Multi-channel audio and video synchronous acquisition board

Abstract

The invention relates to the technical field of audio and video acquisition, in particular to a multichannel audio and video synchronous acquisition board, which comprises a multichannel audio access unit, a photoelectric conversion module, an FPGA (Field Programmable Gate Array), a processor and a power supply module, the output end of the multi-channel audio access unit and the output end of the photoelectric conversion module are both connected with the input end of the FPGA, the output end of the FPGA is connected with the processor, and the power module is used for supplying power to the multi-channel audio access unit, the photoelectric conversion module, the FPGA and the processor. And the requirement of multi-channel synchronous acquisition of different digital video signals and audio signals is met.

Description

Technical Field

[0001] The invention relates to the technical field of audio and video acquisition, and in particular to a multi-channel audio and video synchronous acquisition board. Background Art

[0002] Audio and video acquisition technology is mainly used in the field of security, and plays an important role in security prevention and security monitoring in public places. With the continuous development of technology, audio and video acquisition technology is also increasingly used in other personal places or special spaces, such as internal scene monitoring and acquisition of family cars and special aircraft. The space of these application scenes is usually not large, so the miniaturization and lightweight requirements of audio and video acquisition equipment are high. It is necessary to achieve the simultaneous acquisition of multiple audio and video channels on a small-sized board as much as possible.

[0003] At present, the existing audio and video acquisition modules or devices usually use special audio codec chips and video codec chips to directly connect to external devices to collect audio and video signals input by external devices, and then output the audio and video after chip encoding to other external devices. Therefore, the number of audio and video channels and formats that can be supported depends on the physical interface performance of the audio codec chip and the video codec chip itself. However, the number of channels supported by a single-chip audio / video codec chip is usually small. In order to achieve multi-channel audio and video acquisition, a large number of audio / video codec chips need to be integrated. This leads to the inevitable technical problems of complex design, large board size, and large device size in audio and video multi-channel acquisition equipment, which cannot meet the needs of application scenarios with limited space for multi-channel synchronous acquisition of different digital video signals and audio signals.

[0004] To this end, Chinese patent CN114900622A, a multi-channel audio and video acquisition system based on HiSilicon chips, uses HiSilicon Hi3521D V200 with an integrated quad-core processor as the main control chip, and integrates multiple MIPI D-PHY interfaces in the chip to improve the video input performance of the chip's digital interface. However, even if the existing patent uses a chip with a high degree of integration, it is still a technical problem to keep the audio and video signals of different channels synchronized, especially when processing digital video signals and audio signals of different formats. Moreover, in the existing patent, the data transmission interface between the audio acquisition module, the video acquisition module and the main control chip is a MIPI interface, which requires a short transmission distance between the two. Once the transmission distance increases, it is easy to cause technical problems such as video data transmission errors. It is not suitable for situations where the front-end audio and video source is far away from the back-end main control chip. At the same time, the integration solution of the existing patent limits the scalability of the audio and video acquisition system. If more channels or different signal formats need to be supported in the future, the entire acquisition system may need to be redesigned. Summary of the invention

[0005] In view of the above technical problems, the present invention proposes a multi-channel audio and video synchronous acquisition board, which aims to achieve miniaturization of the acquisition board while meeting the demand for multi-channel synchronous acquisition of different digital video signals and audio signals.

[0006] To this end, the present invention adopts the following technical solutions: A multi-channel audio and video synchronous acquisition board comprises a multi-channel audio access unit, a photoelectric conversion module, an FPGA, a processor and a power module, wherein the multi-channel audio access unit is used to receive audio signals, the input end of the photoelectric conversion module uses optical fiber to receive video signals, the output end of the multi-channel audio access unit and the output end of the photoelectric conversion module are both connected to the input end of the FPGA, the output end of the FPGA is connected to the processor, and the power module is used to supply power to the multi-channel audio access unit, the photoelectric conversion module, the FPGA and the processor.

[0007] Preferably, the photoelectric conversion module has a plurality of independent parallel optical fiber channels.

[0008] Preferably, the output end of the photoelectric conversion module is connected to the input end of the FPGA via a high-speed serial interface.

[0009] Preferably, the output end of the FPGA is connected to the processor using a multi-channel MIPI video transmission interface.

[0010] Preferably, each of the MIPI video transmission interfaces includes at least two Lanes.

[0011] Preferably, the multi-channel audio access unit includes several operational amplifier circuits and a multi-channel A / D converter, the input end of the operational amplifier circuit is used to receive audio signals, the output ends of the several operational amplifier circuits are connected to the input end of the multi-channel A / D converter, and the output end of the multi-channel A / D converter is connected to the input end of the FPGA.

[0012] Preferably, the output end of the FPGA is connected to the processor via a PCIE interface.

[0013] Preferably, the multi-channel audio and video synchronous acquisition board includes a dynamic memory, and the dynamic memory is connected to the FPGA.

[0014] Preferably, the processor uses the HiSilicon Hi3559A chip.

[0015] The beneficial technical effects of the present invention include at least: 1. A multi-channel audio and video synchronous acquisition board is adopted. Through the ingenious design of the multi-channel audio access unit, optoelectronic conversion module, FPGA and other structural components in the acquisition board, the integration of the acquisition board is greatly improved, and the technical difficulty of miniaturized and lightweight audio and video multi-channel acquisition equipment to maintain the synchronization of audio and video signals of different channels is overcome. While meeting the needs of multi-channel synchronous acquisition of different digital video signals and audio signals, the scalability of the acquisition board is greatly improved, and optical fiber is used for video signal reception. After the optoelectronic conversion of the optoelectronic conversion module, the signal is connected to the FPGA, and the FPGA performs parallel acquisition of the input multi-channel video. Compared with the MIPI interface connection method adopted in the prior art, the signal attenuation is smaller, the anti-interference ability is stronger, and the transmission distance is greatly improved, thereby avoiding the technical problem of video data transmission errors caused by the long transmission distance between the front-end video source and the back-end acquisition board; 2. The number of video access channels can be further expanded by connecting multiple photoelectric conversion modules to FPGA. The number of audio access channels can be further expanded by connecting multiple multi-channel A / D converters to FPGA. Combined with the operational amplifier circuit to convert the signal of each front-end audio source, the acquisition board can meet the application requirements of multi-channel synchronous acquisition of digital video signals and audio signals in different formats without changing the main control chip and basic hardware architecture.

[0016] Other features and advantages of the present invention will be disclosed in detail in the following specific embodiments and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The present invention will be further described below in conjunction with the accompanying drawings: Figure 1 The figure is a schematic diagram of the structure of a multi-channel audio and video synchronization acquisition board according to an embodiment of the present invention.

[0018] Figure 2 Schematic diagram of the structure of the photoelectric conversion module according to an embodiment of the present invention.

[0019] Figure 3 The figure is a schematic diagram of the structure of a multi-channel audio access unit according to an embodiment of the present invention.

[0020] Figure 4 Schematic diagram of the structure of the FPGA output terminal of the embodiment of the present invention. DETAILED DESCRIPTION

[0021] The technical solutions of the embodiments of the present invention are explained and described below in conjunction with the drawings of the embodiments of the present invention, but the following embodiments are only preferred embodiments of the present invention, not all. Based on the embodiments in the implementation mode, other embodiments obtained by those skilled in the art without creative work are all within the protection scope of the present invention.

[0022] In the following description, terms such as "inside", "outside", "up", "down", "left", "right", etc. that indicate directions or positional relationships are only used to facilitate the description of the embodiments and simplify the description, and do not indicate or imply that the referred device or element must have a specific direction, be constructed and operate in a specific direction. Therefore, it should not be understood as a limitation of the present invention.

[0023] Please see attached Figure 1 , Figure 1 A schematic diagram of the structure of a multi-channel audio and video synchronization acquisition board provided in an embodiment of this specification is shown.

[0024] like Figure 1 As shown, the multi-channel audio and video synchronous acquisition board may at least include: a multi-channel audio access unit, a photoelectric conversion module, an FPGA, a processor and a power supply module, wherein: The multi-channel audio access unit is used to receive audio signals. The input end of the photoelectric conversion module uses optical fiber to receive video signals. The output end of the multi-channel audio access unit and the output end of the photoelectric conversion module are both connected to the input end of the FPGA. The output end of the FPGA is connected to the processor. The power module is used to power the multi-channel audio access unit, the photoelectric conversion module, the FPGA and the processor.

[0025] Among them, the specific implementation device of the photoelectric conversion module can be various types of photoelectric conversion devices, such as electro-optical modulators, photodiodes, etc. The specific selection depends on the format of the video signal, transmission distance, transmission speed, cost and specific requirements of the system, and this embodiment does not limit this.

[0026] Among them, FPGA (Field-Programmable Gate Array) is an integrated circuit that contains programmable logic blocks (PLBs). Users can define the functions of these logic blocks through hardware description language (HDL). The programmability of FPGA means that they can be reconfigured many times without remanufacturing, which makes FPGA very suitable for applications that require flexibility and scalability. At the same time, FPGA has multiple I / O ports that can be connected to external devices such as sensors, displays, network interfaces, etc.

[0027] It is understandable that the front-end video source can be various visible light or infrared cameras and other types of video sources, and the video source can output the video signal to the photoelectric conversion module through the 10 Gigabit network port or ARINC818 interface. In this embodiment, optical fiber is used to receive the video signal, and the FPGA is connected after the photoelectric conversion of the photoelectric conversion module. The FPGA collects the input multi-channel video in parallel. Compared with the MIPI interface connection method used in the prior art, the signal attenuation is smaller, the anti-interference ability is stronger, and the transmission distance is greatly improved, thereby avoiding the technical problem of video data transmission errors caused by the long transmission distance between the front-end video source and the back-end acquisition board.

[0028] In this embodiment, the output end of the multi-channel audio access unit and the output end of the photoelectric conversion module are connected to the input end of the FPGA, and then the output end of the FPGA is connected to the processor (ie Figure 1 The Hi3559A audio and video encoding circuit in the processor encodes the audio and video signals and outputs the encoded audio and video signals to external devices. Therefore, FPGA can be used to perform synchronous processing during the audio and video acquisition process. FPGA uses logical processing methods such as audio and video data alignment and video frame time stamping to achieve audio and video acquisition synchronization.

[0029] Preferably, the processor in this embodiment can adopt the HiSilicon Hi3559A chip.

[0030] Among them, the HiSilicon Hi3559A chip provides 8K30 / 4K120 broadcast-level image quality digital video recording, supports 8-channel Sensor input, supports H.265 encoding output or film-level RAW data output, and integrates high-performance ISP processing. At the same time, it adopts advanced 12nm low-power technology and miniaturized packaging, and supports DDR4 / LPDDR4, so that Hi3559AV100 can support product miniaturization design. Therefore, this embodiment can use Hi3559A to perform real-time encoding processing such as H.264 / H.265 on each received video signal and PCM encoding on each received audio data.

[0031] It is understood that please refer to the attached Figure 2 Each optoelectronic conversion module can access multiple channels of video. Therefore, using multiple optoelectronic conversion modules to connect to FPGA can further expand the number of video access channels, and the video signal can be format converted or pre-processed through FPGA, so that the acquisition board can meet the application requirements of multi-channel synchronous acquisition of digital video signals in different formats without changing the main control chip (i.e. processor) and basic hardware architecture.

[0032] Furthermore, in this embodiment, the multi-channel audio and video synchronous acquisition board includes a dynamic memory, and the dynamic memory is connected to the FPGA.

[0033] Among them, dynamic memory (i.e. Figure 1 The DDR3 in the embodiment is a volatile memory whose storage unit is based on capacitors and is used to temporarily cache intermediate processing data. It can be understood that the entire multi-channel audio and video synchronization acquisition board provided by this embodiment does not include a data storage module (such as a solid state drive, a hard disk drive, etc.), and the system design is more concise, making the size and weight of the entire acquisition board smaller, more suitable for portable or space-constrained applications, and the dynamic memory can be quickly reconfigured, which helps the FPGA to more flexibly process and cache intermediate processing data to meet different audio and video synchronization acquisition requirements.

[0034] It can be understood that the devices used in this embodiment are not limited to the device models listed in the text, and devices with the same functions can be used instead.

[0035] Furthermore, in this embodiment, the photoelectric conversion module has a plurality of independent parallel optical fiber channels.

[0036] For example, the rate of each channel of the optoelectronic conversion module in this embodiment is 10.3125 Gbps, which can fully meet the bandwidth requirement of video signal transmission.

[0037] Furthermore, in this embodiment, the output end of the photoelectric conversion module is connected to the input end of the FPGA using a high-speed serial interface.

[0038] For example, in this embodiment, the photoelectric conversion module and the FPGA are connected using a GTH high-speed serial interface. Figure 2 As shown, FPGA simultaneously collects the video signals output by two photoelectric conversion modules through the GTH high-speed serial interface, and can realize real-time collection of all input video signals.

[0039] Further, in this embodiment, please refer to the attached Figure 4 ,The output end of FPGA is connected to the processor using a multi-channel MIPI video transmission interface.

[0040] Furthermore, in this embodiment, each MIPI video transmission interface includes at least two Lanes.

[0041] Lane is a differential signal line used to expand data bandwidth. This configuration allows higher data transmission rates because each Lane can transmit data independently at a high rate, and the two Lanes together can provide double the bandwidth.

[0042] It can be understood that in this embodiment, the output end of the FPGA is connected to the processor using a multi-channel MIPI video transmission interface, and each video signal is transmitted using at least two Lane MIPI interfaces, thereby realizing simultaneous processing of video streams with a large amount of data, and achieving high-speed data transmission while maintaining low power consumption.

[0043] On the other hand, in this embodiment, please refer to the attached Figure 3 The multi-channel audio access unit includes a plurality of operational amplifier circuits and a multi-channel A / D converter. The input end of the operational amplifier circuit is used to receive the audio signal. The output ends of the plurality of operational amplifier circuits are connected to the input end of the multi-channel A / D converter. The output end of the multi-channel A / D converter is connected to the input end of the FPGA.

[0044] It can be understood that the analog audio signal input of the front-end audio source is usually a differential signal input. Therefore, in this embodiment, an operational amplifier circuit is used to pre-process the input analog audio signal. The differential signal is converted into a single-ended signal by the operational amplifier circuit and then connected to a multi-channel A / D converter. Each multi-channel A / D converter is interconnected with the FPGA using an independent digital interface. The FPGA controls the multi-channel A / D converter to read the converted single-ended audio signal in parallel, thereby realizing the simultaneous acquisition of all audio inputs.

[0045] In this embodiment, by arranging an operational amplifier circuit before the multi-channel A / D converter to convert the differential signal into a single-ended signal, noise can be further reduced, the quality of the analog audio signal of the front-end audio source can be improved, and the signal-to-noise ratio of the A / D converter can be improved. By adjusting the level of the differential signal to the input range of the multi-channel A / D converter through the operational amplifier circuit, it can be ensured that the signal does not exceed the maximum input voltage of the multi-channel A / D converter, thereby avoiding distortion. At the same time, since the multi-channel A / D converter requires a certain input drive current to ensure the accuracy of the conversion, the operational amplifier circuit can provide sufficient driving capability to drive the input of the multi-channel A / D converter, ensuring that the signal will not be distorted due to insufficient driving capability during the A / D conversion process. Further, in actual applications, the signal line may be subject to various common-mode interferences, such as power line noise, electromagnetic interference, etc., so the operational amplifier circuit in this embodiment can be designed to have a high common-mode rejection ratio (CMRR), thereby effectively suppressing these interferences and ensuring the purity of the signal.

[0046] It is understandable that each multi-channel A / D converter can access multiple channels of analog audio. Therefore, using multiple multi-channel A / D converters to connect to FPGA can further expand the number of audio access channels. Combined with the operational amplifier circuit to convert the signal of each front-end audio source, the acquisition board can meet the application requirements of multi-channel synchronous acquisition of audio signals in different formats without changing the main control chip (i.e., processor) and basic hardware architecture.

[0047] Further, in this embodiment, please refer to the attached Figure 4 The output end of the FPGA is connected to the processor using a PCIE interface.

[0048] like Figure 4 As shown, a PCIE interface is used between FPGA and Hi3559A to transmit audio data. Hi3559A performs PCM encoding and other processing on each channel of audio data received. The encoded video and audio code streams can be packaged according to the frame format pre-defined in the processor and transmitted to other external devices through the Gigabit network port.

[0049] It is understandable that since the bandwidth of audio signals is relatively narrow, usually between a few kilohertz and tens of kilohertz, the bandwidth requirements for the transmission medium are also relatively low. Even if optical fiber is not used for long-distance transmission, it will not have much impact on the quality of the audio signal. PCIE (Peripheral Component Interconnect Express) is a high-speed computer bus standard. The bandwidth of the PCIE interface can reach tens of Gbps, which is much higher than the bandwidth requirement of the audio signal. Therefore, even if a PCIE interface is used to connect to the processor, it will not affect the transmission speed of the audio signal.

[0050] To summarize, the multi-channel audio and video synchronization acquisition board provided in the embodiments of this specification greatly improves the integration of the acquisition board through the ingenious design of the multi-channel audio access unit, optoelectronic conversion module, FPGA and other structural components in the acquisition board, overcomes the technical difficulty that miniaturized and lightweight audio and video multi-channel acquisition equipment is difficult to maintain the synchronization of audio and video signals of different channels, and while meeting the needs of multi-channel synchronous acquisition of different digital video signals and audio signals, greatly improves the scalability of the acquisition board.

[0051] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that the present invention includes but is not limited to the contents described in the drawings and the above specific embodiments. Any modification that does not deviate from the functional and structural principles of the present invention will be included in the scope of the claims.

Claims

1. A multi-channel audio and video synchronous acquisition board, characterized in that: It includes a multi-channel audio access unit, a photoelectric conversion module, an FPGA, a processor and a power module. The multi-channel audio access unit is used to receive audio signals. The input end of the photoelectric conversion module uses optical fiber to receive video signals. The output end of the multi-channel audio access unit and the output end of the photoelectric conversion module are both connected to the input end of the FPGA. The output end of the FPGA is connected to the processor. The power module is used to supply power to the multi-channel audio access unit, the photoelectric conversion module, the FPGA and the processor.

2. A multi-channel audio and video synchronous acquisition board as claimed in claim 1, characterized in that: The photoelectric conversion module has a plurality of independent parallel optical fiber channels.

3. A multi-channel audio and video synchronous acquisition board as claimed in claim 2, characterized in that: The output end of the photoelectric conversion module is connected to the input end of the FPGA by a high-speed serial interface.

4. A multi-channel audio and video synchronous acquisition board as claimed in claim 3, characterized in that: The output end of the FPGA is connected to the processor using a multi-channel MIPI video transmission interface.

5. A multi-channel audio and video synchronous acquisition board as claimed in claim 4, characterized in that: Each of the MIPI video transmission interfaces includes at least two Lanes.

6. A multi-channel audio and video synchronous acquisition board as claimed in claim 1, characterized in that: The multi-channel audio access unit includes several operational amplifier circuits and a multi-channel A / D converter. The input end of the operational amplifier circuit is used to receive audio signals. The output ends of the several operational amplifier circuits are connected to the input end of the multi-channel A / D converter. The output end of the multi-channel A / D converter is connected to the input end of the FPGA.

7. A multi-channel audio and video synchronous acquisition board as claimed in claim 6, characterized in that: The output end of the FPGA is connected to the processor using a PCIE interface.

8. A multi-channel audio and video synchronous acquisition board as claimed in claim 1, characterized in that: The multi-channel audio and video synchronous acquisition board comprises a dynamic memory, and the dynamic memory is connected to the FPGA.

9. A multi-channel audio and video synchronous acquisition board as claimed in claim 1, characterized in that: The processor uses the HiSilicon Hi3559A chip.

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