CN1244084A - Simulation device and method for multi-channel signal - Google Patents

Abstract

A simulation device of multi-channel signal includes an input buffer, a memory, a signal processor coupled to the output ends of the input buffer and the memory and used for inputting audio signal and stored coefficient to do convolution processing, an output buffer coupled to the output end of the signal processor, and a controller coupled to the input buffer, the memory, the signal processor and the output buffer. The simulation method comprises inputting audio signals into an input buffer, storing head-related coefficients in a memory, and performing convolution processing on the received audio signals and the head-related coefficients output by the memory.

Description

Simulation device and method for multi-channel signal

The invention relates to an acoustic signal processing device and method, in particular to a multi-channel signal simulation device and method.

The video and sound quality of Digital Versatile Disk (DVD) is better than that of VCD and LD, so digitized high-quality movies have gradually entered the family. Generally speaking, the AC-3 digital sound source compression standard adopted by DVD must have six sound sources including left, right, center, left surround (Left Surround), right surround (Right Surround), and subwoofer (Low Frequency Effects). channel, so it is necessary to use six speakers as the relative output device, and the subwoofer can be placed at any position, and the digital representation is 5.1 or 5+1 instead of 6. However, a general personal computer or home audio system is only equipped with two speakers due to space constraints, and cannot experience the high-quality sound of six sound source channels. If you want to enjoy high-quality sound but add another set of audio equipment, it is too wasteful.

The main purpose of the present invention is to provide an acoustic signal simulation device and method that can simulate multi-channel presence effects by using a pair of loudspeakers or a pair of earphones. The main principle is to use 3D sound source localization technology to generate several virtual sound sources in space (that is, each speaker of the multi-channel system), which are called virtual speakers, so it can simulate multi-channel effects. As for the principle of 3D sound source localization, it is a physical system that introduces a sound source in a certain direction in space into the left and right ears of a person, and is described by a digital model, which is called the human head related transfer function HRTF (headrelated transfer function). The sound source signal is converted into HRTF and then played back through a pair of speakers or a pair of headphones to produce the effect that sounds come from all directions. Since the HRTF parameters corresponding to sound sources in different positions are different, multiple sets of HRTFs in different directions must be stored in the memory to generate virtual speakers in different directions.

Another object of the present invention is to apply the 3D sound source localization technology to provide a method for simulating the effect similar to 5.1 speakers by using two speakers.

In order to achieve the above object, the present invention uses 3D sound source localization technology to directly simulate the effect of 5.1 sound sources by two loudspeakers, and this technology is implemented in hardware and built into the universal digital disk DVD, so it is applicable for home appliances or personal computers.

The present invention is described in detail as follows in conjunction with accompanying drawing and embodiment:

Description of drawings:

Fig. 1 is the schematic diagram of multi-channel simulation device of the present invention;

Fig. 2 is the method flowchart of multi-channel sound signal simulation device of the present invention;

FIG. 3 is a schematic diagram of sound source processing using 3D sound source localization technology;

Fig. 4 is a circuit block diagram of the multi-channel sound source localization simulation device of the present invention.

Please refer to FIG. 1 . FIG. 1 is a multi-channel analog device of the present invention. An audio signal encoded by the AC standard is first decoded by the AC-3 decoder (1) into six audio signals, namely the left channel, the right channel, the center channel, the left surround channel, the right surround channel and the heavy bass channel. These six decoded audio signals are then sent to the 3D Sound Source Localization to AC-3 Simulator (2) for signal processing to localize the six signals in their respective directions. For example, the middle channel among the original six sound source channels is positioned in front of the listener, the left channel is positioned in the left front, etc. After the six sound source channels are all positioned, mix the sound, and finally broadcast it through a pair of speakers or headphones, and reproduce the sense of direction that should have been formed by six speakers in different directions. Among them, the 3D sound source localization technology uses the human head related transfer function HRTF (Head Related Transfer Function) to localize a sound source, that is, to process the sound source into the time difference between the two ears ( The left and right channels of Interaural Time Difference) and the intensity difference between the two ears (Interaural Intensity Difference) are transmitted to our ears with headphones or speakers, which makes the human ear mistakenly think that the sound is from a certain place in the space. In addition, the Doppler effect, reflection, reverberation, and elimination of interactive interference can be added to achieve a real three-dimensional space effect.

As shown in Figure 2, the steps required for implementing the method of the present invention are described: at first, carry out step 21, calculate the relative position vector respectively of 5+1 loudspeakers in the listener and AC-3 specification, to obtain multi-channel The location of each sound source (speaker) in the system. Since different multi-channel systems have different output sound source (speaker) configuration methods, the purpose of this step is to set the output of each sound source (speaker) in the system by selecting a different multi-channel system by the user. Location. Then go to step 22, pick up the required Head Related Transfer Function (Head Related Transfer Function, HRTF) coefficients according to the above position vector. This step continues the position of each sound source obtained in the previous step, and obtains the corresponding HRTF coefficients in the memory. Then go to step 23, read the input sound source data of six channels of AC-3. Then execute the HRTF 3D calculation step, and perform 3D calculation (convolution integration) according to the read-in sound source data and the corresponding HRTF parameters, so as to obtain the left and right output signals. The schematic diagram of the HRTF 3D processing of the sound source is shown in Figure 3, where h(0), h(1), ... h(N-1) are HRTF coefficients, and Z-1 is the unit time delay. It is then judged whether to use the speaker 25 or not. Since the phenomenon of cross-interference occurs only when the speaker is used, this step judges whether the speaker is used to determine whether to perform the cross-interference elimination operation in the subsequent step. If the speaker is used, the interactive interference elimination operation step 26 is executed to eliminate the interactive interference phenomenon of the left and right speakers. Finally, output the result of 3D positioning processing to a pair of speakers or earphones in real time, so that through the left and right output signals of a pair of speakers or earphones, each sound source in the multi-channel system of 5+1 speakers required by AC-3 can be virtualized (speaker) position.

Please refer to FIG. 4 to illustrate the simulation device of the present invention through an embodiment. The AC-3 coded audio signal is decoded by the AC-3 decoder 1 and restored to six channels, and then sent to the analog device of the present invention for signal processing, wherein the audio signals of the six channels are provided with control signals to The controller 42 that controls and coordinates the operation of the whole device sends a control signal and sends it to an input buffer 43. Since the positioning effect of the subwoofer signal is not very obvious to the human ear, the subwoofer signal can also be It does not need to be sent to the input buffer 43 for subsequent signal processing, but after the audio signals of the remaining five channels are processed, they are synthesized with them and sent to the output device (speaker or earphone). The five-channel audio signals sent to the input buffer 43 are sent to a first signal processor 54 composed of a first multiplier 46 and a first adder 48 . A memory 41 storing multiple groups of HRTF coefficients and cross-interference cancellation filter coefficients. A group of pre-stored HRTF coefficients are also sent to the first register 44 and then sent to the first signal processor 54 . The first multiplier 46 includes a plurality of parallel multipliers to multiply the input multi-channel signal and the HRTF coefficient, and then the multiplied result is sent to the first adder 48 including a plurality of parallel and serial adders for phase comparison. Add operation. That is to say, the operation performed by the first signal processor (54) is a convolution operation. The left and right channel signals processed by the HRTF 3D calculation are sent to the output buffer 50 for storage respectively. If the output device is a pair of earphones, then the signals of the left and right channels can be synthesized with the subwoofer signal by the synthesizer 53 and then directly output to the earphones, so as to achieve the stereo effect of simulating six channels with a pair of earphones.

If the output device used is a pair of loudspeakers, the output signals of the left and right channels are then processed for cross-interference elimination to eliminate the cross-interference signal and improve the sound quality. The cross-interference cancellation processing operation will be illustrated by the following embodiments.

For eliminating the cross-interference of the left and right channel signals, a cross-interference elimination filter 55 (made up of the second register 45, the second multiplier 47 and the second adder 49) is used for further signal processing . The second temporary register 45 is used for storing the transient coefficient of the operation process, and it forms a feedback loop with the second multiplier 47 and the second adder 49, wherein the output of the second adder 49 is coupled to the second temporary register 45 The output of the second register 45 is coupled to the input of the second multiplier 47 . The second multiplier 47 includes a plurality of parallel multipliers to multiply the output results of the cross-interference cancellation filter coefficients from the memory 41 and the HRTF (that is, the above-mentioned left and right channel signals), and then send the multiplication result to the The second adder 49 of the plurality of parallel and serial adders performs an addition operation. The left and right channel signals after cross-interference elimination and filtering are respectively sent to the second output buffer 51 for storage. The signal processed by the mutual interference elimination filter and the subwoofer signal are synthesized by the synthesizer 53 and then directly output to a pair of loudspeakers. The present invention can realize the stereo surround effect of simulating six channels with a pair of loudspeakers.

Compared with the prior art, the present invention has the following effects:

The present invention can also add a data selector (52) to the above-mentioned embodiment to select the output device as a pair of earphones or a pair of speakers.

The invention can simulate six audio channels of a universal digital disk DVD by only utilizing a pair of earphones or a pair of loudspeakers. The simulation device and method of the present invention can utilize a pair of speakers of an existing home audio system or a personal computer to generate high-quality sound of six sound source channels, thus saving the cost and placement space of four additional speakers. In addition, the simulation device and method of the present invention can be implemented in one chip and built into DVD Player, DVD-Rom or other devices with multi-channel surround sound effects, so the extra space of the whole device will not be increased.

The above-mentioned embodiments are only to illustrate the principles and effects of the present invention, but not to limit the present invention.

Claims (29)

1. An analog device for multi-channel signals, comprising: an input buffer for receiving audio signals; A memory storing at least two sets of coefficients; A signal processor, coupled to the output of the input buffer and the memory, and performs convolution integration processing on the received input audio signal and the coefficients output by the memory to generate an output signal; an output buffer, coupled to the output end of the signal processor, for receiving its output signal, and then outputting the output signal to an output device; A controller, coupled to the input buffer, the memory, the signal processor and the output buffer, is used for controlling and coordinating the operation of the analog device. 2. The analog device according to claim 1, wherein the input audio signal is an audio signal decoded by a decoder. 3. The analog device according to claim 2, wherein the input audio signal includes signals of left channel, right channel, center channel, left surround channel, right surround channel and subwoofer channel . 4. The analog device according to claim 3, wherein the subwoofer channel signal is directly sent to the output device without being processed by the signal processor. 5 . The simulation device according to claim 1 , wherein the coefficients stored in the memory are coefficients of a correlation conversion function of a human head and coefficients of an interaction cancellation filter. 6. The analog device according to claim 1, wherein the signal processor comprises a multiplier and an adder. 7. The simulation device according to claim 1, wherein the output device is a pair of earphones. 8. The simulation device according to claim 1, wherein the output device is a pair of speakers. 9. The simulation device of claim 1, wherein the simulation device is fabricated in a chip. 10. The analog device according to claim 3, further comprising a synthesizer for receiving the output signal of the output buffer and the subwoofer channel signal, and synthesizing these signals for output to the output device. 11. A simulation device for a multi-channel signal, comprising: A simulator and a controller, the controller is connected to the simulator to provide control signals to control and coordinate the operation of the simulator, it is characterized in that it also includes: an input buffer for receiving an input audio signal; a memory, storing array coefficients; a first signal processor, coupled to the output of the input buffer and the memory, and performs convolution processing on the received input audio signal and coefficients output by the memory to generate a first output signal; a first output buffer, coupled to the output terminal of the first signal processor, for receiving the first output signal; a cross-interference cancellation filter, coupled to the output end of the first output buffer and the output end of the first register, for receiving the first output signal from the first output buffer and the coefficients output by the memory for convolution integration processing to generate a second output signal; and A data selector, coupled to the first output buffer and the second output buffer, is used for selecting to output the first output signal or the second output signal to an output device. 12. The analog device according to claim 11, wherein the input audio signal is an audio signal decoded by a decoder. 13. The analog device according to claim 12, wherein the input audio signal includes signals of left channel, right channel, center channel, left surround channel, right surround channel and subwoofer channel . 14. The analog device according to claim 13, wherein the subwoofer channel signal is sent to the output device without being processed by the signal processor. 15 . The simulation device according to claim 11 , wherein the coefficients stored in the memory are coefficients of a correlation conversion function of a human head and coefficients of an interaction cancellation filter. 16. The analog device according to claim 11, wherein said first and second signal processors each comprise a multiplier and an adder. 17. The simulation device according to claim 11, wherein said output device is a pair of earphones. 18. The simulation device of claim 11, wherein the output device is a pair of speakers. 19. The simulation device of claim 11, wherein the simulation device is fabricated in a chip. 20. The analog device according to claim 13, further comprising a synthesizer for receiving the output signal of the output buffer and the subwoofer channel signal, and synthesizing these signals for output to the output device. 21. The analog device according to claim 11, further comprising a second register, a second multiplier and a second adder forming a feedback loop. 22. A method for simulating a multi-channel signal, comprising the following steps: input audio signal to an input buffer; storing the coefficients of the head-related transfer function in a memory; performing convolution integral processing on the received input audio signal and the coefficients of the head-related transfer function output from the memory by a signal processor to generate an output signal; and Outputting the output signal to an output device. 23. The analog device according to claim 22, wherein the audio signal is an audio signal decoded by a decoder. 24. The analog device according to claim 23, wherein the audio signal comprises left channel, right channel, center channel, left surround channel, right surround channel and subwoofer channel signals. 25. The analog device according to claim 24, wherein the subwoofer channel signal is directly sent to the output device without being processed by the signal processor. 26 . The simulation device according to claim 22 , wherein the coefficients stored in the memory are coefficients of a correlation conversion function of a human head and coefficients of an interaction cancellation filter. 27. The analog device according to claim 25, comprising a synthesizer for receiving said processed audio signal and unprocessed subwoofer channel signal, and combining these signals for output to said output device. 28. The simulation device of claim 22, wherein said output device is a pair of speakers. 29. The simulation device according to claim 22, wherein said output device is a pair of earphones.

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