RU2376656C1 - Audio signal coding and decoding method and device to this end - Google Patents

Abstract

FIELD: physics; acoustics.

SUBSTANCE: invention relates to audio signal processing. Spatial information related to an audio signal is coded in a bit stream which can be transmitted to a decoder or recorded on a data carrier. The bit stream has a different syntax, which is related to time, frequency and space domains, and also includes one or more data structures (for example frames) which contain ordered sets of time intervals with certain parametres. The data structures can be fixed or varying. An indicator of the type of data structure is included in the bit stream so that the decoder can determine types of data structures and start the corresponding decoding process. The data structure includes information on position, which is used by the decoder to identify the correct time interval for which a given set of parametres is applied. The information on position of the time interval is coded using a fixed number of bits or a varying number of bits based on the type of the data structure, indicated by data structure type indicator. For a varying type data structure, information on position is coded using a varying number of bits based on the position of the time interval in the ordered set of time intervals.

EFFECT: transmission of a multichannnel audio signal at low bit rate.

19 cl, 26 dwg

Description

FIELD OF THE INVENTION

The subject matter of this application relates generally to audio processing.

State of the art

Research is currently underway and new approaches are being developed for perceptual coding of multi-channel audio, which is commonly referred to as spatial audio coding (SAC). SAC allows you to transmit multi-channel audio with low bit rates, which allows you to use SAC for many popular audio applications (for example, streaming over the Internet, downloading music).

Instead of performing discrete coding of individual input audio channels, when using SAC, a spatial image of a multi-channel audio signal is recorded in a compact set of parameters. These parameters can be transmitted to the decoder, where they are used to synthesize or restore the spatial properties of the audio signal.

In some SAC related applications, spatial parameters are transmitted to the decoder as part of the bitstream. The bitstream includes spatial frames that contain ordered sets of time intervals for which sets of spatial parameters can be applied. The bitstream also includes position information that can be used by the decoder to identify the correct time interval for which a given set of parameters is applied.

In some SAC applications, conceptual elements are used in the coding / decoding paths. One element is usually called a one-to-two (OTT) element, and the other element is usually called a two-to-three (TTT) element, where these names include the number of input and output signals of the corresponding decoder element. The OTT encoder element extracts two spatial parameters and produces a signal resulting from the downmix and a residual signal. The TTT element down-mixes the three audio signals, resulting in a stereo signal after down-mixing plus a residual signal. These elements can be combined to create a variety of spatial audio environment configurations (such as surround sound).

Some SAC applications can operate in uncontrolled operating mode, when only the stereo signal is transmitted from the encoder to the decoder after down-mixing without the need for spatial parameters. The decoder synthesizes spatial parameters from the signal obtained as a result of the down-mix, and uses these parameters to create a multi-channel audio signal.

SUMMARY OF THE INVENTION

The spatial information associated with the audio signal is encoded into a bitstream that can be transmitted to a decoder or recorded on a storage medium. The bitstream may contain various syntax related to the time, frequency and spatial domains. In some embodiments, the bitstream includes one or more data structures (eg, frames) that contain ordered sets of time slots for which certain parameters can be applied. These data structures can be fixed or variable. An indicator of the type of data structure can be inserted into the bitstream to enable the decoder to determine the type of data structure and initiate the corresponding decoding process. The data structure may include position information that can be used by the decoder to identify the correct time interval for which a given set of parameters is applicable. The information about the position of the time interval can be encoded using a fixed number of bits or a variable number of bits depending on the type of data structure indicated by the indicator of the type of data structure. For a variable-type data structure, time slot position information can be encoded using a variable number of bits based on the position of the time slot in an ordered set of time slots.

In some embodiments, an audio encoding method includes: determining the number of time slots and the number of parameter sets, the parameter sets including one or more parameters; creating information indicating the position of at least one time interval in an ordered set of time intervals for which a set of parameters is applied; encoding an audio signal in the form of a bit stream including a frame, this frame comprising an ordered set of time intervals; and inserting a variable number of bits into the bitstream, which represent the position of the time interval in an ordered set of time intervals, where the variable number of bits is determined by the position of the time interval.

In some embodiments of the invention, a method for decoding an audio signal includes: receiving a bit stream representing an audio signal, the bit stream comprising a frame; determining the number of time slots and the number of parameter sets from the bitstream, the parameter sets including one or more parameters; determining position information from the bitstream, wherein the position information indicates a position of a time interval in an ordered set of time intervals for which a specified set of parameters is applied, where an ordered set of time intervals is contained in the specified frame; and decoding the audio signal based on the number of time slots, the number of parameter sets and position information, where the position information is represented by a variable number of bits based on the position of the time interval.

Disclosed are other options for encoding the position of the time interval, which relate to systems, methods, devices, data structures and computer-readable media.

It should be understood that the foregoing general description and the following detailed description of embodiments of the invention are illustrative and explanatory and suggest further clarification of the claimed invention.

Brief Description of the Drawings

The accompanying drawings, which are included here for a deeper understanding of the invention and form part of this application, illustrate an embodiment (s) of the invention and together with the description serve to explain the principles underlying the present invention. In the drawings:

FIG. 1 is a diagram illustrating the principle of creating spatial information according to one embodiment of the present invention;

FIG. 2 is a block diagram of an encoder for encoding an audio signal according to one embodiment of the present invention;

FIG. 3 is a block diagram of a decoder for decoding an audio signal according to one embodiment of the present invention;

FIG. 4 is a block diagram of a channel conversion module contained in an upmix unit included in a decoder according to one embodiment of the present invention;

FIG. 5 is a diagram explaining a method for configuring an audio bitstream according to one embodiment of the present invention;

FIG. 6A and 6B are a time / frequency diagram and graph explaining the relationships between a set of parameters, a time interval, and parametric ranges according to one embodiment of the present invention;

FIG. 7A is an illustration of a syntax representing spatial information signal configuration information according to one embodiment of the present invention;

FIG. 7B is a table for several parametric ranges of a spatial information signal according to one embodiment of the present invention;

FIG. 8A is an illustration of a syntax representing several parameter ranges applicable to an OTT block as a fixed number of bits, according to one embodiment of the present invention;

FIG. 8B is an illustration of a syntax representing several parametric ranges applicable to an OTT block using a variable number of bits according to one embodiment of the present invention;

FIG. 9A is an illustration of a syntax representing several parameter ranges applicable to a TTT block as a fixed number of bits, according to one embodiment of the present invention;

FIG. 9B is an illustration of a syntax representing several parametric ranges applicable to a TTT block using a variable number of bits according to one embodiment of the present invention;

FIG. 10A is an illustration of the syntax of spatial extension configuration information for a spatial extension frame according to one embodiment of the present invention;

FIG. 10B and 10C illustrate syntaxes of spatial extension configuration information for a residual signal when the residual signal is contained in a spatial extension frame according to one embodiment of the present invention;

FIG. 10D illustrates syntax for a method for representing the number of parametric ranges for a residual signal according to one embodiment of the present invention;

FIG. 11A is a block diagram of a decoding apparatus using uncontrolled coding according to one embodiment of the present invention;

FIG. 11B is a diagram for a method for representing the number of parametric ranges in a single group according to one embodiment of the present invention;

FIG. 12 is an illustration of the syntax of spatial frame configuration information according to one embodiment of the present invention;

FIG. 13A is an illustration of a syntax of position information of a time interval for which a set of parameters is applied, according to one embodiment of the present invention;

FIG. 13B is an illustration of a syntax for presenting position information of a time interval for which a set of parameters is applied as an absolute value and a difference value according to one embodiment of the present invention;

FIG. 13C is a diagram representing a plurality of information about the position of time intervals for which sets of parameters are applied, as a group according to one embodiment of the present invention;

FIG. 14 is a flowchart of an encoding method according to one embodiment of the present invention;

FIG. 15 is a flowchart of a decoding method according to one embodiment of the present invention; and

FIG. 16 is a block diagram of a device architecture for implementing the encoding and decoding processes described with reference to FIGS. 1-15.

Best Mode for Carrying Out the Invention

In FIG. 1 is a diagram illustrating the principle of creating spatial information according to one embodiment of the present invention. The perceptual coding scheme for multichannel audio signals is based on the fact that a person can perceive audio signals through three-dimensional space. This three-dimensional space of the audio signal can be represented using spatial information, including, but not limited to, the following known spatial parameters: channel level differences (CLD), inter-channel correlation / coherence (ICC), channel variance (CTD), channel prediction coefficients (CPC) ) etc. The CLD parameter describes the differences in energy (level) between the two audio channels, the ICC parameter describes the correlation or coherence between the two audio channels, and the CTD parameter describes the time difference between the two audio channels.

The creation of CTD and CLD parameters is shown in FIG. 1. The first direct sound wave 103 from a distant sound source 101 enters the left human ear 107, and the second direct sound wave 102 diffracts around the person’s head, reaching his right ear 106. The direct sound waves 102 and 103 differ in arrival time and level energy. The CTD and CLD parameters can be created based on differences in the arrival times and energy levels of the sound waves 102 and 103, respectively. In addition, reflected sound waves 104 and 105, respectively, which do not have mutual correlation, enter the ears 106 and 107. The ICC parameter can be created based on the correlation between the sound waves 104 and 105.

In the encoder, spatial information (for example, spatial parameters) is extracted from the multi-channel input audio signal and a signal is generated that is the result of downmixing. The signal after down-mixing and spatial parameters are transmitted to the decoder. For the signal after down-mixing, you can use any number of audio channels, including, but not limited to: mono signal, stereo signal or multi-channel audio signal. In the decoder, a multi-channel signal is created from the signal after down-mixing and spatial parameters, which is the result of up-mixing.

In FIG. 2 is a block diagram of an encoder for encoding an audio signal according to one embodiment of the present invention. The encoder includes a downmix unit 202, a spatial information creation unit 203, a signal encoding unit 207 after the downmix, and a multiplexing unit 209. Other encoder configurations are possible. Encoders can be implemented in hardware, software, or as a combination of hardware and software. Encoders can be implemented in integrated circuits, chipsets, single-chip system (SoC), digital signal processors, general-purpose processors, and various digital and analog devices.

The downmix unit 202 creates from the multi-channel audio signal 201 a signal 204 resulting from the downmix. 2, x ₁ , ..., x _n indicate input audio channels. As mentioned above, the downmix signal 204 may be a mono signal, a stereo signal, or a multi-channel audio signal. In the example shown, x ' ₁ , ..., x' _m indicate the number of channels of the signal 204 after down-mixing. In some embodiments, the encoder, instead of the downmix signal 204, processes the downmix signal 205, which is supplied externally (e.g., downmix to create artistic effects).

The spatial information generating unit 203 extracts spatial information from the multi-channel audio signal 201. In this case, the term “spatial information” refers to information related to the audio channels used in up-mixing of the signal 204 after down-mixing to obtain multi-channel audio in the decoder. The downmix signal 204 is created by downmixing a multi-channel audio signal. Spatial information is encoded to provide an encoded signal 206 with spatial information.

The downmix signal encoding unit 207 creates an encoded downmix signal 208 by encoding the downmix signal 204 created in the downmix unit 202.

The multiplexing unit 209 creates a bitstream 210 including an encoded signal 208 after down-mixing and an encoded signal 206 with spatial information. Bitstream 210 may be transmitted to a subsequent decoder and / or recorded on a storage medium.

FIG. 3 is a block diagram of a decoder for decoding an encoded audio signal according to one embodiment of the present invention. The decoder includes a demultiplexing unit 302, a downmix signal decoding unit 305, a spatial information decoding unit 307, and an upmix unit 309. Decoders can be implemented in hardware, software, or as a combination of hardware and software. Decoders can be implemented in integrated circuits, chipsets, single-chip system (SoC), digital signal processors, general-purpose processors, and various digital and analog devices.

In some embodiments, the demultiplexing unit 302 receives a bitstream 301 representing an audio signal, and then extracts the encoded signal 303 from the bitstream 301 after down-mixing and the encoded signal 304 with spatial information. In Fig. 3, x ' ₁ , ..., x' _m indicates the channels of signal 303 after down-mixing. The downmix signal decoding unit 305 outputs the decoded downmix signal 306 by decoding the encoded downmix signal 303. If the decoder is not capable of delivering a multi-channel audio signal, then the downmix signal decoding unit 305 can directly output the downmix signal 306. 3, y ′ ₁ , ..., y ′ _m indicate the direct output channels of the downmix signal decoding unit 305.

The spatial information signal decoding unit 307 extracts the spatial information signal configuration information from the encoded spatial information signal 304, and then decodes the spatial information signal 304 using the extracted configuration information.

The upmixing unit 309 may perform upmixing the downmix signal 306 to obtain a multi-channel audio signal 310 using the extracted spatial information 308. In FIG. 3, y ₁ , ..., y _n indicate a number of output channels of the upmixing unit 309.

Figure 4 presents a block diagram of a channel conversion module, which can be included in the block 309 up-mixing in the decoder shown in figure 3. In some embodiments, upmix unit 309 may include multiple channel conversion modules. The channel conversion module is a conceptual device that can distinguish the number of input channels from the number of output channels using special information.

In some embodiments, the channel conversion module may include an OTT block (one to two) for converting one channel to two channels, and vice versa, and a TTT block (two to three) for converting two channels to three channels, and vice versa. OTT and / or TTT blocks can be arranged using many different useful configurations. For example, the upmix unit 309 shown in FIG. 3 may include a configuration 5-1-5, a configuration 5-2-5, a configuration 7-2-7, a configuration 7-5-7, etc. In configuration 5-1-5, a signal having one channel after downmixing is created by downmixing five channels into one channel, which can then be upmixed to five channels. Similarly, other configurations can be created using various combinations of OTT and TTT blocks.

Referring to FIG. 4, an example 5-2-5 configuration for upmix unit 400 is shown. In the configuration 5-2-5, the signal 401, which after downmixing has two channels, is input to the upmixing unit 400. In the example shown, the left channel (L) and the right channel (R) are provided as inputs to the upmix unit 400. In this embodiment, the upmix block 400 includes one TTT block 402 and three OTT blocks 406, 407 and 408. A signal 401, which has two channels after downmix, is supplied as input to the TTT block (TTTo) 402, which processes signal 401 after down-mixing and provides three channels 403, 404 and 405 as output signals. One or more spatial parameters (for example, CPC, CLD, ICC) that are used to process signal 401 can be provided as input to the TTT block 402 after down mix i as described below. In some embodiments, a residual signal may be selectively provided as input to the TTT 402. In this case, the CPC parameter can be determined as a prediction coefficient for creating three channels from two channels.

Channel 403, which is provided as an output from the TTT block 402, is an input to the OTT block 406, which creates two output channels using one or more spatial parameters. In the example shown, the two output channels represent the positions of the front left (FL) and rear left (BL) speakers, for example, in a surround sound environment. Channel 404 is provided as an input to the OTT block 407, which creates two output channels using one or more spatial parameters. In the example shown, the two output channels represent the positions of the front right (FR) and rear right (BR) speakers. Channel 405 is provided as an input to the OTT block 408, which creates two output channels. In the example shown, two output channels represent the position of the center (C) speaker and the low-frequency optimization (LFE) channel. In this case, spatial information (e.g., CLD, ICC) may be provided as an input for each of the OTT blocks. In some embodiments, residual signals (Res1, Res2) may be provided as inputs to the OTT blocks 406 and 407. In the indicated embodiment, the residual signal may not be provided as an input signal to the OTT 408 block, which provides the central channel and the LFE channel.

The configuration shown in FIG. 4 is one example configuration for a channel transform module. Other configurations for the channel conversion module are possible, including various combinations of OTT and TTT blocks. Since each of the channel conversion modules can operate in the frequency domain, it is possible to determine the number of parametric ranges applicable to each of the channel conversion modules. A parameter range means at least one frequency range applicable to one parameter. A number of parametric ranges are described with reference to FIG.

5 is a diagram illustrating a method for configuring an audio bitstream according to one embodiment of the present invention. Fig. 5 (a) shows a bit stream of an audio signal including only a spatial information signal, and Figures 5 (b) and 5 (c) show bit streams of an audio signal including a downmix signal and a spatial information signal.

Referring to FIG. 5 (a), where the audio bitstream may include configuration information 501 and frame 503. Frame 503 may be repeated in the bitstream, and in some embodiments, include a single spatial frame 502 containing spatial audio information.

In some embodiments, the configuration information 501 includes information describing the total number of time slots in one spatial frame 502, the total number of parametric ranges covering the frequency range of the audio signal, the number of parametric ranges in the OTT block, the number of parametric ranges in the TTT block, and the number of parametric ranges in the residual signal. If necessary, other information may be included in the configuration information 501.

In some embodiments, the spatial frame 502 includes one or more spatial parameters (eg, CLD, ICC), the type of frame, the number of parameter sets in one frame, as well as time intervals for which parameter sets can be applied. Optionally, other information may be included in the spatial frame 502. The meaning and value of the configuration information 501 and the information contained in the spatial frame 502 are explained below with reference to figures 6 through 10.

Referring to FIG. 5 (b), where the bitstream of an audio signal may include configuration information 504, a downmix signal 505 and a spatial frame 506. In this case, one frame 507 may include a downmix signal 505 and a spatial frame 506, the frame 507 may be repeated in the bitstream.

Referring to FIG. 5 (c), where the bitstream of an audio signal may include a downmix signal 508, configuration information 509 and a spatial frame 510. In this case, one frame 511 may include configuration information 509 and a spatial frame 510 moreover, frame 511 in the bitstream may be repeated. If configuration information 509 is inserted in each frame 511, then the audio signal may be reproduced by the reproducing apparatus from an arbitrary location.

Although FIG. 5 (c) shows that configuration information 509 is inserted into the bitstream using frame 511, it should be apparent that configuration information 509 can be inserted into the bitstream using a plurality of frames that are repeated periodically or periodically .

Figures 6A and 6B are diagrams illustrating the relationships between a set of parameters, a time interval, and parametric ranges according to one embodiment of the present invention. A set of parameters indicates one or more spatial parameters used for a single time interval. Spatial parameters may include spatial information such as CDL, ICC, CPC, etc. A time interval means an interval of an audio signal for which spatial parameters can be applied. One spatial frame may include one or more time slots.

Referring to FIG. 6A, where in a spatial frame several sets of parameters 1, ..., P can be used, and each set of parameters can include one or more data fields 1, ..., Q-1. The set of parameters can be applied to the entire frequency range of the audio signal, and each spatial parameter in the set of parameters can be applied to one or more parts of the frequency band. For example, if a set of parameters includes 20 spatial parameters, then the entire frequency band of the audio signal can be divided into 20 zones (hereinafter referred to as “parametric ranges”), and for 20 parametric ranges you can apply 20 spatial parameters from this set of parameters. Parameters can be applied to parametric ranges based on specific requirements. For example, spatial parameters can be applied to low-frequency parametric ranges without discharge, and to high-frequency parametric ranges with discharge.

Turning to FIG. 6B, a time / frequency graph shows the relationship between parameter sets and time intervals. In the shown example, three sets of parameters (set of 1 parameters, set of 2 parameters, set of 3 parameters) are used for an ordered set of 12 time intervals in one spatial frame. In this case, the entire frequency range of the audio signal is divided into 9 parametric ranges. Thus, the horizontal axis indicates the number of time intervals, and the vertical axis indicates the number of parametric ranges. Each of the three sets of parameters is applied to a specific time interval. For example, the first set of parameters (set of 1 parameters) is used for time interval # 1, the second set of parameters (set of 2 parameters) is used for time interval # 5, and the third set of parameters (set of 3 parameters) is used for time interval # 9. The parameter sets can be applied to other time intervals by interpolating and / or copying the parameter sets for these time intervals. In general, the number of parameter sets may be less than or equal to the number of time intervals, and the number of parametric ranges may be less than or equal to the number of frequency bands of the audio signal. By encoding spatial information for some parts of the time-frequency region of the audio signal, instead of doing this for the entire time-frequency region of the audio signal, it is possible to reduce the amount of spatial information sent from the encoder to the decoder. This reduction in the amount of data is possible because, according to the well-known principles of perceptual audio coding of discharged information in the time-frequency range of frequencies, it is often enough for a person to perceive sound.

An important feature of the embodiments disclosed herein is the encoding and decoding of the positions of time slots for which sets of parameters are applied using a fixed or variable number of bits. The number of parametric ranges can also be represented by a fixed number of bits or a variable number of bits. A coding scheme with a variable number of bits can also be applied to other information used in spatial audio coding, including, but not limited to, information related to the time, spatial and / or frequency domains (for example, for several frequency subbands at the output of a comb filters).

FIG. 7A shows a syntax for representing spatial information signal configuration information according to one embodiment of the present invention. The configuration information includes a plurality of fields 701 to 718, to which a number of bits can be assigned.

The “bsSamplingFreqencyIndex” 701 field indicates the sampling rate obtained from the sampling process of the audio signal. To represent the sampling rate, 4 bits are allocated to the “bsSamplingFreqencyIndex” 701 field. If the value of the “bsSamplingFreqencyIndex” 701 field is 15, that is, the binary number 1111, then the “bsSamplingFreqency” 702 field is added to represent the sampling frequency. In this case, the “bsSamplingFreqency” 702 field is allocated 24 bits.

Field “bsFrameLength” 703 indicates the total number of time intervals (hereinafter referred to as “numSlots”) in one spatial frame, and between “numSlots” and field “bsFrameLength” 703, the relation NumSlots = bsFrameLength + 1 can take place.

The “bsFreqRes” field 704 indicates the total number of parametric ranges covering the entire frequency domain of the audio signal. The “bsFreqRes” field 704 is explained below in FIG.

The “bsTreeConfig” field 705 indicates information for a tree configuration including a plurality of channel conversion modules, such as those described with reference to FIG. 4. Information for the tree configuration includes information such as the type of channel conversion module, the number of channel conversion modules, the type of spatial information used in the channel conversion module, the number of audio input / output channels, etc.

The tree configuration can have one of the following configurations: configuration 5-1-5, configuration 5-2-5, configuration 7-2-7, configuration 7-5-7, etc., according to the type of channel conversion module or number of channels. Figure 4 shows the tree configuration 5-2-5.

Field 706 “bsQuantMode” indicates information about the quantization mode of spatial information.

The bsOneIcc field 707 indicates whether a single subset of ICC parameters is used for all OTT blocks. In this case, a subset of parameters means a set of parameters applied for a specific time interval and a specific channel conversion module.

The “bsArbitraryDownmix” field 708 indicates the presence or absence of an arbitrarily selected gain during downmix. The “bsFixedGainSur” field 709 indicates the gain applied to the surround channel, such as LS (left surround channel) and RS (right surround channel).

The “bsFixedGainLF” field 710 indicates the gain applied to the LFE channel.

The “bsFixedGainDM” field 711 indicates the gain applied to the signal resulting from the downmix.

The “bsMatrixMode” 712 field indicates whether a matrix-compatible stereo signal is generated in the encoder after down-mixing.

The “bsTempShapeConfig” 713 field indicates the operating mode of temporal shaping (eg, TES (temporal envelope shaping) and / or TP (temporal shaping)) in the decoder.

The “bsDecorrConfig” field 714 indicates the operational mode of the decoder decorrelator.

And the “bs3DaudioMode” field 715 indicates whether the signal after downmixing is encoded into a 3D (three-dimensional) signal and whether processing using the inverse HRTF function (human perception modeling function) is used.

After the information from each field in the encoder / decoder has been determined / extracted, information for the number of parametric ranges used for the channel conversion module is determined / extracted in the encoder / decoder. First, the number of parametric ranges used for the OTT block is determined / extracted (716), and then the number of parametric ranges used for the TTT block is determined / extracted (717). The number of parametric ranges for the ATT block and / or the TTT block will be described in detail with reference to figures 8A through 9B.

In the case where an extension frame exists, the “spatialExtensionConfig” block 718 includes configuration information for the extension frame. The information included in the spatialExtensionConfig block 718 is described below with reference to Figures 10A through 10D.

7B is a table for the number of parametric ranges of a spatial information signal according to one embodiment of the present invention. “NumBands” indicates the number of parametric ranges for the entire frequency domain of the audio signal, and “bsFreqRes” indicates index information for the number of parametric ranges. For example, the entire frequency domain of an audio signal can be optionally divided into several parametric ranges (for example, 4, 5, 7, 10, 14, 20, 28, etc.).

In some embodiments, one parameter may be applied for each parametric range. For example, if “numBands” is 28, then the entire frequency domain of the audio signal is divided into 28 parametric ranges and each of 28 parameters can be applied to each of 28 parametric ranges. In another example, if “numBands” is 4, then the entire frequency domain of this audio signal is divided into 4 parametric ranges and each of 4 parameters can be applied to each of the 4 parametric ranges. 7B, the term “Reserved” means that the number of parametric ranges for the entire frequency domain of a given audio signal is not defined.

It should be noted that the human hearing organ is not sensitive to the number of parametric ranges used in the coding scheme. Thus, the use of a small number of parametric ranges can provide the same spatial audio effect for the listener as if more parametric ranges were used.

Unlike the “numBands” parameter, the “numSlots” parameter represented by the “bsFrameLength” 703 field shown in Fig. 7A can represent all values. However, the “numSlots” values can be limited if the number of samples in one spatial frame is exactly divided by “numSlots”. Thus, if the maximum represented value of “numSlots” is 'b', then each value of the “bsFrameLength” 703 field may be represented by ceil {log ₂ (b)} bits. In this case, 'ceil (x)' means the smallest integer greater than or equal to the value of 'x'. For example, if one spatial frame includes 72 time slots, then for the “bsFrameLength” 703 field, ceil {log ₂ (72)} = 7 bits can be allocated, and the number of parametric ranges used for the channel transform module can be taken equal to the value within “numBands”.

FIG. 8A shows a syntax for representing the number of parametric ranges applied to an OTT block using a fixed number of bits according to one embodiment of the present invention. Referring to Figures 7A and 8A, where 'i' has a value from zero to numOttBoxes-1 and where 'numOttBoxes' is the total number of OTT blocks. Namely, the value of 'i' indicates each OTT block, and the number of parametric ranges used for each OTT block is represented by the corresponding value of 'i'. If the OTT block has an LFE channel mode, then the number of parametric ranges (hereinafter referred to as “bsOttBands”) used for the LFE channel of the OTT block can be represented using a fixed number of bits. In the example shown in FIG. 8A, 5 bits are allocated for the “bsOttBands” 801 field. If the OTT block does not have LFE channel mode, then the total number of parametric ranges (numBands) can be applied to the channel of the OTT block.

FIG. 8B shows a syntax for representing the number of parametric ranges used for an OTT block with a variable number of bits according to one embodiment of the present invention. In FIG. 8B, which is similar to FIG. 8A, in contrast to FIG. 8A, the “bsOttBands” 802 field shown in FIG. 8B is represented by a variable number of bits. In particular, the “bsOttBands” 802 field, whose value is less than or equal to “numBands”, can be represented by a variable number of bits using “numBands”.

If “numBands” is in the range greater than or equal to 2 ^ (n-1) and less than 2 ^ (n), then the field “bsOttBands” 802 can be represented by a variable number of bits n.

For example: (a) if “numBands” is 40, then the “bsOttBands” 802 field is represented by 6 bits; (b) if “numBands” is 28 or 20, then the “bsOttBands” 802 field is represented by 5 bits; (c) if “numBands” is 14 or 10, then the “bsOttBands” 802 field is represented by 4 bits; and (d) if “numBands” is 7, 5, or 4, then the “bsOttBands” 802 field is represented by 3 bits.

If “numBands” is in a range greater than 2 ^ (n-1) and less than or equal to 2 ^ (n), then the field “bsOttBands” 802 can be represented by a variable number of bits n.

For example: (a) if “numBands” is 40, then the “bsOttBands” 802 field is represented by 6 bits; (b) if “numBands” is 28 or 20, then the “bsOttBands” 802 field is represented by 5 bits; (c) if “numBands” is 14 or 10, then the “bsOttBands” 802 field is represented by 4 bits; (d) if “numBands” is 7, 5, then the “bsOttBands” 802 field is represented by 3 bits; and (e) if “numBands” is 4, then the “bsOttBands” 802 field is represented by 2 bits.

The “bsOttBands” 802 field can be represented by a variable number of bits through a function (hereinafter referred to as the “smallest integer function”) rounding to the nearest integer value, where “numBands” is taken as a variable.

In particular: (i) in the case when 0 <bsOttBands ≤ numBands or 0 ≤ bsOttBands <numBands, the “bsOttBands” 802 field is represented by the number of bits corresponding to the value of ceil (log ₂ (numBands)); or (ii) in the case where 0 ≤ bsOttBands ≤ numBands, the “bsOttBands” 802 field may be represented by ceil (log ₂ (numBands + 1)) bits.

If a value less than or equal to “numBands” (hereinafter referred to as “numberBands”) is determined arbitrarily, then the field “bsOttBands” 802 can be represented by a variable number of bits through the function of the smallest integer, if “numberBands” is taken as a variable.

In particular: (i) in the case when 0 <bsOttBands ≤ numberBands or 0 ≤ bsOttBands <numberBands, the field “bsOttBands” 802 is represented by ceil (log ₂ (numberBands)) bits; or (ii) in the case where 0 ≤ bsOttBands ≤ numberBands, the “bsOttBands” 802 field may be represented by ceil (log ₂ (numberBands + 1)) bits.

If more than one OTT block is used, then the combination “bsOttBands” can be expressed by formula 1 below.

[Formula 1]

where bsOttBands _i indicates the ith “bsOttBands”. For example, suppose there are three OTT blocks and three values (N = 3) for the “bsOttBands” field 802. In this example, three values of the “bsOttBands” 802 field (indicated below by a1, a2, and a3, respectively) used for the three corresponding blocks OTT can be represented by 2 bits each. Therefore, only 6 bits are required to express the values of a1, a2, and a3. In addition, if the values a1, a2 and a3 are presented as a group, then 27 (= 3 * 3 * 3) options may arise, which can be represented by 5 bits with the saving of one bit. If “numBands” is 3, and the group value represented by 5 bits is 15, then the group value can be represented as 15 = 1 × (3 ^ 2) + 2 * (3 ^ 1) + 0 * (3 ^ 0 ) Therefore, the decoder, applying the reverse formula 1, can determine from the value 15 of the group that the three values a1, a2 and a3 of the field “bsOttBands” 802 are 1, 2 and 0, respectively.

In the case of many OTT blocks, the combination “bsOttBands” can be represented as one of formulas 2 through 4 (defined below) using “numberBands”. Since the representation of “bsOttBands” using “numberBands” is similar to the representation using “numBands” from formula 1, a detailed explanation of the formulas below is omitted.

[Formula 2]

[Formula 3]

[Formula 4]

FIG. 9A shows a syntax for representing the number of parametric ranges applied to a TTT block with a fixed number of bits according to one embodiment of the present invention. Turning to figures 7A and 9A, where 'i' has a value from zero to numTttboxes-1, where 'numTttboxes' is the total number of TTT blocks. Namely, the value of 'i' indicates each TTT block. The number of parametric ranges used for each TTT block is represented according to the value of 'i'. In some embodiments, the TTT block can be divided into a low frequency range and a high frequency range, and different processing processes can be used for the low frequency and high frequency ranges. Other splitting options are possible.

The “bsTttDualMode” field 901 indicates whether this TTT block operates in different modes (hereinafter referred to as “dual mode”) for the low frequency range and high frequency range, respectively. For example, if the value of the “bsTttDualMode” 901 field is zero, then one mode is used for the entire range without a difference between the low-frequency range and the high-frequency range. If the value of the “bsTttDualMode” 901 field is 1, then different modes can be used for the low-frequency range and high-frequency range.

The “bsTttModeLow” 902 field indicates the operating mode of this TTT block, which may have various operating modes. For example, the TTT block may operate in a prediction mode in which, for example, CPC and ICC parameters are used, in an energy estimation based mode in which, for example, CLD parameters are used, etc. If the TTT unit has dual mode, additional information may be required for the high frequency range.

The “bsTttModeHigh” field 903 indicates the operating mode of the high frequency range, in which case the TTT block has a dual mode.

The “bsTttBandsLow” field 904 indicates the number of parametric ranges used for the TTT block.

Field “bsTttBandsHigh” 905 has “numBands”.

If the TTT block has dual mode, then the low-frequency range can be greater than or equal to zero and smaller than “bsTttBandsLow”, while the high-frequency range can be greater than or equal to “bsTttBandsLow” and smaller than “bsTttBandsHigh”.

If the TTT block does not have dual mode, then the number of parametric ranges used for the TTT block may be greater than or equal to zero and less than “numBands” (907).

The “bsTttBandsLow” 904 field may be represented by a fixed number of bits. For example, as shown in FIG. 9A, 5 bits may be allocated to represent the “bsTttBandsLow” 904 field.

FIG. 9B shows a syntax for representing the number of parametric ranges used for a TTT block with a variable number of bits according to one embodiment of the present invention. FIG. 9B is similar to FIG. 9A, but differs from FIG. 9A in that the “bsTttBandsLow” 907 field in FIG. 9B is represented by a variable number of bits, while the “bsTttBandsLow” 904 field in FIG. 9A is a fixed number of bits. In particular, since the “bsTttBandsLow” 907 field has a value less than or equal to “numBands”, the “bsTttBands” 907 field can be represented by a variable number of bits using “numBands”.

In particular, in the case where “numBands” is greater than or equal to 2 ^ (n-1) and less than 2 ^ (n), the field “bsTttBandsLow” 907 may be represented by n bits.

For example: (i) if “numBands” is 40, then the “bsTttBandsLow” 907 field is represented by 6 bits; (ii) if “numBands” is 28 or 20, then the “bsTttBandsLow” 907 field is 5 bits; (iii) if “numBands” is 14 or 10, then the “bsTttBandsLow” 907 field is represented by 4 bits; and (iv) if “numBands” is 7, 5 or 4, then the “bsTttBandsLow” field is 3 bits.

If “numBands” is in a range greater than 2 ^ (n-1) and less than or equal to 2 ^ (n), then the field “bsTttBandsLow” 907 can be represented by n bits.

For example: (i) if “numBands” is 40, then the “bsTttBandsLow” 907 field is represented by 6 bits; (ii) if “numBands” is 28 or 20, then the field “bsTttBandsLow” 907 is represented by 5 bits; (iii) if “numBands” is 14 or 10, then the “bsTttBandsLow” 907 field is represented by 4 bits; (iv) if “numBands” is 7 or 5, then the “bsTttBandsLow” field is represented by 3 bits; and (v) if “numBands” is 4, then the “bsTttBandsLow” 907 field is represented by 2 bits.

The “bsTttBandsLow” 907 field can be represented by the number of bits determined by the smallest integer function, if “numBands” is taken as a variable.

For example: i) in the case when 0 <bsTttBandsLow ≤ numBands or 0 ≤ bsTttBandsLow <numBands, the field “bsTttBandsLow” 907 is represented by the number of bits corresponding to the value ceil (log ₂ (numBands)) or ii) in the case when 0 ≤ bsTttBandsLow ≤ numBands, the “bsTttBandsLow” 907 field may be represented by ceil (log ₂ (numBands + 1)) bits.

If the value is less than or equal to “numBands”, that is, “numberBands” is defined arbitrarily, then the field “bsTttBandsLow” 907 can be represented by a variable number of bits using “numberBands”.

In particular: i) in the case when 0 <bsTttBandsLow ≤ numberBands or 0 ≤ bsTttBandsLow <numberBands, the field “bsTttBandsLow” 907 is represented by the number of bits corresponding to the value of ceil (log ₂ (numberBands)) or ii) in the case when 0 ≤ bsTttBandsLow ≤ numberBands, the “bsTttBandsLow” 907 field can be represented by the number of bits corresponding to ceil (log ₂ (numberBands +1)).

In the case of multiple TTT blocks, the combination of “bsTttBandsLow” can be expressed as formula 5, defined below.

[Formula 5]

In this case, bsTttBandsLow _i indicates the ith “bsTttBandsLow”. Since formula 5 is identical to formula 1, a detailed explanation of formula 5 is omitted in the following description.

In the case of multiple TTT blocks, the combination of “bsTttBandsLow” can be represented by one of formulas 6 through 8 using “numberBands”. Since formulas 6 through 8 are identical to formulas 2 through 4, a detailed explanation of formulas 6 through 8 is omitted in the following description.

[Formula 6]

[Formula 7]

[Formula 8]

The number of parametric ranges used for the channel conversion module (for example, the OTT block and / or the TTT block) can be represented as the division value “numBands”. In this case, the half value “numBands” or the value resulting from dividing “numBands” by a specific number is used as the division value.

Once the number of parametric ranges used for the OTT and / or TTT block is determined, parameter sets that can be applied to each OTT block and / or each TTT block within the number of parametric ranges can be determined. Each of the parameter sets can be applied for each OTT block and / or each TTT block for a time interval taken as a unit of time. Namely, one set of parameters can be applied to one time interval.

As mentioned in the previous description, one spatial frame may include multiple time slots. If a spatial frame refers to a frame of a fixed type, then a set of parameters can be applied for a variety of time intervals of wound duration. If the frame refers to a frame of variable type, then it is necessary to have information about the position of the time interval for which a set of parameters is applied. This is explained in detail below with reference to figures 13A to 13C.

10A shows the syntax for spatial extension configuration information for a spatial extension frame according to one embodiment of the present invention. The spatial extension configuration information may include a “bsSacExtType” field 1001, a “bsSacExtLen” field 1002, a “bsSacExtLenAdd” field 1003, a “bsSacExtLenAddAdd” field 1004, and a “bsFillBits” field 1007. Other fields are possible.

The “bsSacExtType” field 1001 indicates the data type of the spatial extension frame. For example, a spatial expansion frame may be filled with zeros, residual signal data, arbitrary residual signal data after downmixing, or arbitrary tree data.

The “bsSacExtLen” field 1002 indicates the number of bytes of spatial extension configuration information.

The “bsSacExtLenAdd” field 1003 indicates an additional number of bytes of spatial extension configuration information if the number of bytes of spatial extension configuration information has become greater than or equal to, for example, 15.

The “bsSacExtLenAddAdd” field 1004 indicates an additional number of bytes of spatial extension configuration information if the number of bytes of spatial extension configuration information is greater than or equal to, for example, 270.

After determining / highlighting the corresponding fields in the encoder / decoder (1005), configuration information for the data type included in the spatial extension frame is determined.

As mentioned in the above description, the spatial extension frame may contain residual signal data, derivative residual signal data after downmixing, tree configuration data, or the like.

Next, the (1006) number of unused bits is calculated based on the length of the spatial extension configuration information.

The “bsFillBits” field 1007 indicates the number of data bits that can be omitted when filling in unused bits.

Figures 10B and 10C show syntaxes for spatial extension configuration information for a residual signal when the residual signal is included in the spatial extension frame, according to one embodiment of the present invention.

Referring to FIG. 10B, where the “bsResidualSamplingFrequencyIndex” field 1008 indicates the sampling frequency of the residual signal.

The “bsResidualFramesPerSpetialFrame” field 1009 indicates the number of residual frames per spatial frame. For example, in one spatial frame there may be 1, 2, 3 or 4 residual frames.

The “ResidualConfig” block 1010 indicates the number of parametric ranges for the residual signal applied for each OTT and / or TTT block.

Referring to FIG. 10C, a “bsResidualPresent” field 1011 indicates whether a residual signal is applicable for each OTT and / or TTT block.

The “bsResidualBands” field 1012 indicates the number of parametric ranges of the residual signal existing in each OTT and / or TTT block, if a residual signal exists in each OTT and / or TTT block. The number of parametric ranges of the residual signal can be represented by a fixed number of bits or a variable number of bits. In the case where the number of parametric ranges is represented by a fixed number of bits, the residual signal may have a value less than or equal to the total number of parametric ranges of the audio signal. So, to represent all the parametric ranges, the necessary number of bits can be allocated (for example, 5 bits in FIG. 10C).

10D shows a syntax for representing the number of parametric ranges of a residual signal using a variable number of bits according to one embodiment of the present invention. The “bsResidualBands” field 1014 may be represented by a variable number of bits using “numBands”. If numBands is greater than or equal to 2 ^ (n-1) and less than 2 ^ (n), then the field “bsResidualBands” 1014 may be represented by n bits.

For example: (i) if “numBands” is 40, then the field “bsResidualBands” 1014 is represented by 6 bits; (ii) if “numBands” is 28 or 20, then the field “bsResidualBands” 1014 is represented by 5 bits; (iii) if “numBands” is 14 or 10, then the field “bsResidualBands” 1014 is represented by 4 bits; (iv) if “numBands” is 7, 5 or 4, then the “bsResidualBands” 1014 field is represented by 3 bits.

If numBands is greater than 2 ^ (n-1) and less than or equal to 2 ^ (n), then the number of parametric ranges of the residual signal can be represented by n bits.

For example: (i) if “numBands” is 40, then the field “bsResidualBands” 1014 is represented by 6 bits; (ii) if “numBands” is 28 or 20, then the field “bsResidualBands” 1014 is represented by 5 bits; (iii) if “numBands” is 14 or 10, then the field “bsResidualBands” 1014 is represented by 4 bits; (iv) if “numBands” is 7 or 5, then the field “bsResidualBands” 1014 is represented by 3 bits; and (v) if “numBands” is 4, then the “bsResidualBands” 1014 field is represented by 2 bits.

In addition, the “bsResidualBands” field 1014 can be represented by the number of bits determined by the rounding function to the nearest integer if “numBands” is taken as a variable.

In particular: i) in the case when 0 <bsResidualBands ≤ numBands or 0 ≤ bsResidualBands <numBands, the bsResidualBands 1014 field is represented by ceil (log ₂ (numBands)) bits or ii) in the case when 0 ≤ bsResidualBands ≤ numBands, the field “BsResidualBands” 1014 may be represented by ceil (log ₂ (numBands + 1)) bits.

In some embodiments, the “bsResidualBands” field 1014 may be represented using a value (numberBands) less than or equal to numBands.

In particular: i) in the case when 0 <bsResidualBands ≤ numberBands or 0 ≤ bsResidualBands <numberBands, the bsResidualBands 1014 field is represented by ceil (log ₂ (numberBands)) bits or ii) in the case when 0 ≤ bsResidualBands ≤ numberBands, the field “BsResidualBands” 1014 may be represented by ceil (log ₂ (numberBands +1)) bits.

In the case of a plurality of residual signals (N), the combination of “bsResidualBands” can be expressed as formula 9, defined below.

[Formula 9]

In this case, bsResidualBands _i indicates the ith “bsResidualBands”. Since formula 9 is identical to formula 1, a detailed explanation of formula 9 is omitted in the following description.

In the case of multiple residuals, the combination of “bsResidualBands” can be represented by one of formulas 10 through 12 using “numberBands.” Since the representation of “bsResidualBands” using “numberBands” is identical to the representation of formulas 2 through 4, their detailed explanation in the following description omitted.

[Formula 10]

[Formula 11]

[Formula 12]

The number of parametric ranges of the residual signal can be represented as the division value “numBands”. In this case, you can use the half value “numBands” or the value that results from dividing “numBands” by a specific value for the division value.

The residual signal may be included in the bitstream of the audio signal along with the downmix signal and the spatial information signal, and this bitstream may be sent to the decoder. The decoder can extract from the bitstream the signal after down-mixing, the spatial information signal and the residual signal.

Further, the signal resulting from the downmix is subjected to upmix using spatial information. Meanwhile, during the upmix, a residual signal is applied to the downmix signal. In particular, the signal resulting from the downmix is upmixed in a plurality of channel conversion modules using spatial information. When this is done, a residual signal is supplied to the channel conversion module. As mentioned in the previous description, the channel conversion module has several parametric ranges, and a set of parameters for each time interval is supplied to the channel conversion module. When the residual signal is supplied to the channel conversion module, it may be necessary for the residual signal to update the inter-channel correlation information of the audio signal for which the residual signal is applied. The updated cross-channel correlation information is then used in the upmix process.

11A is a block diagram of a decoder for unmanaged coding according to one embodiment of the present invention. Uncontrolled coding means that spatial information is not included in the bitstream of the audio signal.

In some embodiments, the decoder includes an analysis filter bank 1102, an analysis unit 1104, a spatial synthesis unit 1106, and a synthesis filter bank 1108. Although FIG. 11A shows a signal after downmix in a stereo signal, other types of signals after downmix can be used.

During operation, the decoder receives the signal 1101 after the down-mix, and the filter bank 1102 for analysis converts the received signal 1101 after the down-mix to a frequency-domain signal 1103. An analysis unit 1104 creates spatial information based on the transformed signal 1103 after down-mixing. An analysis unit 1104 performs processing for each time interval, and spatial information 1105 may be generated for a plurality of time intervals. In this case, the time interval includes one time interval.

Spatial information can be created in two stages. Firstly, a down-mix parameter is created from the signal after down-mixing. Secondly, the downmix parameter is converted to spatial information, such as a spatial parameter. In some embodiments, the downmix parameter can be created by matrix calculations of the signal after downmix.

The spatial synthesis unit 1106 creates a multi-channel audio signal 1107 by synthesizing the generated spatial information 1105 with a downmix signal 1103. The created multi-channel audio signal 1107 passes through a filter bank 1108 for synthesis to be converted to an audio signal 1109 in the time domain.

Spatial information can be created from predefined positions of time intervals. The distance between these positions may be equal (i.e., equidistant). For example, spatial information can be created over 4 time slots. Spatial information can also be created from the variable positions of time intervals. In this case, information about the position of the time interval from which the spatial information is generated can be extracted from the bitstream. The position information may be represented by a variable number of bits. Information about the position can be presented in the form of an absolute value and a difference value relative to previous information about the position of the time interval.

In the case of uncontrolled coding, the number of parametric ranges (hereinafter referred to as “bsNumguidedBlindBands”) for each channel of the audio signal can be represented by a fixed number of bits. “BsNumguidedBlindBands” can be represented by a variable number of bits using “numBands”. For example, if “numBands” is greater than or equal to 2 ^ (n-1) and less than 2 ^ (n), then “bsNumguidedBlindBands” can be represented by a variable number of n bits.

In particular, (a) if “numBands” is 40, then “bsNumguidedBlindBands” is represented by 6 bits, (b) if “numBands” is equal to 28 or 20, then “bsNumguidedBlindBands” is represented by 5 bits, (c) if “numBands” is 14 or 10, then “bsNumguidedBlindBands” is represented by 4 bits, and (d) if “numBands” is 7.5 or 4, then “bsNumguidedBlindBands” is represented by 3 bits.

If “numBands” is greater than 2 ^ (n-1) and less than or equal to 2 ^ (n), then “bsNumguidedBlindBands” can be represented by a variable number of n bits.

For example: (a) if “numBands” is 40, then “bsNumguidedBlindBands” is represented by 6 bits, (b) if “numBands” is equal to 28 or 20, then “bsNumguidedBlindBands” is represented by 5 bits, (c) if “numBands” is 14 or 10, then “bsNumguidedBlindBands” is represented by 4 bits, (d) if “numBands” is 7 or 5, then “bsNumguidedBlindBands” is represented by 3 bits; and (e) if “numBands” is 4, then “bsNumguidedBlindBands” is represented by 2 bits.

In addition, “bsNumguidedBlindBands” can be represented by a variable number of bits using the minimum integer function, if “numBands” is taken as a variable.

For example, i) if 0 <bsNumguidedBlindBands ≤ numBands or 0 ≤ bsNumguidedBlindBands <numBands, then “bsNumguidedBlindBands” is represented by ceil (log ₂ (numBands)) bits or ii) if 0 ≤ bsNumguidedBlindBands bumindbands ”Can be represented by ceil (log ₂ (numBands + 1)) bits.

If the value is less than or equal to “numBands”, that is, “numberBands” is defined arbitrarily, then “bsNumguidedBlindBands” can be represented as follows.

In particular, i) if 0 <bsNumguidedBlindBands ≤ numberBands or 0 ≤ bsNumguidedBlindBands <numberBands, then “bsNumguidedBlindBands” is represented by ceil (log ₂ (numberBands)) bits or ii) if 0 ≤ bsNumguidedBlindBands ≤ numberBands, bsNumguidedBlindBands ”may be represented by ceil (log ₂ (numberBands + 1)) bits.

If there are N channels, then the combination “bsNumguidedBlindBands” can be expressed as formula 13.

[Formula 13]

In this case, bsNumguidedBlindBands _i indicates the ith “bsNumguidedBlindBands”. Since formula 13 is identical to formula 1, a detailed explanation of formula 13 is omitted in the following description. If there are multiple channels, then “bsNumguidedBlindBands” can be represented by one of the formulas 14 through 16 using “numberBands”. Since the representation of “bsNumguidedBlindBands” using “numberBands” is identical to the representations in formulas 2 through 4, a detailed explanation of formulas 14 through 16 is omitted in the following description.

[Formula 14]

[Formula 15]

[Formula 16]

11B is a diagram for a method for representing the number of parametric ranges as a group according to one embodiment of the present invention. The number of parametric ranges includes information on the number of parametric ranges used for the channel conversion module, information on the number of parametric ranges used for the residual signal, and information on the number of parametric ranges for each channel of the audio signal in the case of uncontrolled coding. In the case where there is a lot of information about the number of parametric ranges, a lot of information about the quantity (for example, “bsOttbands”, “bsTttbands”, “bsResidualBand” and / or “bsNumguidedBlindBands”) can be presented in at least one or more groups.

Turning to FIG. 11B, where if there is (kN + L) information about the number of parametric ranges and if Q bits are needed to represent each information about the number of parametric ranges, then a lot of data on the number of parametric ranges can be represented as the following group. In this case, 'k' and 'N' are arbitrary non-zero integers, and 'L' is an arbitrary integer satisfying the inequality 0≤L <N.

The grouping method includes the steps of creating k groups by linking N information about the number of parametric ranges and creating the last group by linking the last L information about the number of parametric ranges. k groups can be represented as M bits, and the last group can be represented as p bits. In this case, it is preferable that M bits be less than N * Q bits used in the case of presenting each information about the number of parametric ranges without grouping them. The p bit is preferably less than or equal to L * Q bits used in the case of presenting each information about the number of parametric ranges without grouping them.

Suppose, for example, that the information on the number of parametric ranges is b1 and b2, respectively. If each of the values b1 and b2 can have five values, then to represent each of the values b1 and b2 it is necessary to have 3 bits. In this case, although eight values can be represented in 3 bits, in fact only five values are required. That is, each of the quantities b1 and b2 has three redundant values. In addition, in the case of representing b1 and b2 as a group by linking b1 and b2 together, instead of 6 bits (= 3 bits + 3 bits), 5 bits can be used. In particular, since all combinations of b1 and b2 include 25 (= 5 * 5) options, a group of b1 and b2 can be represented by 5 bits. Since 5 bits can represent 32 values, when presented as a group, seven redundant values are created. In addition, in the case of representing by grouping b1 and b2, the redundancy is less than in the case of representing each of the values of b1 and b2 as 3 bits. A method of representing a plurality of data on the number of parametric ranges in the form of groups can be implemented in various ways as follows.

If the data set on the number of parametric ranges has 40 values each, then k groups are created using N, values 2, 3, 4, 5, or 6. k groups can be represented by 11, 16, 22, 27, and 32 bits, respectively. Alternatively, k groups are represented by combining the appropriate options.

If the set of information about the number of parametric ranges has 28 values for each, then k groups are created using 6 as N, and k groups can be represented as 29 bits.

If a lot of information about the number of parametric ranges has 20 values for each, then k groups are created using N, values 2, 3, 4, 5, 6 or 7. k groups can be represented 9, 13, 18, 22, 26 and 31 bits respectively. Alternatively, k groups may be represented by combining appropriate cases.

If the set of information on the number of parametric ranges has 14 values for each, then k groups are created using N as the value 6. 6. k groups can be represented by 23 bits.

If a lot of information about the number of parametric ranges has 10 values for each, then k groups are created using N, values 2, 3, 4, 5, 6, 7, 8, or 9. k groups can be represented 7, 10, 14, 17, 20, 24, 27 and 30 bits respectively. Alternatively, k groups may be represented by combining appropriate cases.

If the set of information about the number of parametric ranges has 7 values for each, then k groups are created using N, values 6, 7, 8, 9, 10 or 11. k groups can be represented 17, 20, 23, 26, 29 and 31 bits respectively. Alternatively, k groups are represented by combining appropriate cases.

If a lot of information about the number of parametric ranges has, for example, 5 values for each, then k groups are created using N, values 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, or 13. k groups can be represented by 5, 7, 10, 12, 14, 17, 19, 21, 24, 26, 28, and 31 bits, respectively. Alternatively, k groups are represented by combining appropriate cases.

In addition, a lot of information about the number of parametric ranges can be configured to represent in the form of the above groups, or for sequential presentation by generating each information about the number of parametric ranges in the form of an independent bit sequence.

12 is a syntax showing spatial frame configuration information according to one embodiment of the present invention. The spatial frame includes a FramingInfo block 1201, a bsIndependencyfield block 1202, an OttData block 1203, a TttData block 1204, a SmgData block 1205, and a tempShapeData block 1206.

The “FramingInfo” block 1201 includes information about the number of parameter sets and information about the time interval for which each parameter set is applied. The “FramingInfo” block 1201 is explained in detail with reference to FIG. 13A.

The bsIndependencyfield 1202 field indicates whether the current frame can be decoded without information about the previous frame.

The OttData block 1203 includes all spatial parameter information for all OTT blocks.

The “TttData” block 1204 includes all spatial parameter information for all TTT blocks.

The “SmgData” block 1205 includes temporal smoothing information used for the dequantized spatial parameter.

The “tempShapeData” block 1206 includes information for generating the temporal envelope used for the decorrelated signal.

13A shows a syntax for representing position information of a time slot for which a set of parameters is applied, according to one embodiment of the present invention. The “bsFramingType” field 1301 indicates whether the spatial frame of the audio signal is a fixed frame or a variable frame. Fixed frame means a frame in which a set of parameters is applied to a preset time interval. For example, a set of parameters is applied to a time interval predefined at an equal interval. A variable frame means a frame that selectively receives information about the position of a time interval for which a set of parameters is applied.

The “bsNumParamSets” field 1302 indicates the number of parameter sets in one spatial frame (hereinafter referred to as “NumParamSets”), and the relation “NumParamSets = bsNumParamSets +1” exists between “NumParamSets” and “bsNumParamSets”.

For example, since 3 bits are allocated for the “bsNumParamSets” field 1302 in FIG. 13A, a maximum of eight sets of parameters can be provided in one spatial frame. Since the number of allocated bits is not limited, more sets of parameters can be provided in a spatial frame.

If the spatial frame is of a fixed type, then information about the position of the time interval for which the set of parameters is applied can be determined according to a predefined rule, and there is no need for additional information about the position of the time interval for which the set of parameters is applied. However, if the spatial frame is of a variable type, then it is necessary to have information about the position of the time interval for which the set of parameters is applied.

The “bsParamSlot” field 1303 indicates the position information of the time interval for which the parameter set is applied. The “bsParamSlot” field 1303 may be represented by a variable number of bits using multiple time intervals in one spatial frame, that is, “numSlots”. In particular, in the case where “numSlots” is greater than or equal to 2 ^ (n-1) and less than 2 ^ (n), the field “bsParamSlot” 1303 may be represented by n bits.

For example: (i) if “numSlots” is between 64 and 127, then the “bsParamSlot” 1303 field may be represented by 7 bits; (ii) if “numSlots” is between 32 and 63, then the “bsParamSlot” 1303 field may be represented by 6 bits; (iii) if “numSlots” is between 16 and 31, then the “bsParamSlot” 1303 field may be represented by 5 bits; (iv) if “numSlots” is between 8 and 15, then the “bsParamSlot” 1303 field may be represented by 4 bits; (v) if “numSlots” is between 4 and 7, then the “bsParamSlot” 1303 field may be represented by 3 bits; (vi) if “numSlots” is between 2 and 3, then the “bsParamSlot” 1303 field may be represented by 2 bits; (vii) if “numSlots” is 1, then the field “bsParamSlot” 1303 may be represented by 1 bit; and (viii) if “numSlots” is 0, then the “bsParamSlot” field 1303 may be represented with 0 bits. Similarly, if “numSlots” is between 64 and 127, then the “bsParamSlot” 1303 field may be represented by 7 bits.

If there are many (N) parameter sets, then the combination “bsParamSlot” can be represented according to formula 9.

[Formula 9]

In this case, “bsParamSlot _i ” indicates the time interval for which the ith set of parameters is applied. Suppose, for example, that “numSlots” is 3 and that the field “bsParamSlot” 1303 can have ten values. In this case, three information is needed for the “bsParamSlot” field 1303 (hereinafter referred to as c1, c2 and c3, respectively). Since 4 bits are needed to represent each (c1, c2 and c3), a total of 12 (= 4 * 3) bits are required. In the case of representing c1, c2 and c3 as a group by linking them together, 1000 (= 10 * 10 * 10) cases may arise that can be represented by 10 bits, which will save 2 bits. If “numSlots” is 3 and if the read value in the form of 5 bits is 31, then this value can be represented as 31 = 1 × (3 ^ 2) + 5 * (3 ^ 1) + 7 * (3 ^ 0). The decoding device can determine that c1, c2 and c3 are 1, 5 and 7, respectively, by applying the inverse of formula 9.

FIG. 13B shows a syntax for presenting position information of a time interval for which a set of parameters is applied as an absolute value and a difference value according to one embodiment of the present invention. If the spatial frame is a variable type frame, then the “bsParamSlot” field 1303 in FIG. 13A can be represented as an absolute value and a difference value taking into account the fact that the “bsParamSlot” information value is monotonically increasing.

For example: (i) the position of the time interval for which the first set of parameters is applied can be formed as an absolute value, that is, “bsParamSlot [0]”; and (ii) the position of the time interval for which the second or subsequent set of parameters is applied can be formed as a difference value, that is, a “difference value” between “bsParamSlot [ps]” and “bsParamSlot [ps-1]” or “difference value-1 ”(hereinafter referred to as“ bsDiffParamSlot [ps] ”). In this case, “ps” means a set of parameters.

The “bsParamSlot [0]” field 1304 may be represented by the number of bits (hereinafter referred to as “nBitsParamSlot (0)”) calculated using “numSlots” and “numParamSets”.

The “bsDiffParamSlot [ps]” field 1305 may be represented by the number of bits (hereinafter referred to as “nBitsParamSlot (ps)”) calculated using “numSlots”, “numParamSets” and the position of the time interval for which the previous parameter set is applied, that is, “bsParamSlot [ps-1]. ”

In particular, to represent “bsParamSlot [ps]” with the minimum number of bits, the number of bits to represent “bsParamSlot [ps]” can be adopted based on the following rules: (i) the set “bsParamSlot [ps]” increases in ascending order (bsParamSlot [ps ]> bsParamSlot [ps-1]); (ii) the maximum value of “bsParamSlot [0]” is equal to “numSlots - numParamSets”; and (iii) if 0 <ps <numParamSets, “bsParamSlot [ps]” can only mean between “bsParamSlot [ps-1] +1” and “numSlots - numParamSets + ps”.

For example, if “numSlots” is 10 and if “numParamSets” is 3, then since “bsParamSlot [ps]” is increasing, then the maximum value of “bsParamSlot [0]” becomes '10 -3 = 7 '. Namely, “bsParamSlot [0]” must be selected from values from 0 to 7. The reason for this is that the number of time intervals for the remaining sets of parameters (for example, if ps is 1 or 2) is not enough if “bsParamSlot [0] ”Has a value greater than 7.

If “bsParamSlot [0]” is 5, then the position of bsParamSlot [1] of the time interval for the second set of parameters should be selected from the values between '5 + 1 = 6' and '10 -3 + 1 = 8 '.

If “bsParamSlot [1]” is equal to 7, then “bsParamSlot [2]” can become equal to 8 or 9. If “bsParamSlot [1]” is equal to 8, then “bsParamSlot [2]” can become equal to 9.

Therefore, “bsParamSlot [ps]” can be represented by a variable number of bits using the above features instead of being represented as a fixed number of bits.

When configuring “bsParamSlot [ps]” in the bitstream, if “ps” is 0, then “bsParamSlot [0]” can be represented as an absolute value using the number of bits corresponding to “nBitsParamSlot (0)”. If “ps” is greater than 0, then “bsParamSlot [ps]” can be represented as the difference value using the number of bits corresponding to “nBitsParamSlot (ps)”. When reading the “bsParamSlot [ps]” configured above from the bitstream, the length of the bitstream for each data, that is, “nBitsParamSlot (ps),” can be found using formula 10.

[Formula 10]

In particular, “nBitsParamSlot (ps)” can be found as nBitsParamSlot (0) = f _b (numSlots - numParamSets +1). If 0 <ps <numParamSets, then “nBitsParamSlot (ps)” can be found as nBitsParamSlot (ps) = f _b (numSlots - numParamSets + ps - bsParamSlot [ps-1]). “NBitsParamSlot (ps)” can be defined using formula 11, which complements formula 10 to 7 bits.

[Formula 11]

The following is an example of the function f _b (x). If “numSlots” is 15 and if “numParamSets” is 3, then this function can be evaluated as nBitsParamSlot (0) = f _b (15-3 + 1) = 4 bits.

If “bsParamSlot [0]” represented by 4 bits is 7, then the specified function can be evaluated as nBitsParamSlot (1) = f _b (15-3 + 1-7) = 3 bits. In this case, the field “bsDiffParamSlot [1]” 1305 may be represented by 3 bits.

If the value represented by 3 bits is 3, then “bsParamSlot [1]” becomes 7 + 3 = 10. Therefore, nBitsParamSlot (2) = f _b (15-3 + 2-10) = 2 bits. In this case, the field “bsDiffParamSlot [2]” 1305 may be represented by 2 bits. If the number of remaining time intervals is equal to the number of remaining parameter sets, then 0 bits can be allocated for the “bsDiffParamSlot [ps]” field. In other words, additional information is not required to represent the position of the time interval for which this set of parameters is applied.

Thus, the number of bits for “bsParamSlot [ps]” can be accepted as a variable. The number of bits for “bsParamSlot [ps]” can be read from the bitstream using the f _b (x) function in the decoder. In some embodiments, the function f _b (x) may include the function ceil (log ₂ (x)).

When reading the information for “bsParamSlot [ps]”, presented as an absolute value and a difference value, “bsParamSlot [0]” can be read from the bit stream first from the bit stream and then “bsDiffParamSlot [ps]” can be read for 0 <ps <numParamSets. Then you can find “bsParamSlot [ps]” for the interval 0≤ps <numParamSets using “bsParamSlot [0]” and “bsDiffParamSlot [ps]”. For example, as shown in FIG. 13B, “bsParamSlot [ps]” can be found by adding “bsParamSlot [ps-1]” to “bsDiffParamSlot [ps] +1”.

FIG. 13C illustrates a syntax for presenting position information of a time interval for which a set of parameters is applied as a group according to one embodiment of the present invention. In the case where there are multiple parameter sets, the multiple “bsParamSlots” 1307 for the multiple parameter sets may be represented by at least one or more groups.

If the number of “bsParamSlots” 1307 is equal to (kN + L) and if Q bits are required to represent each “bsParamSlots” 1307, then “bsParamSlots” 1307 can be represented as the following group. In this case, 'k' and 'N' are arbitrary non-zero integers, and 'L' is an arbitrary integer satisfying the inequality 0≤L <N.

The grouping method may include the steps of creating k groups by linking N “bsParamSlots” 1307 and creating the last group by linking the last L “bsParamSlots” 1307. k groups can be represented by M bits, and the last group can be represented by p bits. In this case, it is preferable that the M bits be less than the N * Q bits used in the case of representing each of the “bsParamSlots” 1307 without grouping them. The p bit is preferably less than or equal to L * Q bits used in the case of representing each “bsParamSlots” 1307 without grouping them.

Suppose, for example, that the pair “bsParamSlots” 1307 for two sets of parameters is d1 and d2, respectively. If each of the values of d1 and d2 can have five values, then to represent each of the values of d1 and d2 it is necessary to have 3 bits. In this case, although eight values can be represented in 3 bits, five values are actually required. That is, each of the quantities d1 and d2 has three redundant values. In addition, if d1 and d2 are represented as a group by linking d1 and d2 together, instead of 6 bits (= 3 bits + 3 bits), 5 bits can be used. In particular, since all combinations of d1 and d2 include 25 (= 5 * 5) types, a group of d1 and d2 can only be represented by 5 bits. Since 5 bits can represent 32 values, when presented as a group, seven redundant values are created. In addition, in the case of representing by grouping d1 and d2, the redundancy is less than in the case of representing each of the values of d1 and d2 as 3 bits.

When configuring a group, the data for the group can be configured using “bsParamSlot [0]” for the initial value and the difference between the pairs “bsParamSlot [ps]” for the second or subsequent value.

When configuring a group, bits can be allocated directly without grouping if the number of parameter sets is 1, and bits can be distributed after grouping is completed if the number of parameter sets is greater than or equal to 2.

FIG. 14 is a flowchart of an encoding method according to one embodiment of the present invention. The following explains the encoding method of the audio signal and the operation of the encoder according to the present invention.

First, (S1401), the total number of time slots (numSlots) in one spatial frame and the total number of parametric ranges (numBands) of the audio signal are determined.

Then (S1402), the number of parametric ranges used for the channel conversion module (OTT block and / or TTT block) and / or the residual signal are determined.

If the OTT block has an LFE channel mode, then the number of parametric ranges used for the OTT block is separately determined.

If the OTT block does not have the LFE channel mode, then “numBands” is used as the number of parameters used for the OTT block.

Next, the type of spatial frame is determined. In this case, the spatial frame may be assigned to a frame of a fixed type or a frame of variable type.

If the spatial frame is of a variable type (S1403), then the number of parameter sets used in one spatial frame is determined (S1406). In this case, a set of parameters can be used for the channel conversion module at each time interval.

Next (S1407), the position of the time interval for which this set of parameters is applied is determined. In this case, the position of the time interval for which this set of parameters is applied can be represented as an absolute value and a difference value. For example, the position of the time interval for which the first set of parameters is applied can be represented as an absolute value, and the position of the time interval for which the second or subsequent set of parameters is applied can be represented as the difference value relative to the position of the previous time interval. In this case, the position of the time interval for which this set of parameters is applied can be represented by a variable number of bits.

In particular, the position of the time interval for which the first set of parameters is applied can be represented by the number of bits computed using the total number of time intervals and the total number of parameter sets. The position of the time interval for which the second or subsequent set of parameters is applied may be represented by the number of bits calculated using the total number of time intervals, the total number of parameter sets and the position of the time interval for which the previous parameter set is applied.

If the spatial frame is of a fixed type, then the number of parameter sets used in one spatial frame is determined (S1404). In this case, the position of the time interval for which this set of parameters is applied is selected using a predetermined rule. For example, the position of the time interval for which the parameter set is applied can be determined so that it is at an equal distance from the position of the time interval for which the previous parameter set is applied (S1405).

Next, the downmix block and the spatial information creation block create a signal after downmix and spatial information, respectively, using the total number of time intervals defined above, the total number of parametric ranges, the number of parametric ranges used for the channel transform block, the total number of parameter sets in one spatial frame and information about the position of the time interval for which the set of parameters is applied (S1408).

Finally, the multiplexing unit creates a bit stream including a signal after down-mixing and spatial information (S1409), and then transfers the created bit stream to a decoder (S1409).

15 is a flowchart of a decoding method according to one embodiment of the present invention. The audio decoding method and the operation of the decoder according to the present invention is explained below.

First, the decoder receives the bitstream of the audio signal (S1501). The demultiplexing unit extracts the signal after down-mixing and the spatial information signal from the obtained bit stream (S1502). Next, the spatial information signal decoding unit extracts from the configuration information of the spatial information signal information on the total number of time intervals in one spatial frame, the total number of parametric ranges and the number of parametric ranges used for the channel conversion module (S1503).

If the spatial frame is of a variable type (S1504), the number of parameter sets in one spatial frame and information about the position of the time interval for which this set of parameters is applied is extracted from the spatial frame (S1505). Information about the position of the time interval can be represented by a fixed or variable number of bits. In this case, information about the position of the time interval for which the first set of parameters is applied can be represented as an absolute value, and information about the position of time intervals for which the second or subsequent sets of parameters are applied can be represented as the difference value. Valid information about the position of the time intervals for which the second or subsequent sets of parameters are applied can be found by adding the difference value to the information about the position of the time interval for which the previous set of parameters is applied.

Finally, the signal after down-mixing is converted to a multi-channel audio signal using the extracted information (S1506).

The above disclosed embodiments of the invention provide a number of advantages over standard audio coding schemes.

First, when encoding a multi-channel audio signal by presenting the position of a time interval for which a set of parameters is applied, using a variable number of bits in the disclosed embodiments of the invention, it is possible to reduce the amount of transmitted data.

Secondly, by representing the position of the time interval for which the first set of parameters is applied, in the form of an absolute value and presenting the positions of the time intervals for which the second or subsequent sets of parameters are applied, as the difference value in the disclosed embodiments of the invention, the amount of transmitted data can be reduced.

Thirdly, by representing the number of parametric ranges used for the specified channel conversion module as an OTT block and / or TTT block using a fixed or variable number of bits, the amount of transmitted data can be reduced in the disclosed embodiments of the invention. In this case, the positions of the time intervals for which the parameter sets are applied can be represented using the principle discussed above, where the parameter sets can be within the number of parametric ranges.

FIG. 16 is a block diagram of an example architecture 1600 of an apparatus for implementing an audio encoder / decoder described with reference to FIGS. 1-15. The device architecture 1600 is applicable to many different devices, including, but not limited to: personal computers, server computers, user electronic devices, mobile phones, personal digital assistants (PDAs), electronic tablets, television systems, set-top boxes, game consoles, media players, music players, navigation systems, or any other device capable of decoding audio signals. Some of these devices may have a modified architecture that uses a combination of hardware and software.

Architecture 1600 includes one or more processors 1602 (e.g., PowerPC®, Intel Pentium® 4, etc.), one or more display devices 1604 (eg, a CRT, a liquid crystal display (LCD)), and an audio subsystem 1606 (e.g., hardware / software audio), one or more network interfaces 1608 (e.g., Ethernet, FireWire®, USB bus, etc.), input devices 1610 (e.g., keyboard, mouse, etc.) and one or several computer-readable media 1612 (e.g., RAM, ROM, synchronous dynamic RAM (SDRAM), hard disk, optical disk, flash memory, etc.). These components can exchange messages and data through one or more buses 1614 (for example, standards EISA, PCI, PCI Express, etc.).

The term “computer-readable medium” refers to any medium that is involved in providing the processor 1602 with instructions for executing them, including but not limited to non-volatile media (eg, optical or magnetic disks), volatile media (eg, memory) and the environment transmission. The transmission medium includes, but not limited to, coaxial cables, copper wires, and optical fiber. The transmission medium may also exist in the form of acoustic, light or radio frequency waves.

Computer-readable media 1612 also includes an operating system 1616 (eg, Mac OS®, Windows®, Linux, etc.), a network communication module 1618, an audio codec 1620, and one or more applications 1622. The operating system 1616 may be multi-user , multiprocessor, multitasking, multithreaded, have a real-time mode of operation, etc. Operating system 1616 performs basic tasks, including, but not limited to: recognition of input data coming from input devices 1610; sending output to the display devices 1604 and the audio subsystem 1606; tracking files and directories on computer-readable media 1612 (e.g., memory or storage device); peripheral device management (for example, disk drives, printers, etc.); and traffic control on one or more buses 1614.

The communication network module 1618 includes various components for setting up and maintaining network connections (for example, software for implementing communication protocols such as TCP / IP, HTTP, Ethernet, etc.). The communication network module 1618 may include a browser enabling device architecture operators 1600 to search for information (e.g., audio content) on the network (e.g., the Internet).

The audio codec 1620 is responsible for implementing all or part of the processing processes associated with encoding and / or decoding and described with reference to figures 1-15. In some embodiments, the audio codec operates in conjunction with hardware (e.g., processor (s) 1602, audio subsystem 1606) for processing audio signals, including encoding and / or decoding of audio signals, as described herein.

Applications 1622 may include any software application related to audio content and / or to encoding and / or decoding audio content, including but not limited to: media players, music players (e.g., MP3 players), mobile phone applications, PDA devices, television systems, set-top boxes. In one embodiment, the audio codec may be used by an application service provider to provide encoding / decoding services over a network (e.g., the Internet).

In the above description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the invention. However, it should be apparent to those skilled in the art that the invention can be practiced without these specific details. In other examples, structures and devices are shown in block diagrams in order to avoid obscuring the invention.

In particular, those skilled in the art should understand that other architectures and graphical environments can be used and that the present invention can be implemented using graphical tools and products other than those described above. In particular, the client / server approach is just an example of an architecture providing instrumental functionality of the present invention; it will be apparent to those skilled in the art that other approaches other than a client / server scheme may also be used.

Some sections of the detailed description are presented in the language of algorithms and symbolic representations of operations on data bits in computer memory. These algorithmic descriptions and representations are the means used by specialists in the field of data processing for the most efficient transfer of the essence of their work to other specialists in this field of technology. Here, as in the general case, an algorithm is understood as a self-consistent sequence of steps leading to the desired result. These steps require physical manipulations with physical quantities. Usually, although not necessarily, these quantities take the form of electrical or magnetic signals that can be stored, transmitted, combined together, compared and otherwise manipulated with them. In practical use, these signals are conveniently called bits, values, elements, symbols, signs, members, numbers, or the like.

Industrial applicability

However, it should be borne in mind that all these and similar terms should be associated with the corresponding physical quantities and are simply convenient notations used for these quantities. As obviously follows from this discussion, unless expressly agreed otherwise, in the entire description of reasoning, where terms such as “processing”, “calculation”, “calculations”, “definition” or “display”, etc. are used, refer to the actions and processes of a computer system or similar electronic computing device that manipulates data and converts data presented in the form of physical (electronic) quantities in registers and storage devices of a computer system into other data represented by anal similar way as the physical quantities in the memories and registers of the computer system or other devices for storing, transmitting or displaying information.

The present invention also relates to a device for performing operations. This device can be specially designed for the required purposes or it can contain a general-purpose computer selectively activated or reconfigurable by a computer program stored in a computer. The specified computer program may be stored on a computer-readable medium, such as, but not limited to: any type of disk, including floppy disks, optical disks, compact discs (CD-ROM) and magneto-optical disks, read-only memory (ROM), random-access memory access (RAM), electrically erasable read-only memory devices (EPROM), electrically erasable programmable memory devices (EEPROM), magnetic or optical cards or any type of media suitable for storing electronic commands and connected to the bus computer system.

The algorithms and modules presented here are essentially not related to any particular computer or other device. General-purpose systems with programs can be used in accordance with the basic principles set forth here, or it may be more convenient to design more specialized devices to perform the steps described here. The necessary structure for these various systems follows from the description below. In addition, the present invention is not described with reference to any particular programming language. It is valuable that for the implementation of the basic principles of the invention described here, you can use many different programming languages. In addition, it should be clear to those skilled in the art that these modules, features, attributes, techniques, and other aspects of the invention may be implemented in the form of software, hardware, firmware, or any combination thereof. Of course, when a component of the present invention is implemented as a software tool, it can be implemented as a stand-alone program, as part of a larger program, many separate programs, a statically or dynamically linked library loaded into the core of the module, and / or in any other way, known at the present time or which may appear in the future at the disposal of specialists in the field of computer programming. In addition, the present invention is not limited to implementation within any particular operating system or environment.

Those skilled in the art will appreciate that various changes and modifications may be made to the embodiment of the invention discussed herein without departing from the spirit or scope of the invention. Thus, it is intended here that the present invention covers all of these modifications and variations of the embodiments disclosed herein, provided that these modifications and modifications are not beyond the scope of the appended claims and their equivalents.

Claims (19)

1. A method of decoding an audio signal, comprising:
receiving a bit stream representing an audio signal, the bit stream having a frame;
determining the number of time slots and the number of parameter sets from the bitstream, the parameter sets including one or more parameters;
determining position information from the bitstream, wherein the position information indicates a position of a time interval in an ordered set of time intervals for which a set of parameters is applied where an ordered set of time intervals is included in the frame; and
decoding an audio signal based on the number of time slots, the number of parameter sets and position information,
where the position information is represented by a variable number of bits based on the position of the time interval. 2. The method according to claim 1, in which a variable number of bits is determined using the number of time slots. 3. The method according to claim 1, additionally containing:
if the number of time intervals to be decoded is equal to the number of sets of parameters used, then information about the position of the time interval for which the set of parameters is applied is not determined. 4. The method according to claim 3, in which if the number of parameter sets is greater than or equal to 2 ^ (n-1) and less than 2 ^ (n), then the variable number of bits is defined as n bits. 5. The method according to claim 3, in which if the number of parameter sets is greater than 2 ^ (n-1) and less than or equal to 2 ^ (n), then a variable number of bits is defined as n bits. 6. The method according to claim 2, in which the position information is represented as the sum of the previous value and the difference value, where the previous value indicates the position information of the time interval for which the first set of parameters is applied, and the difference value indicates information about the position of the time interval, for which the second set of parameters is applied. 7. The method according to claim 6, in which the previous value is represented by a variable number of bits determined using at least one of: the number of time intervals and the number of sets of parameters. 8. The method according to claim 7, in which a variable number of bits is determined using the difference between the number of time intervals and the number of sets of parameters. 9. The method according to claim 6, in which the difference value is represented by a variable number of bits determined using at least one of: the number of time intervals, the number of parameter sets and the information about the position of the time interval for which the previous parameter set is applied. 10. The method according to claim 9, in which a variable number of bits is determined using the difference between the number of time intervals and at least one of: the number of sets of parameters and information about the position of the time interval for which the previous set of parameters is applied. 11. An apparatus for decoding an audio signal, comprising:
a demultiplexer separating the downmix signal and the spatial information from the bitstream representing the audio signal, the bitstream comprising a frame;
a unit for decoding the downmix signal;
a spatial information decoding unit determining a number of time intervals, a number of parameter sets and position information indicating a position of a time interval in an ordered set of time intervals included in a frame to which the parameter set is applied; and
an upmixing unit decoding an audio signal based on the number of time slots, the number of parameter sets and position information,
moreover, the position information is represented by a variable number of bits based on the position of the time interval. 12. The device according to claim 11, in which a variable number of bits is determined using the number of time intervals. 13. The device according to claim 11, in which if the number of time intervals to be decoded is equal to the number of parameter sets to be applied, the spatial information decoding unit does not determine information about the position of the time interval to which the parameter set is applied. 14. The device according to claim 11, in which, if the number of parameter sets is greater than or equal to 2 ^ (n-1) and less than 2 ^ (n), then the variable number of bits is defined as n bits. 15. The device according to claim 11, in which the position information is represented as the sum of the previous value and the difference value, where the previous value indicates the position information of the time interval for which the first set of parameters is applied, and the difference value indicates information about the position of the time interval, for which the second set of parameters is applied. 16. The device according to clause 15, in which the previous value is represented by a variable number of bits determined using at least one of: the number of time intervals and the number of sets of parameters. 17. The device according to clause 16, in which a variable number of bits is determined using the difference between the number of time intervals and the number of sets of parameters. 18. A method of encoding an audio signal, comprising:
determining the number of time slots and the number of parameter sets, the parameter sets including one or more parameters;
generating information indicating the position of at least one time interval in an ordered set of time intervals to which a set of parameters is applied;
encoding the audio signal in the form of a bit stream including a frame, the frame including an ordered set of time slots; and
inserting into the bit stream a variable number of bits that represent the position of said time interval in an ordered set of time intervals, the variable number of bits being determined by the position of the time interval. 19. An apparatus for encoding an audio signal, comprising:
a down-mix unit performing down-mix from an audio signal to a down-mix signal;
a downmix signal coding unit encoding a downmix signal;
a spatial information generation unit generating spatial information defining a number of time intervals and a number of parameter sets, and indicating a position of at least one time interval in an ordered set of time intervals to which the parameter set is applied; and
a multiplexer that multiplexes the encoded downmix signal and spatial information into the bitstream and inserts a variable number of bits into the bitstream that represents the position of the time interval in an ordered set of time intervals, the variable number of bits being determined by the position of the time interval.

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