TW201116078A - Apparatus and method for generating a level parameter, apparatus and method for generating a multi-channel representation and a storage media stored parameter representation - Google Patents

Abstract

A parameter representation of a multi-channel signal having several original channels includes a parameter set, which, when used together with at least one down-mix channel allows a multi-channel reconstruction. An additional level parameter (rM) is calculated such that an energy of the at least one downmix channel weighted by the level parameter isI equal to a sum of energies of the original channels. The additional level parameter is transmitted to a multi-channel reconstructor together with the parameter set or together with a down-mix channel. An apparatus for generating a multi-channel representation uses the level parameter to correct (902) the energy of the at least one transmitted down-mix channel before entering the down-mix signal into an up-mixer or within the up-mixing process.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to encoding of a multi-channel representation of an audio signal using spatial parameters. The present invention teaches a new method for estimating and defining appropriate parameters that can be used to reconstruct a multi-channel signal from some channels (less than the number of output channels). In particular, emphasis is placed on minimizing the bit rate of the multi-channel representation and providing an encoded representation of the multi-channel signal that can easily encode and decode the data for all possible channel configurations. Φ [Prior Art] The invention titled "Efficient and Adjustable Parametric Stereo Coding for Low Bit Rate Audio Coding Applications" PCT/SE02/0 1 3 72 has been shown to be reconstructable from a mono signal a very similar to the original Stereo image of a stereo image (assuming a very tight representation of the stereo image). The basic principle is to divide the input signal into frequency bands and time segments, and to estimate inter-channel intensity difference (IID) and inter-channel coherence (ICC) for these bands and time segments. The first parameter is a measure of the power distribution between two channels in a particular frequency band, and the second parameter is an estimate of the correlation between the two channels of that particular frequency band. On the decoder side, by assigning the mono signal between the two output channels in accordance with the IID data and by adding a decorrelated signal to maintain the channel correlation of the original stereo channel, from the mono channel The signal reconstructs the stereo image. For a multi-channel case (multiple channels in the context represent more than two output channels), several additional questions must be accounted for. There are now several multi-channel configurations. The most commonly known is the 5.1 configuration (middle channel, front left/right channel, surround left/right channel, and LEE channel). However, there are now many other -4- 201116078 configurations. From a complete encoder/decoder system perspective, it is desirable to have one or the same set of parameters (e.g., IID and ICC) or subgroups for all channel configurations. ITU-R BS.775 defines several downstream mix architectures (d〇wn-mix schemes) so that they can be obtained from a particular channel configuration - including less channel configurations. Instead of having to decode all the channels and relying on the next line of mixing, it is desirable to have a multi-channel representation that enables a receiver to retrieve parameters relating to the configuration of the hand channel before decoding the channels. It is desirable from an adjustable or inline coding perspective to have an inherently adjustable set of parameters, in which case φ can store data corresponding to the surround channels in one of the bitstream enhancement layers. Contrary to the above, it may also be desirable to use different parameter definitions depending on the characteristics of the signal being processed in order to switch between parameterizations that would result in the lowest bit rate burden for the current signal segment being processed. Another representation of a multi-channel signal using a summed or downmix signal and additional parameter additional information is known as Binaural Cue Coding (BCC). This technique was described in 2003. #十一月6期11 The author of the IEEE Speech Processing Journal is F.

Baumgarte and C. Faller's "Two-Channel Signal Coding, Part I: Fundamentals and Design Principles of Auditory Psychology" and the author of the IEEE Speech Processing Journal, Issue No. 6 of January, 2003, is C. Faller and F. Baumgarte's "Two-Channel Signal Encoding - Part 2: Architecture and Applications" In general, two-channel signal coding is a method of multi-channel spatial representation based on the next line of mixing channels and additional information. For audio reconstruction or audio, the number of parameters calculated by a BCC encoder and used by a BCC decoder is 参S3 -5- .201116078. The number includes inter-channel level difference, inter-channel time difference, and inter-channel coherence. parameter. These inter-channel signals are the determining factor for the perception of a spatial image. These parameters are the blocks of time samples supplied to the original multi-channel signal and are also frequency selective such that each block of the multi-channel signal samples has several signals for several frequency bands. In the general case of C-playing channels, each of the sub-bands between the complex pairs of channels (i.e., for each channel relative to a reference channel) takes into account the level differences of the channels and such The time difference between channels. One channel is defined as a reference channel for the level difference between each channel. Due to the inter-channel power Φ adjustment and the time difference between the channels, it is possible to provide any direction from one source to one of the plurality of pairs of speakers used in a playback device. In order to determine the width of the diffusion of the supplied sound source, it is sufficient to consider a parameter of each sub-band of all audio channels. This parameter is the coherence parameter between the channels. The width of the supplied sound source is controlled by modifying the sub-band signals so that all possible channel pairs have the same inter-channel co-modulation parameters. In BCC encoding, the level difference between all channels between the reference channel and any other channel is determined. When, for example, determining that the center channel is the reference channel, calculating a level difference between the first channel between the left channel and the center channel, between the right channel and the center channel Level difference between two channels, level difference between the left channel between the left surround channel and the center channel, and level between the fourth channel between the right surround channel and the center channel difference. This episode describes a 5-channel architecture. When the 5-channel architecture additionally includes a low frequency enhanced channel (also known as a "sub-wo〇fer" channel), the low frequency enhanced channel is calculated The level difference between the fifth channel and the center channel (the single reference channel). I S3 -6- .201116078 When using this single downmix channel (also known as "single" channel) and transmitting signals, such as: ICLD (inter-channel potential difference, ICTD (inter-channel time difference) and ICC (sound) The inter-channel coherence)) When reconstructing the original multi-channel, these signals are used to modify the spectral coefficients of the single signal. A positive real number is used to determine the level modification of each spectral coefficient to implement the level modification. A complex number is used to determine the phase modification of each spectral coefficient to produce the inter-channel time difference. Another feature determines the coherence effect. The factor of the level modification of each channel is calculated by first calculating the factor of the reference channel. The factor of the reference channel is calculated such that for each frequency portion, the sum of the powers of all channels is the same as the power of the combined signal. Then, based on the level modification factor of the reference channel, the individual ICLD parameters are used to calculate the level modification factor of the other channels. Therefore, in order to perform BCC synthesis, the level correction factor of the reference channel is calculated. For this calculation, all ICLD parameters for a band are required. Then, based on the level modification of the mono, the level modification factor of the other channels (i.e., the channels other than the reference channel) can be calculated. The disadvantage of this method is that for a complete reconstruction, a level difference between each φ channel is required. This requirement poses a greater problem when an error-prone transmission channel is present. Since each level difference between channels is required to calculate each multi-channel output signal, each error within the level difference between the transmission channels will result in an error in the reconstructed multi-channel signal. In another case, although the level difference between the one channels is only required for, for example, the left surround channel or the right surround channel, 'the reconstruction cannot be performed when the inter-channel level difference is lost during transmission'. Since the important information is included in the front left channel (hereinafter referred to as the left channel), the front stone channel (hereinafter referred to as the right channel), and the center channel, the left surround channel ί S3 201116078 And right surround channels are not important for multi-channel reconstruction. This situation gets worse when the level difference between the channels of the low frequency enhanced channel is lost during the transmission. In this case, although the low frequency enhanced channel is not decisive for the listener's listening comfort, there may be no multi-channel reconstruction or only one error multi-channel reconstruction. Because the error in the level difference between the single channels is propagated to the error in each reconstructed output channel. The problem with parameter multi-channel representation is that it usually provides a level difference between channels (for example: ICLD in BCC encoding or 値 in other parameters multi-channel representation) as a relative rather than an absolute 値. In BCC, an ICLD parameter describes the level difference between a channel and a reference channel. Balance 値 can also be provided as the ratio between the two channels in a pair of channels. When the multi-channel signal is reconstructed, the level difference or balance parameter is applied to a basic channel, which may be a mono basic channel or a stereo basic sound with two basic channels. Signal. Thus, the energy contained in at least one of the basic channels is distributed along five or six reconstructed output channels. Thus, the absolute energy in a reconstructed output channel is determined by the level difference between the channels or the balance parameter and the energy of the downmix signal at the receiver input. « A level change occurs when the energy of the downmix signal on the receiver input appears as a function of a change in the downmix signal output by an encoder. In this context, it is emphasized that when the parameters are frequency selective, depending on the parametric architecture used, this level change not only results in a general volume change of the established signal, but also a large number of artifacts. When, for example, a frequency band of the downlink mix signal is more frequently manipulated in the frequency range than in one of the other positions, because the frequency component in the output sound m -8 - 201116078 of the certain frequency band There is a level that is too low or too high, so this manipulation is clearly visible in the reconstructed output signal. In addition, changing the level operation in a timely manner will also cause the total level of the reconstructed output signal to change over time and is therefore considered an annoying artifact. Although the above situation is concentrated on the level operation caused by encoding, transmitting and decoding the next line of the mixed signal, other level shifts may occur. Due to the phase dependence between the different channels to be downmixed into one or two channels, the following occurs: the mono signal has a sum that is not equal to the energy in the original signal. Since the downmix is usually implemented, for example, by adding a time waveform to sample-wise, although the left and right signals of course have a certain signal energy, for example, a phase of 180 degrees between the two signals The difference will result in complete cancellation of the two channels in the downstream mix signal, which in turn results in zero energy. Although it is very unlikely that this will happen under normal conditions, energy changes will still occur because all signals are of course not completely uncorrelated. Since the energy of the reconstructed output signal will be different from the energy of the original multi-channel signal, such variations will also cause a change in volume in the reconstructed output signal and will also result in artifacts. SUMMARY OF THE INVENTION One object of the present invention is to provide a parametric concept that can result in a multi-channel reconstruction with improved output quality. The object is to generate a device for reconstructing a multi-channel representation according to a device for generating a level parameter according to item 1 of the patent application scope, according to claim 7 of the patent application scope, according to the scope of claim 9 M -9- 201116078 A method for generating a level parameter, a method for generating a reconstructed multi-channel representation according to claim 10, a computer program according to claim 11 or This is achieved in accordance with a parameter representation of item 12 of the scope of the patent application. The present invention is based on the following findings: for high quality reconstruction and in view of the elastic coding/transmission and decoding architecture, an additional level parameter is transmitted along with a multi-channel signal down-mix signal or parameter representation such that A multi-channel reconstructor can use the level parameter together with the level difference parameter and the down-mix signal to reproduce a multi-channel output signal without encountering level changes or frequency selective power The artificial factor caused by Ping. In accordance with the present invention, the level parameter is calculated such that at least the energy of the next mixing channel is weighted (e.g., multiplied or divided) by the level parameter equal to the sum of the energies of the original channels. In one embodiment, the level parameter is obtained from the ratio of the energy of the (equal) downmix channel to the sum of the energy of the original channels. In this embodiment, any level difference between the (equal) downstream mixing channel and the original multi-channel signal is calculated on the encoder side and input to the data stream as an electric The level correction factor, which is considered as an additional parameter, may also be provided to a block of the sample of the (equal) downmix channel and to a certain frequency band. Therefore, a new level parameter is added for each region and frequency band (there is an inter-channel level difference or balance parameter). The present invention also provides flexibility because the present invention allows one of the transmissions of a multi-channel signal to be different from the downstream mix of the line-mixed sounds according to the parameters. When, for example, a broadcast station does not wish to play one of the multi-channel decoders

-10- 201116078 Line mixing signal, however, it is desirable to play a downmix. Signal generated by a sound engineer in a studio (which is based on human subjective and creative impressions). Happening. However, the player may also wish to transmit multi-channel parameters related to this "main downmix". According to the present invention, the level parameter is used to provide an adaptation between the parameter group and the main downmix, in which case the level parameter is the level between the main downmix and the parameter downmix. Poor, where the parameter group is downmixed according to the parameter. An advantage of the present invention is that the additional level parameter is provided because the parameter set for the next line of mixing signal can also be adapted to another downstream mix, wherein the other downstream mix is not generated during parameter calculation. Improved output quality and improved flexibility. In order to reduce the bit rate, it is preferable to apply the Δ-encoding of the new level parameter as well as quantization and entropy coding. In particular, because the variation between inter-band or time blocks will not be so high that relatively small differences can be obtained, the use of this concatenation followed by entropy coding (eg, Huffman coder) to allow for good coding gain The possibility, so Δ-encoding will result in a high coding gain. In a preferred embodiment of the invention, a multi-channel signal parameter representation comprising at least two different balance parameters is used, the at least two different balance parameters representing a balance between two different channel pairs. In particular, flexibility, adjustability, error resistance, and even bit rate rate efficiency are the result of the fact that the first channel pair (the basis of the first balance parameter) is different from the second channel pair (the second balance parameter) According to the fact that the four channels in which these channel pairs are formed are different from each other. Thus, the inventive concept differs from the single reference channel concept and the use of a multi-balance or over-balance concept that is more straightforward and more natural to the human voice t S3 -11-201116078. In particular, the pairs of channels that make up the first and second balance parameters may include some combination of the original channel, the downmix channel, or preferably the input channel. A balance parameter obtained from the center channel (as the first channel) and the addition of the left original channel and the right original channel (as the second channel of the channel pair) have been found It is always useful to provide a precise energy distribution between the center channel and the left and right channels. It is noted that in this context these three channels usually comprise most of the information of the sound field, wherein in particular the left-right vertical Φ body localization is not only affected by the balance between the left and the right, but also by the center and left and right. The effect of the balance between the total. This observation is reflected by the use of this balancing parameter in accordance with a preferred embodiment of the present invention. Preferably, when transmitting a single single downmix signal, it has been found that in addition to the center/left ten right balance parameter, there is a left/right balance parameter, a back-left/back-right balance parameter, and a front The /after balance parameter is the best solution for one-bit rate-effective parameter representation, which is elastic, error-resistant and immune to large artificial factors. On the receiver side, the multi-balance representation of the present invention is additionally used to generate a line mix for the downmix channel as compared to the BCC synthesis for each channel of φ by the transmitted information alone. Architectural information. Therefore, the data on the downstream mixing architecture (not used in the prior art system) is also used in addition to the balancing parameters for the uplink mix. Therefore, the upstream mixing operation is implemented to achieve the balance. The parameters determine the balance between the channels in a reconstructed multi-channel signal (forming a pair of channels for a balanced parameter). This concept (i.e., different balance parameters have different pairs of channels) can produce some channels without knowing each transmission balance parameter. In particular, the I S3 •12- 201116078 left, right and center channels can be reconstructed without knowing any post-left/back-right balance or without knowing the front/rear balance. This result allows for very fine-tuning of the ability to adjust, either by taking an extra parameter from a bit stream or by transmitting an extra balance parameter to a receiver, thus allowing reconstruction of one or more additional channels. This is in contrast to the prior art single reference system in which a level difference between channels is required to reconstruct all subgroups or only a subgroup of all reconstructed output channels. Since the selection of the balance parameters can be adapted to a certain reconstruction environment, the concept of the invention is also flexible. A front-and-back balance parameter allows calculation of the combined surround when, for example, a 5-channel setup forms the original multi-channel signal setup and when a 4-channel setup forms a reconstructed multi-channel setup The channel does not require any knowledge of the left surround channel and the left surround channel, wherein the reconstructed multi-channel device has only a single surround speaker, and the single surround speaker is, for example, disposed behind the listener. This is in contrast to a single reference channel system in which the inter-channel level difference of the left surround channel and the inter-channel level of the right surround channel must be retrieved from the stream. difference. After that, the left surround channel and the right surround channel must be calculated. Finally, two channels must be added to obtain the single surround speaker channel for a 4-channel reconstruction. Because the more intuitive and user-oriented balanced parameter representation is not limited to a single reference channel, the combination of the original channels can be allowed to be used as a balanced channel pair of channels and thus automatically The combined surround channel is sent, so it is not necessary to implement all of these steps in the balanced parameter representation. The invention relates to a parameterized multi-channel representation of an audio signal

-13- 201116078 Question. The present invention provides an efficient way to define the appropriate parameters for the multi-channel representation and also provides the ability to retrieve parameters for representing the desired channel configuration without having to decode all of the channels. The present invention further addresses the problem of selecting an optimal parameter configuration for a particular signal segment in order to minimize the bit rate required to encode the spatial parameter for that particular signal segment. The present invention also describes how to apply a decorrelation method that was previously only applicable to two channels in a general multi-channel environment. In a preferred embodiment, the invention includes the following features: Φ - downmixing the multi-channel signal to one or two channel representations on the encoder side; - the multi-channel signal is known, Defining the parameters used to represent the multi-channel signals to minimize the bit rate in an elastic per-frame basis or to enable the decoder to capture the channel configuration at one bit stream level: - Assumption The channel configuration is currently supported by the decoder, which retrieves the relevant parameter set on the decoder side; - assuming the current channel configuration, produces the required number of mutual decorrelated signals, - assuming The parameter set is decoded by the bit stream data and the decorrelated signals to reconstruct the output signals; - defining a parameterization of the multi-channel audio signal so that the same parameter or a subset of the parameters can be used, Regardless of the channel configuration; - defining the parameterization of the multi-channel audio signal so that the parameters can be used in an adjustable coding architecture at which the subset of the parameter set is transmitted In different layers of flow; l S1 -14- 201116078 Defining the parameterization of the multi-channel audio signal such that energy reconstruction from the output signal of the decoder is not compromised by an audio codec for encoding the downstream mix signal; Switching between different parameterizations of the multi-channel audio signal to minimize the bit rate burden for numbering the parameterization; defining a parameterization of the multi-channel audio signal, including one for indicating the downlink mix a parameter of the energy correction factor of the tone signal; - using a plurality of de-correlated decorrelators to reconstruct the multi-channel signal; Φ and - reconstructing the multi-voice from an upstream mixing matrix calculated from the set of transmission parameters Signal. The present invention will be described by way of example with reference to the accompanying drawings, which are not intended to limit the scope or spirit of the invention. [Embodiment] The embodiments described below are only for explaining the principle of the multi-channel representation of the audio signal of the present invention. It will be appreciated that modifications and variations of the configurations and details described herein will be apparent to those skilled in the art. Therefore, the meaning of the present invention is defined by the specific examples of the patent application to be described, and not by the specific details presented in the description and description of the embodiments herein. In the following description of the present invention, which describes how to parameterize IID and ICC parameters and how to apply these parameters in order to reconstruct a multi-channel representation of an audio signal, assume that all of the mentioned signals are sub-band signals or corresponding in a filter block. Some other frequency selective representation of a portion of the entire frequency range of the channel. Thus, it is understood that the invention is not limited to a particular filter bank, and m -15-201116078 for a frequency band represented by the subband of the signal. The invention, as well as the same operation, applies to all sub-band signals. Although a balance parameter is also referred to as an "inter-channel intensity difference (IID)" parameter, it is not necessary to emphasize the balance parameter of one channel pair as the energy or intensity in the first channel of the channel pair. And the energy or intensity of the second channel in the pair of channels. Typically, the balance parameter represents the localization of a sound source between the two channels of the pair of channels. While this localization is typically provided by energy/level/intensity differences, other characteristics of the signal can be used (e.g., power measurements of two p-channels or time or frequency encapsulation of such channels, etc.). In Fig. 1, a different channel of a 5.1 channel configuration is presented, where a(t) 101 represents the left surround channel, b(t) 102 represents the left front channel, and c(t) 103 represents the center. The channel, d(t) 104 represents the right front channel, e(t) 105 represents the right surround channel, and f(t) 106 represents the LEF (low frequency effect) channel. The expected operator is: and therefore the energy of the channel described above can be defined as follows (here the left surround channel is used as an example): A = E[a\t)\0 on the encoder side The 5 channel downmix is made into a 2-channel representation or a 1-channel representation. This can be done in several ways, and one commonly used way is the ITU Downmix as defined below: 5.1 to 2-channel downmix: ί S3 -16- 201116078 ld = ab(t) + Pa(t) + yc(t) + 5f(t) rd (t) = ad (1) + pe(t) + yc(t) tens 5f (1) and 5.1 to 1-channel downmix: mAO = JjUAO+rAO The usual constants a, p, γ, and δ are: a = 1, β = χ = ^ > and at 0 » define the IID parameter as two arbitrary channel or weighted group The energy ratio of the road. If there is the above described energy for the 5.1 channel configuration, then the IID parameters for several groups can be defined. Figure 7 shows a conventional downmixer 700 that uses the above equation to calculate a mono m or two optimal stereo channels and rd. Typically, the downstream mixer uses some downstream mix information. In a preferred embodiment of a linear downmix, the downmix information includes weighting factors a, |3, γ, and δ. It is known in the art that more or less constants or non-constant weighting factors can be used. In an ITU recommended downmix, a is set to 1, ρ and γ are set equal to the square root of 0.5, and the delta system is set. Is 0. Generally, the factor a can vary between 1.5 and 0.5. Further, the factors β and γ are different from each other and vary between 〇 and 1. This low frequency enhanced channel f(t) has the same fact. The channel factor δ can vary between 0 and 1. Furthermore, the factors of the left-downmix and the right-downmix do not have to be equal to each other. This becomes clearer when considering a non-automatic downmix performed by a sound engineer, for example. Further guide the sound engineering to implement a creative downstream mix instead of any

17· 201116078 The mathematics law governs the mixing of the lines. Instead, the sound engineer is dominated by his own creative feelings. When a certain parameter group records this "creative" downstream mix, the "creative" downstream mix will be used in accordance with the invention by the invention of the upstream mixer shown in Fig. 8, which is not only by the parameters It is dominated and is also dominated by additional information about the downstream mix architecture. When a linear downmix is implemented as in Figure 7, the weighting parameters are the best information to be used by the upstream mixer on the downstream mix architecture. However, when presenting other information used in the downlink mixing architecture, an upstream mixer can also use this other information as information for the downstream mixing architecture. Such other information may, for example, also be some matrix elements or certain factors or functions within a matrix element of an upstream mix-matrix (e.g., as shown in Figure 11). Suppose there is a 5.1 channel configuration as described in Figure 1 and how the other channel configurations are related to the 5.1 channel configuration: for the 3 channel case where no surround channel is available, ie B, C, and D can be obtained based on the above symbols. For a 4-channel configuration, B, C, and D are available, but a combination of A and E for the single surround channel or the subsequent channels in this context is also available. The present invention uses IID parameters applied to all of these channels, i.e., the 4-channel sub-group of the 5.1 channel configuration has a corresponding sub-group within the IID parameter set describing the 5.1 channel. The following IID parameter group resolves this issue:

L a2B + fi2A + y2C + 62F Γ, ~ Λ ~ aiD + p2E + y1C-v51F

r22C h ~ a\B + D) IS] •18- 201116078 _ β\Α + Ε)

A2(B + D) + y22C

β2Α A r'= ~We ~ Ί. __δ1 IF_

r$ = a\B + D) + p2{A + E) + Y12C It is obvious that the n parameter corresponds to the energy ratio between the left downmix channel and the right down mix channel. The r2 parameter corresponds to the energy ratio between the center channel and the left and right front channels. The r3 parameter corresponds to the energy ratio between the three front channels and the two surround channels. The Γ4 parameter corresponds to the energy ratio between the two surround channels. The r5 parameter corresponds to the energy ratio between the LFE channel and all other channels. In Figure 4, the energy ratios described above are described. The different output channels are denoted by 101 to 105 and are identical to those shown in Figure 1 and thus will not be described in detail herein. The speaker assembly is divided into left and right halves, wherein the central channel 103 is part of two halves. The energy ratio between the left half plane and the right half plane is exactly the η parameter. This is indicated by the solid line below η in Figure 4. Furthermore, the energy distribution between the center channel 103 and the left front 102 and right front 103 channels is represented by r2. Finally, the energy distribution between the entire pre-channel assembly (102, 103 and 104) and the rear channel (101 and 105) is described by the arrows in Figure 4 with the r3 parameter. Suppose there is the above parameterization and the energy of the single downlink mixing channel: Μ = -{α\Β + Ω)·¥β2{Α + Ε)^ 1γ20 + 2S2F) 2 , the energy of the reconstructed channels can be Expressed as:

F= 2M 2γ2 \ + r5 ί S3 -19- ^4201 116078 β2 \ + rAl + r3l + rs

2M Ε

C 1 + r4 1 + r3 1 + r5 _1__r2__1__1_ 2γ2 1 + r2 1 + r3 1 + rs

2M

2M

B 2-^-M-/32A-r2C-S2F 1 + Ί , 1 , 2 --M-fi2E-Y2C-d2F .1 + > Re-directing the sound of the channel and so on. The amount can be matched to the original number of the voice channel, and the letter M will be the same as ^__ ΠΠ, and this is the reason why the above-mentioned better uplink mixing architecture is described in 8 in the picture. From the equations of F, A, E, C, B, and D, it is clear that the information used by the upstream mixer of the downlink mixing architecture is the weighting factors α, γ, and δ, which are weighted or The unweighted channels are added together or subtracted from each other to obtain a certain number of lower line mixing channels, and the weighting factors are used to weight the original channels, wherein the number of downstream mixing channels is less than the number of original channels . Therefore, it is clear from Fig. 8 that the energy of the reconstructed channels according to the present invention is determined not only by the balance parameters transmitted from an encoding side to a decoding side, but also by the downstream mixing factors α, β, γ, and δ. . When considering Fig. 8, it becomes clear that in order to calculate the left and right energy Β and D, the calculated vocal energy F, α, Ε and C can be used in the equation. However, it is not necessary to include a continuous upstream mixing architecture. Instead, in order to obtain a fully parallel upstream mixing architecture implemented using, for example, an upstream mixing matrix (with certain upstream mixing matrix elements), the equations of A, C, E & F are inserted into the equations of Β and D. . Therefore, it becomes clear that the I S3 -20- 201116078 channel reconstruction channel energy is determined only by the balance parameters, the downmix channel, and the information of the downmix architecture (for example, the downmix factors). As will be apparent from the following, assuming the above IID parameters, it is apparent that the problem of defining an IID parameter of a parameter set (available for several channel configurations) has been solved. Observing the three-channel configuration (that is, reconstructing three front channels from an available channel) as an example, it is obvious that since the a, e, and F channels do not exist, 'Γ3,' And the r5 parameter is not significant. It can also be clearly known because the parameter h describes the energy ratio between the left and right front channels and the parameter Γ2 φ describes the energy ratio between the center channel and the left and right front channels, so the parameters Ri and r2 are sufficient to reconstruct the three channels from the next line of mixing. In a more general case, 'the above IID parameters (Γι...Γ5) can be easily seen to be used from m The channel reconstructs all subgroups of n channels, where m<r^6. Looking at Figure 4, it can be said that: - For a system that reconstructs 2 channels from 1 channel, the ri parameter is obtained to maintain Full information on the correct energy ratio between the channels; - For a system that reconstructs 3 channels from 1 channel, the ^ and Γ2 parameters φ are obtained to maintain the correct energy ratio between the channels. Information; - For a system that reconstructs 4 channels from 1 channel, obtained from the ri, 12, and Γ3 parameters to maintain the sound Full information on the correct energy ratio between the two; - For a system that reconstructs 5 channels from 1 channel, obtain sufficient information from the ^, ^, ^, and Ν parameters to maintain the correct energy ratio between the channels. - For a system that reconstructs 5.1 channels from 1 channel, the ri, r2, r3, 『4 and r5 parameters are used to maintain the correct energy ratio between the channels. m -21- 201116078 Information; - For a system that reconstructs 5.1 channels from 2 channels, sufficient information is obtained from the r2, r3, r4, and r5 parameters to maintain the correct energy ratio between the channels. It is described by the list in the l〇b diagram. The adjustable bit stream described in the l〇a diagram and described later can also be applied to the list in the 1st Ob map in order to obtain the ratio 1 The finer adjustable ability described in Figure 0a (I) The advantage of the invention is in particular that the left and right channels can be easily reconstructed from a single balanced parameter , without knowing or taking any other balancing parameters. For this purpose, in the equations of B and D in Fig. 8, the channels A, C, F, and Ε are simply set to zero. In another case, when only the balance parameter r2 is considered, the reconstructed channels are the sum of the center channel and the low frequency channel (the channel is not set to zero) and the left and right sounds The sum of the tracks. Therefore, the center channel and the tone signal can be reconstructed using only a single parameter. This feature is useful for a simple 3-channel• representation, for example by halving from left And the right sum obtains the left and right signals, and wherein the energy between the center and the sum of the left and right is correctly determined by the balance parameter r2. In this context, the balance parameters ri or r2 are located at one In the lower adjustment layer, the second item in the list of the l〇b diagram shows how to replace all five balance parameters with only two balance parameters to generate three channels b, D, and the addition of C and F. In total, one of these parameters η and r2 may already be in a higher adjustment layer than the parameter π or ~, -22- 201116078 located in the lower adjustment layer. When considering the equation in Fig. 8, it becomes clear that in order to calculate C, the untaken parameter r5 and the other non-taken parameter 13 are set to zero. In another case, the unused channels A, E, and F are also set to zero so that the three channels B, D and the combination of the center channel and the low frequency enhanced channel F can be calculated. . When a 4-channel is indicated for the upstream mix, only ri, i"2, and r3 are sufficient from the parameter stream. In this context, φ r3 can be in a next higher adjustment layer than the parameter η or r2. Since the third balance parameter r3 has been obtained from the combination of the front channel and the rear channels as described later with respect to FIG. 6, the 4-channel configuration is particularly suitable for the super-related to the present invention. Balance parameter representation. This is based on the fact that the parameter Γ3 is a pre- and post-equalization parameter obtained from the pair of channels, the pair of channels having the combination of the rear channels A and E (as the first channel) and having A combination of left channel B, right channel E, and center channel C (as the front channel). Thus, as in the case of a single parametric channel installation, the combined channel energy of the two surround channels can be automatically obtained without any further separation calculations and subsequent combinations. When five channels must be reconstructed from a single channel, another balancing parameter Γ4 is required. This parameter r4 can again be located in the next higher adjustment layer. Each balance parameter is required when a 5.1 reconstruction must be implemented. Therefore, it is necessary to compile a higher adjustment layer (including the next balance parameter r5) to be transmitted to and estimated by the receiver. However, using the same method of expanding the IID parameter according to the number of expansions of the channel [S3-23-201116078, the above IID parameter can be expanded to cover a channel group having a larger number of channels than the 5.1 configuration. state. Therefore, the present invention is not limited to the examples described above. Now observe that the channel configuration is a 5.1 channel configuration, which is one of the most common use cases. Again, assume that the 5.1 channel is reconstructed from both channels. For this case, the parameters of a different group can be defined by replacing the parameters r3 and r4 with the following formula:

Ε2Ε

a^D These parameters q3&q4 represent the energy ratio between the front and rear left channels and the energy ratio between the front and rear right channels. Imagine a few other parameterizations. In Figure 5, the parameterization of the modification can be seen. Instead of having a parameter for arranging the energy distribution between the front and rear channels (as described in r3 in FIG. 4) and one for describing the energy between the left surround channel and the right surround channel Distribution (as described in r4 in Figure 4), using the parameters q3 and q4 to describe the energy ratio between the left front 1〇2 and the left surround 1〇1 channel and the right front channel 104 and the right The energy ratio between the surround channels and the 05. The teachings of the present invention may use several sets of parameters to represent the multi-channel signals. An additional feature of the present invention is that different parameterizations can be selected depending on the type of quantization of the parameters used. As an example of a system using parameterized coarse quantization, due to the high bit rate limitation, a parameterization that does not expand the error in the upstream mix should be used. I S3 -24- 201116078 Observe two representations of the above reconstructed energy in a system for reconstructing 5.1 channels from one channel: 1 ( r \ 5 = _L ΐ-^-Μ-β^-γ^- δ^ « I 1 + n

D

M-fi2E-Y2C-S2F clearly shows that due to the relatively small quantization effect of the M, A, C and F parameters, the reduction will produce a large change in the energy of B and D. According to the present invention, an almost The quantification of parameters is not sensitive to different parameterizations. Therefore, if coarse quantization is used, the Γ1 parameter defined above:

L a2B + p2A + Y2C + 52F

Γ' =Ί~ a2D + fi2E + y2C + 52F can be replaced by an alternative definition according to the following formula:

B 1 D. This produces an equation for the reconstruction energy according to the following formula: „ 1 Κ 1 1 1 ... α 1 + r, 1 + r21 + r31 + rs „ 1 1 1 1 1 ... a 1 + r, 1 + r21 + r31 + r5 and The equations for the reconstruction energies of A, E, C, and F remain the same as described above. It is apparent that this parameter represents an optimal state system from a quantitative point of view. In Fig. 6, the energy ratios described above are described. The different output channels are denoted by 101 to 105 and are identical to Fig. 1 and therefore will not be described in detail herein. The speaker assembly is divided into a front portion and a rear portion. The energy distribution between the entire front channel arrangement (102, 103 and 1〇4) and the rear channels (101 and 105) is described by the arrows indicated by the parameters in Figure 6-25-201116078. . Another important distinguishing feature of the invention is that when observing the parameterized r - r22C 2 a\B + D)

B

At 1 D, it is not only a better state system from a quantitative point of view. The above parameterization also has the advantage that parameters for reconstructing the three front channels can be obtained without φ having any effect on the surround channels. The relationship between the center channel and all other channels can be described as a parameter r2. However, this would have the following disadvantages: The surround channels would be included in the estimates of the parameters described in the front channels. It is to be noted that the parameterization described in the present invention can also be applied to the measurement of the correlation or coherence between the channels. It is apparent that the inclusion of the rear channel pairs in the calculation of r2 is successful in accurately reconstructing the front channels. Significant negative impact. It can be seen as an example of the same signal in all the front channels and the absence of relevant signals in the back channels. This is not uncommon ^, assuming that the back channels are often used to reconstruct the surrounding information of the original sound. If the description of the center channel is for all other channels, the degree of correlation between the center and all other channels will be quite low because the back channels are completely uncorrelated. For a parameter used to estimate the correlation between the front left/right channel and the rear left/right channel, therefore, we achieve a parameterization that correctly reconstructs the energy, however, the parameter The information does not include all of the same (ie, very relevant) I S3 -26- 201116078. The parameterization does include de-correlating the left and right front channels to the back channels and also correlating the center channels to the back channels. However, the fact that all front channels are the same cannot be inferred from this parametric. Since the back channels are not included in the estimation of the parameters used on the decoder side to reconstruct the front channels, this can be achieved by using the following invention

The formula taught to overcome: y22C h = a2(B + D)

B ri = - The energy distribution between the center channel 103 and the left front 102 and right front 103 channels is represented by r2 in accordance with the present invention. The energy distribution between the left surround channel 101 and the right surround channel 105 is described by r4. Finally, the energy distribution between the left front channel 102 and the right front channel 104 is provided by η. It is apparent that, except for the energy distribution between the left front speaker and the right front speaker (as opposed to the entire left and the entire right side), all parameters are the same as described in FIG. Based on the integrity, the parameter Γ5 is also provided to describe the energy distribution between the central channel 1〇3 and the LFE channel 106. Figure 6 shows a summary of a preferred parametric embodiment of the present invention. The first balance parameter η (represented by the solid line) constitutes a front left/front-right balance parameter. The second balance parameter Γ2 is a central left-right balance parameter. The third balance parameter r3 constitutes a pre/post balance parameter. The fourth balance parameter r4 constitutes a back-left/back-right balance parameter. Finally, the fifth parameter r5 constitutes a central/LFE balance parameter. Figure 4 shows a related situation. The first balance parameter ri (described in a downlink I S3 -27-201116078 mix left/right balance by the solid line in FIG. 4) may be in one of the channels B and D (the lower channel pair) The original pre-left/pre-right balance parameters defined between them are replaced. This is described by the broken line ri in Fig. 4 and corresponds to the solid line ri in Figs. 5 and 6.

In the case of a two-channel, the parameters r3 and r4 (i.e., the front/back balance parameter and the back-left/right balance parameter) are replaced by two one-sided front/rear parameters. The first one-sided front/rear parameter q3 can also be regarded as the first balance parameter, wherein the first balance parameter is obtained from the pair of channels formed by the left surround channel A and the left channel B. The second one-sided front/left balance parameter is the parameter q^' which can be regarded as the second parameter, and the second parameter is based on the right channel D and the right surround channel E. Right. Furthermore, the two channel pairs are not related to each other. The center/left-right balance parameter! *2 also has the same fact 'The central/left-right balance parameter ^ has a center channel C as a first channel and the sum of the left and right channels B and D as a second Channel. Another parameterization is defined in accordance with the present invention which is inherently suitable for coarse quantization for a system that reconstructs 5.1 channels from one or two channels.

As for -_ β2Α channel to 5.1 channel α2Β ~αΓ 2d Μ β1Εnr and % S2Fnr and as for the two channels to 5.1 channel £A,

L <h

2B r2c 2d β2Ε

L

R

R

It is apparent from s2f ~M that the above parameterization includes more parameters than is required by the strict theoretical point of view to correctly redistribute the energy of the transmitted signals to the reconstructed signals. However, the sensitivity of this parameterization to quantization errors is very slow. ί S3 28- 201116078 The above mentioned reference sets for a 2-channel installation use several reference channels. However, compared to the parameter configuration in Figure 6, the parameter set in Figure 7 is only used as the reference channel based on the downstream mix channel instead of the original channel. The equalization parameters qi, q3 and q4 are obtained from completely different pairs of channels. Although several embodiments of the present invention have been described, the channel pair in which the balance parameter is obtained includes only the original channel (Figs. 4, 5, and 6) or includes the original channel and the downmix channel ( 4 and 5) or only the downlink mixing channel as the reference channel represented at the bottom of FIG. 7, but the most φ is included in the surround data encoder 206 of FIG. The parameter generator is operative to use only a combination of the original channel or the original channel rather than a combination of a base channel or a base channel of the channel in the pair of channels, wherein the balance parameters are based on Equal channel pair. This is due to the inability to fully guarantee that the single fundamental channel or the two stereo base channels will not undergo an energy change during transmission from a surround encoder to a surround decoder. It can be operated in a low-bit rate state by an audio encoder 20 5 (Fig. 2) or an audio decoder 3〇2 (Fig. 3) to cause the downmix channel or the single downmix The energy of the sound channel φ changes. This condition may result in manipulation of the energy of the single downmix channel or the stereo downmix channels, which may be different or even frequency selective between the left and right stereo downmix channels Or time selective. In order to completely safely oppose this energy change, an additional level parameter is transmitted in accordance with the present invention for each region and frequency band of each of the downstream mixing channels. Therefore, when the balance parameters are based on the original signal instead of the downmix signal, since any energy correction will not affect the balance between the original channels, a single correction factor pair Each band is sufficient. Even when no extra level parameters are transmitted, any downmix channel energy changes will not cause distortion localization of the source in the audio image, but will only result in a general volume change, which will not be like a normal volume change. The migration of sound sources caused by changing the balance state is as annoying. It is important to note that care must be taken so that the energy of the downstream mixing channels is the sum of the energies B, D, A, E, C and F described above. This is not always the case because of the phase dependent φ nature between the different channels that are downmixed to one channel. The energy correction factor can be transmitted as an additional parameter rM, and thus the line mix signal received on the decoder side is defined as: = \ia\B + ΰ) + β\Α + Ε) + 2y2C + 2S2F) In Figure 9, the additional parameters in accordance with the present invention are described! ^ Application. The downlink mix signal is modified by the additional parameter rM in 901 before the downlink mix signal is transmitted to the upstream mix module 70 1 -705. These are the same φ as described in Figure 7 and will not be described in further detail herein. It is obvious to those skilled in the art that the parameters of the above mono downmixing example can be extended to one parameter of each downmix and thus are not limited to a single downmix channel. Figure 9a depicts an inventive level parameter. Calculator 900, however, Figure 9b shows an inventive level corrector 902. Fig. 9a shows the case on the encoder side' and Fig. 9b depicts the correspondence on the decoder side. The level parameter or "extra" parameter rM is used to provide a correction factor for a certain energy ratio. The following exemplary scenarios are assumed to be explained. For a single original multi-channel I S] -30- 201116078 signal, on one hand there is a "main downmix" and on the other hand a "parameter down mix". The primary downmix has been generated by a sound engineer in a studio based on, for example, a subjective quality impression. In addition, an audio storage medium also includes the parameter downlink mix. The parameter downmix has been implemented by, for example, the surround encoder 203 of FIG. The parameter downmix includes a base channel or two base channels that use the balance parameter set of the original multichannel signal or any other parameter representation to form the basis for the multichannel reconstruction. For example, it may be the case that the broadcaster wishes to not transmit the parameter down φ mix, but it is desirable to transfer the main downmix from a transmitter to the receiver. In addition, in order to promote the main downmix to a multi-channel representation, the broadcaster also transmits a parameter representation of the original multi-channel signal. Since (in a frequency band and in a block) energy can (or will typically) vary between the main downmix and the parameter downmix, a relative level parameter γμ is generated in block 900. And pass it to the receiver as an additional parameter. The level parameter is obtained from the main downmix and the downmix of the parameter and preferably the ratio of the φ of the energy in a block of the main downmix and the downmix of the parameter and a frequency band. Typically, the level parameter is calculated to be the ratio of the sum of the energy of the original channels (Edg) to the energy of the (equal) downmix channel, wherein the (equal) downmix channel can be This parameter is Downmix (EPD) or the Main Downmix (EMD) or any other downstream mix signal. Typically, the energy of a particular downstream mix signal transmitted from a codec to a decoder is used. Figure 9b depicts the implementation of this level parameter using one of the decoder sides. The level parameter and the downmix signal are input to the level corrector block 90 2 .

-31- 201116078 The level corrector corrects the single basic channel or the basic channels according to the level parameter. Since the additional parameter is a relative enthalpy, the relative enthalpy is manipulated by the energy of the corresponding elementary channel. Although the 9a and 9b. figures show the case where a level correction is applied to the pair of downmix channels or the downmix channels, the level parameters can also be integrated into the upmix matrix. For this purpose, each occurrence of m in the equation of Fig. 8 is replaced by "rMM". When the 5.1 channel is reconstructed from the 2 channel, the following description can be observed. If the present invention having the codecs 205 and 322 described in Figs. 2 and 3 is used, some more considerations are required. Observe the nD parameter defined earlier] where Π is defined according to the following formula:

_L a2B + fi2A + Y2C + S2F Γ, a2D + p2E + Y2C + 52F because the system reconstructs 5.1 sonar from 2 channels, assuming that the two transmission channels are stereo downmixes of the surround channels, so This parameter is implicitly available on the decoder side. However, an audio codec operating at a one-bit rate limit can modify the spectral distribution such that the measured L and R energy on the decoder side is different from the number on the encoder side. According to the present invention, the effect of the energy distribution on the reconstructed channel disappears by transmitting the following parameters for the case of reconstructing 5.1 channels from two channels:

B D〇 If a means of signaling is provided, the decoder can use different parameter sets to encode the target signal segment and select the IID parameter to provide the minimum burden of is] -32- 201116078 for the particular signal segment to be processed. The energy levels between the right front and rear channels may be similar, and the energy levels between the front and rear left channels may be similar, however the levels in the right front and back channels are significantly different. . Assuming that there is parameter delta coding and subsequent entropy coding, it is more efficient to use parameters q3 and q4 instead of r3 and r4. For another signal segment with different characteristics, a different parameter set can provide a lower bit rate burden. The present invention allows for free switching between different parameter representations in order to minimize the bit rate burden of the currently encoded signal segment, wherein the characteristics of the signal segment are known. The ability to switch between different parameterizations of the IID parameters in order to obtain the lowest possible bit rate burden and to provide means of signaling to indicate what parameterization is currently used is an essential feature of the present invention. Furthermore, the difference encoding of the parameters can be done in the frequency direction or in the time direction, and the difference encoding between the different parameters can be completed. In accordance with the present invention, assuming that a means of signaling is provided to indicate the particular delta encoding used, a parameter can be differentially encoded with respect to any other parameter. An important feature of any coding architecture is the ability to implement tunable coding. This means that the encoded bit stream can be split into several different layers. The core layer can be decoded by itself, and the higher layer can be decoded to enhance the decoded core layer signal. The number of available layers may vary for different situations, but as long as the core layer is available, the decoder can produce output samples. The parameterization of the multi-channel coding described above using the ^ to Μ parameter is quite suitable for the tunable coding. Therefore, for example, the data of the two surround channels (A and E) can be stored in an enhancement layer (that is, the parameters corresponding to the front channels in the parameters ^ and r4 and in the core layer (by The parameters ^ and Γ2 are indicated)) IS3 -33- 201116078. In Fig. 10, the implementation of the adjustable bit stream in accordance with the present invention is described. The bit stream layer is described by 1001 and 1002, wherein 1001 is the core layer, which holds the waveform encoded downmix signal and holds the front channel (102, 103 and 104) for reconstruction. The enhancement layers described by parameters η and r2. 1002 hold parameters for reconstructing the back channels (101 and 105). Another gist of the present invention is the use of a decorrelator in a multi-channel configuration. In the PCT/SE02/01 372 patent document, the use of a decorrelator has been detailed for one or two acoustic φ channels. . However, when this theory is expanded to more than two channels, several problems to be solved by the present invention arise. Basic mathematics shows that in order to complete a mutual de-correlation signal from one signal, a 解-Ν decorrelator is needed, in which all the different decorrelators are used to generate a plurality of mutually orthogonal output signals from a common input signal. Suppose an input x(t) produces an output y(t)l£|>fj=4c|2j and almost eliminates the correlation correlation ]/], then a decorrelator is usually an all-pass or almost all-pass filter . An additional perceptual criterion can be used to design a good decorrelator. Some φ examples of the design method can minimize the comb filter characteristics and minimize one of the transient signals when adding the original signal to the decorrelated signal. Sometimes the effect of an impulse response that is too long. Some conventional art decorators use an artificial mirror to de-correlate. Conventional techniques can also achieve higher echo densities and thus longer diffusions by, for example, modifying the phase of complex sub-band samples to include fractional delays. The present invention proposes a method for modifying a mirror-based decorrelator to achieve a plurality of decorrelators that can generate a plurality of mutually de-correlated outputs m-34-201116078 signals from a common input signal. If the outputs of the two decorrelators yi(t) and y2(t) have an alternating or disappearing correlation (assuming the same input), then the two decorrelators are decorrelated to each other. Assuming that the input is static white noise, then the pulse Μ and h2 must be orthogonal in the perception of five [vd disappearing or almost disappearing. Pairwise de-correlation decorrelators of complex arrays can be constructed in several ways. One effective way to implement this modification is to change the phase rotation factor q (which is part of the fractional delay). The particular phase rotation factor of the present invention may be part of the delay line in the all-pass filter or just a total fractional delay. In this latter case, the method is not limited to all-pass or mirror filters, but can be applied to, for example, a simple delay including a fractional delay. One of the all-pass filter connections in the decorrelator can be described in a Z-domain as: where q is the complex phase rotation factor (M = l), m is the delay line length in the sample, and the a-line filtering Factor. For stability reasons, the size of the filter φ coefficient must be limited to |«| <1 » However, by using the alternative filter coefficient a' = -a to define a new mirror with the same reflection delay characteristics However, there is an output that is significantly uncorrelated with the output of the unmodified mirror. Furthermore, the modification of the phase rotation factor q can be accomplished by, for example, adding a fixed phase offset cf = qeje. This constant C can be used as a fixed phase offset or can be adjusted in such a way that for all bands to which the constant C is applied, the constant C will correspond to a fixed time offset. The phase offset constant C can also be a random chirp, which is different for all frequency bands. [S3 - 35- • 201116078 According to the present invention, by applying an upstream mixing matrix 具有 having an nx(m + p) size to a row vector signal having a size of (m + p) x 1 to implement from m Each channel produces n channels. m y = s where m is the m downmixed and encoded signals, and the P signals in s are de-correlated with each other and de-correlated with all signals in m. These decorrelated signals are generated by the signal in m by the decorrelator. Then, n reconstructed signals a', b', ... are included in the row vector. X' = H y. The above is described by Figure 11, wherein the decorrelated signals are generated by the decorrelators 1 102, 1 103 and 1 104. The upstream mixing matrix is provided by 1101 to operate on the vector y to provide the output signal X'. Assume = the correlation matrix of the original signal vector, assuming that R| = E[xix〃] is the correlation matrix of the reconstructed signal. Here and in the following, for a matrix having a vector X of complex terms, X' denotes a complex conjugate transpose of the adjoint matrix ---X. The diagonal of R contains the energy 値A, B, C··. and can be decoded into a total energy level by the energy quotation defined above. Because, so there are only n(n-l)/2 different non-diagonal cross-correlation 値, which contain information that will be completely or partially reconstructed by adjusting the upstream mixing matrix 。. The reconstruction of the complete correlation structure corresponds to the case R' = R. The reconstruction of the correct energy level corresponds only to the following cases, where "' and the ruler are equal on the diagonal. M -36- 201116078 In the case of changing from m=l channel to n channel, the reconstruction of the complete correlation structure is achieved by using a mutual decorrelation decorrelator (an upstream mixing matrix H) The tone matrix Η satisfies the following conditions: ΗΗ, = upper R Μ where Μ is the energy of the single transmitted signal. Because R is a positive semi-definite matrix, it is well known to be an answer now. Furthermore, n(n-l)/2 degrees of freedom are reserved for the design of Η, which is used in the present invention to obtain additional desirable characteristics of the upstream mixing matrix. A central design criterion is that the dependencies on the transmission-related data should be smooth. One of the traditional ways of parameterizing the upstream mixing matrix is H = UDV, where U and V are orthogonal matrices and D is a pair of angular matrices. The square of the absolute 値 of d can be chosen to be equal to the characteristic R of R/M. Deleting V and selecting the features 値 to apply the maximum 値 to the first coordinate will minimize the total energy of the decorrelated signal in the output. In the real case, the orthogonal matrix U is parameterized by an n(n-l)/2 rotation angle. Transmitting the relevant data in the form of those angles and the η diagonals of I D will immediately provide the desired smoothness of η. However, this method sacrifices the ability to adjust because the energy data must be transformed into a characteristic 値. The second method taught by the present invention defines a normalized correlation matrix R〇 by R = GR 〇 G to separate the energy portion in R from the correlation portion, wherein the G system has a diagonal term equal to R The diagonal matrix of the square roots (ie, A, #...), the RQ has the same diagonal 对 on the diagonal. It is assumed that H0 is an orthogonal up-mixing matrix that defines a better normalized upstream mix in the case of completely unrelated signals of equal energy. An example of this preferred upstream mixing matrix m -37- 201116078 • 1 1 Ί 1 1 Γ "1 -Γ 1 9 A 1 1 -V2 1 » A 11-1-1 1 1 2 β -V2 0 2 1 -1-1 1 1-11-1 Then, with if = 05^. /, / to define the upstream mix, where the matrix S solves SS, R 〇. The choice of this solution is continuous for the normalized interaction correlation 在 in the RG, so that S is equal to the identity matrix in the case of R 〇 = I. Segmenting the n channels into groups of fewer channels is a convenient way to reconstruct a portion of the cross-correlation structure. According to the present invention, for the case of reconstructing 5.1 channels from 1 channel, a particularly advantageous grouping is {a, e}, {c}, {b, d}, {f}, where no decorrelation is applied to the The equal groups {c} and {f}, and the groups {a, e} and {b, d} are generated by the same downmixing/de-correlated pair of upstream mixes. For both subsystems, the preferred normalized upstream mix in the completely unrelated case is: 丄 "1 -1"! _]^[1 1' million 1 j, 10,000 b -1. Therefore, only two of the 15 cross-correlation totals will be transmitted and reconstructed, that is, the interaction between the channels {a, e} and {b, d}. In the terms used above, this An example of design is the case for n = 6, m = 1, and p = 1. The upstream mix matrix is 6x2 in size and corresponds to the second row on the 3rd and 6th columns. The two terms of the outputs c1 and Γ are zero. The third method for invoking the decorrelated signal as taught by the present invention is a simpler view: each output channel has a different decorrelator to cause a decorrelated signal Sa, sb then make these reconstruction signals: -38- 201116078 α = 4αΪΜ (mcos% + sfl sin%), b = 4bTm (wcos% + sin outside), etc. These parameters cpa, <Pb... The number of decorrelated signals presented in the output channels a', b', ... is controlled. The relevant data is transmitted in the form of these angles. It can be easily calculated: for example The normalized interaction relationship between the paths a' and N is equal to the product COSCpaCOS (pb. When the number of pairwise interactions is n(n-1)/2 and there are n decorrelators, if n>3, then usually Impossible • Matching in this way—a specific correlation structure, but the advantage is a very simple and stable decoding method and direct control over the number of generated de-correlated signals presented in each output channel. The correlation of the correlation signals is based on the perceptual quasi-IJ of the energy level difference such as the channel pair. For the case of reconstructing the n channel from the m>I channel, the correlation matrix Ry = E[yy is no longer used. ] assumed to be a diagonal matrix, and must take into account R, = HRyH· matches the target R. Because Ry has a block matrix structure "圪〇1 Rv = m

〇 K L· ·> Δ thus produces a simplification' where Rm = E[mm*;^ Rs = E[ss·]. Furthermore, it is assumed that the decorrelator is mutually de-correlated. The matrix Rs is a diagonal matrix. Note that this will also affect the upstream mix design with respect to the reconstruction of the correct energy. The solution is to calculate or transmit from the encoder the information about the correlation structure Rm of the downlink mixing signals. In the case of reconstructing the 5.1 channel from the 2-channel, the preferred method of the upstream mixing is ·· -39- I $} 201116078 a 'κ 0 0 b' κ 0 Κ 0 c κ Κ 0 0 ά 0 Κι 0 κ e 0 Κ 0 Κ /. Λ Κι 0 0 m2

Sl s2 where Si can be obtained from the decorrelation of mi = ld and s2 can be obtained from the solution of m2 = rd. Here, the groups {a, b} and {d, e} are regarded as separated 1-> 2-channel systems that have been considered to be pairwise interactively related. For channels c and f, the weighting is adjusted so that 丨+Vw2|2j=C, the present invention can be implemented on a hardware chip for various systems using arbitrary codecs for storage or transmission of analog or digital signals. And DSP. Figures 2 and 3 show possible implementations of the invention. In this example, a system (a 5.1 channel configuration) for operating six input signals is shown. In the second diagram showing the side of the code φ coder, the analog input signals such as the separated channels are converted into a digital signal 20 1 and the filter bank using each channel is analyzed 202. The output of the filter bank is fed to the surround encoder 203, which includes a parameter generator 'which performs a line mix to produce one or two channels encoded by the audio encoder 205 . Furthermore, in accordance with the present invention, surround parameters such as IID and ICC parameters are captured, and a time frequency grid for deduplicating the data and which parameterized control data 204 are used in accordance with the present invention are retrieved. As taught by the present invention, the parameters -40-201116078 2 06 are encoded to switch between different parameterizations or to configure the parameters in an adjustable manner. The surround parameter 2 07, the control signal, and the numbered downmix signal 208 multiplex processing 209 are a series of bit streams.

In Fig. 3, a typical decoder implementation (i.e., a device for generating multi-channel reconstruction) is shown. Here, it is assumed that the audio decoder outputs a signal in a frequency domain representation, for example, the output of an MPEG-4 high efficiency AAC decoder in front of the QMF synthesis filter bank. Performing a demultiplexing process 301 on the serial bit stream and feeding the encoded surround data into the surround data decoder 303 and feeding the downlink mixed code channels to the audio decoder 302 (in this example For MPEG-4 high efficiency AAC decoder). The surround data decoder decodes the surround data and feeds it into the surround decoder 305. The surround decoder 305 includes an upstream mixer, according to the decoded downlink mix channel and the surround data and the control signals. To reconstruct 6 channels. The frequency domain output of the surround decoder is synthesized 306 to become a time domain signal, which is then converted to an analog signal by the DAC 307. Although the present invention has been described primarily with respect to the generation and use of balance parameters, it is emphasized here that the same grouping of channel pairs for obtaining balanced parameters is preferably used to calculate inter-channel coherence parameters or both. The "width" parameter between the channel pairs. In addition, a channel time difference or a "phase signal" can also be obtained using the same channel pair used for the calculation of the balance parameter. On the receiver side, these parameters can be used in addition to or as an alternative to the equalization parameters to produce a multi-channel reconstruction. In another case, the inter-channel co-modulation parameters or even the inter-channel time differences may be used in addition to other inter-channel level differences as determined by other reference channels. However, in view of the adjustable capability feature of the present invention as described in Figures 1 S3 - 41 - 2011 16078 10a and 10b, it is preferred to use the same channel pair for all parameters in order to be in an adjustable bit stream. An adjustment layer includes all parameters for reconstructing an output channel of the subgroup, wherein the output channels of the subgroup are identifiable by the individual adjustment layers recited in the penultimate row of the list of the lth diagram To produce. The present invention is useful in calculating only the coherence parameters or time difference parameters between individual channel pairs and transmitting them to a decoder. In this case, when a multi-channel reconstruction is implemented, the level parameters are already present at the decoder for use. g The process of the invention may be carried out in a hard or soft manner in accordance with certain implementation requirements of the process of the invention. It can be implemented using a digital storage medium (particularly a disk or optical disk storing electronically readable control signals) that cooperate with a programmable computer system to carry out the method of the present invention. Accordingly, the present invention is generally a computer program product having a program code stored in a mechanically readable carrier, the program being operative to carry out the method of the present invention when the computer program product is executed on a computer. Thus, in other words, the method of the present invention is a computer program having a program code for performing at least one of the methods of the present invention when the φ computer program is executed on a computer. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 depicts an academic term used in a 5.1 channel configuration in the present invention; Fig. 2 depicts a suitable encoder implementation in accordance with a preferred embodiment of the present invention; A suitable decoder of a preferred embodiment of the present invention is implemented in an S S -42 - 201116078; FIG. 4 depicts a preferred parameterization of a multi-channel signal in accordance with the present invention; FIG. 5 depicts a plurality of preferred embodiments in accordance with the present invention; A preferred parameterization of the channel signal; Figure 6 depicts a preferred parameterization of the multi-channel signal in accordance with the present invention; Figure 7 depicts a method for generating a single basic channel or two basic channels below A schematic representation of a mixing architecture; Figure 8 depicts a schematic representation of an upstream mixing architecture that balances parameters and information of the downstream mixing architecture in accordance with the present invention; φ Figure 9a is described Determination of level parameters on the encoder side in accordance with the present invention; Figure 9b is a schematic depiction of the use of level parameters on the decoder side in accordance with the present invention; Figure 10a depicts a bit stream flow The multi-channel parameterization in different layers The same part of the adjustable bit stream; Figure 10b depicts an adjustable capability table that indicates which balance parameters are used to construct which channels and which balance parameters and channels are not used and calculated; and Φ Figure 11 depicts the basis The application of the inventive upstream mixing matrix. [Main component symbol description] 101 Left loop around channel 102 Left 声 Channel 103 Central channel 104 Right front jtsn* Channel 105 Right ring Tour 7*?/y Channel 106 LEF *ru Channel i S) -43- 201116078

20 1 ADC 202 Analysis 203 Surround 204 Control 205 Audio 206 Surround 207 Surround 208 No. 209 Multiplex 30 1 Solution 302 Audio 303 Surround 304 Control 305 Surround 306 Synthetic 307 D AC 700 Downstream 900 Level 902 Level 1001 Bit 1002 Bit Element 110 1 Dephase 1 103 Dephase 1104 Deconstruction Filter Bank Encoder Signal Encoder Data Encoder Parameter Downmix Mixer Worker Decoder Data Decoder Signal Decoder Filter Group Mixer Parameter Calculator Corrector Flow laminar flow gate closing device [s] -44- 201116078

Ld,rd best body channel m, 1,n mono ri parameterΓ2 parameterΓ3 parameterΓ4 parameterΓ5 parameterΓΜ extra parameter a weighting factor β weighting factor y weighting factor δ weighting factor A channel B channel C channel D channel E channel EMD main downstream mix E 〇rig original channel energy E p D parameter downmixing F reconstructing channel energy I S3 -45-

Claims (1)

201116078 VII. Patent application scope: 1. A device for generating a level parameter in a parameter representation of a multi-channel signal, the multi-channel signal having a plurality of original channels 'this parameter representation includes a parameter group The parameter set allows for a multi-channel reconstruction when used with at least the next line of mixing channels, the apparatus comprising: - a level parameter calculator (900) for calculating a level parameter (rM) 'this power The flat parameter is a level difference between a main downmix and a parametric downmix, wherein the parameter indicates a downmix according to the parameter; and an output interface for generating output data, the output data including the a level parameter and the parameter group or the level parameter and the at least one lower line mixing channel. 2. The device of claim 2, wherein the parameter comprises a parameter group for each of a plurality of frequency bands of the at least one of the next mixing channels, and wherein the parameter calculator (9 00) The system operates to calculate a level parameter for each of the bands. Φ 3,. The device of claim 1, wherein the parameter representation comprises a parameter set for one of a continuous period of one of the at least one of the next mixing channels and wherein the level parameter calculator (9 00) is operative to calculate a level parameter for each of the successive periods of the at least one lower mixing channel. 4. The apparatus of claim 1, wherein the output interface is operative to adjust a data stream, the adjustable data stream including a parameter of the first to the subgroup of the parameter group in the lower adjustment layer, the first The subgroup parameter allows reconstruction of the output channel of the first I S3 -46 - 201116078 subgroup, the adjustable data stream including parameters of the second subgroup of the parameter set in a higher adjustment layer, the second sub The group, along with the first subgroup, allows reconstruction of the output channels of the second subgroup, and wherein the output interface is further operative to cause the level parameter to enter the lower adjustment layer. 5. The apparatus of claim 1, further comprising a parameter generator configured to generate a left/right balance parameter as a first balance parameter and a central balance parameter as A second balance parameter, a front/back balance parameter is used as a third balance parameter, a back-left/right balance parameter is used as a fourth balance parameter and a low frequency enhancement balance parameter is used as a fifth balance parameter. 6. A device for reconstructing a multi-channel representation using one of the parameter representations to produce one of the original multi-channel signals, the original multi-channel signal having at least three original channels, the parameter representation having a parameter set, the parameter The group allows for a multi-channel reconstruction when used with at least the next mixing channel, the parameter representation including a level parameter 'the level parameter is the level between a primary downmix and a parametric downmix. Poor, wherein the parameter indicates that the downmix is based on the parameter, the apparatus includes: - a level corrector (902) for using the level parameter to apply level correction of the at least one downmix channel, using The level parameter weights the at least one lower mixing channel so that an upmixing can be performed by using parameters in the parameter set to obtain a corrected multi-channel reconstruction. 7. An I S3 -47 - 201116078 method for generating a level parameter in a parameter representation of a multi-channel signal. Method 'The multi-channel signal has a plurality of original channels, the parameter representation comprising a parameter group' The parameter set allows for a multi-channel reconstruction when used with at least the next line of mixing channels, the method comprising: calculating (9 0 0) - level parameter (Γμ), the level parameter is in a main downstream mix a level difference between a parameter and a downmix, wherein the parameter indicates that the line is mixed according to the parameter; and generating an output data, wherein the output data includes the level parameter and the parameter group or the level parameter and the at least one Line mixing channels. φ 8. A method of reconstructing a multi-channel representation using one of the parameter representations to generate one of the original multi-channel signals, the original multi-channel signal having at least three original channels, the parameter representation having a parameter set, The parameter set allows for a multi-channel reconstruction when used with at least the next line of mixing channels. The parameter representation includes a level parameter 'the level parameter is between a main downstream mix and a parameter downstream mix. Adjustment, wherein the parameter representation is downmixing according to the parameter, the method comprising: using the level parameter to implement (902) φ level correction of the at least one lower mixing channel, using the level parameter to weight The at least one line of mixing channels is such that an upmixing can be performed by using parameters in the parameter set to obtain a corrected multi-channel reconstruction. A recording medium having a computer program with mechanically readable instructions, which can be implemented on a computer as described in claim 7 or 8. -48-