KR960003625B1 - Encoding and decoding method of multi-channel audio - Google Patents

Abstract

The system includes a codec control unit which is to select encoding mode, a multi channel input unit which inputs 4 digital audio channels selectively, a clock generating unit which supplies clocks to the multi channel input unit, a reset unit which outputs reset signal, a first high speed digital signal processor which processes coding, a second digital signal processor which processes coding through a communication port, a third digital signal processor which processes coding through the communication ports of first and second digital signal processors, an external transfer unit which transmits encoded audio data to an external device, and first and second memory units which han data storage space and stores operation program.

Description

Multichannel Audio Encoder Systems and Coding Methods

1 is a schematic diagram of a multi-channel audio encoder system in accordance with the present invention.

2 and 3 are flowcharts of the encoding method according to the present invention.

* Explanation of symbols for main parts of the drawings

1: Codec control unit 2: Multi channel input unit

3: clock generator 4: external transmitter

6,8,10: High speed digital signal processor (DSP)

7,9,11: memory

The present invention relates to a multichannel audio encoder system and an encoding method for encoding a multichannel audio signal.

The audio signal that is widely used is composed of two left and right channels, but even in a pepper house, two or more channels of audio signals are expected to be handled in order to provide a cinema-like reality. In addition, the transmission of audio signals is a trend that is shifting from the conventional analog transmission form to the digital transmission form. Therefore, the need for digital transmission of multi-channel audio signals will be increased in the future.

In order to meet the above needs, the present invention obtains a multi-channel digital audio signal for digital transmission of a multi-channel audio signal, and then performs compression encoding processing on the digital audio signal to reduce a transmission channel bandwidth required for transmission. The purpose of the present invention is to provide a multi-channel audio encoder system and encoding method which can be effectively used in the multi-channel audio transmission and broadcasting field.

In order to achieve the above object, a configuration of an apparatus for achieving the present invention includes: codec control means for selecting an encoding mode; Multi-input means for selectively inputting 6 analog audio channels by A / D conversion and selectively inputting 4 digital audio channels according to the digital audio interface standard; Clock generating means for generating a clock required by an encoder and providing the clock to the multi-channel input means; Reset means for outputting a reset signal; A first DSP connected to the codec control means, the multi-channel input means, the reset means and the clock generation means for encoding processing; A second DSP connected to the reset means, the clock generation means, and the first DSP using a communication port for encoding processing; A third DSP connected to the reset means and the clock generation means and interconnected to the first DSP and the second DSP using a communication port for encoding processing; External transmission means for transmitting the encoded audio data from the first DSP to an external device; And first to third memory means connected to each of the first to third DSPs to provide a program and data storage space for each operation.

In the audio encoding method of the present invention, there is data to receive multi-channel audio data from the first DSP, transmit a part of the input data to the DSP, process data to be processed by the DSP, and then exchange data with the DSP. First step to investigate whether After performing the first step, if there is data to be exchanged, the data is exchanged with the DSP, and if there is no data to be exchanged, it is examined whether additional data processing is required as it is, and the data processing process is repeated until no additional data processing is required. Second step; After performing the second step, if no additional data processing is required, data received from the second and third DSPs and data processed by the first DSP 6 are collected to form final encoded data, and the encoded data is transmitted to an external device. Performing a third step until the step of artificially terminating the process of doing so; A fourth step of checking whether audio data transmitted from the first DSP is received after performing the first step, processing the received data if data is received, and examining whether there is data to be exchanged with another DSP; And after performing the fourth step, if there is data to be exchanged, exchange data with another DSP and if there is no data to be exchanged, examine whether additional data processing is still required, and repeat the data processing process until no additional data processing is required. The fifth step was to repeat the whole process until the end of the deliberate end.

One way to encode a multichannel audio signal is to reduce the amount of data needed to represent the audio signal by analyzing the effects of multiple channels of audio signals on human hearing and removing components that are relatively invisible to humans. have. However, this method analyzes the audio signal components of each channel and compares them with each other to classify them according to the degree of human detection.To do this, the components are analyzed at high speed with respect to the audio signal of each channel and each analysis data is analyzed There is a need for a device that efficiently exchanges with each other.

The present invention has a multi-channel audio signal input function and an external transmission function while satisfying the above-described requirements, thereby performing encoding processing in real time on a multi-channel audio signal that is continuously input, and transmitting the result data to the outside. It is configured to be possible. In particular, in audio signal processing, various audio encoding methods can be applied by enabling high-speed signal processing using a high-speed digital signal processor (DSP) and by varying the signal processing method as needed. It is configured to.

Hereinafter, with reference to the accompanying drawings will be described an embodiment of the present invention;

1 is a configuration diagram of a multi-channel audio encoder system according to the present invention, in which 1 is a codec control unit, 2 is a multi-channel input unit, 3 is a clock generator, 4 is an external transmission unit, 5 is a reset circuit unit, 6, 8, 10 denotes a high speed digital signal processor (DSP), and 7, 9 and 11 denote memory units, respectively.

In the multi-channel audio encoder system as shown in the figure, first, the codec controller 1 has two selection methods of a function of selecting one of various possible encoding modes. One is to manually manipulate the four ON / OFF positions located inside the codec, and DSP # 1 (6) reads this information to determine the mode designation status. In this mode, the coding mode information is written by an external system, and the DSP # 1 (6) reads it to find the mode designation state.

The multi-channel input unit 2 acquires digital audio data by analog / digital (A / D) conversion of six analog channels (left, right, center, left surround, right surround, low frequency effect channels) from the outside, or digital audio. Acquire two digital stereo audio data according to the interface standard from the outside.

The use of each input audio data is determined according to the encoding mode selected by the codec controller 1.

Over-sampling clock of the clock generator 3 is DSP # 1 (6), DSP # 2 (8), DSP # 3 (10) operating clock (50MH _Z) and a multi-channel input (2) of the _(Z 12.288MH) Has the function of supplying.

The external transmitter 4 has a function of transmitting the encoded audio data to external equipment. Transmitted bit clock signals and frame sync signals from external devices are transmitted in serial bit form according to these signals.

The reset circuit section 5 provides a signal for resetting the DSP # 1 (6), the DSP # 2 (8), and the DSP # 3 (10). The DSP # 1 (6), the DSP # 2 (8), and the DSP # 3 (10) have a function of encoding audio data input from the multichannel input unit (3).

DSP # 1 (6) transfers a part of the input audio data to DSP # 2 (8) and DSP # 3 (10), and receives DSP # 2 (8) and DSP # 3 (10) which received the transmitted data. And DSP # 1 (6) having the rest of the input audio data perform their assigned calculation processing, then aggregate the result back into DSP # 1 (6), and then form an appropriate form by mutual agreement. The encoded data is generated from the DSP # 1 (6) to the external device via the external transmitter (4). Even during the calculation process, DSP # 1 (6), DSP # 2 (8) and DSP # 3 (10) can exchange data with each other as needed. At this time, data exchange between each DSP is performed by using two high speed communication ports built in each DSP. The memory units 7, 9, and 11 are composed of an external RAM, an external EPROM, and peripheral logic circuits for operating the DSP # 1 (6), DSP # 2 (8), and DSP # 3 (10). Are all the same. The external EPROM has a built-in program to download, and the external RAM is used to store the downloaded program or to provide a storage space for data processing.

The operations of the DSP # 1 (6), the DSP # 2 (8), and the DSP # 3 (10) for the audio encoding described above will be described in detail with reference to FIG. 2 and FIG. Here, the operation process of DSP # 2 (8) and DSP # 3 (10) is the same.

The operation of DSP # 1 (6) inputs multichannel audio data 12 as shown in FIG. 2, and transfers some data to DSP # 2 (8) and DSP # 3 (10) (13). DSP # 1 (6) processes (14) the data to be processed. Then, if there is data to be exchanged with other DSPs 8 and 10, the data is exchanged 15 to see if additional data is needed. Repeat steps 14 and 15 below until no further data processing is required. If no additional data processing is required, the data received from DSP # 2 (8) and DSP # 3 (10) and the data processed by DSP # 1 (6) are collected to form final encoded data (16), and then external equipment The coded data is transmitted (17). The new multi-channel audio data is then input 12 again. This process is repeated unless it is stopped externally.

The operation of DSP # 2 (8) and DSP # 3 (10) first checks whether audio data transmitted from DSP # 1 (6) is received as shown in FIG. 3 and then processes the received data. (18) It then checks if there is data to exchange with the DSP and if necessary exchanges data with another DSP (19). If there is an additional data curry, the above process (18, 19) is repeated. No additional data processing is required, and return to the initial procedure for processing new audio data and check whether data is received from DSP # 1 (6).

As a preferred embodiment of the multi-channel audio encoder configuration described above, the following system configuration may be mentioned. The codec control unit 1 is an ON / OFF switch, and is composed of a general dip switch, a general latch logic accessible as a register, and the like. The multi-channel input unit 2 is used for analog signal input. It is composed of three LS5336 chips from Crystal Semiconductor, two CS8412 chips of the company for digital signal input, peripheral circuits and decoder logic circuits of these chips, and the clock generator 3 includes a general oscillator and a counter. The external transmission unit 4 is composed of a parallel / to-serial shift register (165 logic) and a peripheral decoder logic circuit, and DSP # 1 (6), DSP # 2 (8) and DSP # 3 (10) are all composed of T1's TMS320C40, the reset circuit section 5 is composed of a well-known TMS320C40 reset circuit, and the memory sections 7, 9, and 11 are all 256 KBytes in general. Two sets of general high-speed RMA with EPROM and 64KWord and peripheral decoder logic Furnace is constructed.

If the audio coding method needs to be changed, it is easy to solve the problem by writing a new program in the EPROM of the memory units 7, 9 and 11. Therefore, the present invention has a merit that it can be flexibly used according to an application because a program can be changed as a system capable of encoding a multi-channel audio signal.

Accordingly, the present invention as described above is an audio encoder system capable of encoding a multi-channel audio signal, and can be used as an audio encoding system because it provides sufficient performance for encoding processing of a first multi-channel audio signal. If you need to change the coding method, you can easily accommodate the changing of the coding method by simply reprogramming the EPROM without changing the hardware.To date, there is no commercial system for encoding multi-channel audio signals. In this situation, the present invention can be used in various applications in which a multi-channel audio signal must be encoded.

Claims (2)

Codec control means 1 for selecting an encoding mode; Multi-channel input means (2) capable of selectively inputting six analog audio channels by A / D conversion and selectively inputting four digital audio channels according to the digital audio interface standard; Clock generating means (3) for generating a clock required by an encoder and providing the same to the multi-channel input means (2); Reset means 5 for outputting a reset signal; A first high speed digital signal processor (DSP) connected to the codec control means 1, the multi-channel input means 2, the reset means 5, and the clock generation means 3 to perform an encoding process; (6); A second DSP (8) connected to the reset means (5), the clock generation means (3), and the first DSP (6) using a communication port for encoding processing; A third DSP (10) connected to the reset means (5) and the clock generation means (3) and interconnected to the first DSP (6) and the second DSP (8) by using a communication port; External transmission means (4) for transmitting the encoded audio data from the first DSP (6) to external equipment; And first to second memory means (7, 9, 11) connected to each of the first to third DSPs (6, 8, 10) to provide a program and data storage space for each operation. Multichannel audio encoder system. In an audio encoding method applied to a multi-channel audio encoder system, a first high-speed digital signal processor (DSP) 1 receives multi-channel audio data and replaces a part of the received data. A first step (12 to 15) of transmitting data to the DSP, processing data to be processed by the DSP, and then examining whether there is data to be exchanged with another DSP; After performing the first steps (12 to 15), if there is data to be exchanged, the data is exchanged with other DSPs (8, 10). A second step (16, 17) of repeating the data processing process until not doing so; After performing the second steps (16, 17), if no additional data processing is required, the data received from the second and third DSPs (8, 10) and the data processed by the first DSP (6) are collected and the final encoded data. A third step (18, 19) of constructing a sig- nal until the process of transmitting encoded data to an external device is artificially terminated; After performing the first steps 12 and 15, it is checked whether audio data transmitted from the DSP 6 is received. If data is received, the received data is processed, and data to be exchanged with another DSP exists. A fourth step (20 to 22) of checking whether to do; And after performing the fourth step (20 to 22), if there is data to be exchanged, it is exchanged with another DSP and if there is no data to be exchanged, it is checked whether additional data processing is required, until no further data processing is necessary. And a fifth step (23, 24) of repeating the entire process until there is an intentional termination by repeating the data processing process.