

As described above, the first invention divides the area of a plurality of channel groups into 1 / N for each frame, and manages the positions of the pointers by a register for holding the positions of the pointers. The data is alternately read and decoded for each data obtained by dividing the area of the channel group.

Thus, when decoding / reproducing audio data composed of a plurality of channel groups, the required capacity of the buffer memory is 1 / N of the size of one frame of the decoded data of the main channel and the decoding of the extension channel. The sum of the 1 / N size of one frame of data thus obtained is sufficient, and the capacity of the buffer memory can be reduced.

According to a second aspect of the present invention, there is provided a first pointer for reading data in a memory, a register for holding the position of the first pointer, and a first position of valid data in the memory. A second pointer to be held,
The area before the second pointer on the memory can overwrite new data regardless of the position of the first pointer,
Even when the control of the first pointer is complicated when reading the areas of a plurality of channel groups alternately, the writable area on the memory can be easily determined by referring to the second pointer. By writing new data, the memory can be used efficiently.

In the third invention, since a pointer and a first-in first-out memory are prepared for each channel group,
When data is read from different channel group areas in the memory and transferred to the first-in-first-out memory, invalid data transfer is eliminated and the memory bandwidth can be reduced, and underflow of the first-in-first-out memory when changing the channel group to be read out Can be eliminated.

Further, the fourth invention comprises a condition holding means for holding a condition for switching an area of a channel group read by a pointer in a memory, and a channel group to be read when the condition held by the condition holding means is satisfied. By switching, when reading data from the memory and writing to the first-in first-out memory, there is no invalid data transfer, the memory bandwidth can be reduced, and the underflow of the first-in first-out memory when changing the channel group to be read can be eliminated. it can.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating an audio data decoding device according to a first embodiment of the present invention.

FIG. 2 is a block diagram illustrating an audio data decoding device according to a second embodiment of the present invention.

FIG. 3 is a block diagram illustrating an audio data decoding device according to a third embodiment of the present invention.

FIG. 4 is a block diagram illustrating an audio data decoding device according to a fourth embodiment of the present invention.

FIG. 5 is a diagram illustrating movement of a pointer in the audio data decoding device according to the first embodiment of the present invention.

FIG. 6 is a diagram for explaining movements of a first pointer and a second pointer in the audio data decoding device according to the second embodiment of the present invention.

FIG. 7 is a view for explaining movements of a first pointer and a second pointer in the audio data decoding device according to the third embodiment of the present invention.

FIG. 8 is a block diagram for explaining a conventional audio data decoding / reproducing apparatus.

[Explanation of symbols]

01 Memory 010 Header of first channel group 011 Data of first channel group 012 Header of second channel group 013 Data of second channel group 0111, 0112, 0113, 0114 Data of first channel group divided Area 0121, 0122, 0123, 0124 Area of the divided second channel group 02 Pointer 03 Pointer control unit 04 First-in first-out memory 05 Decoding unit 06 Buffer memory 07 Audio output unit 08 Register 09 Condition holding unit 014 Before the second pointer Writable area 021, 023 First pointer 0211 Register 022, 024 Second pointer 041 First first-in first-out memory 042 Second first-in-first-out memory 043 Multiplexer 11 Mori 110 main channel of the header 111 main channel data 112 extended channel header 113 extended channel data 12 pointer 13 pointer controller 14 FIFO 15 decoding unit 16 buffer memory 17 sound output means

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Hirotoshi Uehara 1006 Kazuma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. F term (reference) 5D045 DA20

Claims (4)

[Claims] A memory for temporarily storing compressed audio data; a pointer for holding a storage position of the audio data to be read from the memory; a pointer control unit for controlling the content of the pointer; A first-in first-out memory that temporarily holds the audio data, a decoding unit that issues an instruction to move the position of the pointer to the pointer control unit, and decodes the audio data read from the memory; In the case where the audio data composed of channel groups is temporarily stored in the memory, when reading out the audio data from the memory, the pointer control unit divides the plurality of channel groups into a plurality of units by an instruction of the decoder unit. Area, and the plurality of channels are provided for each of the plurality of divided areas. Setting the pointer to read by switching group, wherein the decoding unit includes the audio data decoding apparatus characterized by decoding the voice data for each region divided into a plurality. 2. The audio data decoding device according to claim 1, wherein the pointer is a first pointer for reading data in the memory, a register for holding the value of the first pointer, and a write in the memory. 2. The audio data decoding apparatus according to claim 1, wherein the second pointer stores a last position of a possible area. 3. The audio data decoding apparatus according to claim 2, wherein the pointer is constituted by the same number of pointers as the number of channel groups for reading the areas of the plurality of channel groups, and the first-in first-out memory stores the data of the plurality of channel groups. 2. The audio data decoding apparatus according to claim 1, wherein the number of first-in first-out memories is equal to the number of channel groups for temporarily storing. 4. The audio data decoding apparatus according to claim 1, further comprising condition storage means for storing conditions for switching a region of a channel group read by the pointer control unit using the pointer, wherein the conditions are stored when the audio data is read from the memory. 2. The audio data decoding device according to claim 1, wherein a channel group to be read is switched by controlling a position held by said pointer with reference to a condition held by said means.