JPH11262100A - Audio signal encoding / decoding method and apparatus - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To encode / decode left / right sense information or spread sense information simultaneously when encoding / decoding a digital audio signal. SOLUTION: In the encoding method of the audio signal,
By encoding the bitstream ancillary data including the left-right sense information or the spread sense information,
It becomes easy to synchronize the audio signal with the left-right sense or the spread sense. At the time of decoding, the reproduced left-right sense or spread sense is added to the audio signal and output.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a method and apparatus for encoding and decoding an audio signal including a sense of right and left and a sense of spread of a sound image.

[0002]

2. Description of the Related Art In recent years, a digital audio signal encoding method has been actively developed. In particular, MPEG1 audio encoding (ISO / IEC 1117) has been proposed as a high quality audio encoding method.
2-3) is known.

FIG. 7 is a block diagram showing a basic structure of an encoder for MPEG1 audio encoding. When audio samples are input to the encoder 71, the mapping unit 72 filters the input audio samples and generates a thinned representation. The psychoacoustic model unit 73 generates a data set that controls quantization and encoding. The quantization and coding unit 74 performs a process according to any of the layer 1, layer 2, and layer 3 coding methods. Frame assembly part 75
Constructs an actual bit stream from the output data of the quantization and encoding unit 74 and the ancillary data, and adds other information (eg, error check) as necessary.

FIG. 8 is a block diagram showing a basic structure of a decoder for MPEG1 audio encoding. When the bit stream is input to the decoder 81, the frame decomposer 82 separates the bit stream to recover various parts of the information. The restoration unit 83 restores a quantized form of a series of mapping samples. The inverse mapping unit 84 returns these mapping samples to PCM audio samples.

[0005] A bit stream generated by MPEG1 audio is composed of three types: layer 1, layer 2 and layer 3. Although the complexity of the coding algorithm increases as the number of layers increases, efficient coding with good sound quality can be realized even at a low bit rate. Here, for the sake of simplicity, description will be made on layer 1.

FIG. 9 is a schematic diagram showing a layer 1 bit stream. FIG. 9 shows a bit stream format of the MPEG1 audio encoding layer 1. The bit stream is composed of one or more consecutive frames, and FIG. 9 is a format of one frame. The frame is composed of a header, an error check, bit allocation as audio data, scale factors and samples, and ancillary data.

[0007]

In the conventional method, when information other than audio data such as character information is included in a bit stream, it is encoded in ancillary data. However, a method of encoding information related to an audio signal, such as a sense of right and left directions and a sense of spread of a sound image, has not been clearly defined. For this reason, there has been a problem that the audio signal and the characteristic of the signal, that is, the feeling in the left-right direction and the feeling of spread, are not encoded, or are encoded separately from the audio signal, so that it is difficult to achieve synchronization. .

SUMMARY OF THE INVENTION The present invention solves such a conventional problem. The present invention provides a method of extracting the right and left direction and the spread of a sound image extracted from an input audio signal in synchronization with the audio signal. An object of the present invention is to provide an audio signal encoding / decoding method and an apparatus for encoding and decoding ancillary data.

[0009]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention extracts a sense of right and left direction and a sense of spread of a sound image, and includes information on right and left sense of the sound image in ancillary data of an audio bit stream. The spreading feeling information is encoded.

Further, in order to achieve the above object, the present invention decodes left-right sense information and spread sense information of a sound image from ancillary data of an audio bit stream and reproduces an audio signal. It is.

[0011]

According to a first aspect of the present invention, there is provided a method for encoding an audio signal, wherein information on a left and right direction of a sound image is included in a generated bit stream. This has the effect that encoding can be performed while synchronizing the audio signal and the left-right sense information, which is the characteristic of the audio signal.

According to a second aspect of the present invention, in the audio signal encoding method, the generated bit stream includes information on a feeling of the spread of the sound image. This has an effect that encoding can be performed while synchronizing certain spread feeling information.

According to a third aspect of the present invention, in the audio signal decoding method, the right and left direction sense information of the sound image included in the bit stream is decoded, and the audio signal and the characteristics of the signal are decoded. This has the effect that decoding can be performed while synchronizing the left-right direction sense information.

According to a fourth aspect of the present invention, in the audio signal decoding method, information on a feeling of spreading of a sound image included in a generated bit stream is decoded, and the audio signal and the signal of the signal are decoded. This has an effect that decoding can be performed while synchronizing the spread feeling information which is a characteristic.

According to a fifth aspect of the present invention, a mapping unit for performing a filtering process and a decimation process on an input audio sample signal, and controls quantization and encoding from the audio sample signal and the output of the mapping unit. A psychoacoustic model unit for generating a data set, a quantization and encoding unit for quantizing and encoding the output of the mapping unit, and an actual bit stream from the output of the quantization and encoding unit and ancillary data A frame assembling unit for assembling the input audio sample signal, comprising: a left-right sense extracting unit that extracts left-right sense information of the input audio sample signal and sends the information to the frame assembler; A coder that incorporates left-right sense information into ancillary data. An effect that can be encoded synchronously sense of direction information.

According to a sixth aspect of the present invention, a mapping unit for performing a filtering process and a thinning-out process on an input audio sample signal, and controls quantization and encoding from the audio sample signal and the output of the mapping unit. A psychoacoustic model unit for generating a data set, a quantization and encoding unit for quantizing and encoding the output of the mapping unit, and an actual bit stream from the output of the quantization and encoding unit and ancillary data A frame assembling unit for assembling the input audio sample signal, wherein the frame assembling unit extracts a spreading feeling information of the input audio sample signal and sends the information to the frame assembling unit. A coder that incorporates information into ancillary data. An effect that can be encoded while synchronizing the broadcast.

According to a seventh aspect of the present invention, there is provided a frame decomposing unit for decomposing a frame of an input coded bit stream, a restoring unit for decoding the data of the decomposed frame, and A reverse mapping section for returning to an audio sample signal, the left and right direction information is reproduced from the ancillary data obtained by the frame decomposition section, and the left and right audio sample signals output from the reverse mapping section are converted to the left and right audio sample signals. The decoder is provided with a left / right sensation reproducing unit for adding and outputting directional perception information, and has an effect that decoding can be performed while synchronizing an audio signal with left / right sensation information which is a characteristic of the signal.

The invention according to claim 8 is a frame decomposing unit for decomposing a frame of an input coded bit stream, a restoring unit for decoding the data of the decomposed frame, and An inverse mapping unit for returning to an audio sample signal, the information processing unit reproduces spread feeling information from the ancillary data obtained by the frame decomposing unit, and outputs the spread sense information to the audio sample signal output from the inverse mapping unit. This is a decoder including a spread feeling reproducing unit for adding and outputting information, and has an effect that decoding can be performed while synchronizing an audio signal and spread feeling information which is a characteristic of the signal.

Hereinafter, an embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG. (Embodiment 1) FIG. 1 shows a bit stream format in which an audio signal and a sense of right and left directions are encoded in Embodiment 1. The bit stream is composed of one or more consecutive frames, and FIG. 1 describes only the format of one frame. The frame includes a header, an error check, audio data, and ancillary data.

In the ancillary data, left-right sense information of the sound image is encoded. The left / right direction sense information is, for example,
With 0 degrees as the center, it can be expressed in the range of 90 degrees to the left and right respectively, so that information of 180 degrees as a whole may be expressed. Assuming that the resolution is 1 degree, it is sufficient to represent 180 kinds of data, and 8 bits are sufficient. If the resolution can be further reduced, the number of bits for encoding the sense of right and left direction can be reduced. In the case of FIG. 1, the sense of right and left direction is represented by 8 bits, and its value is +40 degrees.

FIG. 2 shows the blocks of the encoder. When the audio sample is input to the encoder 21, the mapping unit 22
Filters the input audio samples to produce a thinned representation. The psychoacoustic model unit 23 generates a data set for controlling quantization and encoding. The quantization and coding unit 24 performs a process according to any of the layer 1, layer 2, and layer 3 coding methods. The left / right sense extraction unit 26 extracts the left / right sense of the input audio sample and sends the extracted audio sample to the frame assembling unit 25. The frame assembling unit 25 assembles an actual bit stream from the output data of the quantization and encoding unit 24, the output data of the left / right sense extraction unit, and ancillary data input from outside the encoder, and outputs other information (eg, : Error check) is added as necessary.

(Embodiment 2) FIG. 3 shows an audio signal and a bit stream format in which a sense of spaciousness is encoded in Embodiment 2. A bit stream is made up of one or more consecutive frames,
Describe only the frame format. The frame is
It consists of a header, an error check, audio data, and ancillary data.

[0023] In the ancillary data, information about a feeling of spreading of a sound image is encoded. The spread feeling information can be expressed, for example, in a range from 0 degrees to 180 degrees, so that the information corresponding to 180 degrees as a whole may be expressed. Assuming that the resolution is 1 degree, it is sufficient to represent 180 kinds of data, and 8 bits are sufficient. If the resolution can be further reduced, the number of bits for encoding the feeling of spreading can be reduced. In the case of FIG. 3, the feeling of spreading is represented by 8 bits, and its value is +88 degrees.

FIG. 4 shows the blocks of the encoder. When the audio sample is input to the encoder 41, the mapping unit 42
Filters the input audio samples to produce a thinned representation. The psychoacoustic model unit 43 generates a data set for controlling the quantization and the encoding. The quantization and coding unit 44 performs a process according to any of the layer 1, layer 2, and layer 3 coding methods. The spaciousness extraction unit 46 extracts the spaciousness of the input audio sample and sends it to the frame assembling unit 45. The frame assembling unit 45 assembles an actual bit stream from the output data of the quantization and encoding unit 44, the output data of the spaciousness extracting unit, and the ancillary data input from outside the encoder. : Error check) is added as necessary.

(Embodiment 3) FIG. 5 shows a block diagram of a decoder according to Embodiment 3. When the bit stream is input to the decoder 51, the frame decomposer 52 separates the bit stream to recover various parts of the information. The restoration unit 53 restores a quantized form of a series of mapping samples. The inverse mapping unit 54 uses these mapping samples as P
Return to CM audio sample. On the other hand, the left / right sense reproduction unit 55 restores the left / right sense from the ancillary data,
The left and right sense information is added to the PCM audio sample output from the inverse mapping unit 54 to reproduce the audio sample.

(Embodiment 4) FIG. 6 shows a block diagram of a decoder according to Embodiment 4. When the bit stream is input to the decoder 61, the frame decomposer 62 separates the bit stream to recover various parts of the information. The restoration unit 63 restores a quantized form of a series of mapping samples. The inverse mapping unit 64 converts these mapping samples into P
Return to CM audio sample. On the other hand, the spread feeling reproducing unit 65 restores the spread feeling from the ancillary data, and reproduces the audio sample by adding the spread feeling information to the PCM audio sample output from the inverse mapping unit 64.

[0027]

As described above, according to the present invention, MPEG1
Since the ancillary data of the audio bit stream can be encoded so as to include the information on the sense of right and left and the sense of spread of the sound image, the information on the sense of right and left and spread is separated from the bit stream of the audio signal and encoded. Therefore, the amount of information is reduced, and it is easy to synchronize the audio signal with the left-right sense and the spread sense.

Further, according to the present invention, since the bit stream in which the information about the sense of right and left and the spread of the sound image is included in the ancillary data can be decoded, the sense of right and left and the sense of spread synchronized with the audio signal can be decoded. The information can be decoded and the PCM audio samples can be played.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a bit stream format including left-right sense information according to Embodiment 1 of the present invention.

FIG. 2 is a block diagram showing a configuration of an encoder including left-right sense information according to Embodiment 1 of the present invention.

FIG. 3 is a diagram illustrating a bit stream format including expansiveness information according to Embodiment 2 of the present invention.

FIG. 4 is a block diagram showing a configuration of an encoder including spread feeling information according to Embodiment 2 of the present invention.

FIG. 5 is a block diagram showing a configuration of a decoder including left-right sense information according to Embodiment 3 of the present invention.

FIG. 6 is a block diagram showing a configuration of a decoder including spaciousness information according to Embodiment 4 of the present invention.

FIG. 7 is a block diagram showing a configuration of a conventional encoder.

FIG. 8 is a block diagram showing a configuration of a conventional decoder.

FIG. 9 is a diagram illustrating a bit stream format of MPEG1 layer 1;

[Explanation of symbols]

 11, 31, 91 Header 12, 32, 92 Error check 13, 33, 93 Audio data 14, 34, 94 Ancillary data 15 Left / right direction sense information 21, 41, 71 Encoder 22, 42, 72 Mapping unit 23, 43 73, psychoacoustic model unit 24, 44, 74 quantization and encoding unit 25, 45, 75 frame assembling unit 26 left-right sense extracting unit 35 spreading sense information 46 spreading sense extracting unit 51, 61, 81 decoder 52, 62 , 82 Frame decomposing unit 53, 63, 83 Restoring unit 54, 64, 84 Inverse mapping unit 55 Left-right sense reproduction unit 65 Spread sense reproduction unit

Claims (8)

[Claims] 1. A method for encoding an audio signal, comprising:
A method for encoding an audio signal, characterized in that the generated bit stream includes left-right sense information of a sound image. 2. A method for encoding an audio signal, comprising:
A method for encoding an audio signal, characterized in that the generated bit stream includes information on a feeling of spreading of a sound image. 3. A method for decoding an audio signal, comprising decoding left-right sense information of a sound image included in a bit stream. 4. A method for decoding an audio signal, the method comprising: decoding information on a feeling of spreading of a sound image included in a bit stream. 5. An auditory unit for performing a filtering process and a decimation process on an input audio sample signal, and an auditory system for generating a set of data for controlling quantization and encoding from the audio sample signal and an output of the mapping unit. A psychological model unit, a quantization and encoding unit for quantizing and encoding the output of the mapping unit, and a frame assembling unit for assembling an actual bit stream from the output of the quantization and encoding unit and ancillary data. A coder for extracting left-right sense information of the input audio sample signal and sending the same to the frame assembler, wherein the frame assembler converts the left-right sense information into an ancillary image. An encoder characterized by being incorporated into data. 6. A mapping unit for performing a filtering process and a decimation process on an input audio sample signal, and an auditory system for generating a set of data for controlling quantization and encoding from the audio sample signal and an output of the mapping unit. A psychological model unit, a quantization and encoding unit for quantizing and encoding the output of the mapping unit, and a frame assembling unit for assembling an actual bit stream from the output of the quantization and encoding unit and ancillary data. An encoder having a spread extracting unit for extracting the spread sense information of the input audio sample signal and sending the spread sense information to the frame assembling unit, wherein the frame assembling unit incorporates the spread sense information into ancillary data An encoder characterized in that: 7. A frame decomposer for decomposing a frame of an input coded bit stream, a decompression unit for decoding data of the decomposed frame, and an inverse mapping for returning the decoded data to an original audio sample signal. And a decoder comprising: a unit for reproducing left-right sense information from the ancillary data obtained by the frame decomposition unit, and adding the left-right sense information to an audio sample signal output from the inverse mapping unit. A decoder with a left-right directional sense reproduction unit that outputs. 8. A frame decomposer for decomposing a frame of an input coded bit stream, a decompression unit for decoding data of the decomposed frame, and an inverse mapping for returning the decoded data to an original audio sample signal. And reproducing the spread sense information from the ancillary data obtained by the frame decomposing unit, and adding the spread sense information to the audio sample signal output from the inverse mapping unit and outputting the signal. A decoder with a spreading feeling reproduction unit.