KR20170031604A - Usac audio signal encoding/decoding apparatus and method for digital radio services - Google Patents

Abstract

Disclosed are an apparatus and a method for encoding/decoding a unified speech and audio coding (USAC) audio signal for digital radio services. The method for encoding an audio signal includes the steps of: receiving the audio signal; determining a coding scheme for the received audio signal; encoding the audio signal based on the determined coding scheme; and configuring, as an audio super frame of a fixed size, an audio stream generated as a result of encoding the audio signal, wherein the coding scheme includes a first coding scheme associated with an extended high efficient advanced audio codec (HE-AAC) and a second coding scheme associated with an existing advanced audio codec (AAC) line.

Description

[0001] USAC AUDIO SIGNAL ENCODING / DECODING APPARATUS AND METHOD FOR DIGITAL RADIO SERVICES [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a USAC (Unified Speech and Audio Coding) audio signal encoding / decoding apparatus and method for digital radio service, and more particularly, To an apparatus and a method for encoding / decoding an audio signal.

USAC is an audio codec technology that has been standardized in MPEG in 2012. USAC showed improved performance results for voice / audio signals even when comparing performance with previous best technologies (HE-AACv2, AMR-WB +), and it is worth using as next generation audio codec technology.

Previously, there was DAB (Digital Audio Broadcasting) transmission method for digital radio service. The DAB + transmission method, which has been introduced since then, is a way to provide better quality digital radio service by improving the audio codec technology used in DAB. The present invention deals with a bitstream structure and a framing method necessary to utilize the USAC audio codec technology, which is the latest codec, in DAB +, and aims to achieve improvement of digital radio service in the future.

The present invention relates to an apparatus and method for encoding / decoding a USAC audio signal for digital radio service, and more particularly, to an apparatus and method for providing USAC-based DAB + service by providing syntax information and a frame structure for applying USAC to an existing DAB + ≪ / RTI >

According to another aspect of the present invention, there is provided an audio signal encoding method comprising: receiving an audio signal; Determining a coding scheme for the received audio signal; Encoding the audio signal based on the determined coding scheme; And configuring an audio stream generated as a result of encoding the audio signal into an audio superframe of a fixed size, wherein the coding scheme includes a first coding scheme of an Extended HE-AAC (High Efficiency Advanced Audio Codec) Lt; RTI ID = 0.0 > AAC < / RTI >

Determining whether the type of the received audio signal is a multi-channel audio signal or a mono / stereo audio signal; And performing MPS encoding if the received audio signal is determined to be a multi-channel audio signal.

Wherein the encoding comprises: performing an MPS 212 on the received audio signal if the coding scheme for the received audio signal is determined to be a first coding scheme; Performing eSBR on the output audio signal as a result of performing the MPS 212; And performing core encoding on the audio signal output as a result of performing the eSBR.

Performing the PS / SBR on the received audio signal when the coding scheme for the received audio signal is determined to be the second coding scheme; And encoding the audio signal output from the PS / SBR using a second coding scheme.

The audio superframe includes a header section including information on a boundary number of audio frames included in the audio superframe and information on a reservoir fill level of a first audio frame, A payload section including bit information of audio frames, and a directory section including boundary position information of bitstreams per audio frame included in the audio superframe.

Further comprising applying a forward error correction technique for the audio super frame, wherein the applying step corrects a bit error generated in the process of transmitting the configured audio super frame on the communication line.

An apparatus for encoding an audio signal according to an embodiment of the present invention includes: a receiver for receiving an audio signal; A determining unit determining a coding scheme for the received audio signal; An encoding unit encoding the audio signal based on the determined coding scheme; And a configuration unit configured to convert the audio stream generated as a result of encoding the audio signal into an audio superframe of a fixed size, wherein the coding scheme includes a first coding scheme of an Extended HE-AAC (High Efficiency Advanced Audio Codec) Lt; RTI ID = 0.0 > AAC < / RTI >

If the coding scheme for the received audio signal is determined to be the first coding scheme, the encoder performs MPS 212 on the received audio signal, performs eSBR on the audio signal output as a result of performing the MPS 212, Core encoding can be performed on the audio signal output as a result of performing eSBR on the output audio signal.

Wherein the encoding unit performs PS / SBR on the received audio signal when the coding scheme for the received audio signal is determined to be the second coding scheme, performs a PS / SBR on the received audio signal, 2 coding scheme can be used to perform encoding.

The audio superframe includes a header section including information on a boundary number of audio frames included in the audio superframe and information on a reservoir fill level of a first audio frame, A payload section including bit information of audio frames, and a directory section including boundary position information of bitstreams per audio frame included in the audio superframe.

According to another aspect of the present invention, there is provided an audio signal decoding method comprising: receiving an audio superframe; Determining a decoding scheme for an audio signal from the received audio superframe; And decoding the audio superframe based on the determined decoding scheme, wherein the decoding method includes a first decoding method of the Extended HE-AAC (Advanced Efficient Advanced Audio Codec) and a second decoding of the existing AAC sequence Method.

Wherein the determining comprises: extracting decoding parameters from the received audio superframe; And determining at least one of a first decoding method and a second decoding method based on the extracted decoding parameter.

Wherein the decoding parameters are automatically determined according to a user parameter required when encoding an audio signal, the user parameters including bit rate information of a codec for the audio signal, layout type information of the audio signal, and MPEG Surround usage And information on at least one of the information.

Wherein the decoding comprises: performing core decoding on the received audio superframe when the decoding scheme for the received audio superframe is determined to be a first decoding scheme; Performing eSBR on an audio signal output as a result of performing core decoding; And performing the MPS 212 on the audio signal output as a result of performing the eSBR.

Wherein the decoding comprises decoding the received audio superframe using a second decoding scheme when the decoding scheme for the received audio superframe is determined to be a second decoding scheme; And performing PS / SBR on the audio signal output as a result of performing the second decoding scheme.

The audio superframe includes a header section including information on a boundary number of audio frames included in the audio superframe and information on a reservoir fill level of a first audio frame, A payload section including bit information of audio frames, and a directory section including boundary position information of bitstreams per audio frame included in the audio superframe.

An apparatus for decoding an audio signal according to an exemplary embodiment of the present invention includes a receiver for receiving an audio superframe; A determining unit for determining a decoding scheme for an audio signal from the received audio super frame; And a decoding unit decoding the audio superframe based on the determined decoding scheme, wherein the decoding scheme includes a first decoding scheme of the Extended HE-AAC (Advanced Efficient Advanced Audio Codec) and a second decoding scheme of the existing AAC sequence Method.

The determining unit may extract a decoding parameter from the received audio superframe and determine at least one of a first decoding method and a second decoding method based on the extracted decoding parameter.

Wherein the decoding parameters are automatically determined according to a user parameter required when encoding an audio signal, the user parameters including bit rate information of a codec for the audio signal, layout type information of the audio signal, and MPEG Surround usage And information on at least one of the information.

According to an embodiment of the present invention, USAC-based DAB + services can be enabled by providing syntax information and a frame structure for applying USAC in addition to the existing DAB +.

1 is a diagram illustrating an encoding system structure of an Extended HE-AAC (xHE-AAC) according to an embodiment of the present invention.
2 is a diagram illustrating an encoding apparatus according to an embodiment of the present invention.
FIG. 3 is a diagram illustrating a decoding system structure of Extended HE-AAC (xHE-AAC) according to an embodiment of the present invention.
4 is a diagram illustrating a decoding apparatus according to an embodiment of the present invention.
5 is a diagram illustrating an example of a structure of an xHE-AAC super frame according to an embodiment of the present invention.
6 is a diagram illustrating an example of a superframe payload configuration of a plurality of xHE-AAC audio frames according to an embodiment of the present invention.

It is to be understood that the specific structural or functional descriptions of embodiments of the present invention disclosed herein are presented for the purpose of describing embodiments only in accordance with the concepts of the present invention, May be embodied in various forms and are not limited to the embodiments described herein.

Embodiments in accordance with the concepts of the present invention are capable of various modifications and may take various forms, so that the embodiments are illustrated in the drawings and described in detail herein. However, it is not intended to limit the embodiments according to the concepts of the present invention to the specific disclosure forms, but includes changes, equivalents, or alternatives falling within the spirit and scope of the present invention.

The terms first, second, or the like may be used to describe various elements, but the elements should not be limited by the terms. The terms may be named for the purpose of distinguishing one element from another, for example without departing from the scope of the right according to the concept of the present invention, the first element being referred to as the second element, Similarly, the second component may also be referred to as the first component.

It is to be understood that when an element is referred to as being "connected" or "connected" to another element, it may be directly connected or connected to the other element, . On the other hand, when an element is referred to as being "directly connected" or "directly connected" to another element, it should be understood that there are no other elements in between. Expressions that describe the relationship between components, for example, "between" and "immediately" or "directly adjacent to" should be interpreted as well.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In this specification, the terms "comprises ", or" having ", and the like, are used to specify one or more of the features, numbers, steps, operations, elements, But do not preclude the presence or addition of steps, operations, elements, parts, or combinations thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries are to be interpreted as having a meaning consistent with the meaning of the context in the relevant art and, unless explicitly defined herein, are to be interpreted as ideal or overly formal Do not.

Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. However, the scope of the patent application is not limited or limited by these embodiments. Like reference symbols in the drawings denote like elements.

In the description of the present invention, the name of Extended HE-AAC (xHE-AAC) will be used instead of the name of USAC. This is because USAC is actually defined in the xHE-AAC profile and can utilize the xHE-AAC profile to support USAC and HE-AACv2 simultaneously. Therefore, in the present specification, xHE-AAC is regarded as USAC.

1 is a diagram illustrating an encoding system structure of an Extended HE-AAC (xHE-AAC) according to an embodiment of the present invention.

In order to transmit the xHE-AAC audio stream through the DAB network, a profile corresponding to the range and characteristics of parameters for the xHE-AAC audio codec must be defined. In addition, when the compressed xHE-AAC audio stream is to be multiplexed and transmitted through the DAB main service channel, the xHE-AAC encoding apparatus should configure the compressed xHE-AAC audio stream as an audio superframe and transmit it according to the actual transmission conditions .

In addition, the encoding apparatus of the present invention should apply a separate forward error correction (FEC) technique to ensure robust transmission of the xHE-AAC audio stream, and the xHE-AAC decoding apparatus should use a DAB + It should support decoding function of audio stream.

The encoding system structure of xHE-AAC can be shown in Fig. The audio signal can be encoded through an optional structure of an xHE-AAC coding scheme (first coding scheme) and a conventional AAC scheme coding scheme (second coding scheme). First, the encoding system structure may determine a coding scheme for an audio signal according to preset conditions, and may encode an audio signal based on the determined coding scheme.

At this time, the encoding system structure determines whether the type of the audio signal is a multi-channel audio signal or a mono / stereo signal. If the audio signal is determined to be a multi-channel audio signal, MSP (MPEG Surround) encoding can be performed first. The encoding system structure may then perform the MPS encoding and the encoding process for the output mono or stereo audio signal.

When the coding scheme for the audio signal is determined to be the first coding scheme, the encoding system structure performs MPS 212 on the received audio signal, performs enhanced spectral band replication (eSBR) on the audio signal output as a result of performing MPS 212 And core encoding can be performed on the output audio signal as a result of performing eSBR.

In addition, when the coding scheme for the audio signal is determined to be the second coding scheme, the encoding system structure performs PS (Spectral Band Replication) / PSBR (SBR) on the received audio signal, performs PS / SBR And the encoding is performed using the second coding scheme for the output audio signal.

The components of the xHE-AAC coding scheme, like the AAC-based coding tools, include SBR and stereo coding tools. However, since the standard is not an independent revision draft but is included in the xHE-AAC standard technology, It is appropriate to represent it as an encoding block 110. [ If there is a difference in the stereo coding tools, the existing AAC-based coding tools utilize the PS coding method, but the xHE-AAC can utilize the stereo version of the MPS212 to provide better stereo sound quality. The SBR module of xHE-AAC coding method is also defined as eSBR (enhanced SBR) by adding several functions.

2 is a diagram illustrating an encoding apparatus according to an embodiment of the present invention.

The encoding apparatus 200 according to an exemplary embodiment of the present invention may include a receiving unit 210, a determining unit 220, an encoding unit 230, and a configuration unit 240. The receiving unit 210 may receive an audio signal to be encoded. At this time, the audio signal received by the receiving unit 210 may be a multi-channel audio signal or a mono / stereo audio signal.

The receiving unit 210 may determine whether the type of the received audio signal is a multi-channel audio signal or a mono / stereo audio signal. At this time, when the receiving unit 210 determines that the received audio signal is a multi-channel audio signal, the receiving unit 210 may perform MPS encoding to convert the multi-channel audio signal into a mono or stereo audio signal.

The determining unit 220 may determine a coding scheme for the audio signal received through the receiving unit 210. At this time, the coding scheme may include a first coding scheme of Extended HE-AAC (xHE-AAC) and a second coding scheme of an existing AAC sequence.

The encoding unit 230 may encode the received audio signal based on the coding scheme determined by the determining unit 220. [ For example, when the coding scheme for the received audio signal is determined to be the first coding scheme, the encoding unit 230 performs the MPS 212 on the received audio signal, performs eSBR on the audio signal output as a result of performing the MPS 212, (enhanced spectral band replication), and core encoding can be performed on the output audio signal as a result of performing eSBR.

In other cases, if the coding scheme for the received audio signal is determined to be the second coding scheme, the encoding unit 230 performs PS (Spectral Band Replication) / SBR (Spectral Band Replication) on the received audio signal, / SBR, encoding can be performed on the output audio signal using the second coding scheme.

The configuration unit 240 may configure the audio stream generated as a result of encoding the received audio signal into an audio super frame of a fixed size. At this time, the audio stream encoded in the first coding scheme can be transmitted in a plurality of frames composed of one audio super frame without boundaries.

The application (not shown) may apply the forward error correction technique for the audio super frame. At this time, the application unit can correct a bit error generated in the process of transmitting the configured audio super frame on the communication line.

FIG. 3 is a diagram illustrating a decoding system structure of Extended HE-AAC (xHE-AAC) according to an embodiment of the present invention.

The xHE-AAC specification is defined as a total of four profile levels, and all profile levels include USAC profile level 2. USAC Profile Level 2 is a profile that supports decoding for mono and stereo signals. Therefore, the xHE-AAC standard must be capable of decoding USAC for mono and stereo audio signals. In this transmission specification, it is assumed that only xHE-AAC profile level 2 is supported.

That is, the decoding system structure according to the present invention should be able to decode a bit stream for mono and stereo audio signals of USAC, and at the same time to decode a bit stream for mono and stereo audio signals of HE-AAC v2 . Support for multi-channel signals can be maintained with backward compatibility with mono and stereo audio signals by utilizing MPEG Surround technology.

The decoding system structure of xHE-AAC can be shown in Fig. The audio superframe received in the decoding system structure can be decoded through an optional structure of the xHE-AAC coding scheme (first coding scheme) and the existing AAC scheme coding scheme (second coding scheme). First, the decoding system may extract the decoding parameters from the received audio superframe and determine a decoding scheme based on the extracted decoding parameters. The coding scheme for the audio signal may be determined according to a preset condition, and the audio signal may be encoded based on the determined coding scheme.

At this time, the extracted decoding parameter may be automatically determined according to a user parameter required when encoding an audio signal. The user parameter may include at least one of bit rate information of a codec for an audio signal, layout type information of an audio signal, and information on whether to use MPEG Surround for an audio signal.

The decoding system structure performs core decoding on the received audio superframe if the coding scheme for the audio superframe is determined by the first decoding scheme, performs eSBR on the output audio signal as a result of performing core decoding, , and the MPS 212 can be performed on the output audio signal as a result of performing eSBR.

In addition, if the decoding scheme for the received audio superframe is determined to be the second decoding scheme, the decoding system structure may perform decoding using the second decoding scheme for the received audio superframe, PS / SBR can be performed on the output audio signal.

At this time, the decoding system structure decodes the received audio superframe to determine whether the output audio signal is a multi-channel audio signal or a binaural stereo signal for multiple channels. If the audio signal is a multi- Or a binaural stereo signal for multi-channel, MPS decoding can be performed.

4 is a diagram illustrating a decoding apparatus according to an embodiment of the present invention.

The decoding apparatus 400 according to an embodiment of the present invention may include a receiving unit 410, an extracting unit 420, and a decoding unit 430. The receiving unit 410 may receive the audio superframe to be decoded. At this time, the audio superframe received by the receiver 410 includes a header section including information on the number of boundaries of audio frames included in the audio superframe and information on a reservoir fill level of the first audio frame, A payload section including bit information of audio frames included in the audio superframe, and a directory section including boundary position information of bitstreams per audio frame included in the audio superframe.

The extraction unit 420 may extract a decoding parameter for decoding the audio superframe from the audio superframe received through the receiving unit 410. [ At this time, the decoding parameters extracted through the extracting unit 420 may be automatically determined according to the user parameters required when encoding the audio signal. The user parameters include bit rate information of the codec for the audio signal, layout type information of the audio signal, And information on whether to use MPEG Surround for audio signals.

The decoding unit 430 may decode the received audio superframe based on the decoding parameters extracted through the extraction unit 420. [ If the coding scheme for the received audio super frame is determined to be the first decoding scheme, the decoding unit 430 performs core decoding on the received audio super frame, and outputs eSBR is performed, and the MPS 212 can be performed on the output audio signal as a result of performing eSBR.

On the other hand, if the decoding scheme for the received audio superframe is determined to be the second decoding scheme, the decoding unit 430 performs decoding using the second decoding scheme for the received audio superframe, As a result, the PS / SBR can be performed on the output audio signal.

An audio stream encoded in the first coding scheme can be transmitted in a plurality of frames composed of one audio super frame without boundaries.

[Table 1]

Therefore, prior to interpreting the transmitted audio superframe, syntax information for the basic transmitted audio frame should be extracted. Table 1 above is a syntax function including syntax information indicating this.

[Table 2]

Table 2 above provides a scheme of the audio codec used to generate the transmitted audio frames. At this time, the transmission audio frame can express the audio coding scheme through 2 bits.

For example, as shown in Table 2, the transmitted audio frame indicates that encoding is performed using the existing AAC sequence coding scheme when the 2 bits to be represented are 00, and the encoding is performed using the xHE-AAC coding scheme when the 11 bits are used . Therefore, when decoding the corresponding transmission audio frame, the decoding apparatus of the existing AAC sequence coding scheme or the xHE-AAC coding scheme can be selected from the syntax information.

[Table 3]

Table 3 above may be syntax information for indicating a profile (audio mode) of xHE-AAC for a corresponding transport audio frame when a transport audio frame is decoded using a decoding apparatus of the xHE-AAC coding scheme. At this time, the transmission audio frame can express the mode of the audio mode through 2-bit.

For example, as shown in Table 3, the coding mode for the mono audio signal is determined when the 2-bit represented by the transmitted audio frame is 00, and the coding mode for the stereo audio signal is determined when the transmitted bit is 10.

 [Table 4]

Table 4 above may be syntax information for a sample frequency for decoding a transmission audio frame when the transmission audio frame is decoded using the decoding apparatus of the xHE-AAC coding scheme. At this time, the transmitted audio frame can represent the sampling frequency through 3 bits.

For example, as shown in Table 4, when the 3 bits of the transmitted audio frame are 000, the decoding apparatus of the xHE-AAC coding scheme can perform decoding based on the sample frequency of 12 Hz. Or when the 3-bit represented by the transmitted audio frame is 010, the decoding apparatus of the xHE-AAC coding scheme can perform decoding based on the sampled frequency of 24 Hz of the transmitted audio frame.

[Table 5]

Table 5 above may be syntax information on whether or not the transport audio frame includes header information of xHE-AAC when the transport audio frame is decoded using the decoding apparatus of the xHE-AAC coding scheme. At this time, the transmitted audio frame can express the header information of xHE-AAC through 2 bits.

For example, as shown in Table 5, if the 2 bits represented by the transmitted audio frame are 00, the transmitted audio frame does not include the header information of the xHE-AAC. In the case of 01, the transmitted audio frame includes the header information of the xHE- May be included.

As described above, the decoding apparatus and the related decoding parameters are determined according to the bitstream information of the transmitted audio frame, and such decoding parameters can be automatically determined by the user parameters required when encoding the audio signal as follows.

Audio codec bit rate: Bit rate setting of audio signal according to transmission environment

Audio layout type: mono audio signal or stereo audio signal

Enable MPEG Surround: Provides backward compatibility with multi-channel services and stereo signals

The audio encoding apparatus of the xHE-AAC coding scheme can automatically set the parameters for encoding when the broadcasting operator simply inputs the user parameters as described above. Most user parameters are set and transmitted as static parameters, and there are also user parameters that are changed frame by frame. SBR's Dynamic Config information is an example, but most user parameters can be used as they are once they are set statically. The Static Config information of the xHE-AAC coding scheme can be defined by the following syntax function. Next, a decoder parameter value can be extracted from each syntax element information starting from xHEAACStaticConfig () as a statically defined syntax element for setting an optimal encoder parameter value from the user parameter information set by the broadcasting company.

[Table 6]

Table 6 may be a syntax function containing information for determining the shape of the decoding apparatus. Starting from this function, the shape of the decoding device can be set.

[Table 7]

 [Table 8]

Table 8 may be a syntax function that provides information necessary for setting a decoding apparatus for decoding a mono audio signal. The following syntax functions and information are the same as those defined in xHE-AAC. The UsacCoreConfig function can call up syntax information necessary for driving the decoding apparatus corresponding to the core coding in the xHE-AAC coding scheme. Define only the noiseFilling syntax information that affects the sound quality in the xHE-AAC coding scheme, and define that the time-warpping tool (tw_mdct), which requires a high degree of computation, is not used.

[Table 9]

Table 9 may be a syntax function that provides information necessary for setting a decoding apparatus for decoding a stereo audio signal.

[Table 10]

Table 10 may be syntax information defining the shape of the SBR decoding apparatus for the xHE-AAC coding scheme. HarmonicSBR, which affects the main performance, parses and uses syntax information from transmitted bit information, and does not use other tools that increase complexity without significantly affecting performance (bs_interTes, bs_pvc, etc.)

[Table 11]

Table 11 may be syntax information related to settings for decoding SBR parameters. All are the same as USAC syntax and there are no additional changes.

[Table 12]

Table 12 is a syntax function for setting the shape of the decoding apparatus of the MPS 212. The shape of the MPS in the xHE-AAC coding scheme can be variously set in combination with the SBR coding mode according to the bit rate. Each syntax information is the same as xHE-AAC, and the uniqueness is that the syntax information for 'bsDecorrConfig' is not transmitted. This is because the MPS module of the xHE-AAC coding scheme is always bsDecorrConfig == 0.

5 is a diagram illustrating an example of a structure of an xHE-AAC super frame according to an embodiment of the present invention.

The encoding apparatus 200 according to an exemplary embodiment of the present invention may configure an audio stream generated as a result of encoding a received audio signal into an audio super frame having a fixed size. At this time, the audio stream encoded by the xHE-AAC coding scheme can be transmitted in a plurality of frames composed of one audio superframe without boundaries.

An audio superframe configured with the xHE-AAC coding scheme has a fixed size and can be configured with a header section, a payload section, and a directory section.

The header section may have information on the number of the boundaries of the audio frame included in the audio superframe and information on the reservoir fill level of the first audio frame.

The payload section is a section having bit information for an audio frame, and can store a bit stream in units of bytes. The boundary between the audio frames can be continuously attached without any extra padding bytes, regardless of the length of the bit string for each audio frame.

The directory section may have border position information of bitstreams per audio frame. At this time, the location information is defined only within the corresponding superframe, can be described by the byte unit count, and the location information about the 'b' frame boundary extracted from the header section can be provided.

[Table 13]

In Table 13, bsFrameBorderCount is Information indicating the number of boundaries of the audio frame bit string that can be carried in any one audio superframe payload portion. If the bit stream of the last audio frame included in the audio superframe can be contained entirely in the audio superframe, the number of boundary counts for the audio frame may be equal to the number of audio frames transmitted in the payload section.

bsBitReservoirLevel can indicate the bit exhaustion level of the first audio frame included in the audio superframe. If there is no boundary of the included audio frame, it may indicate the full bit exhaustion level of the audio superframe. The FixedHeaderCRC can allocate 8 bits as a CRC (Cyclic Redundancy Check) code for the header section. The bsFrameBorderIndex may provide the position information in reverse order from the boundary of the last audio frame included in the audio super frame. In this case, the index information on the position information can be represented using 14 bits. bsFrameBorderCount may provide information about the boundary count of the audio frame. In this case, the information on the boundary count can be represented using 4 bits. Even if an error occurs in the header information, since there are a plurality of boundary count information, there is no problem in searching for the audio frame boundary in the decoding apparatus.

6 is a diagram illustrating an example of a superframe payload configuration of a plurality of xHE-AAC audio frames according to an embodiment of the present invention.

The bit stream of the audio frame transmitted to the channel load portion of the audio superframe can constitute an audio frame by expressing the result of encoding the audio signal of the actually fixed audio frame unit as a bit stream. At this time, the bit string is configured in byte units and includes a 16-bit CRC code.

The xHE-AAC access unit (AU) is information used to generate an audio signal through the decoding apparatus of the actual xHE-AAC coding scheme. Since the encoding is performed according to the variable bit rate of the xHE-AAC coding scheme, the size of the AU may be different from the audio frame signal of the same size. The first bit of the AU is usacIndependencyFlag, and the usacIndependencyFlag is '1' so that the audio signal of the current frame can be decoded without information of the previous frame. Therefore, there should be at least one audio frame in one audio superframe, and at least one usacIndependencyFlag should be 1.

The xHE-AAC access unit CRC also generates a CRC code for the xHE-AAC access unit and can generate a CRC code by allocating 16 bits per audio frame.

The successively input audio frame signals can be converted into AUs through an encoding process using the xHE-AAC coding scheme. The fixed bit rate can be guaranteed over a long interval, but the number of bits exhausted for each audio frame may not be fixed. Thus, the AU of an audio frame can be defined differently in its length in the audio superframe. This is to increase the quality of the audio signal to be encoded, and it is determined by referring to the bit exhaustion level so as to allocate a large number of bits to audio frames having a high difficulty in a long section and allocate a small number of bits to audio frames not perceptually important . The transmission of the bit exhaustion level to the decoding apparatus can reduce the input AU buffer size and reduce the delay time of the additional audio decoding apparatus.

The encoding apparatus of the xHE-AAC coding scheme can generate a superframe for transmission. The xHE-AAC AU can fill in the null bit to fit in byte units for byte alignment of the bit stream for the audio frame.

The boundary of the audio frame is not necessarily aligned with the boundary of the audio superframe. The bit stream for the AU of the audio frame is sequentially connected to the variable bit stream according to the input of the audio signal, and is cut according to the fixed bit rate of the audio super frame, .

Therefore, one audio superframe may include an AU of a variable number of audio frames. However, the AU of the audio frame can be extracted and decoded based on the header information of the audio superframe and the AU boundary information extracted from the directory information.

If the bit stream for the AU of any audio frame does not span more than one byte in one audio superframe, the directory section may not contain syntax information for the 'frame boundary information'. The boundary information of the audio frame data AU of less than 3 bytes including 2 bytes related to 'frame boundary information' can not extract boundary information in the current audio super frame.

In this case, the last 'frame boundary information' of the directory section may represent information about it in the next audio superframe. For example, if the last 'frame boundary information' is specified as 0xFFF, then the last byte information of the AU for the last audio frame spans the previous frame, and the decoding device will decode the previous audio frame At the payload part, 2 bytes of data should always be buffered.

The bit exhaustion control device is a mechanism commonly used in MPEG codes. This shows a variable bit rate in a short interval, but can output a fixed bit rate in a long interval, so it can provide the best sound quality in a given interval. Thus, the xHE-AAC coding scheme can allocate additional bits when coding the current frames and lower the bit exhaustion level if the bit exhaustion level is sufficiently high. On the other hand, if the bit is no longer needed to be exhausted, the bit exhaustion level may be increased to enable the bit to be utilized in the required interval thereafter.

The apparatus described above may be implemented as a hardware component, a software component, and / or a combination of hardware components and software components. For example, the apparatus and components described in the embodiments may be implemented within a computer system, such as, for example, a processor, a controller, an arithmetic logic unit (ALU), a digital signal processor, a microcomputer, a field programmable gate array (FPGA) , A programmable logic unit (PLU), a microprocessor, or any other device capable of executing and responding to instructions. The processing device may execute an operating system (OS) and one or more software applications running on the operating system. The processing device may also access, store, manipulate, process, and generate data in response to execution of the software. For ease of understanding, the processing apparatus may be described as being used singly, but those skilled in the art will recognize that the processing apparatus may have a plurality of processing elements and / As shown in FIG. For example, the processing unit may comprise a plurality of processors or one processor and one controller. Other processing configurations are also possible, such as a parallel processor.

The software may include a computer program, code, instructions, or a combination of one or more of the foregoing, and may be configured to configure the processing device to operate as desired or to process it collectively or collectively Device can be commanded. The software and / or data may be in the form of any type of machine, component, physical device, virtual equipment, computer storage media, or device , Or may be permanently or temporarily embodied in a transmitted signal wave. The software may be distributed over a networked computer system and stored or executed in a distributed manner. The software and data may be stored on one or more computer readable recording media.

The method according to an embodiment may be implemented in the form of a program command that can be executed through various computer means and recorded in a computer-readable medium. The computer-readable medium may include program instructions, data files, data structures, and the like, alone or in combination. The program instructions to be recorded on the medium may be those specially designed and configured for the embodiments or may be available to those skilled in the art of computer software. Examples of computer-readable media include magnetic media such as hard disks, floppy disks and magnetic tape; optical media such as CD-ROMs and DVDs; magnetic media such as floppy disks; Magneto-optical media, and hardware devices specifically configured to store and execute program instructions such as ROM, RAM, flash memory, and the like. Examples of program instructions include machine language code such as those produced by a compiler, as well as high-level language code that can be executed by a computer using an interpreter or the like. The hardware devices described above may be configured to operate as one or more software modules to perform the operations of the embodiments, and vice versa.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. For example, it is to be understood that the techniques described may be performed in a different order than the described methods, and / or that components of the described systems, structures, devices, circuits, Lt; / RTI > or equivalents, even if it is replaced or replaced.

Therefore, other implementations, other embodiments, and equivalents to the claims are also within the scope of the following claims.

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Claims (19)

Receiving an audio signal;
Determining a coding scheme for the received audio signal;
Encoding the audio signal based on the determined coding scheme; And
Configuring an audio stream resulting from encoding the audio signal into an audio superframe of a fixed size;
Lt; / RTI >
In the coding scheme,
A first coding scheme of an Extended HE-AAC (High Efficient Advanced Audio Codec) and a second coding scheme of an existing AAC sequence,
The audio superframe includes:
And if the received audio signal is encoded based on a first coding scheme, syntax information on whether or not the header information of the first coding scheme is included. The method according to claim 1,
Wherein the receiving comprises:
Determining whether the type of the received audio signal is a multi-channel audio signal or a mono / stereo audio signal; And
Performing MPS encoding if the received audio signal is a multi-channel audio signal
And outputting the audio signal. The method according to claim 1,
Wherein the encoding step comprises:
Performing MPS 212 on the received audio signal if the coding scheme for the received audio signal is determined to be a first coding scheme;
Performing eSBR on the output audio signal as a result of performing the MPS 212; And
Performing core encoding on the output audio signal as a result of performing eSBR;
/ RTI > The method according to claim 1,
Wherein the encoding step comprises:
Performing PS / SBR on the received audio signal when the coding scheme for the received audio signal is determined to be a second coding scheme; And
Performing encoding using the second coding scheme on the output audio signal as a result of performing the PS / SBR;
/ RTI > The method according to claim 1,
The audio superframe includes:
A header section including information on a boundary number of audio frames included in the audio superframe and information on a reservoir fill level of a first audio frame, And a directory section including boundary position information of a bit stream for each audio frame included in the audio superframe. The method according to claim 1,
Applying a forward error correction technique for the audio superframe;
Further comprising:
Wherein the applying comprises:
And correcting a bit error generated in the process of transmitting the configured audio super frame on the communication line. A receiver for receiving an audio signal;
A determining unit determining a coding scheme for the received audio signal;
An encoding unit encoding the audio signal based on the determined coding scheme; And
And an audio superframe having a fixed size, the audio stream being generated by encoding the audio signal,
Lt; / RTI >
In the coding scheme,
A first coding scheme of an Extended HE-AAC (High Efficient Advanced Audio Codec) and a second coding scheme of an existing AAC sequence,
The audio superframe includes:
And syntax information on whether or not the received audio signal includes header information of the first coding scheme when the audio signal is encoded based on the first coding scheme. 8. The method of claim 7,
The encoding unit may include:
When the coding scheme for the received audio signal is determined to be the first coding scheme, MPS 212 is performed on the received audio signal, eSBR is performed on the audio signal output as a result of performing MPS 212, And performing core encoding on the output audio signal as a result of performing eSBR on the audio signal. 8. The method of claim 7,
The encoding unit may include:
Performing a PS / SBR on the received audio signal when the coding scheme for the received audio signal is determined to be a second coding scheme, performing a PS / SBR on the received audio signal, To perform encoding using the audio signal. 8. The method of claim 7,
The audio superframe includes:
A header section including information on a boundary number of audio frames included in the audio superframe and information on a reservoir fill level of a first audio frame, And a directory section including boundary position information of a bit stream for each audio frame included in the audio super frame. Receiving an audio superframe;
Determining a decoding scheme for an audio signal from the received audio superframe; And
Decoding the audio superframe based on the determined decoding scheme
Lt; / RTI >
In the decoding method,
A first decoding method of the Extended HE-AAC (Advanced Efficient Advanced Audio Codec) and a second decoding method of an existing AAC sequence,
The audio superframe includes:
Wherein the decoding information includes syntax information on whether or not header information of the first coding scheme is included when decoding is performed based on the first coding scheme. 12. The method of claim 11,
Wherein the determining comprises:
Extracting decoding parameters from the received audio superframe; And
Determining at least one of a first decoding method and a second decoding method based on the extracted decoding parameter
/ RTI > 13. The method of claim 12,
Wherein the decoding parameter comprises:
Is automatically determined according to a user parameter required when encoding an audio signal,
Wherein the user parameter comprises:
And information on at least one of bit rate information of the codec for the audio signal, layout type information of the audio signal, and MPEG Surround use information for the audio signal. 12. The method of claim 11,
Wherein the decoding comprises:
Performing core decoding on the received audio superframe when the decoding scheme for the received audio superframe is determined to be a first decoding scheme;
Performing eSBR on an audio signal output as a result of performing core decoding; And
Performing the MPS 212 on the output audio signal as a result of performing the eSBR
/ RTI > 12. The method of claim 11,
Wherein the decoding comprises:
Performing decoding on the received audio superframe using a second decoding scheme when the decoding scheme for the received audio superframe is determined to be a second decoding scheme; And
Performing PS / SBR on the audio signal output as a result of performing the second decoding scheme
/ RTI > 12. The method of claim 11,
The audio superframe includes:
A header section including information on a boundary number of audio frames included in the audio superframe and information on a reservoir fill level of a first audio frame, And a directory section including boundary position information of a bit stream for each audio frame included in the audio superframe. A receiving unit for receiving an audio superframe;
A determining unit for determining a decoding scheme for an audio signal from the received audio super frame; And
A decoding unit decoding the audio superframe based on the determined decoding scheme,
Lt; / RTI >
In the decoding method,
A first decoding method of the Extended HE-AAC (Advanced Efficient Advanced Audio Codec) and a second decoding method of an existing AAC sequence,
Wherein the received audio superframe comprises:
Wherein the header information includes syntax information on whether header information of the first coding scheme is included when the information is decoded based on the first coding scheme. 18. The method of claim 17,
Wherein,
Extracts a decoding parameter from the received audio superframe, and determines at least one of a first decoding method and a second decoding method based on the extracted decoding parameter. 19. The method of claim 18,
Wherein the decoding parameter comprises:
Is automatically determined according to a user parameter required when encoding an audio signal,
Wherein the user parameter comprises:
And information on at least one of bit rate information of the codec for the audio signal, layout type information of the audio signal, and MPEG Surround use information for the audio signal.

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