CN2862174Y

CN2862174Y - VGA data-gathering card

Info

Publication number: CN2862174Y
Application number: CN 200520103263
Authority: CN
Inventors: 曹伟; 刘江
Original assignee: BEIJING JINGYEDA DIGITAL TECHNOLOGY Co Ltd
Current assignee: BEIJING JINGYEDA DIGITAL TECHNOLOGY Co Ltd
Priority date: 2005-08-05
Filing date: 2005-08-05
Publication date: 2007-01-24
Anticipated expiration: 2015-08-05

Abstract

The utility model relates to a VGA data capture card which comprises programmable logic gate array FPGA circuit, A/D converter, memory circuit, peripheral component interconnect (PCI) bus bridge chip, and external interface circuit. The A/D converter receives input VGA analog signals (i.e. RGB analog signals) and converts them into digital signals. The digital signals are written into a SDRAM as cache memory by the FPGA circuit, and then read out from the SDRAM by the FPGA circuit and transmitted through the PCI bus bridge chip to an upper computer through a PCI local bus BUS interface. The upper computer serves to process the digital signals, such as display, compression and transmission. The VGA data capture card realizes real-time acquisition and compression of VGA analog data, thereby ensuring continuous real-time data capture and preventing data distortion.

Description

The VGA data collecting card

Technical field

The utility model relates to high speed signal digitizing communication technique field, relates in particular to a kind of VGA data collecting card.

Background technology

Modern society's forward digitizing, information-based direction high speed development in this course, often need great amount of data transmission.Along with the continuous development of digital multimedia technology and modern educational technology, more and more to the real-time collection compression requirements of VGA (Video GraphicArray shows the drawing array) output signal.Under environment such as remote teaching, the Web-based instruction, what client wished to receive is not only the video (teachers' instruction picture) of character activities, also wish to receive simultaneously the display frame of the notebook, teacher computer etc. of the employed teaching usefulness of teacher, so that understand the content of courses in all directions.Here it is so-called " two video streaming ", " multiple video strems " technology.

The classic method of gathering the VGA signal has two kinds:

The first, by VGA/AV (sound, video) transition card, for example video converters such as Key300, Key500, Key700 transfer analog video to simulating VGA, adopt the video acquisition compressing card to handle again.The advantage of this method be not need be on teacher computer install software, only need VGA output received on the equipment and get final product, simultaneously, the real-time height can be accomplished the collection and the compression of complete real-time (per second 25 frames) substantially.But shortcoming also is well-known: the resolution of VGA signal is generally 1024 * 768 or 800 * 600, the resolution of AV video generally adopts CIF (a kind of graphical format) form, promptly 352 * 288, after the VGA conversion of signals was the AV vision signal, even do not compress, sharpness also reduced greatly, basically content such as literal, webpage almost can't be seen clearly, again through overcompression, the non-constant of signal quality is difficult to satisfy the demand of field research.

The second, adopt software to grab the screen mode.This is the method that traditional softwares such as electronic classroom adopt usually, and a software need be installed on teacher computer, with fixing frame per second (such as per second 5 frames) seizure screen, and compresses with software.Its advantage is to accomplish low distortion even undistorted compression, has guaranteed the clear of contents such as literal, picture, webpage.But simultaneously, there are two fatal shortcoming:

1, owing to install software on teacher computer is grabbed screen and compression, can have a strong impact on the performance of teacher computer.Statistics shows, even on the Pentium IV of high primary frequency machine, reach the collection compression speed of per second 10 frames, also can take the cpu resource up to 30%～50%d, and this certainly will seriously disturb normal software operation and performance;

2, when playing video file, software is grabbed the screen mode can't collect picture.This is that what video section collected when grabbing screen is a black window because video card generally adopts when displaying video is the mode that Video Overlay (video coverings) technology is handled.Some is grabbed the screen software mode that can take to forbid DirectX (interface to hardware programming of Microsoft) and gets access to the content of institute's displaying video, but can cause display performance sharply to reduce like this, be actual use unallowed.

The real-time collection compression of VGA simulating signal is very high to hardware requirement.Resolution is 1024 * 768,24 true color, and during refreshing frequency 75Hz, the sample rate of requirement reaches 1024 * 768 * 75 * 24bps at least, promptly surpasses the data volume of 1Gbps, and this does not also consider the time of horizontal blanking, field blanking.So high data volume has all proposed very high requirement to integrated circuit board design, software algorithm etc., and this also is the major reason that does not have ripe VGA capture card to come out for a long time.Simultaneously, general analog video compression how to realize real-time high-efficiency compression to resolution up to 1024 * 768 VGA signal only at CIF form or D1 (a kind of graphical format) form (resolution 720 * 576) signal, also is one of difficult problem.

This just need develop the VGA data collecting card of a VGA real-time signal acquisition compression, and it can gather compression to the VGA simulating signal of input in real time, can guarantee the real-time continuously of signal, can guarantee clear undistorted again.

Summary of the invention

In view of above-mentioned existing in prior technology problem, the purpose of this utility model is the VGA data collecting card of a VGA real-time signal acquisition compression of exploitation, it can gather compression to the VGA simulating signal of input in real time, can guarantee the real-time continuously of signal, can guarantee clear undistorted again.

The purpose of this utility model is achieved through the following technical solutions:

A kind of VGA data collecting card is by FPGA (Field Programmable Gate Array) gate array FPGA circuit, analog/digital signal A/D converter, memory circuit, Peripheral Component Interconnect Standard PC I bus bridge chip and external interface circuit; A/D converter, memory circuit, pci bus bridge chip link to each other with the FPGA circuit respectively, the VGA simulating signal of A/D converter collection input, and the external interface circuit connects host computer.

Described A/D converter is for becoming component vide RGB analog signal conversion the A/D converter of digital signal.

Described A/D converter is for becoming brightness the A/D converter of digital signal with aberration YUV analog signal conversion.

Described memory circuit can be synchronous dynamic random access memory SDRAM.

Described external interface circuit is a PCI local bus BUS interface.

By above technical scheme VGA data collecting card described in the utility model as can be known, by FPGA (Field Programmable Gate Array) gate array FPGA circuit, analog/digital signal A/D converter, memory circuit, Peripheral Component Interconnect Standard PC I bus bridge chip and external interface circuit; The VGA simulating signal of A/D converter collection input, just RGB simulating signal; The RGB simulating signal is converted to digital signal after sampling through A/D, write SDRAM as buffer memory by the FPGA circuit, the data of gathering are read by the pci bus bridge chip from SDRAM through the FPGA circuit again and are transferred to host computer by PCI local bus BUS interface, by host computer to data show, processing such as compression, transmission.It can gather compression to the VGA simulating signal of input in real time, can guarantee the real-time continuously of signal, can guarantee clear undistorted again.

Description of drawings

Fig. 1 is a data bus adapter structural representation described in the utility model.

Embodiment

VGA data collecting card described in the utility model, its embodiment be as shown in Figure 1:

A kind of VGA data collecting card is by FPGA (Field Programmable Gate Array) gate array FPGA circuit, analog/digital signal A/D converter, memory circuit, Peripheral Component Interconnect Standard PC I (Peripheral Component Interconnect) bus bridge chip and external interface circuit; A/D converter, memory circuit, pci bus bridge chip link to each other with the FPGA circuit respectively.Described A/D converter is for becoming component vide RGB analog input InPut conversion of signals the A/D converter of digital signal.Described memory circuit is synchronous dynamic random access memory SDRAM (SynchronousDRAM).Described external interface circuit is a PCI local bus BUS interface.

The VGA simulating signal of A/D converter collection input, just RGB simulating signal; The RGB simulating signal is converted to digital signal after sampling through A/D, write SDRAM as buffer memory by the FPGA circuit, the data of gathering are read by the pci bus bridge chip from SDRAM through the FPGA circuit again and are transferred to host computer by PCI local bus BUS interface, by host computer to data show, processing such as compression, transmission.

RGB simulating signal described here can also be brightness and aberration YUV simulating signal (also claiming YCrCb), a kind of colour coding method that is adopted by the eurovision system.

VGA data collecting card described in the utility model is with 24 high-precision A/D the VGA picture to be gathered, and guarantees that like this height of the picture of gathering is clear true to nature.Has high-precision advantage.

VGA data collecting card described in the utility model carries out real-time sampling to rgb signal, can satisfy the above real-time collection compression of per second 25 frames.Has real-time advantage.

The sampling bandwidth of VGA data collecting card described in the utility model can reach 600MHZ, the VGA picture of being supported comprises all resolution and the refresh rate of VGA～ultra extended graphics array UXGA, maximum can be supported 1024*768*75HZ, and it is irrelevant with the picture displaying contents, no matter what show is video, literal, picture, webpage, it is clear, continuous, stable all can to guarantee, thereby satisfies user's demand to greatest extent.Advantage with wide ranges.

VGA data collecting card described in the utility model is not done processing such as any compression to the data after sampling, and can guarantee the integrality of sampled data, has guaranteed the quality of VGA picture.Has the good advantage of integrality.

VGA data collecting card described in the utility model changes at external VGA signal, when for example resolution, refreshing frequency change, can be with interrupt mode notice driver, driver can be adjusted display mode automatically according to this signal, also this information can be sent to upper level applications, thereby realize the automatic identification of signal.Simultaneously, application program also can be by corresponding interface function read-write hardware register, and parameters such as the brightness of acquired signal, colourity, contrast, sharpness are adjusted.

The above data bus adapter and data processing equipment thereof only are preferable embodiment of the utility model and representational embodiment, and the structure of described data bus adapter also only is representational structure simultaneously; But protection domain of the present utility model is not limited thereto, and anyly is familiar with those skilled in the art in the technical scope that the utility model discloses, and the variation that can expect easily or replacement all should be encompassed within the protection domain of the present utility model.Therefore, protection domain of the present utility model should be as the criterion with the protection domain of claims.

Claims

1, a kind of VGA data collecting card is characterized in that, by FPGA (Field Programmable Gate Array) gate array FPGA circuit, analog/digital signal A/D converter, memory circuit, Peripheral Component Interconnect Standard PC I bus bridge chip and external interface circuit; A/D converter, memory circuit, pci bus bridge chip link to each other with the FPGA circuit respectively, the VGA simulating signal of A/D converter collection input, and the external interface circuit connects host computer.

2, VGA data collecting card according to claim 1 is characterized in that, described A/D converter is for becoming component vide RGB analog signal conversion the A/D converter of digital signal.

3, VGA data collecting card according to claim 1 is characterized in that, described A/D converter is for becoming brightness the A/D converter of digital signal with aberration YUV analog signal conversion.

4, VGA data collecting card according to claim 1 is characterized in that, described memory circuit can be synchronous dynamic random access memory SDRAM.

5, VGA data collecting card according to claim 1 is characterized in that, described external interface circuit is a PCI local bus BUS interface.