UA119808C2 - Decoding audio bitstreams with enhanced spectral band replication metadata in at least one fill element - Google Patents

Abstract

Embodiments relate to an audio processing unit that includes a buffer, bitstream payload deformatter, and a decoding subsystem. The buffer stores at least one Mock of an encoded audio bitstream. The block includes a till element that begins with an identifier followed by till data. The fill data includes at least one flag identifying whether enhanced spectral band replication (eSBR) processing is to be performed on audio content of the block. Л corresponding method for decoding mi encoded audio bitstream is also provided.

Description

Cross reference to related applications

The filed application claims priority to European patent application Mo 15159067.6, filed Mar. 13, 2015, and prior US patent application Mo 62/133,800, filed Mar. 16, 2016, each of which is incorporated herein in its entirety by reference

The field of technology.

The invention relates to the processing of audio signals. Some embodiments relate to the encoding and decoding of audio bitstreams (for example, bitstreams having the format

MPRES-4 AAS), which include metadata for managing extended spectral band copying (ESB). Other embodiments include decoding such bitstreams using legacy decoders that are not capable of performing eSEE processing and which ignore such metadata, or decoding an audio bitstream that does not include such metadata, which includes shaping eZzVK control data in response to the bit stream.

Technical level.

A typical audio bitstream includes both audio data (eg, encoded audio data) indicating one or more channels of audio content and metadata indicating at least one characteristic of the audio data or audio content. One well-known format for forming an encoded audio bitstream is the MPEC-4 Advanced Audio Coding format (MPEC-4

Aduapsey Aitsaiyo Sodipo, AAS), described in the P5OLES 14496-3:2009 standard). In the MREO-4 standard, the abbreviation AAS stands for "admapsei acido sodipd (advanced audio coding)", and the abbreviation NE-AAS means "Admapsei acido sodipd (high-efficiency advanced audio coding)".

The МРЕС-4 ААдАС standard specifies several audio profiles that determine which objects and encoding tools are present in a compatible encoder or decoder. Three of these audio profiles are (1) AAS profile, (2) NON-AAS profile, and (3) NON-AAS m2 profile. The AAS profile includes the object type AAS of low complexity (or "AAS-I C"). The AAS-Y C object is a low-complexity analog of the MPRES-2 AAS profile with some adjustments and does not include either the Spectral Band Copy (SBA) object type or the Parametric Stereo ("P") object type.

The NON-AAS profile is an extension of the AAS profile and additionally includes the 5VE object type.

З The НЕ-ААС profile ум2 is an extension of the НЕ-ААС profile and additionally includes the object type

RB.

The ZVC object type contains a spectral band copy tool, which is an important coding tool that greatly improves the compression efficiency of perceptual audio codecs. ZVK reproduces the high-frequency components of the audio signal on the receiver side (for example, in a decoder). Thus, the encoder only has to encode and transmit low-frequency components, resulting in much higher audio quality at low data rates. ZVC is based on copying sequences of harmonics, previously clipped to reduce the data rate, from a signal with limited available bandwidth and control data received from the encoder. The ratio between tonal and noise-like components is maintained using adaptive inverse filtering, as well as the optional addition of noise and sine waves. In the MRES-4 AAS standard, the ZVE tool performs spectral insertion, in which several adjacent subbands of the quadrature mirror filter (Otsaigaishge Miggog Riyeg, OME) are copied from the transmitted low-band part of the audio signal to the high-band part of the audio signal, which is formed in the decoder.

Spectral insertion may not be ideal for some types of audio, such as music with a relatively low frequency response. Thus, techniques are needed to improve spectral band copying.

Brief description of variants of the invention.

The first class of variants of the implementation belongs to the audio processing units, which include a memory, a unit for removing the formatting of the useful data of the bit stream and a decoding subsystem. The memory is made with the ability to store at least one block of an encoded audio bit stream (for example, a MPRES-4 AAS bit stream). The block for removing the formatting of the useful data of the bit stream is made with the ability to demultiplex the encoded audio block. The decoding subsystem is designed to decode the audio content of an encoded audio block. An encoded audio block includes a padding element with an identifier indicating the beginning of the padding element and padding data after the identifier. The padding data includes at least one flag identifying whether enhanced spectral band copy (eBSC) processing should be performed for the audio content of the encoded audio block.

The second class of embodiments relates to methods of decoding an encoded audio bit stream. The method includes receiving at least one block of an encoded audio bit stream, demultiplexing at least some parts of at least one block of an encoded audio bit stream and decoding at least some parts of at least one block of an encoded audio bit stream. At least one block of the encoded audio bitstream includes a padding element with an identifier indicating the beginning of the padding element and padding data after the identifier. The padding data includes at least one flag identifying whether enhanced spectral band copy (eBSP) processing should be performed for the audio content of at least one block of the encoded audio bit stream.

Other classes of embodiments relate to the encoding and transcoding of audio bitstreams containing metadata identifying whether enhanced spectral band copy (ESB) processing should be performed.

Brief description of the drawings.

Fig. 1 is a block diagram of a variant of the implementation of the system, which can be performed with the possibility of performing a variant of the implementation of the method of the invention.

Fig. 2 is a block diagram of an encoder, which is an embodiment of the audio processing unit of the invention.

Fig. C is a block diagram of a system including a decoder, which is an embodiment of the audio processing unit of the invention, and optionally also a post-processor connected to it.

Fig. 4 is a block diagram of a decoder, which is an embodiment of the audio processing unit of the invention.

Fig. 5 is a block diagram of a decoder, which is another embodiment of the audio processing unit of the invention.

Fig. 6 is a block diagram of another embodiment of the audio processing unit of the invention.

Fig. 7 - a block diagram of the MRES-4 AAS bit stream, which includes the segments into which it is divided.

Notation and terminology.

In this disclosure, including the claims, the expression "perform an operation on" a signal or data (eg, filtering, scaling, transforming the signal or data, or applying a gain factor to the signal or data) is used broadly to mean performing an operation directly over the signal or data, or over a processed version of the signal or data (for example, over a version of the signal that has been pre-filtered or pre-processed before a further operation is performed).

In this disclosure, including the claims, the expression "audio processing unit" is used in a broad sense to denote a system or device designed to process audio data. Examples of audio processing units include, but are not limited to, encoders (eg, transcoders), decoders, encoder-decoders, preprocessing systems, postprocessing systems, and bitstream processing systems (sometimes called bitstream processing tools). Virtually all consumer electronics, such as mobile phones, televisions, laptops and tablet computers, contain an audio processing unit.

In this disclosure, including the claims, the term "connects" or "connected" is used broadly to mean either a direct or an indirect connection.

Thus, if the first device connects to the second device, the connection can be through a direct connection, or through an indirect connection through other devices and connections. In addition, components that are integrated into other components or with other components are also connected to each other.

Detailed description of variants of implementation of the invention.

The MPEC-4 AAC standard assumes that the encoded MPEC-4 AAC bitstream includes metadata that indicates each type of AAC processing that must be applied (if applicable) by the decoder to decode the audio content of the bitstream, and/or which control such 5VE processing, and/or specify at least one characteristic or parameter of at least one VE tool that should be used to decode the content of the audio bitstream. In this document, we use the expression "VK metadata" to refer to metadata of this type that is described or mentioned in the МРЕС-4 АС standard.

The upper level of the MPRES-4 AAS bitstream is a sequence of data blocks ("am data riosK" elements), each of which is a data segment (referred to in this document as a "block") that contains audio data (typically for a time period of 1024 or 960 counts) and relevant information and/or other data. This document uses the term "block" to refer to a segment of an MPEC-4 AAS bitstream containing audio data (and associated metadata, and optionally other associated data) that defines or is indicative of one (but not 60 more than one) of the "gam/ daia Biosk" element.

Each block of the MPEC-4 AAS bit stream can include several syntactic elements (each of which is also implemented in the bit stream as a data segment). Seven types of such syntactic elements are specified in the MPEC-4 AAS standard. Each syntactic element is identified by a different value of the data element "iy b5up eIie". Examples of syntactic elements include "5ipdie spappe! eietepiO", "sapppei! A single channel element is a container that includes the audio data of one audio channel (a monophonic audio signal). A pair of channels element includes the audio data of two audio channels (ie, a stereophonic audio signal).

A padding element is a container of information that includes an identifier (for example, the value of the "id 5up eee" element mentioned above) followed by data referred to as "padding data". Padding elements have historically been used to adjust the current bitrate (bit tracking frequency) of bitstreams that must be transmitted over a channel at a constant rate. By adding an appropriate amount of padding data to each block, a constant data rate can be achieved.

According to embodiments of the invention, padding data may include one or more additional payloads that expand the type of data (eg, metadata) that can be transmitted in a bit stream. A decoder that accepts bitstreams with padding data containing a new data type may optionally be used by a device receiving the bitstream (eg, a decoder) to extend the functionality of the device. Thus, as one skilled in the art can appreciate, padding elements are a special type of data structure and are distinct from data structures commonly used to transmit audio data (eg, audio payloads containing channel data).

In some embodiments of the invention, the identifier used to identify the padding element may consist of a three-bit unsigned integer, which is first transmitted with the most significant bit ("citeri!") having a value of 0xb. Several instances of a syntactic element of the same type can occur in one block (for example, several filler elements).

Another standard for encoding audio bitstreams is the Standard for Unified Speech and Audio Coding of MPRES (MPRES Opiiva Zreesp apa Atchaio Sodipd, OBAS) PZOLES 23003-3:20121.

The МРЕС IО5BAS standard describes the encoding and decoding of audio content using spectrum band copying processing (including 5VK processing, as described in the standard

MPRES-4 AAS, as well as including other advanced forms of spectral band copying processing). This processing uses the spectral band copying tools (sometimes referred to in this document as "Extended 5VE Tools" or "e5BA Tools") of the extended and improved version of the 5VK toolset described in the МРЕС-4 AAS standard. Thus, eZVK (as specified in the OBAS standard) is an improvement of VC (as specified in the MREO-4 standard

AAS).

This document uses the term "enhanced ESR processing" (or "eSR processing") to refer to spectral band copying processing using at least one ESR tool (for example, at least one ESR tool described or referenced in the OBAS MREC standard) that is not described and not mentioned in the MREOS-4 AAS standard. Examples of such EZVK tools are harmonic transposition, additional pre-processing of the OME-insert, or "pre-smoothing", and the formation of a time envelope (Tetroga! EpmeIore Zparipo) counting between sub-bands, or "inter-TE5".

A bitstream formed according to the IBAS MREC standard (sometimes referred to in this document as a "YUBAS bitstream") includes encoded audio content and typically includes metadata indicating each type of spectral band copy processing to be applied by a decoder to decode the content of the OBAS audio bitstream, and/or the metadata that controls such spectral band copy processing, and/or specifies at least one characteristic or parameter of at least one ZVC tool and/or e5VE tool to be used to decode the audio bitstream content OBAS.

This document uses the expression "Extended 5BE metadata" (or "e5ZBEA metadata") to refer to metadata specifying each type of spectral band copying processing that must be applied by a decoder to decode the content of an audio-encoded audio bitstream (e.g., an O5AC bitstream ), and/or which control such spectral band copy processing, and/or specify at least one characteristic or parameter of at least one ZVC tool and/or ezVE tool to be used 60 to decode such audio content, but which is not described or mentioned in the MPRES-4 AADS standard.

An example of ezVE metadata. is metadata (indicating or controlling spectrum copy processing) that is described or referenced in the МРЕС 5АС standard, but not in the МРЕОС-4 standard

AAS. Thus, e5VvVK metadata in the provided document means metadata that is not VC metadata, and 5VK metadata in the provided document means metadata that is not ezvVk metadata.

The OBAS bit stream can include both 5VE and e5VE metadata. More specifically, the OBAS bitstream may include ezvkK metadata that controls the operation of eZVEC processing by the decoder, and 5VE metadata that controls the operation of ZVK processing by the decoder. According to typical embodiments of the present invention, ezVvVK metadata (e.g., ezVK specific configuration data) is included (according to the provided invention) in the bit stream of MPEC-4 AAS (for example, in the container 5bg ehiepvsiop/) at the end of the useful data of З5VK).

The operation of ezVK processing during decoding of an encoded bit stream using a plurality of ezVK tools (containing at least one ezVK tool) with the help of a decoder restores the high-frequency band of the audio signal based on copying the harmonic sequences that were cut off during encoding. Such e5VEK processing usually corrects the contour of the spectrum of the formed high-frequency band and applies inverse filtering and adds noise and sinusoidal components to reproduce the spectral characteristics of the original audio signal.

According to typical embodiments of the invention, EZVK metadata is included (e.g., a small number of control bits that are ezVK metadata are included) in one or more metadata segments of an encoded audio bitstream (e.g., an MPEC-4 bitstream

AAS), which also includes encoded audio data in other segments (audio data segments). Typically, at least one such metadata segment of each bitstream block is (or includes) a padding element (which includes an identifier indicating the beginning of the padding element), and the EZVK metadata is included in the padding element after the identifier.

Fig. 1 is a block diagram of an illustrative audio signal processing sequence (audio data processing system) in which one or more system elements may be configured in accordance with an embodiment of the present invention. The system includes the following elements connected together as shown: encoder 1, subsystem 2 delivery, decoder C and unit 4 further processing. In variations of the system shown, one or more elements are omitted, or additional audio data processing units are included.

In some implementations, encoder 1 (which optionally includes a preprocessing unit) is configured to accept ROM counts (in a time domain) containing audio content as input and output an encoded audio bitstream (having a format that is compatible with with the MPRES-4 DAAS standard), which indicates the audio content. Bitstream data indicating audio content is sometimes referred to herein as "audio data" or "encoded audio data". If the encoder is made in accordance with a typical embodiment of the present invention, the output of the audio bitstream from the encoder includes ezVE metadata (and typically other metadata as well) as well as audio data.

One or more encoded audio bitstreams issued from the encoder 1 may be placed in the encoded audio delivery subsystem 2. Subsystem 2 is configured to store and/or deliver each encoded bitstream output from encoder 1. The encoded audio bitstream output from encoder 1 may be stored by subsystem 2 (e.g., in the form of an OMO or Whi-gau disk) or transmitted by the subsystem 2 (which may implement a transmission line or network), or may be both stored and transmitted by subsystem 2.

Decoder C is made with the ability to decode the encoded bit stream of MPRES-4 audio

AAS (formed by encoder 1), which it receives through subsystem 2. In some embodiments, decoder C is configured with the ability to extract e5VE metadata from each block of a bit stream and decode the bit stream (including by performing ezVvk processing using the extracted e5VkC metadata) , to form decoded audio data (eg streams of decoded PCM audio data counts). In some embodiments, the C decoder is configured to extract the UE metadata from the bitstream (but ignore the UE metadata included in the bitstream) and decode the bitstream (including by performing 5VC processing using the extracted 5VC metadata) to form decoded audio data (for example, streams of decoded readings of PCM audio data). As a rule, decoder C includes a buffer that stores (for example, in a non-volatile manner) segments of the encoded audio bit stream received from subsystem 2.

Block 4 of further processing in fig. 1 is designed with the ability to receive a stream of decoded audio data from decoder C (for example, decoded readings of PCM audio data) and perform their further processing. The post-processing unit 4 may also be configured to reproduce the post-processed audio content (or decoded audio data received from the decoder 3) for playback through one or more speakers.

Fig. 2 is a block diagram of an encoder (100), which is an embodiment of the audio processing unit of the invention. Any of the components or elements of the encoder 100 may be implemented as one or more processes and/or one or more circuits (eg, user-programmable gate arrays (PUAs) or other integrated circuits) in hardware hardware, software or a combination of hardware and software. The encoder 100 includes an encoder 105, a formatting module 107, a metadata generating module 106, and a buffer memory 109 connected as shown. Typically, encoder 100 also includes other processing elements (not shown). Encoder 100 is configured to convert an input audio bitstream to an output encoded bitstream

MRES-4 AADb.

Metadata generator 106 is connected and configured to generate (and/or pass to module 107) metadata (including eZVK metadata and 5VE metadata) to be included by module 107 in an encoded bitstream to be issued from encoder 100.

Encoder 105 is connected and configured to encode (eg, by performing compression) input audio data and place the resulting encoded audio data into module 107 for inclusion in the encoded bitstream to be output from module 107.

The module 107 is configured to multiplex the encoded audio data from the encoder 105 and the metadata (including EZVK metadata and ZVK metadata) from the generator 106 to form an encoded bitstream to be output from the module 107, preferably such that the encoded bitstream has the format defined by one of the embodiments of the present invention.

The buffer memory 109 is configured to store (for example, in a non-volatile manner) at least one block of the encoded audio bit stream issued from the module 107, and

A sequence of blocks of the encoded audio bitstream is then moved from buffer memory 109 as output from encoder 100 to the delivery system.

Fig. C is a block diagram of a system including a decoder (200), which is an embodiment of an audio processing unit, and optionally also a post-processor (300) connected thereto. Any of the components or elements of decoder 200 and post-processor 300 may be implemented as one or more processes and/or one or more circuits (eg, user-programmable gate arrays (PUAs) or other integrated circuits). , in hardware, software or a combination of hardware and software. The decoder 200 includes a buffer memory 201, a unit 205 for removing formatting (parsing) of the useful data of the bit stream, an audio decoding subsystem 202 (which is sometimes called a "basic" decoding module or a "basic" decoding subsystem), an EE processing module 203 and a module 204 forming control bits connected as shown. Typically, the decoder 200 also includes other processing elements (not shown).

The buffer memory (buffer) 201 stores (for example, in a non-volatile manner) at least one block of the encoded audio bit stream received by the decoder 200. During the operation of the decoder 200, the sequence of blocks of the bit stream is moved from the buffer 201 to the block 205 of removing formatting.

In variations of the embodiments in fig. With (or the embodiments of FIG. 4 that will be described), an ARI unit that is not a decoder (eg, ARI unit 500 in FIG. 6 ) includes a buffer memory (e.g., a buffer memory identical to the 201), which stores (for example, in a non-volatile manner) at least one block of an encoded audio bit stream (for example, an MPEC-4 AAS audio bit stream) of the same type received by the buffer 201 in Fig. With or fig. 4 (ie, an encoded audio bitstream that includes ezVK metadata).

Referring again to FIG. 3, the deformatting unit 205 is connected and configured to demultiplex each block of the bitstream to extract metadata therefrom

EZV (including quantized envelope data) and ezVe metadata (and typically other metadata as well), place at least evZVK metadata and 5VK metadata in the evZVK processing module 203 and typically also place other extracted metadata in the decoding subsystem 202 ( and optionally also in the control bit generator 204). The deformatting unit 205 is also connected and configured to extract audio data from each block of the bitstream and place the extracted audio data into the decoding subsystem 202 (decoding module).

The system in fig. C optionally also includes a post-processor 300. The post-processor 300 includes a buffer memory (buffer) 301 and other processing elements (not shown), including at least one processing element connected to the buffer 301. The buffer 301 stores (for example, in a nonvolatile manner) at least one block (or frame) of decoded audio data received by the postprocessor 300 from the decoder 200. The processing elements of the postprocessor 300 are connected and configured to receive and adaptively process a sequence of blocks (or frames) of decoded audio issued from buffer 301, using metadata issued from decoding subsystem 202 (and/or deformatting unit 205), and/or control bits issued from module 204 decoders 200.

The audio decoding subsystem 202 of the decoder 200 is configured to decode the audio data extracted by the parsing unit 205 (such decoding may be referred to as a "base" decoding operation) to form the decoded audio data, and to place the decoded audio data into the e5VK processing module 203. Decoding is performed in the frequency domain and, as a rule, includes inverse quantization, followed by spectral processing. Typically, the final stage of processing in the subsystem 202 applies the conversion from the frequency domain to the time domain to the decoded audio data of the frequency domain, so that the output of the subsystem is the decoded audio data in the time domain. Module 203 is configured to apply ZVK tools and eZVK tools specified using ezVK and e5VK metadata (extracted by parsing unit 205) to decoded audio data (ie, perform ZVK processing and eZVK processing at the output of decoding subsystem 202 using ZVK metadata and e5VK metadata ) to form fully decoded audio data that is output (e.g., to postprocessor 300) from decoder 200. Typically, decoder 200 includes memory (accessible to subsystem 202 and module 203) that stores deformatted audio data and metadata, issued from the unformatting block 205, and the module 203 is configured to access the audio data and metadata (which includes the metadata of the C5VE. and the metadata of the ezVkK) as necessary during the processing of the 5VK and the processing of the e5VK. 5VK processing and ezVK processing in module 203 can be considered as further

Ko) processing at the output of the main decoding subsystem 202. Optionally, the decoder 200 also includes a final up-mixing subsystem (which may apply the parametric stereo ("RB") tools specified in the MPEC-4 AAS standard, using the P5 metadata extracted by the deformatting unit 205, and/or control bits, formed in subsystem 204) which is connected and configured to perform up-mixing at the output of module 203 to form fully decoded, up-mixed audio output from decoder 200. Alternatively, post-processor 300 is configured to perform up-mixing at the output decoder 200 (for example, using P5 metadata extracted by deformatting unit 205 and/or control bits generated in subsystem 204).

In response to the metadata extracted by the deformatting unit 205 , the control bit generator 204 may generate control data, and the control data may be used in the decoder 200 (e.g., in a final up-mixing system) and/or placed as an output of the decoder 200 (e.g., in postprocessors 300 for use during further processing). In response to metadata extracted from the input bitstream (and not necessarily in response to control data), module 204 may generate (and place in postprocessor 300) control bits indicating that the decoded audio data output from processing module 203 e5BE, must be subjected to a certain type of further processing. In some implementations, the decoder 200 is configured to place the metadata extracted by the deformatting unit 205 from the input bitstream into the post-processor 300, and the post-processor 300 is configured to post-process the decoded audio data output from the decoder 200 using the metadata.

Fig. 4 is a block diagram of an audio processing unit (210) ("APO"), which is another embodiment of the audio processing unit of the invention. Block 210 ARI is a decoder of earlier versions, which is not designed with the ability to perform EZVK processing. Any of the components or elements of APO 210 may be implemented as one or more processes and/or one or more circuits (eg, user-programmable integrated circuits (PUAs) or other integrated circuits) in hardware hardware, software or a combination of hardware and software. Block 210 AR 60 contains buffer memory 201, block 215 of removing formatting (parsing block)

payload data bit stream, audio decoding subsystem 202 (sometimes referred to as a "basic" decoding module or "basic" decoding subsystem), and a VCR processing module 213, connected as shown. Typically, the APO Block 210 also includes other processing elements (not shown).

Elements 201 and 202 of the block 210 ARI are identical to the identically numbered elements of the decoder 200 (Fig. 3), and their above description will not be repeated. During the operation of the AR unit 210, the sequence of blocks of the coded audio bit stream (MRES-4 DAS bit stream), received by the AR unit 210, is moved from the buffer 201 to the formatting removal unit 215.

Deformatting unit 215 is connected and configured to demultiplex each block of the bitstream to extract 5VC metadata therefrom (which includes quantized surround data), and typically other metadata as well, but to ignore eZzVC metadata that may be included into a bit stream, according to any embodiment of the present invention. Block 215 of removing formatting is made with the ability to place, at least, metadata of ZVK in module 213 of ZVK processing. The deformatting unit 215 is also connected and configured to extract audio data from each block of the bitstream and place the extracted audio data in the decoding subsystem 202 (decoding module).

The decoding subsystem 202 of the audio decoder 200 is configured to decode the audio data extracted by the deformatting unit 215 (such decoding may be referred to as a "base" decoding operation) to form decoded audio data, and to place the decoded audio data into the 5VC processing module 213. Decoding is performed in the frequency domain.

Typically, the final stage of processing in subsystem 202 applies a frequency-domain-to-time-domain transformation to the decoded audio data of the frequency domain, so that the output of the subsystem is the decoded audio data in the time domain. The module 213 is configured to apply the SVC tools (but not the eSVC tools) specified by the SVC metadata (extracted by the deformatting unit 215) to the decoded audio data (ie, perform SVC processing at the output of the decoding subsystem 202 using the SVC metadata) to form a fully decoded audio data that is output (eg, to postprocessor 300) from ARI unit 210. As a rule, Block 210 ARO includes memory

Zo (accessible to subsystem 202 and module 213), which stores deformatted audio data and metadata issued from deformatting unit 215, and module 213 is configured to access audio data and metadata (including metadata

ZVE) as necessary during the processing of 5VK. Processing 5VK in the module 213 can be considered as further processing at the output of the main decoding subsystem 202. Not necessarily block 210

The ARI also includes a final upmixing subsystem (which can apply the parametric stereo ("P5") tools specified in the MPEC-4 AAS standard, using the P5 metadata extracted by the deformatting unit 215), which is connected and implemented with the perform upmixing on the output of module 213 to form a fully decoded, upmixed audio output from AP unit 210. Alternatively, the post-processor is configured to perform up-mixing on the output of AR block 210 (for example, using P5 metadata extracted by deformatting block 215 and/or control bits generated in AR block 210).

Various implementations of the encoder 100, the decoder 200, and the ARI block 210 are made with the ability to perform various variants of the method of the invention.

According to some embodiments, the metadata of ezVkC (for example, a small number of control bits that ARE metadata of ezVK are included) are included in the encoded audio bitstream (for example, the bitstream of MPEC-4 AAS), as a result of which the decoders of earlier versions (which are not designed to be able to analyze ecv metadata or use any ecv tool to which the ecv metadata belongs) may ignore the ecv metadata but nevertheless decode the bitstream as far as possible without using the ecvc metadata or any ecv tool to which the ecv metadata belongs, usually without any significant loss in the quality of the decoded audio. However, EZVC decoders configured to analyze the bitstream to identify ezVC metadata and use at least one ezVC tool in response to the ezVE metadata will have the benefit of using at least one such ezVC tool. Thus, embodiments of the invention provide a means for efficient transfer of control data or extended spectrum copy (ESB) metadata while maintaining backward compatibility.

As a rule, eZVK metadata in a bitstream indicates (for example, specifies at least one characteristic or parameter) one or more of the following eZVK tools (which are described in the МРЕС ШЗАС standard, and which may or may not be applied by the encoder during the formation of the bitstream): - harmonic transposition; - additional pre-processing of the OME insert (pre-smoothing); and - the formation of a time loop of counting between sub-bands, or "inter-TE5".

For example, the eZVK metadata included in the bit stream can indicate the values of the parameters (described in the МРЕС ZАС standard and in the provided disclosure): 5PpareGspI(epmi|)

Here, the notation HISPI, where X is some parameter, means that the parameter belongs to the channel ("sp") of the content of the audio encoded bit stream to be decoded. For simplicity, we sometimes omit the expression (sp) and assume that the relevant parameter belongs to the channel of the audio content.

Here, the notation ХИспИ(епм|, where Х is some parameter) means that the parameter belongs to the surround ZVEK ("epu") of the channel ("sp") of the content of the audio coded bit stream to be decoded. For simplicity, we sometimes omit the Hepmi expressions and ISP) and we assume that the relevant parameter belongs to the surround ZVK of the audio content channel.

As indicated, the standard of the МРЕС ОЗАС assumes that the ШОБАС bit stream includes eZzVK metadata, which controls the operation of e5VK processing with the help of a decoder. The eZVK metadata includes the following one-bit metadata parameters: pagtopiszVEe; p5 ipiegtEZ5 and p5 rus.

The parameter "Naptopis53BA" indicates the use of harmonic insertion (harmonic transposition) for the ZVK. More specifically, pagptopis5VK-O indicates a non-harmonic spectral insertion, as described in section 4.6.18.6.3 of the MPEC-4 AAS standard; and pappopis53VK-1 indicates the harmonic insertion of 5BE. (of the type used in EZVK, as described in section 7.5.3 or 7.5.4 of the МРЕС ИО5АС standard). Harmonic interpolation of ZVK is not used according to the copying of a spectral band that is not eZVE (ie, ZVEK, not eZzVK). In this disclosure, the spectral

Zo interpolation is referred to as the basic form of spectral band copying, while harmonic transposition is referred to as the extended form of spectral band copying.

The value of the "re ipietTE5" parameter indicates the use of the inter-TE5 e5BB tool.

The value of the "p5 pic" parameter indicates the use of the RUS eZzVE tool.

During the decoding of the encoded bitstream, the operation of harmonic transposition during the processing stage of ezvk decoding (for each "si" channel of the audio content specified by the bitstream) is controlled by the following eZzVE metadata parameters: 5бгРаиспипаМоае|сп|; 5rgOmegazatriiponiad(sp); 5бгРИСПИpВип5 Radius; and 5бгРИСПИpВИip5|СНИ.

Value "5BbgRaispipuaMode|sp)|" indicates the type of transposition used in ezvk: 5ргРагспипамМоде|снп|-1 indicates non-harmonic insertion as described in section 4.6.18.6.3 of the standard

MPRES-4 AAS; 5ргРаиспипдаМоае|снп|-О indicates the harmonic insertion of ZVE, as described in section 7.5.3 or 7.5.4 of the МРЕС BAS standard.

The meaning of "збгОмегзатриипа Иаяа|сп|!" indicates the use of signal adaptive oversampling in the frequency domain in e5VK in combination with OET-based harmonic interpolation of ZVK, as described in section 7.5.3 of the МРЕС О5АС standard. This flag controls the size

OET used during transposition: 1 indicates that signal adaptive oversampling in the frequency domain is available, as described in section 7.5.3.1 of the MREOS standard

BASS; 0 indicates that the signal adaptive oversampling in the frequency domain is not available, as described in section 7.5.3.1 of the МРЕС ZАС standard.

The value "5BgRiispipVipz Riad|sp)" controls the interpretation of the parameter 5rGRiispIPVip5(|sp|: 1 indicates that the value in the parameter 5rGRiispIPVip5(|сSp| is valid and greater than zero; 0 indicates that the value of 5BgRiiSpiPVip5(|sp| is set equal to zero

The value "zrBgRiispipVipe|сSp)" controls the addition of the vector product multipliers during the harmonic transposition of 5VK. The value 5ргРииспипВип5|сп) is an integer value in the range

IO, 127| and displays the distance measured in frequency binary symbols for the 1536-line OET conversion acting on the sampling frequency of the main encoder.

In the case where the MRES-4 AAS bit stream indicates a pair of 5VE channels, the channels of which are not connected (and not a single 5VK channel), the bit stream indicates two instances of the syntax mentioned above (for harmonic or non-harmonic transposition), one for each channel 5Bg spappei! rai eietepi).

Harmonic transposition of the EZVK instrument generally improves the quality of decoded music signals during relatively low frequency transitions. Harmonic transposition must be implemented in the decoder using either OET-based or OME-based harmonic transposition. Non-harmonic transposition (ie, spectral interpolation of earlier versions) tends to improve speech signals. Therefore, the starting point when deciding which type of transposition is preferred for encoding a given audio content is to choose a transposition method based on speech/music detection, with harmonic transposition used for music and spectral interpolation used for speech.

The operation of pre-smoothing during e5BE processing is controlled by the value of a one-bit metadata parameter of the eZzBE known as "b5 5bg rgergosezzip" in that pre-smoothing is either performed or not performed depending on the value of this single bit. When the algorithm of OME-insertion of ZVE is used, as described in section 4.6.18.6.3 of the МРЕС-4 AADAS standard, a pre-smoothing stage can be performed (when marked with the "р5 вбг ргергосезвипа" parameter) to avoid inhomogeneities in the contour shape of the high-frequency signal spectrum, which is entered into the subsequent contour correction block (the contour correction block performs another stage of e5vk processing). Pre-smoothing generally improves the operation of the subsequent envelope adjustment stage, resulting in a high-band signal that is perceived more stably.

The functioning of the formation of the time contour count between subbands ("inter-TE5" tool) during the processing of ezZVE in the decoder is controlled by the following parameters of the ezZVK metadata for each bypass ZVC ("epu") of each channel ("si") of the audio content of the decoded bit stream

OBAS: re ietr 5Pare(Gspi(epmi; and 5 ipieg Tetr 5Ppare tode(spCIepmi.

The inter-TE5 tool processes the OME of the subrange readings after the bypass correction block.

This stage of processing forms a time envelope of a higher frequency range with a higher degree of temporal detail than the block of correction of the envelope. By applying the amplification factor to each OME of the sub-range reading in the bypass ZVE, inter-TE5 forms a time envelope among the OME of the sub-band readings.

Parameter "p5 Tetr 5pPareGspIepm|» is a flag that signals the use of inter-

TE5. Parameter "p5 ipieg yetr 5Ppare toade(spiI(epm|" indicates (as specified in the MREOS standard

From OZAS) the value of parameter y in inter-TE5.

The overall bit rate requirement for the inclusion of the eZVK metadata specifying the above-mentioned ezVK tools (harmonic transposition, pre-smoothing and inter-TE5) in the MPRES-4 AAS bit stream is assumed to be on the order of several hundreds of bits per second, since only the distinctive control data required for processing ezVE, are transferred according to some variants of the implementation of the invention. Decoders from earlier versions can ignore this information because it is included for backwards compatibility (as described later). Thus, the adverse effect on the bit rate associated with the inclusion of eZVE metadata is insignificant for a number of reasons, including the following: - Bit rate losses (due to the inclusion of eZVE metadata) represent a very small part of the total bit rate, since only distinctive control data necessary to perform ezVK processing (not parallel transfer of control data

ZV); - Setting of control information belonging to Z5VE, as a rule, does not depend on detailed information about transposition; and - The inter-TE5 tool (used during the processing of ezZzVK) performs one-sided post-processing of the transposed signal.

Thus, embodiments of the invention provide a means for efficient transfer of control data or metadata of extended spectral band copying (ESBCC) with observance of backward compatibility. This efficient transfer of EZVK control data reduces memory requirements in decoders, encoders and transcoders employing aspects of the invention without causing any appreciable negative effect on bitrate. In addition, the complexity and processing requirements associated with performing an EZVK in accordance with embodiments of the invention are also reduced, since the 5VEK data needs to be processed only once, rather than being transmitted in parallel, which would be the case if the ezVvKC was treated as a completely separate object type in MPRES-4 AAS, instead of being integrated into the MPRES-4 AAS encoder-decoder with backward compatibility.

Next, with reference to fig. 7 we describe the elements of a block ("tam daia riosk") of a bit stream

MRES-4 AAS, which includes eZzVK metadata, according to some variants of implementation of the given invention. Fig. 7 is a block diagram (there is a BiosK) bit stream of MPEC-4 AAS, showing 60 some of its segments.

A block of bitstream MPEC-4 AAS may include at least one element "effect spappe! eietepi)" (for example, the single channel element shown in Fig. 7) and/or at least one element "sappe! raig eietepi)" (not specifically shown in Fig. 7, although it may be present), which includes audio data for the audio program. The block may also include several elements of "its eietepes" (for example, filler element 1 and/or filler element 2 in Fig. 7), which include data (for example, metadata) belonging to the program. Each element "zipdie spappe! eietepi)" includes an identifier (for example, "IU01" in Fig. 7) indicating the beginning of a single-channel element, and may include audio data indicating another channel of a multi-channel audio program.

Each element "spappe! rai eIetepi""" includes an identifier (not shown in Fig. 7) indicating the beginning of the element of a pair of channels, and may include audio data indicating two channels of the program.

An element of a bit stream (hereafter referred to as a "filler element") of a bit stream

MPRES-4 AAS includes an identifier ("702" in Fig. 7), which indicates the beginning of the filler element, and filler data after the identifier. Identifier 02 may consist of a three-bit unsigned integer with the most significant bit (quote5er) of 0x first transmitted. Padding data may include an echiepsiop rauisaidi() element (which is sometimes referred to in this document as an optional payload) , the syntax of which is shown in Table 4.57 of the AAS МРЕС-4 standard.There are several types of additional payloads, and they are identified by the parameter "echiepviop iure", which is a four-bit unsigned integer whose most significant bit ("pit5ri") is transmitted first.

The padding data (eg, its additional payload) may include a header or identifier (eg, "Header 1" in Fig. 7) that indicates the segment of the padding data that indicates the 5VK object (ie, the header initializes the type "about "ZVA object", which is called 5bg ekhiepsiop daia) in the MRES-4 AAS standard). For example, a Spectrum Copying Additional Payload (5VC) is identified by the value "1101" or "1110" for the field header field, and an identifier of "1101" identifies an additional payload with data VC and "1110" identifies an additional payload with data ZVK with cyclic redundancy check (SKS) for checking the correctness of ZV data.

When a header (for example, an ehiepviop iure field) initializes a 5VK object type, the UE metadata (sometimes referred to in this document as "spectral band copy data" and called 5bg daga() in the MPEC-4 AAS standard) follows the header, and at least one additional element of copying the spectral band (for example, "additional element 5VK" of the filling element 1 in Fig. 7) can follow the metadata of 5VK. Such an additional spectral band copying element (bit stream segment) is referred to as a "5bg ehiepsiopO" container in the AADS MPEC-4 standard. The additional spectral band copying element does not necessarily include a header (for example, "additional header ZVK" of the filler element 1 in Fig. 7).

The MPEC-4 AAS standard suggests that an additional element of spectral band copying may include P5 (parametric stereo) data for program audio data. Standard

MPRES-4 AAS assumes that when the header of a filler element (for example, its additional useful data) initializes the type of the VC object (as "Header 1" does in Fig. 7), and the additional element of copying the spectral band of the filler element includes the data P5, the padding element (eg, its additional payload) includes the spectral band copy data and the "p5 echiepviop id" parameter, the value of which (ie, p5 echiepsiop ia-2) indicates that the P5 data is included in the spectral band copy additional element filler element.

According to some embodiments of the present invention, ezVvK metadata (eg, a flag indicating whether enhanced spectral band copying (eSBR) processing should be performed for the content of the audio block) is included in the additional spectral band copying element of the padding element. For example, such a flag is marked in the filler element 1 in fig. 7, where the flag takes place after the header ("additional header ZVK" of filler element 1) "additional element 5VE" of filler element 1. Optionally, such a flag and additional metadata ezvkK are included in the additional element of copying the spectral band after the header of the additional element of copying the spectral band (for example, in the additional element 5VK of the filling element 1 in Fig. 7, after the additional header

ZVK). According to some embodiments of the present invention, a padding element that includes ezVK metadata also includes a parameter "p5 echiepvsiop id", the value of which (eg, p5 echiepsiop ii-3) indicates that the eZVkK metadata is included in the padding element 60 , and that eZzVK processing must be performed for the audio content of the relevant block.

According to some variants of the implementation of the invention, the ezVvkK metadata is included in the filler element (for example, the filler element 2 in Fig. 7) of the MPEC-4 AAS bit stream, which differs from the additional element of copying the spectral band (the additional element

ZVK) of the filling element. This is caused by the fact that the padding elements containing the ehiepviop rauibadO) with ZVK data or ZVK data from SCS do not contain any other additional payload of any other additional type. Thus, in embodiments where the ez5VK metadata stores its own additional payload, a separate padding element is used to store the ezVK metadata. Such a filler element includes an identifier (for example, "02" in Fig. 7) indicating the beginning of the filler element, and filler data after the identifier. The padding data may include an element (sometimes referred to in this document as an additional payload), the syntax of which is shown in Table 4.57 of the standard

MPRES-4 AAS. The padding data (e.g., additional payload) includes a header (e.g., "Header 2" of padding element 2 in FIG. 7 ) that indicates an eZvVE object (i.e., the header initializes the object type of the enhanced spectrum copy (ezVvE )), and padding data (for example, additional payload) includes e5VK metadata after the header. For example, the filling element 2 in fig. 7 includes such a header ("Header 2"), and also includes after the header ezVE metadata (ie, a "flag" in padding element 2 indicating whether enhanced spectrum copy (ezVC) processing should be performed for the content audio unit). Optionally, additional EZVK metadata is also included in the padding data of the padding element 2 in FIG. 7 after

Header 2. In the embodiments described in this paragraph, the header (e.g.

Title 2 in fig. 7) has an identification value that is not one of the traditional values defined in table 4.57 of the МРЕС-4 AAS standard, and instead indicates the additional payload of the EZVK (so that the header field indicates that the padding data includes metadata eZVK).

In the first class of embodiments, the invention is an audio processing unit (e.g., a decoder) containing: a memory (e.g., buffer 201 in Fig. 3 or 4), designed to store at least one block of an encoded audio bit stream (e.g. , at least one bitstream block of MPRES-4 AAS); a block for removing the formatting of the useful data of the bit stream (for example, element 205 in Fig. C or element 215 in Fig. 4), connected to the memory and made with the ability to demultiplex at least one part of the mentioned block of the bit stream; and a decoding subsystem (eg, elements 202 and 203 in FIG. 3 or elements 202 and 213 in FIG. 4) connected and configured to decode at least one portion of the audio content of said bitstream block, wherein the block includes: an element that includes an identifier indicating the beginning of a filler element (for example, the identifier "ii 5up еие", having the value О0х6б, table 4.85 of the standard

MRES-4 AAS), and padding data after the identifier, and the padding data includes: at least one flag identifying whether enhanced spectral band copy (ESB) processing should be performed for the content of the audio block (eg, using spectral copy data band and eZzVK metadata included in the block).

A flag is eZVEK metadata, and an example of a flag is the 5bgRaispipdaMode flag. Another example of a flag is the paptopis5VE flag. Both of these flags indicate whether a basic form of spectral band copying or an advanced form of spectral band copying should be performed for the block's audio data. The basic form of spectral band copying is spectral insertion, and the advanced form of spectral band copying is harmonic transposition.

In some embodiments, the padding data also includes additional eZVE metadata (ie, non-flag eZVE metadata).

The memory can be a buffer memory (for example, the implementation of the buffer 201 in Fig. 4), which stores (for example, in a non-volatile manner) at least one block of an encoded audio bit stream.

It is assumed that the complexity of processing e5VK (with the use of tools of harmonic transposition, pre-smoothing and inter-TE5 ezvKK) with the help of the eZzVEK decoder during the decoding of the MRES-4 AAS bit stream, which includes ezVK metadata (indicating these ezVEK tools) will be as follows (for a typical 60 decoding with the specified parameters):

- Harmonic transposition (16 Kbit/s, 14400/28800 Hz) -- based on OET: 3.68 MUMORZ5Z (weighted million operations per second); -- based on OME: 0.98 M/MOR5; - Pre-treatment of OME insert (pre-smoothing): 0.1 M/MOR5; and - Formation of a time loop of counts between sub-bands (inter-TE5): to a greater extent 0.16

M/MORB.

OET-based transposition is known to generally perform better than OME-based transposition for transients.

According to some embodiments of the present invention, the padding element (of the encoded audio bitstream) that includes the ezVK metadata also includes a parameter (e.g., the parameter "p5 ehiepviop iy"), the value of which (e.g. p5 ehieppiop iy4-3) signals that EZVK metadata is included in the padding element, and that EZVK processing should be performed on the content of the audio relevant block, and/or a parameter (for example, this same parameter "p5 echivpbiop iy") whose value (eg, p5 echivpbiop id-2 ) signals that the container 5bg ehiepsiop() of the filling element includes P5 data. For example, as shown in Table 1 below, such a parameter having a value of p5 ehiepsiop iii-2 may signal that the container 5bg ehiepsiop) of the padding element includes P5 data, and such a parameter having a value of p5 ehiepsiop id-3 , can signal that the container 5бг ехиепсиоп() of the filling element includes the eZzVE metadata:

Table 1 threads En NOYA 0000111 vareyurvovayu 11lneoyuyu0 1

According to some embodiments of the invention, the syntax of each additional spectral band copying element that includes eZVE metadata and/or P5 data is as indicated in Table 2 below, "where (5bg ehiepsiop()" means a container that is an additional copying element spectral band, "b5 ehiepbviop her" is described in Table 1 above, "p5 daia" means P data, and "ezbg daia" means ezZVK metadata):

Table 2 5Bg ehiepviop (re ehiepsiop iy, pit biiye Iey) ny shi

PO NIKY PIKA nn PO I save ECHTEMIUM 10. EVE: ni ni nn I I 00000000

AIR FORCE OF NIKY PIKA

POOOO and POKI KOH

Approx. 1: ro daia() returns the number of bits counted.

Approx. 2: ezbg adaga0 returns the number of bits counted.

Approx. 3: parameter B5 PT bBii5 contains M bits, where M-pyt biv ey.

In an illustrative variant of the implementation of ezbg daia(), mentioned in Table 2 above, indicates the value of the following metadata parameters: 1. each of the one-bit metadata parameters described above "nappopis5 VA"; "p5 ipivgtTE5"; i"r5 5bg rhergosezvipa"; 2. for each channel ("sp") of the content of the audio coded bit stream to be decoded, each of the parameters described above: "vBgRaispipamMode!|sni"; "vBgOmegazatriipoNiad(sni"; "zBbgRISPIpVip5 Radius)"; and "bgRYSAIpVipvi(sp1); and

C. for each surround ZVE ("epu") of each channel ("si") of the content of the audio coded bitstream to be decoded, each of the 3 parameters described above: then (spTCI (epmi|»).

For example, in some embodiments, ezbg daia(/) may have the syntax shown in Table 3 to specify these metadata parameters:

Table Z teo 00100101 pcs: nin s NOYA orders 101 p nn pcs KO PO 7 tnonateiuniyuh 1111001 oevenyuvnnayayu 11111001 nin tn lo POYA p nn tele 000101110000011 0 oteesesuretyuvnsnem; pPO111011

In table C, the number in the central column indicates the number of bits of the corresponding parameter in the left column.

The above syntax allows for an efficient implementation of an advanced form of spectral band copying, such as harmonic transposition, as an extension to the earlier decoder. More specifically, the e5BE data in Table C include only those parameters necessary to perform an extended form of spectral band copying, which are either not already supported in the bitstream, or can be directly derived from parameters already supported in the bitstream. All other parameters and processing data required to perform the advanced form of spectral band copying are extracted from pre-existing parameters at pre-defined locations in the bitstream. This is in contrast to an alternative (and less efficient) implementation that simply passes all the processing metadata used for extended spectral band copying.

For example, a decoder compatible with MPEC-4 NON-AAS or NON-AAS m2 can be extended to include an advanced form of spectral band copying, such as harmonic transposition. This advanced form of spectral band copying complements the basic form of spectral band copying already supported by the decoder. In the context of a decoder compatible with

MRES-4 NON-ADS or NON-AAS m2, this basic form of spectral band copying is the OME 5VE spectral insertion tool, as specified in section 4.6.18 of the MRES-4 DAS standard.

When performing an advanced form of spectral band copying, an advanced decoder

NON-AAS can re-use many bitstream parameters already included in the additional payload of the RMS. bit stream. Specific parameters that can be reused include, for example, the various parameters that define the main table of frequency bands. These parameters include p5 5iagi yed (a parameter that defines the beginning of the main frequency table parameter), b5 5ior yed (a parameter that defines the end of the main frequency table), 05 yed 5saIe (a parameter that defines the number of frequency bands per octave), and Бб5 ayeg 5saiie (a parameter that changes the scale of frequency ranges).

Parameters that can be reused also include the parameters that define the noise band table (05 bit Bapi5) and the limiter band table parameters (65 Itieg Brapabv).

In addition to the numerous parameters, other data elements may also be reused by the extended NO-AAS decoder when performing an extended form of spectral band copying according to embodiments of the invention. For example, envelope data and noise floor data can also be extracted from p5 daia epm and B5 poiibze epm data and used during an extended form of spectral band copying.

Essentially, these implementation options use the configuration parameters and bypass data, already supported by the non-AAS or non-AAS m2 decoder of previous versions, in the additional payload of the ZVE to enable an advanced form of spectral band copying, requiring as little additional transmitted data as possible. Accordingly, extended decoders that support an extended form of spectral band copying can be built very efficiently by relying on already defined bitstream elements (e.g., in the additional ZVEK payload) and adding only those parameters that are required to support the extended form of copying spectral band (in the additional payload of the filling element). This data reduction feature, combined with the placement of newly added parameters in a reserved data field such as an extra container, greatly reduces the barriers to creating a decoder that supports extended spectral band copying, ensuring that the bitstream is backward compatible with the decoder of previous versions , which does not support the extended form of spectral band copying.

In some embodiments, the invention is a method comprising the step of encoding audio data to form an encoded bitstream (eg, a bitstream

MPRES-4 AAS), including by including metadata of ezVvkK, at least, in one segment of at least one block of the coded bit stream and audio data, at least in one more segment of the block. In typical embodiments, the method includes the step of multiplexing audio data with e5VK metadata in each block of the encoded bit stream. In a typical decoding of an encoded bitstream in an ezVE decoder, the decoder extracts eb5VEC metadata from the bitstream (including parsing and demultiplexing the ezVE metadata and audio data) and uses the ezVE metadata to process the audio data to form a stream of decoded audio data.

Another aspect of the invention is an ezVE decoder configured to perform ezVK processing (eg, using at least one of the ezVK tools known as harmonic transposition, pre-smoothing, or inter-TE5) when decoding an encoded audio bitstream (eg, an MPEC bitstream 4 AAS), which does not include e5VK metadata. An example of such a decoder will be described with reference to fig. 5.

Decoder (400) eZVEK in fig. 5 includes a buffer memory 201 (which is identical to memory 201 in Figs. 3 and 4), a bitstream payload deformatting unit 215 (which is identical to a deformatting unit 215 in Fig. 4), an audio decoding subsystem 202 ( which is sometimes referred to as the "base" decoding module or "base" decoding subsystem, which is identical to the base decoding subsystem 202 of FIG. 3), the e5ZVE control data generation subsystem 401, and the eZVE processing module 203 (which is identical to the module 203 of FIG. 3), with 'connected as shown. Typically, the decoder 400 also includes other processing elements (not shown).

In the operation of the decoder 400, the sequence of blocks of the coded audio bit stream (MRES-4 AAS bit stream), received by the decoder 400, is moved from the buffer 201 to the block 215 of removing formatting.

The deformatting unit 215 is connected and configured to demultiplex each block of the bit stream in order to extract the BE metadata (including quantized envelope data) and, typically, other metadata as well. Block 215 of removing formatting is made with the ability to place, at least, metadata of ZVK in module 203 of e5BE processing. The deformatting unit 215 is also connected and configured to extract audio data from each block of the bit stream and place the extracted audio data into the decoding subsystem 202 (decoding module).

The decoding subsystem 202 of the audio decoder 400 is configured to decode the audio data extracted by the deformatting unit 215 (such decoding may be referred to as a "base" decoding operation) to form decoded audio data, and to place the decoded audio data into the e5BE processing module 203. Decoding is performed in the frequency domain.

Typically, the final stage of processing in subsystem 202 applies a frequency-domain-to-time-domain transformation to the decoded audio data of the frequency domain, so that the output of the subsystem is the decoded audio data in the time domain. Module 203 is made with the ability to use VC tools (and ezVK tools) specified using 5VE metadata (extracted by the formatting removal unit 215) and evk metadata,

Co) formed in the subsystem 401, to the decoded audio data (ie, perform ZVK processing and eZzVK processing at the output of the decoding subsystem 202 using the 5VE metadata and the ezVK metadata) to form the fully decoded audio data that is output from the decoder 400. Typically, the decoder 400 includes memory (accessible to subsystem 202 and module 203) that stores deformatted audio data and metadata output from deformatting unit 215 (and optionally also subsystem 401), and module 203 is configured to access audio data and metadata as necessary during processing

ZVE and ezVK processing. The processing of 5VE in 203 can be considered as further processing at the output of the main decoding subsystem 202. Optionally, the decoder 400 also includes a final up-mixing subsystem (which can apply the parametric stereo ("P5") tools specified in the MPEC-4 AAS standard using metadata

P5 extracted by deformatting unit 215) which is connected and configured to perform up-mixing on the output of module 203 to form fully decoded, up-mixed audio output from ARI unit 210.

Control data generation subsystem 401 in fig. 5 is connected and configured to detect at least one property of the encoded audio bitstream to be decoded and to generate the control data ezVkC (which may be or include ezVK metadata of any of the types included in the encoded audio bitstreams and according to other embodiments of the invention) in response to at least one result of the detection step.

Control data ezVE is placed in the module 203 to initiate the application of individual ezVK tools or a combination of e5VE tools upon detection of a given property (or combination of properties) of the bitstream, and/or to control the application of such e5VK tools. For example, to control the operation of eZzVK processing using harmonic transposition, some embodiments of the control data generation subsystem 401 include: a music sensor (eg, a simplified version of a traditional music sensor) to set the parameter 5BbgRaispipaMoade|stp| (ii placing the set parameter in module 203) in response to detecting that the bit stream indicates or does not indicate music; a transition sensor for setting the parameter 5bgOmegazatriipoRiIad(sp) (and placing the set parameter in module 203) in response to detecting the presence or absence of transients in the audio content indicated by the bit stream; and/or the tone sensor for setting the parameters and zbBgRSspIpVip5Isp| (and placing the set parameters in module 203) in response to detecting the tone of the audio content specified by the bitstream. Other aspects of the invention are methods of decoding an audio bit stream, performed using any embodiment of the decoder of the invention described in this paragraph and the previous paragraph.

Aspects of the invention include a method of encoding or decoding the type that any embodiment of the AR unit, system, or device of the invention is capable of performing (eg, programmed). Other aspects of the invention include a system or device configured to (eg, programmed) to perform any embodiment of the method of the invention, and a machine-readable medium (eg, a disk) that stores code (eg, in a non-volatile manner) to implement any variant implementation of the method of the invention or its stages. For example, the system of the invention may be or include a general purpose programmable processor, digital signal processing processor, or microprocessor programmed by software or hardware and/or otherwise configured to perform any number of operations on data, which include a variant of the method of the invention or its stages. Such a general-purpose processor may be or include a computer system including an input device, memory, and processing circuitry programmed (and/or otherwise capable of) performing an embodiment of the method of the invention (or steps thereof ) in response to the data placed in it.

Embodiments of the present invention may be implemented in hardware, software, or software, or a combination thereof (eg, as a programmable logic array). Unless otherwise specified, the algorithms or processes included as part of the invention do not originally belong to any particular computer or other device. In particular, various general-purpose machines may be used with programs written according to the ideas in this document, or it may be more convenient to build a more specialized device (eg, integrated circuits) to perform the steps of the desired method. Thus, the invention may be implemented in one or more computer programs running on one or more programmable computer systems (eg, an implementation of any of the elements in FIG. 1, or encoder 100

From in fig. 2 (or its element), or the decoder 200 in fig. With (or its element), or the decoder 210 in fig. 4 (or an element thereof), or the decoder 400 in FIG. 5 (or its element)), each of which includes at least one processor, at least one data storage system (including volatile and non-volatile memory and/or storage elements), at least one device or input port and at least one output device or port. The program code is used to enter data to perform the functions described in the provided document and generate output information. The output information is applied to one or more output devices in a known manner.

Each such program may be implemented in any desired computer language (including machine language, assembly language, or high-level procedural, logical, or object-oriented programming languages) to interact with the computer system. In either case, the language can be a compiled or interpreted language.

For example, when implemented using sequences of computer program instructions, various functions and stages of embodiments of the invention may be implemented using multi-threaded sequences of program instructions operating in suitable digital signal processing hardware, in which case the various devices, modules and functions of the variants implementation may correspond to parts of program commands.

Each such computer program is preferably stored or loaded on a storage medium or device (eg, solid state memory or media, or magnetic or optical media) readable by a general purpose or special purpose programmable computer for configuration and computer operation when a storage medium or device is read by a computer system to perform the procedures described in this document. The system of the invention may also be implemented as a machine-readable storage medium configured by (i.e., storing) a computer program, wherein the storage medium so configured causes the computer system to operate in a specified and predetermined manner to perform functions, described in this document.

A number of embodiments of the invention have been described. However, it should be understood that various modifications may be made without departing from the spirit and scope of the invention. Numerous modifications and variations of the present invention are possible in light of the above ideas. It should be understood that within the scope of the appended claims, the invention can be implemented differently than specifically described in the given document.

Any reference numbers contained in the following claims are for illustrative purposes only and should not be used to construe or limit the claims in any way.

Claims (21)

FORMULA OF THE INVENTION 1. Unit (210) of audio processing, containing: a buffer (201), designed to store at least one block of encoded audio bit stream; block (215) of removing the formatting of the useful data of the bit stream, connected to the buffer and made with the possibility of demultiplexing at least a part of at least one block of the encoded bit stream of audio; and a decoding subsystem (202) connected to the bitstream payload deformatting unit (215) and configured to decode at least a portion of at least one block of the encoded audio bitstream, wherein the at least one block of the encoded audio bitstream includes: a padding element with an identifier indicating the start of a padding element and padding data following the identifier, wherein the padding data includes: at least one flag identifying whether a basic form of spectral band copying or an enhanced form of spectral band copying is to be performed for the audio content of at least one block of an encoded audio bitstream, wherein the basic form of spectral band copying includes spectral interpolation, the enhanced form of spectral band copying includes harmonic transposition, one value of the flag indicates that said enhanced form of spectral band copying is to be performed on the audio content, and the other the value of the flag indicates that said basic form of spectral band copying, rather than said harmonic transposition, should be performed on the audio content. 2. The audio processing unit according to claim 1, in which the padding data additionally includes extended spectral band copying metadata. Zo 3. The audio processing unit according to claim 2, in which the extended spectrum copy metadata is contained in the additional payload of the filler element. 4. The audio processing unit according to any one of claims 2-3, in which the extended spectral band copying metadata includes one or more parameters defining a basic table of frequency bands. 5. The audio processing unit according to any one of claims 2-3, in which the metadata of the extended spectral band copy includes the scale coefficients of the envelope or the scale coefficients of the minimum noise level. b. The audio processing unit of any of the preceding claims, wherein the audio processing unit is an audio decoder, and the identifier is a three-bit unsigned integer to which the most significant bit is transmitted first, and which has a value of Ox6b. 7. The audio processing unit of any of the preceding claims, wherein the padding data includes an additional payload, the additional payload includes additional spectral band copy data, and the additional payload is identified by a four-bit unsigned integer first transmitted significant bit, and having a value of "1101" or "1110", and optionally the additional spectrum copy data includes: an optional spectrum copy header, spectrum copy data after the header, and an additional spectrum copy element after the spectral band copying data, and the first flag is included in the additional spectral band copying element. 8. The audio processing unit according to any of the preceding items, wherein the at least one block of the encoded audio bitstream includes a first padding element and a second padding element, and the spectral band copy data is included in the first padding element and the first flag, but not spectral band copy data included in the second filler element. 9. The audio processing unit of any of the preceding items, wherein the advanced form of spectral band copying processing includes harmonic transposition, the basic form of spectral band copying processing includes spectral interpolation, one value of the first flag indicates that said advanced form of processing spectral band copying must be 60 performed on the audio content of at least one block of the encoded audio bitstream, and a different value of the first flag indicates that spectral interpolation, rather than said harmonic transposition, must be performed on the audio content of at least one block of the encoded audio bitstream. 10. The audio processing unit of claim 7, wherein the extended spectrum copy element includes extended spectrum copy metadata that is different from the first flag, and wherein the extended spectrum copy metadata includes a parameter indicating whether to perform pre-smoothing. 11. The audio processing unit of claim 7, wherein the extended spectral band copying element includes extended spectral band copying metadata that is different from the first flag and the second flag, and wherein the extended spectral band copying metadata includes a parameter indicating whether it is necessary to perform the formation of time bypass counts between sub-ranges. 12. The audio processing unit according to any of the preceding clauses, further comprising an extended spectral band copying processing subsystem (203) configured to perform extended spectral band copying processing using the first flag, and the extended spectral band copying includes harmonic transposition . 13. An audio processing unit according to any of the preceding items, wherein if at least one flag identifies an advanced form of spectral band copying processing, a second flag identifies whether or not signal adaptive oversampling in the frequency domain is available. 14. A method of decoding an encoded audio bitstream, and the method includes the steps of: receiving at least one block of an encoded audio bitstream; demultiplex at least a part of at least one block of the encoded audio bit stream; and decode at least a portion of at least one block of the encoded audio bitstream, wherein the at least one block of the encoded audio bitstream includes: a padding element with an identifier indicating the beginning of the padding element, and padding data after the identifier, and the padding data includes: one flag identifying whether a basic form of spectral band copy processing or an advanced form of spectral band copy processing is to be performed on the audio content of at least one block of the encoded audio bitstream, wherein the basic form of spectral band copy includes spectral insertion, the advanced form of spectral band copy is to be performed includes harmonic transposition, one value of the flag indicates that said enhanced form of spectral band copying is to be performed for audio content, and another flag value indicates that said basic form of spectral band copying, rather than said harmonic transposition, has be performed for audio content. 15. The method according to claim 14, in which the identifier is a three-bit unsigned integer, in which the most significant bit is transmitted first, and such that it has a value of Ох6. 16. The method according to claim 14 or 15, in which the padding data additionally includes extended spectrum copy metadata. 17. The method of any one of claims 14-16, wherein the padding data includes an additional payload, the additional payload includes additional spectral band copy data, and the additional payload is identified by a four-bit unsigned integer that is initially transmitted most significant bit, and having the value "1101" or "1110", and optionally, the additional spectrum copy data includes: optional spectrum copy header, spectrum copy data after the header, additional the spectral band copying element after the spectral band copying data, and the first flag is included in the additional spectral band copying element. 18. The method according to any one of claims 14-17, wherein the advanced form of spectral band copying processing is harmonic transposition, the basic form of spectral band copying processing is spectral insertion, one value of the first flag indicates that said advanced spectral band copying processing should be performed on the audio content of at least one block of the encoded audio bitstream, and a different value of the first flag indicates that spectral interpolation, rather than said harmonic transposition, is to be performed on the audio content of at least one block of the encoded audio bitstream. 19. The method according to claim 17 or claim 18, wherein the additional spectral band copying element includes extended spectral band copying metadata that is not a first flag, and wherein the extended spectral band copying metadata includes a parameter indicating whether to perform pre-smoothing, or wherein the additional spectral band copy element includes enhanced spectral band copy metadata that is different from the first flag, and wherein the enhanced spectral band copy metadata includes a parameter indicating whether to perform time-wrapping between subbands. 20. The method according to any one of claims 14-19, which additionally includes the step of performing the processing of extended copying of the spectral band using the first flag and the second flag, and the extended copying of the spectral band includes harmonic transposition. 21. The method according to any of claims 14-20 or the audio processing unit according to any of claims 1-8, and the coded audio bit stream is the MPRES-4 AAS bit stream. and BIT FLOW MREB-Z AAS i ! y I a input sk vod M dostyavkYi DECODER --o FURTHER oo tIG. ии я т05 я и Т05 AUDIUSE CODERO) - BLOCK nya BUFFER sen BIT FLOW Di sennya 1 BARMATATION FROM ши: MREB-YAA AAS input sk «este sokok v . The ham is the generator of the metadata a "TRO! (Coderi fig. 2 I give the elasticity of the honeycomb of the honeycomb. . ho sh zo oh ho soh xxx xxx oo xxx xxx xxx xxx xxx xxx xxx xxx xxx xxx FIG. From g KT pln nn nn nn nn to mn nn nn nn nn : IBLOJ ARI nn in EX oblique ro FORMAT | ; 5 and I "oo ANNYA / peneyu, and ; oonnnnnnnnnnnnnnnnai 0 METADATA 5VA nn j s 2187 2137 FIG. 4 Uh 00 BIJODR OO 0000000000ayaya 00000 r - PPE i i i z it ! entrance and E Z . DELETE | i r to sha le MNN, o t eerdtor y in KE ben kvrRuval BITS PROCESSING: yo e5VE shi tn nn tek nizel len yah teh not same pek ono okho zhk ya lek yah eh ya kyu okt zn ya en FIG. 5 ENTRANCE TO THE BATTLE (BLOCKERS 0) -2O0i FIG. b EYAEMENT beer CHANNEL rea unnnentn on rent si i ; Е и И З Z Я is И ; ; и: not NO; and and and Z and I Mak 3 MORE: I Shi SHON run yang - flag tot What - and her . What is the food? 7