CN112530445A - Coding and decoding method and chip of high-order Ambisonic audio - Google Patents
Coding and decoding method and chip of high-order Ambisonic audio Download PDFInfo
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Abstract
The invention provides a coding and decoding method and a chip of high-order Ambisonic audio, wherein the chip comprises the following components: the high-order Ambisonic audio coding chip comprises a trigonometric function arithmetic unit, a Legendre function arithmetic unit and an integrator, the trigonometric function arithmetic unit, the Legendre function and the integrator are carried out on input audio signals, and then complex space transformation is carried out to obtain output B of spherical harmonic decomposition. The decoding chip of the high-order Ambisonic audio realizes the decoding process of the high-order stereo audio through an addition and a multiplier. The chip of the invention realizes the hardware of the spherical harmonic decomposition and the inverse transformation thereof to accelerate the encoding and decoding process of the HOA signal and expand the application range of the HOA audio frequency, so that the chip is suitable for occasions with higher real-time requirements, such as streaming media playing and the like.
Description
Technical Field
The invention relates to the technical field of coding and decoding of high-order stereo audio, in particular to a coding and decoding method and a chip of high-order Ambisonic audio.
Background
The Higher Order stereo audio technique (HOA) is an extension of the First Order stereo audio technique (FOA) that fits the sound field by reconstructing the sound field distribution in space. The higher-order stereo audio technology is mainly based on the following two principles: (1) a sound field can be viewed as a superposition of multiple spherical harmonics; (2) the acoustic function may be approximated by a plurality of spherical harmonics.
The principle of spherical harmonic decomposition is explained below. Any function p (θ, λ) on a unit sphere can be expressed in the form:
wherein, anmAnd bnmIs the spherical harmonic coefficient, θ and λ are the angles of the spherical coordinates, n and m are the order and number of regularization, RnmAnd SnmIs a normalized spherical harmonic, Rnm(θ,λ)＝Pnm(cosθ)cosmλ，Snm(θ,λ)＝Pnm(cosθ)sinmλ，PnmIs a fully regularized associative legendre function. At present, the HOA audio coding process is a process of performing spherical harmonic decomposition on an original audio signal to obtain an HOA signal, and the decoding process is a process of obtaining a driving signal of the spherical harmonic on a loudspeaker by using inverse transformation. The encoding and decoding of the HOA audio signals are mostly realized on a general-purpose CPU or a GPU by software, so that the encoding and decoding speed of the HOA audio signals is slow, and there is no dedicated chip for hardware acceleration in the high-order stereo audio encoding and decoding process.
Disclosure of Invention
The embodiment of the invention provides a coding and decoding method and a chip of a high-order Ambisonic audio, which solve the technical problems that in the prior art, the coding and decoding speed of an HOA audio signal is low, and a special chip for accelerating hardware in a high-order stereo audio coding and decoding process is not provided.
The embodiment of the invention provides a high-order Ambisonic audio coding method, which is used for carrying out pipeline design aiming at the coding process of HOA audio and carrying out vectorization operation on audio signals, and is favorable for the rapid operation of spherical harmonic coding.
The high-order Ambisonic audio coding method comprises the following steps:
the method comprises the steps that angles uniformly sampled along the lambda direction and an original sound wave function are used as input of a first operation algorithm, a trigonometric function result of the angles uniformly sampled along the lambda direction is calculated by the aid of the first operation algorithm, and the result obtained by multiplying the trigonometric function result of the angles uniformly sampled along the lambda direction and the original sound wave function is integrated to obtain a first result;
taking the angle uniformly sampled along the theta direction and the first result as input of a second operation algorithm, calculating a trigonometric function result of the angle uniformly sampled along the theta direction and a Legendre function result of the trigonometric function result of the angle uniformly sampled along the theta direction by using the first operation algorithm, and integrating the trigonometric function result of the angle uniformly sampled along the theta direction, the Legendre function result of the trigonometric function result of the angle uniformly sampled along the theta direction and a multiplication result of the first result to obtain a second result;
taking the order n of the spherical harmonic decomposition, the specific angle along the theta direction and the second result as the input of a third operation algorithm, calculating a trigonometric function result of the specific angle along the theta direction by using the third operation algorithm, calculating a legendre function result of the trigonometric function result of the specific angle along the theta direction by using the third operation algorithm, and integrating the legendre function result of the trigonometric function result of the specific angle along the theta direction and the result of multiplication of the second result to obtain a third result;
taking the number m of spherical harmonic decomposition, the specific angle along the lambda direction and the third result as the input of a fourth operation algorithm, calculating the number m of spherical harmonic decomposition and the trigonometric function result of the specific angle along the lambda direction by using the fourth operation algorithm, and integrating the multiplication result of the number m of spherical harmonic decomposition and the trigonometric function result of the specific angle along the lambda direction with the third result to obtain a fourth result;
the first operation algorithm, the second operation algorithm, the third operation algorithm and the fourth operation algorithm are obtained by decomposing spherical harmonics; the fourth result is mapped to the HOA coded signal of which the coefficient matrix is the original sound wave function in the complex space.
The embodiment of the invention also provides a high-order Ambisonic audio decoding device, which is designed aiming at the streamline of the decoding process of the HOA audio and carries out vectorization operation on the audio signal, thereby being beneficial to the rapid operation of spherical harmonic decoding.
The high-order Ambisonic audio decoding comprises:
determining a coefficient matrix of the loudspeakers according to the number and the positions of the loudspeakers;
performing pseudo-inverse operation on the coefficient matrix of the loudspeaker to obtain a pseudo-inverse operation matrix;
determining a drive signal for the loudspeaker based on the inverse operation matrix and the HOA encoded signal of the original sound wave function.
The embodiment of the invention provides a high-order Ambisonic audio coding device, which comprises:
the first operation algorithm module is used for taking the angle uniformly sampled along the lambda direction and the original sound wave function as input of a first operation algorithm, calculating a trigonometric function result of the angle uniformly sampled along the lambda direction by using the first operation algorithm, and integrating a result obtained by multiplying the trigonometric function result of the angle uniformly sampled along the lambda direction by the original sound wave function to obtain a first result;
the second operation algorithm module is used for taking the angle uniformly sampled along the theta direction and the first result as the input of a second operation algorithm, calculating a trigonometric function result of the angle uniformly sampled along the theta direction and a Legendre function result of the trigonometric function result of the angle uniformly sampled along the theta direction by using the first operation algorithm, and integrating the trigonometric function result of the angle uniformly sampled along the theta direction, the Legendre function result of the trigonometric function result of the angle uniformly sampled along the theta direction and a multiplication result of the first result to obtain a second result;
the third operation algorithm module is used for taking the order n of the spherical harmonic decomposition, the specific angle along the theta direction and the second result as the input of a third operation algorithm, calculating a trigonometric function result of the specific angle along the theta direction by using the third operation algorithm, calculating a Legendre function result of the trigonometric function result of the specific angle along the theta direction by using the third operation algorithm, and integrating the Legendre function result of the trigonometric function result of the specific angle along the theta direction and the result obtained by multiplying the second result to obtain a third result;
the fourth operation algorithm module is used for taking the number m of spherical harmonic decomposition times, the specific angle along the lambda direction and the third result as the input of a fourth operation algorithm, calculating the number m of spherical harmonic decomposition times and the trigonometric function result of the specific angle along the lambda direction by using the fourth operation algorithm, and integrating the multiplication result of the number m of spherical harmonic decomposition times, the trigonometric function result of the specific angle along the lambda direction and the third result to obtain a fourth result;
the first operation algorithm, the second operation algorithm, the third operation algorithm and the fourth operation algorithm are obtained by decomposing spherical harmonics; the fourth result is mapped to the HOA coded signal of which the coefficient matrix is the original sound wave function in the complex space.
The embodiment of the invention provides a high-order Ambisonic audio decoding device, which comprises:
the coefficient matrix determining module is used for determining the coefficient matrix of the loudspeaker according to the number and the position of the loudspeaker;
the matrix operation module is used for performing pseudo-inverse operation on the coefficient matrix of the loudspeaker to obtain a pseudo-inverse operation matrix;
and the driving signal determining module is used for determining a driving signal of the loudspeaker according to the inverse operation matrix and the HOA coding signal of the original sound wave function.
The embodiment of the invention provides a high-order Ambisonic audio coding chip, which realizes the hardware realization of spherical harmonic decomposition to accelerate the coding process of an HOA signal and expand the application range of an HOA audio so as to be suitable for occasions with higher real-time requirements, such as streaming media playing and the like.
The high-order Ambisonic audio coding chip comprises:
the first arithmetic unit is used for taking the angle uniformly sampled along the lambda direction and the original sound wave function as the input of a first arithmetic algorithm, calculating a trigonometric function result of the angle uniformly sampled along the lambda direction by using the first arithmetic algorithm, and integrating the result obtained by multiplying the trigonometric function result of the angle uniformly sampled along the lambda direction by the original sound wave function to obtain a first result;
the second arithmetic unit is used for taking the angle uniformly sampled along the theta direction and the first result as the input of a second arithmetic algorithm, calculating a trigonometric function result of the angle uniformly sampled along the theta direction and a Legendre function result of the trigonometric function result of the angle uniformly sampled along the theta direction by using the first arithmetic algorithm, and integrating the trigonometric function result of the angle uniformly sampled along the theta direction, the Legendre function result of the trigonometric function result of the angle uniformly sampled along the theta direction and a multiplication result of the first result to obtain a second result;
a third arithmetic unit, configured to take the order n of the spherical harmonic decomposition, the specific angle in the θ direction, and the second result as inputs of a third arithmetic algorithm, calculate a trigonometric function result of the specific angle in the θ direction using the third arithmetic algorithm, calculate a legendre function result of the trigonometric function result of the specific angle in the θ direction using the third arithmetic algorithm, and integrate a product of the legendre function result of the trigonometric function result of the specific angle in the θ direction and the second result to obtain a third result;
the fourth arithmetic unit is used for taking the number m of times of spherical harmonic decomposition, the specific angle along the lambda direction and the third result as the input of a fourth arithmetic algorithm, calculating the number m of times of spherical harmonic decomposition and a trigonometric function result of the specific angle along the lambda direction by using the fourth arithmetic algorithm, and integrating the multiplication result of the number m of times of spherical harmonic decomposition and the trigonometric function result of the specific angle along the lambda direction with the third result to obtain a fourth result;
the first operation algorithm, the second operation algorithm, the third operation algorithm and the fourth operation algorithm are obtained by decomposing spherical harmonics; the fourth result is mapped to the HOA coded signal of which the coefficient matrix is the original sound wave function in the complex space.
The embodiment of the invention provides a high-order Ambisonic audio decoding chip, which realizes the inverse transformation of spherical harmonic decomposition by hardware to accelerate the decoding process of an HOA signal and expand the application range of the HOA audio so as to be suitable for occasions with higher real-time requirements, such as streaming media playing and the like.
The high-order Ambisonic audio decoding chip comprises:
the first arithmetic unit is used for carrying out pseudo-inverse operation on the coefficient matrix of the loudspeaker to obtain a pseudo-inverse operation matrix;
a second operator for determining a drive signal for the loudspeaker from the violating operation matrix and the HOA encoded signal of the original sound wave function;
wherein the coefficient matrix of the loudspeakers is determined according to the number and the positions of the loudspeakers.
An embodiment of the present invention further provides a computer chip, including: the high-order Ambisonic audio coding chip and the high-order Ambisonic audio decoding chip are disclosed.
The embodiment of the present invention further provides a computer device, which includes a memory, a processor, and a computer program stored in the memory and executable on the processor, and the processor implements the method when executing the computer program.
The embodiment of the invention also provides a computer readable storage medium, and the computer readable storage medium stores a computer program for executing the method.
In the embodiment of the invention, the pipeline design is carried out on the HOA signal coding and decoding process, for example, the spherical harmonic function is decomposed into four operation algorithms, the HOA audio decoding process is divided into multi-step matrix calculation, and meanwhile, hardware realization is carried out, thereby being beneficial to the rapid operation of the spherical harmonic coding and decoding.
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In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
FIG. 1 is a flowchart of a method for high-order Ambisonic audio coding according to an embodiment of the present invention;
FIG. 2 is a block diagram of an exemplary high-order Ambisonic audio encoding apparatus according to the present invention;
FIG. 3 is a schematic diagram of an internal arithmetic unit of an advanced Ambisonic audio coding chip according to an embodiment of the present invention;
FIG. 4 is a flowchart of a high-order Ambisonic audio decoding method according to an embodiment of the present invention;
FIG. 5 is a flowchart of a method for decoding an audio signal with high-order Ambisonic according to an embodiment of the present invention;
FIG. 6 is a block diagram of an exemplary high-order Ambisonic audio decoding apparatus according to the present invention;
FIG. 7 is a schematic diagram of an internal arithmetic unit of an advanced Ambisonic audio decoding chip according to an embodiment of the present invention;
fig. 8 is a block diagram of a computer chip structure according to an embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
In the embodiment of the invention, the existing HOA audio coding process is a process of performing spherical harmonic decomposition on an original audio signal to obtain an HOA signal, the decoding process is a process of obtaining a driving signal of the spherical harmonic on a loudspeaker by using inverse transformation, the speed of the HOA audio signal coding and decoding mode is low, and a special chip for accelerating the hardware of a high-order stereo audio coding and decoding process is not provided. Based on the scheme, the invention provides a split strategy of the HOA audio coding and decoding process, which splits the high-order stereo audio coding process into four sub-processes and splits the high-order stereo audio decoding process into multi-step matrix calculation. The strategy can be realized by a high-order Ambisonic audio coding and decoding method, device and chip, and the flow splitting mode is favorable for hardware realization of HOA audio coding and decoding processes and quick operation of spherical harmonic coding and decoding.
Based on the two principles of higher-order stereo audio techniques mentioned in the background and equation (1), the operation of spherical harmonic decomposition can be expressed as the following four-step integral form:
the operations of equations (3), (4), (5) and (6) are similar, and all include trigonometric functions and integral operations (integral operations include multiplication and addition operations), and (4) and (5) also include legendre function calculation, so that the process of spherical harmonic decomposition is divided into four operation processes, and HOA audio coding is performed based on the four operation processes.
Fig. 1 is a flowchart of a method for encoding an audio signal with higher order Ambisonic according to an embodiment of the present invention, as shown in fig. 1, the method includes:
decomposing the spherical harmonic function to obtain four operation algorithms;
step 101: the method comprises the steps of taking an angle uniformly sampled along the lambda direction and an original sound wave function as input of a first operation algorithm, calculating a trigonometric function result of the angle uniformly sampled along the lambda direction by using the first operation algorithm, and taking the trigonometric function result of the angle uniformly sampled along the lambda direction and the original sound wave functionIntegrating the multiplication result of the function to obtain a first result
Step 102: taking the angle uniformly sampled along the theta direction and the first result as the input of a second operation algorithm, calculating a trigonometric function result of the angle uniformly sampled along the theta direction and a Legendre function result of the trigonometric function result of the angle uniformly sampled along the theta direction by using the first operation algorithm, integrating the trigonometric function result of the angle uniformly sampled along the theta direction, the Legendre function result of the trigonometric function result of the angle uniformly sampled along the theta direction and a multiplication result of the first result to obtain a second result
Step 103: taking the order n of the spherical harmonic decomposition, the specific angle along the theta direction and the second result as the input of a third operation algorithm, calculating a trigonometric function result of the specific angle along the theta direction by using the third operation algorithm, calculating a legendre function result of the trigonometric function result of the specific angle along the theta direction by using the third operation algorithm, integrating the legendre function result of the trigonometric function result of the specific angle along the theta direction and the result of multiplying the second result to obtain a third result
Step 104: taking the number m of spherical harmonic decomposition, the specific angle along the lambda direction and the third result as the input of a fourth operation algorithm, calculating the number m of spherical harmonic decomposition and the trigonometric function result of the specific angle along the lambda direction by using the fourth operation algorithm, and integrating the multiplication result of the number m of spherical harmonic decomposition and the trigonometric function result of the specific angle along the lambda direction with the third result to obtain a fourth result p (theta, lambda);
the first operation algorithm, the second operation algorithm, the third operation algorithm and the fourth operation algorithm are obtained by decomposing spherical harmonics; the fourth result is mapped to the HOA coded signal of which the coefficient matrix is the original sound wave function in the complex space. Complex space is a planar vector space, i.e., a set of integers consisting of a pair of ordered real numbers.
In the embodiment of the present invention, as can be seen from formula (2), the first operation algorithm includes trigonometric function operation, multiplication operation, and addition operation;
step 101 specifically includes:
and respectively multiplying the sine function result and the cosine function result of the angle uniformly sampled along the lambda direction by the original sound wave function by multiplication and addition to obtain a first result.
In the embodiment of the present invention, as can be seen from formula (3), the second operation algorithm includes trigonometric function operation, legendre function operation, multiplication operation and addition operation;
step 102 specifically includes:
calculating a sine function result and a cosine function result of the angle uniformly sampled along the theta direction by utilizing trigonometric function operation, calculating a Legendre function result of the cosine function result of the angle uniformly sampled along the theta direction by utilizing Legendre function operation, multiplying the sine function result of the angle uniformly sampled along the theta direction, the Legendre function result of the cosine function result of the angle uniformly sampled along the theta direction and the first result by utilizing multiplication operation and addition operation, and then adding to obtain a second result.
In the embodiment of the present invention, as can be seen from formula (4), the third operation algorithm includes trigonometric function operation, legendre function operation, multiplication operation and addition operation;
step 103 specifically includes:
and multiplying the Legendre function result of the cosine function result of the specific angle along the theta direction by multiplication and addition, and then adding the Legendre function result and the second result to obtain a third result.
In the embodiment of the present invention, as can be seen from formula (5), the fourth operation algorithm includes trigonometric function operation, multiplication operation, and addition operation;
step 104 specifically includes:
and calculating the number m of spherical harmonic decomposition times and the result of the sine function and the result of the cosine function at the specific angle along the lambda direction by utilizing trigonometric function operation, and adding the result obtained by multiplying the number m of the spherical harmonic decomposition times, the result of the sine function and the result of the cosine function at the specific angle along the lambda direction by the third result to obtain a fourth result.
The "specific angle" in steps 103 and 104 is a preselected angle.
In the embodiment of the present invention, the operation result of the trigonometric function and the legendre function in the formula (5) and the formula (6) is most likely to be operated in the formula (3) and the formula (4), so the method may further include:
caching one or more of trigonometric functions of the angles uniformly sampled along the lambda direction, trigonometric functions of the angles uniformly sampled along the theta direction, and Legendre function results of trigonometric function results of the angles uniformly sampled along the theta direction.
Thus, the invention fully utilizes the local consistency of the calculation result, caches the results of Legendre function and trigonometric function, and can quickly acquire the cosm lambda, sinm lambda and P of the cache from the cache (step 103 and step 104)nm(cos θ), thereby reducing the repetition of the legendre function and the trigonometric function. However, when the cache capacity is limited, the cache may not be available, and the possibility that the operations of step 103 and step 104 need to be performed again is not excluded.
Based on the same inventive concept, the embodiment of the present invention further provides a higher order Ambisonic audio encoding apparatus, as described in the following embodiments.
Fig. 2 is a block diagram of a high-order Ambisonic audio encoding apparatus according to an embodiment of the present invention, as shown in fig. 2, including:
first arithmetic algorithm module201, for taking the angle of uniform sampling along the λ direction and the original acoustic wave function as the input of a first operation algorithm, calculating the trigonometric function result of the angle of uniform sampling along the λ direction by using the first operation algorithm, integrating the result of the trigonometric function result of the angle of uniform sampling along the λ direction and the result of multiplication of the original acoustic wave function to obtain a first result
I.e. lambda-wise integrating array;
a second operation algorithm module 202, configured to use the angle uniformly sampled in the θ direction and the first result as input of a second operation algorithm, calculate, by using the first operation algorithm, a trigonometric function result of the angle uniformly sampled in the θ direction, a legendre function result of the trigonometric function result of the angle uniformly sampled in the θ direction, integrate the trigonometric function result of the angle uniformly sampled in the θ direction, the legendre function result of the trigonometric function result of the angle uniformly sampled in the θ direction, and a result obtained by multiplying the first result, and obtain a second result
Theta direction integral array;
a third operation algorithm module 203, configured to use the order n of the spherical harmonic decomposition, the specific angle in the θ direction, and the second result as inputs of a third operation algorithm, calculate a trigonometric function result of the specific angle in the θ direction using the third operation algorithm, calculate a legendre function result of the trigonometric function result of the specific angle in the θ direction using the third operation algorithm, integrate the legendre function result of the trigonometric function result of the specific angle in the θ direction and a result obtained by multiplying the second result, and obtain a third result
Namely n-direction integral arrays;
a fourth operation algorithm module 204, configured to use the number m of spherical harmonic decomposition times, the specific angle along the λ direction, and the third result as inputs of a fourth operation algorithm, calculate the number m of spherical harmonic decomposition times and a trigonometric function result of the specific angle along the λ direction by using the fourth operation algorithm, and integrate the result obtained by multiplying the number m of spherical harmonic decomposition times and the trigonometric function result of the specific angle along the λ direction by the third result to obtain a fourth result p (θ, λ), that is, an m-direction integral array;
the first operation algorithm, the second operation algorithm, the third operation algorithm and the fourth operation algorithm are obtained by decomposing spherical harmonics; the fourth result is mapped to the HOA coded signal of which the coefficient matrix is the original sound wave function in the complex space.
According to the audio coding method, a plurality of audio frames are spliced to be used as vector input, integral operation (namely multiplication and addition) is carried out on an input variable (and/or) trigonometric function (and/or) Legendre function in each module according to an angle sequence or an order and frequency sequence, the integral results of the first three modules are input into the next module, and the integral result of the last module is converted into a complex space to obtain an output B of spherical harmonic decomposition.
In the embodiment of the present invention, the first operation algorithm includes trigonometric function operation, multiplication operation and addition operation;
the first operation algorithm module 201 is specifically configured to:
and respectively multiplying the sine function result and the cosine function result of the angle uniformly sampled along the lambda direction by the original sound wave function by multiplication and addition to obtain a first result.
In the embodiment of the present invention, the second operation algorithm includes trigonometric function operation, legendre function operation, multiplication operation and addition operation;
the second operation algorithm module 202 is specifically configured to:
calculating a sine function result and a cosine function result of the angle uniformly sampled along the theta direction by utilizing trigonometric function operation, calculating a Legendre function result of the cosine function result of the angle uniformly sampled along the theta direction by utilizing Legendre function operation, multiplying the sine function result of the angle uniformly sampled along the theta direction, the Legendre function result of the cosine function result of the angle uniformly sampled along the theta direction and the first result by utilizing multiplication operation and addition operation, and then adding to obtain a second result.
In the embodiment of the present invention, the third operation algorithm includes trigonometric function operation, legendre function operation, multiplication operation, and addition operation;
the third operation algorithm module 203 is specifically configured to:
and multiplying the Legendre function result of the cosine function result of the specific angle along the theta direction by multiplication and addition, and then adding the Legendre function result and the second result to obtain a third result.
In the embodiment of the present invention, the fourth operation algorithm includes trigonometric function operation, multiplication operation, and addition operation;
the fourth operation algorithm module 204 is specifically configured to:
and calculating the number m of spherical harmonic decomposition times and the result of the sine function and the result of the cosine function at the specific angle along the lambda direction by utilizing trigonometric function operation, and adding the result obtained by multiplying the number m of the spherical harmonic decomposition times, the result of the sine function and the result of the cosine function at the specific angle along the lambda direction by the third result to obtain a fourth result.
In an embodiment of the present invention, the apparatus for encoding Ambisonic audio signal further includes:
and the caching module is used for caching one or more of the trigonometric function of the angle uniformly sampled along the lambda direction, the trigonometric function of the angle uniformly sampled along the theta direction and the Legendre function result of the trigonometric function result of the angle uniformly sampled along the theta direction.
The operation process of the high-order Ambisonic audio coding device is controlled by a control signal, and the operation process is in information interaction with the cache.
The above is to realize the high-order Ambisonic audio coding through the computer program, and the high-order Ambisonic audio coding can also be realized from the hardware perspective below.
Based on the same inventive concept, the embodiment of the present invention further provides a high-order Ambisonic audio coding chip, as described in the following embodiments.
Fig. 3 is a schematic structural diagram of an advanced Ambisonic audio coding chip according to an embodiment of the present invention, and as shown in fig. 3, the advanced Ambisonic audio coding chip includes:
the first arithmetic unit is used for taking the angle uniformly sampled along the lambda direction and the original sound wave function as the input of a first arithmetic algorithm, calculating a trigonometric function result of the angle uniformly sampled along the lambda direction by using the first arithmetic algorithm, and integrating the result obtained by multiplying the trigonometric function result of the angle uniformly sampled along the lambda direction by the original sound wave function to obtain a first result;
the second arithmetic unit is used for taking the angle uniformly sampled along the theta direction and the first result as the input of a second arithmetic algorithm, calculating a trigonometric function result of the angle uniformly sampled along the theta direction and a Legendre function result of the trigonometric function result of the angle uniformly sampled along the theta direction by using the first arithmetic algorithm, and integrating the trigonometric function result of the angle uniformly sampled along the theta direction, the Legendre function result of the trigonometric function result of the angle uniformly sampled along the theta direction and a multiplication result of the first result to obtain a second result;
a third arithmetic unit, configured to take the order n of the spherical harmonic decomposition, the specific angle in the θ direction, and the second result as inputs of a third arithmetic algorithm, calculate a trigonometric function result of the specific angle in the θ direction using the third arithmetic algorithm, calculate a legendre function result of the trigonometric function result of the specific angle in the θ direction using the third arithmetic algorithm, and integrate a product of the legendre function result of the trigonometric function result of the specific angle in the θ direction and the second result to obtain a third result;
the fourth arithmetic unit is used for taking the number m of times of spherical harmonic decomposition, the specific angle along the lambda direction and the third result as the input of a fourth arithmetic algorithm, calculating the number m of times of spherical harmonic decomposition and a trigonometric function result of the specific angle along the lambda direction by using the fourth arithmetic algorithm, and integrating the multiplication result of the number m of times of spherical harmonic decomposition and the trigonometric function result of the specific angle along the lambda direction with the third result to obtain a fourth result;
the first operation algorithm, the second operation algorithm, the third operation algorithm and the fourth operation algorithm are obtained by decomposing spherical harmonics; the fourth result is mapped to the HOA coded signal of which the coefficient matrix is the original sound wave function in the complex space.
In the embodiment of the present invention, as shown in fig. 3, the first arithmetic unit includes a trigonometric function arithmetic unit, a multiplication arithmetic unit and an addition arithmetic unit;
the second arithmetic unit comprises a trigonometric function arithmetic unit, a Legendre function arithmetic unit, a multiplication arithmetic unit and an addition arithmetic unit (a synthesis integrator of the trigonometric function arithmetic unit and the Legendre function arithmetic unit);
the third arithmetic unit comprises a trigonometric function arithmetic unit, a Legendre function arithmetic unit, a multiplication arithmetic unit and an addition arithmetic unit;
the fourth arithmetic unit comprises a trigonometric function arithmetic unit, a multiplication arithmetic unit and an addition arithmetic unit.
Wherein, the order n and the degree m represent coefficient input, and the lambda and the theta represent angle input.
The trigonometric function arithmetic unit is realized by hardware in a cordic mode, and a cordic (coordinate Rotation Digital computer) algorithm, namely a coordinate Rotation Digital calculation method, is mainly used for calculating trigonometric functions, hyperbolas, exponents and logarithms. The algorithm replaces multiplication operation with basic addition and shift operation, so that functions such as trigonometric functions, multiplication, evolution, inverse trigonometry, exponents and the like are not needed for calculation of rotation and orientation of the vector.
In the embodiment of the present invention, as shown in fig. 3, the method further includes:
and the buffer is used for buffering one or more of the trigonometric function of the angle uniformly sampled along the lambda direction, the trigonometric function of the angle uniformly sampled along the theta direction and the Legendre function result of the trigonometric function result of the angle uniformly sampled along the theta direction.
The operation process of the chip is controlled by the control signal, and the operation process of the chip is interacted with the information cached. Of course, the data buffer may also be buffered in a buffer external to the chip.
Based on the above-mentioned higher-order Ambisonic audio coding, the present invention also provides a method, an apparatus and a chip from the aspect of higher-order Ambisonic audio decoding, as described in the following embodiments.
Fig. 4 is a flowchart of a method for decoding an Ambisonic audio according to an embodiment of the present invention, and as shown in fig. 4, the method for decoding an Ambisonic audio according to an embodiment of the present invention includes:
step 401: determining a coefficient matrix of the loudspeakers according to the number and the positions of the loudspeakers;
step 402: performing pseudo-inverse operation on the coefficient matrix of the loudspeaker to obtain a pseudo-inverse operation matrix;
step 403: determining a drive signal for the loudspeaker based on the inverse operation matrix and the HOA encoded signal of the original sound wave function.
In the embodiment of the present invention, as shown in fig. 5, step 402 specifically includes:
step 4021: determining a transposed matrix C of the coefficient matrix from the coefficient matrix CT；
Step 4022: multiplying the coefficient matrix and the transposed matrix of the coefficient matrix to obtain a square matrix CTC；
Step 4023: performing inverse operation on the square matrix to obtain an inverse matrix (C) of the square matrixTC)-1；
Step 4024: inverse matrix (C) of square matrixTC)-1Transposed matrix C of sum coefficient matrixTMultiplying to obtain a pseudo-inverse operation matrix (C)TC)-1CT；
Step 403 specifically includes:
will violate the inverse operation matrix (C)TC)-1CTAnd multiplying the HOA coded signal B of the original sound wave function to obtain a driving signal D of the loudspeaker.
In an embodiment of the present invention, the driving signal of the speaker is determined according to the following formula:
D＝(CTC)-1CTB；
wherein D is a driving signal of the loudspeaker; c is a coefficient matrix of the loudspeaker; the superscript T represents transposing the matrix; superscript-1 represents the inverse operation on the matrix; b is the HOA encoded signal of the original sound wave function.
In the above method, when the sound field is reconstructed using L speakers, the coefficient matrix C may be determined according to the number and positions of the speakers. For a given spherical harmonic signal B (i.e. the HOA-coded signal of the original sound wave function), a drive signal D for the loudspeaker is obtained by calculating pinv (C) B, where pinv (C) isTC)-1CTIs a pseudo-inverse operation of the matrix.
In this embodiment of the present invention, the method for decoding an Ambisonic audio signal further includes:
one or more of a transpose matrix of the coefficient matrix, a square matrix, an inverse of the square matrix, and a pseudo-inverse operation matrix are cached.
Therefore, the spherical harmonic coefficient matrix C and the spherical harmonic signal B are cached in the calculation process, and repeated addressing of data in the operation process is reduced.
Based on the same inventive concept, the embodiment of the present invention further provides a high-order Ambisonic audio decoding apparatus, as described in the following embodiments.
Fig. 6 is a block diagram of a high-order Ambisonic audio decoding apparatus according to an embodiment of the present invention, and as shown in fig. 6, the high-order Ambisonic audio decoding apparatus includes:
a coefficient matrix determining module 601, configured to determine a coefficient matrix of the speakers according to the number and the positions of the speakers;
a matrix operation module 602, configured to perform a pseudo-inverse operation on the coefficient matrix of the speaker to obtain a pseudo-inverse operation matrix;
a driving signal determination module 603 for determining a driving signal for the loudspeaker from the HOA encoded signal violating the inverse operation matrix and the original sound wave function.
In this embodiment of the present invention, the matrix operation module 602 is specifically configured to:
determining a transposed matrix of the coefficient matrix according to the coefficient matrix;
multiplying the coefficient matrix and the transposed matrix of the coefficient matrix to obtain a square matrix;
carrying out inverse operation on the square matrix to obtain an inverse matrix of the square matrix;
multiplying the inverse matrix of the square matrix and the transposed matrix of the coefficient matrix to obtain a pseudo-inverse operation matrix;
the driving signal determination module 603 is specifically configured to:
and multiplying the hot coding signal of the original sound wave function by the inverse operation matrix to obtain a driving signal of the loudspeaker.
In the embodiment of the present invention, the method further includes:
and the cache module is used for caching one or more of a transposed matrix of the coefficient matrix, a square matrix, an inverse matrix of the square matrix and a pseudo-inverse operation matrix.
The above is to realize the decoding of the higher order Ambisonic audio by the computer program, and the decoding of the higher order Ambisonic audio can also be realized from the hardware perspective.
The high-order Ambisonic audio decoding chip comprises:
the first arithmetic unit is used for carrying out pseudo-inverse operation on the coefficient matrix of the loudspeaker to obtain a pseudo-inverse operation matrix;
a second operator for determining a drive signal for the loudspeaker from the violating operation matrix and the HOA encoded signal of the original sound wave function;
wherein the coefficient matrix of the loudspeakers is determined according to the number and the positions of the loudspeakers.
The HOA audio decoding method in the chip is realized by two-step matrix multiplication and one-step matrix inversion operation.
In the embodiment of the present invention, as shown in fig. 7, the first operator includes a multiplication operator and a cordic operator (matrix inversion);
the second operator comprises a multiplication operator;
the multiplier of the first operator is specifically configured to:
multiplying the coefficient matrix and the transposed matrix of the coefficient matrix to obtain a square matrix;
the cordic operator in the first operator is specifically configured to:
carrying out inverse operation on the square matrix to obtain an inverse matrix of the square matrix;
the multiplier of the first operator is specifically configured to:
multiplying the inverse matrix of the square matrix and the transposed matrix of the coefficient matrix to obtain a pseudo-inverse operation matrix;
the multiplier of the second operator is specifically configured to:
and multiplying the hot coding signal of the original sound wave function by the inverse operation matrix to obtain a driving signal of the loudspeaker.
In the embodiment of the present invention, as shown in fig. 7, the method further includes:
the buffer is used for buffering one or more of a transpose matrix of the coefficient matrix, a square matrix, an inverse matrix of the square matrix and a pseudo-inverse operation matrix.
The HOA audio decoding method in the chip may also be implemented by two-step matrix multiplication and one-step matrix inversion, that is, the multiplication of the last step in the first operator (multiplication of the inverse matrix of the square matrix and the transposed matrix of the coefficient matrix) may be combined into the multiplication of the HOA encoded signal of the original acoustic function by the illicit operation matrix in the second operator.
The operation process of the chip is controlled by the control signal, and the operation process of the chip is interacted with the information cached. Of course, the matrix buffer may also be buffered in a buffer external to the chip.
Based on the same inventive concept, the embodiment of the present invention further provides a computer chip, as shown in fig. 8, including: the high-order Ambisonic audio coding chip and the high-order Ambisonic audio decoding chip are provided.
The chip designed by the invention uses FPGA to carry out principle verification, but the product of the chip is not limited to the FPGA implementation form.
An FPGA (field Programmable Gate array) device belongs to a semi-custom circuit in an application-specific integrated circuit, is a Programmable logic array, and can effectively solve the problem that the number of Gate circuits of the original device is small. The basic structure of the FPGA comprises a programmable input/output unit, a configurable logic block, a digital clock management module, an embedded block RAM, wiring resources, an embedded special hard core and a bottom layer embedded functional unit. The FPGA has the characteristics of abundant wiring resources, high repeatable programming and integration level and low investment, and is widely applied to the field of digital circuit design.
The FPGA adopts a concept of a Logic Cell array lca (Logic Cell array), and includes three parts, namely, a configurable Logic module clb (configurable Logic block), an input Output module iob (input Output block), and an internal connection (Interconnect). A Field Programmable Gate Array (FPGA) is a programmable device that has a different structure than traditional logic circuits and gate arrays (such as PAL, GAL and CPLD devices). The FPGA utilizes small lookup tables (16 multiplied by 1RAM) to realize combinational logic, each lookup table is connected to the input end of a D flip-flop, and the flip-flops drive other logic circuits or drive I/O (input/output) circuits, so that basic logic unit modules which can realize both combinational logic functions and sequential logic functions are formed, and the modules are mutually connected or connected to an I/O module by utilizing metal connecting wires. The logic of the FPGA is implemented by loading programming data into the internal static memory cells, the values stored in the memory cells determine the logic function of the logic cells and the way of the connections between the modules or between the modules and the I/O and finally the functions that can be implemented by the FPGA, which allows an unlimited number of programming.
The embodiment of the present invention further provides a computer device, which includes a memory, a processor, and a computer program stored in the memory and executable on the processor, and the processor implements the method when executing the computer program.
The computer device provided by the invention can also comprise one or more computer chips and one or more readable storage media. The computer apparatus may operate the HOA audio signal in the readable storage medium through a computer chip to enable an encoding and decoding method in the computer chip.
The embodiment of the invention also provides a computer readable storage medium, and the computer readable storage medium stores a computer program for executing the method.
In summary, the coding and decoding method, device and chip of the high-order Ambisonic audio provided by the invention have the following beneficial effects:
(1) the invention realizes hardware aiming at the HOA coding and decoding process to expand the application range of the HOA audio frequency, so that the HOA audio frequency is suitable for occasions with higher real-time requirements, such as streaming media playing and the like.
(2) The invention carries out pipeline design aiming at the encoding and decoding process of the HOA audio and carries out vectorization operation on the audio signal, and the design is beneficial to the quick operation of spherical harmonic encoding;
(3) the invention fully utilizes the local consistency of matrix reading and writing and function calculation in the HOA signal coding and decoding process, and carries out cache design aiming at the consistency, and the design reduces redundant reading and writing and operation in the HOA signal coding and decoding process;
as will be appreciated by one skilled in the art, embodiments of the present invention may be provided as a method, system, or computer program product. Accordingly, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.
The present invention is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes may be made to the embodiment of the present invention by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. A high-order Ambisonic audio coding method, comprising:
the method comprises the steps that angles uniformly sampled along the lambda direction and an original sound wave function are used as input of a first operation algorithm, a trigonometric function result of the angles uniformly sampled along the lambda direction is calculated by the aid of the first operation algorithm, and the result obtained by multiplying the trigonometric function result of the angles uniformly sampled along the lambda direction and the original sound wave function is integrated to obtain a first result;
taking the angle uniformly sampled along the theta direction and the first result as input of a second operation algorithm, calculating a trigonometric function result of the angle uniformly sampled along the theta direction and a Legendre function result of the trigonometric function result of the angle uniformly sampled along the theta direction by using the first operation algorithm, and integrating the trigonometric function result of the angle uniformly sampled along the theta direction, the Legendre function result of the trigonometric function result of the angle uniformly sampled along the theta direction and a multiplication result of the first result to obtain a second result;
taking the order n of the spherical harmonic decomposition, the specific angle along the theta direction and the second result as the input of a third operation algorithm, calculating a trigonometric function result of the specific angle along the theta direction by using the third operation algorithm, calculating a legendre function result of the trigonometric function result of the specific angle along the theta direction by using the third operation algorithm, and integrating the legendre function result of the trigonometric function result of the specific angle along the theta direction and the result of multiplication of the second result to obtain a third result;
taking the number m of spherical harmonic decomposition, the specific angle along the lambda direction and the third result as the input of a fourth operation algorithm, calculating the number m of spherical harmonic decomposition and the trigonometric function result of the specific angle along the lambda direction by using the fourth operation algorithm, and integrating the multiplication result of the number m of spherical harmonic decomposition and the trigonometric function result of the specific angle along the lambda direction with the third result to obtain a fourth result;
the first operation algorithm, the second operation algorithm, the third operation algorithm and the fourth operation algorithm are obtained by decomposing spherical harmonics; the fourth result is mapped to the HOA coded signal of which the coefficient matrix is the original sound wave function in the complex space.
2. The method of claim 1, wherein the first algorithm comprises trigonometric function operation, multiplication operation, and addition operation;
calculating a trigonometric function result of the angle uniformly sampled along the lambda direction by using a first operation algorithm, and integrating the trigonometric function result of the angle uniformly sampled along the lambda direction and a result obtained by multiplying an original sound wave function to obtain a first result, wherein the method comprises the following steps of:
and respectively multiplying the sine function result and the cosine function result of the angle uniformly sampled along the lambda direction by the original sound wave function by multiplication and addition to obtain a first result.
3. The method of claim 2, wherein the second algorithm comprises trigonometric function operation, legendre function operation, multiplication operation, and addition operation;
calculating a trigonometric function result of the angle uniformly sampled along the theta direction, a legendre function result of the trigonometric function result of the angle uniformly sampled along the theta direction by using a first operation algorithm, and integrating the trigonometric function result of the angle uniformly sampled along the theta direction, the legendre function result of the trigonometric function result of the angle uniformly sampled along the theta direction, and a result of multiplying the first result to obtain a second result, including:
calculating a sine function result and a cosine function result of the angle uniformly sampled along the theta direction by utilizing trigonometric function operation, calculating a Legendre function result of the cosine function result of the angle uniformly sampled along the theta direction by utilizing Legendre function operation, multiplying the sine function result of the angle uniformly sampled along the theta direction, the Legendre function result of the cosine function result of the angle uniformly sampled along the theta direction and the first result by utilizing multiplication operation and addition operation, and then adding to obtain a second result.
4. The method of claim 3, wherein the third algorithm comprises trigonometric function operation, legendre function operation, multiplication operation, and addition operation;
calculating a trigonometric function result of the specific angle along the theta direction by using a third operation algorithm, calculating a legendre function result of the trigonometric function result of the specific angle along the theta direction by using the third operation algorithm, and integrating a result obtained by multiplying the legendre function result of the trigonometric function result of the specific angle along the theta direction by the second result to obtain a third result, wherein the third result comprises:
and multiplying the Legendre function result of the cosine function result of the specific angle along the theta direction by multiplication and addition, and then adding the Legendre function result and the second result to obtain a third result.
5. The method of claim 4, wherein the fourth algorithm comprises trigonometric function operation, multiplication operation, and addition operation;
calculating the number m of spherical harmonic decomposition times and a trigonometric function result of a specific angle along the lambda direction by using a fourth operation algorithm, and integrating the result obtained by multiplying the number m of spherical harmonic decomposition times and the trigonometric function result of the specific angle along the lambda direction by the third result to obtain a fourth result, wherein the fourth result comprises the following steps:
and calculating the number m of spherical harmonic decomposition times and the result of the sine function and the result of the cosine function at the specific angle along the lambda direction by utilizing trigonometric function operation, and adding the result obtained by multiplying the number m of the spherical harmonic decomposition times, the result of the sine function and the result of the cosine function at the specific angle along the lambda direction by the third result to obtain a fourth result.
6. The method of higher order Ambisonic audio coding of claim 1, further comprising:
caching one or more of trigonometric functions of the angles uniformly sampled along the lambda direction, trigonometric functions of the angles uniformly sampled along the theta direction, and Legendre function results of trigonometric function results of the angles uniformly sampled along the theta direction.
7. A high-order Ambisonic audio decoding method, comprising:
determining a coefficient matrix of the loudspeakers according to the number and the positions of the loudspeakers;
performing pseudo-inverse operation on the coefficient matrix of the loudspeaker to obtain a pseudo-inverse operation matrix;
determining a drive signal for the loudspeaker based on the inverse operation matrix and the HOA encoded signal of the original sound wave function.
8. A high-order Ambisonic audio coding chip, comprising:
the first arithmetic unit is used for taking the angle uniformly sampled along the lambda direction and the original sound wave function as the input of a first arithmetic algorithm, calculating a trigonometric function result of the angle uniformly sampled along the lambda direction by using the first arithmetic algorithm, and integrating the result obtained by multiplying the trigonometric function result of the angle uniformly sampled along the lambda direction by the original sound wave function to obtain a first result;
the second arithmetic unit is used for taking the angle uniformly sampled along the theta direction and the first result as the input of a second arithmetic algorithm, calculating a trigonometric function result of the angle uniformly sampled along the theta direction and a Legendre function result of the trigonometric function result of the angle uniformly sampled along the theta direction by using the first arithmetic algorithm, and integrating the trigonometric function result of the angle uniformly sampled along the theta direction, the Legendre function result of the trigonometric function result of the angle uniformly sampled along the theta direction and a multiplication result of the first result to obtain a second result;
a third arithmetic unit, configured to take the order n of the spherical harmonic decomposition, the specific angle in the θ direction, and the second result as inputs of a third arithmetic algorithm, calculate a trigonometric function result of the specific angle in the θ direction using the third arithmetic algorithm, calculate a legendre function result of the trigonometric function result of the specific angle in the θ direction using the third arithmetic algorithm, and integrate a product of the legendre function result of the trigonometric function result of the specific angle in the θ direction and the second result to obtain a third result;
the fourth arithmetic unit is used for taking the number m of times of spherical harmonic decomposition, the specific angle along the lambda direction and the third result as the input of a fourth arithmetic algorithm, calculating the number m of times of spherical harmonic decomposition and a trigonometric function result of the specific angle along the lambda direction by using the fourth arithmetic algorithm, and integrating the multiplication result of the number m of times of spherical harmonic decomposition and the trigonometric function result of the specific angle along the lambda direction with the third result to obtain a fourth result;
the first operation algorithm, the second operation algorithm, the third operation algorithm and the fourth operation algorithm are obtained by decomposing spherical harmonics; the fourth result is mapped to the HOA coded signal of which the coefficient matrix is the original sound wave function in the complex space.
9. The high-order Ambisonic audio coding chip of claim 8, in which the first operator comprises a trigonometric function operator, a multiplication operator and an addition operator;
the second arithmetic unit comprises a trigonometric function arithmetic unit, a Legendre function arithmetic unit, a multiplication arithmetic unit and an addition arithmetic unit;
the third arithmetic unit comprises a trigonometric function arithmetic unit, a Legendre function arithmetic unit, a multiplication arithmetic unit and an addition arithmetic unit;
the fourth arithmetic unit comprises a trigonometric function arithmetic unit, a multiplication arithmetic unit and an addition arithmetic unit.
10. The higher-order Ambisonic audio coding chip of claim 8, further comprising:
and the buffer is used for buffering one or more of the trigonometric function of the angle uniformly sampled along the lambda direction, the trigonometric function of the angle uniformly sampled along the theta direction and the Legendre function result of the trigonometric function result of the angle uniformly sampled along the theta direction.
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