It can capture video information and obtain sound at the same time, so that the audio part and the video part can be stored and played synchronously when they are digitized. Video capture card, "video capture card", its function is to collect video signals into the computer and save them on the hard disk in the form of data files. It is an indispensable hardware device for video processing. Through it, we can transfer the video signal shot by the camera from the video tape to the computer, and use the relevant video editing software to post-edit the digital video signal, such as cutting the picture, adding ytterbium, subtitles and sound effects, setting the transition effect and adding various video special effects. Finally, the edited video signal is converted into standard VCD, DVD and online streaming media formats for easy dissemination.
Edit this paragraph classification
Video capture card can be divided into digital capture card (using digital interface) and analog capture card according to video signal source. Video capture board
Video capture card can be divided into external capture card (box) and built-in board card according to the installation link mode. According to the video compression method, the video acquisition card can be divided into soft compression card (consuming CPU resources) and hard compression card. According to the video signal input/output interface, the video capture card can be divided into 1394 capture card, USB capture card, HDMI capture card, VGA video capture card, PCI graphics card and PCI-E video capture card. Video capture card can be divided into TV card, image capture card, DV capture card, computer video card, monitoring capture card, multi-screen card, streaming media capture card, component capture card, HD capture card, notebook capture card, DVR card, VCD card and nonlinear editing card according to its performance. Video capture cards can be divided into broadcast video capture cards, professional video capture cards and civil video capture cards according to their uses. Their grades are mainly different in the quality of the captured images. The difference between them is mainly the difference of image index. There are many methods of video image acquisition, which can be basically divided into two categories: digital signal acquisition and analog signal acquisition. Therefore, the common image acquisition card also includes digital acquisition card, analog acquisition card and AV+DV two-in-one acquisition card. Generally, the highest acquisition resolution of broadcast video acquisition card is 768X576 (root mean square) PAL system, or 720X576(CCIR-60 1) PAL system with 25 frames per second, or 640X480/720X480 NTSC system with 30 frames per second, and the lowest compression ratio is generally within 4: 1. This kind of product is characterized by high resolution and high video signal to noise ratio, but the disadvantage is that the video file is huge, with at least 200MB of data per minute. The performance of professional video capture card is slightly lower than that of broadcast video capture card, and the resolution is the same, but the compression ratio is slightly higher, and its minimum compression ratio is generally within 6: 1. I/O interfaces are AV composite terminals and S terminals. The maximum dynamic resolution of general civil video capture card is 384X288, and PAL system is 25 frames per second.
The acquisition principle of editing this paragraph.
Video is a mixed medium in which a plurality of still images (image frames) and continuous audio information move synchronously on the time axis. Multi-frame images change with time to produce a sense of motion, so videos are also called moving images. Video can be divided into analog video and digital video according to different storage and processing methods. Video capture is the process of converting analog signals of video sources into digital signals (namely 0 and 1) through processing, and storing these digital information on the computer hard disk. This analog/digital conversion is carried out through the acquisition chip on the video acquisition card. The analog video signal from the video input can be received by the video acquisition card on the computer, and the signal is collected and quantized into a digital signal, and then compressed and encoded into the digital-to-analog A/D conversion process of the digital video acquisition card.
. Most graphics cards have the function of hardware compression. When collecting video signal, the video signal is compressed on the card first, and then the compressed video data is transmitted to the host through PCI interface. Ordinary PC video capture cards use intra-frame compression algorithm to store digitized video as AVI files, while high-end video capture cards can directly compress the collected digital video data into MPEG- 1 files in real time. Because the analog video input terminal can provide uninterrupted information source, the video acquisition card should collect each frame of image in the analog video sequence and transmit these data to the PC system before collecting the next frame of image. Therefore, the key to real-time acquisition is the processing time required for each frame. If the processing time of each video image exceeds the interval between two adjacent frames, there will be data loss, that is, frame loss. The acquisition card compresses the obtained video sequence first, and then stores it in the hard disk, which means that the acquisition and compression of the video sequence are completed together, which saves the inconvenience of re-compression. Different grades of acquisition cards have different acquisition quality and compression performance. The video acquisition chip converts analog signals into digital signals, and then transmits them to the temporary storage of the board card. Then, the video compression chip on the card executes the compression algorithm to reduce the huge video signal. Finally, these compressed signals enter PCI directly or through the PCI bridge chip and are stored in the hard disk. The latter adopts general video A/D converter to realize image acquisition, which is characterized by high speed requirement for the processor, low cost and easy implementation, and can meet the needs of some image acquisition systems. In the aspect of high-definition video acquisition and recording, VGA image acquisition card is a high-end product with the rapid development of digital information industry, and the demand for VGA signal acquisition in many fields is increasing. Nowadays, machine vision system is widely used in industry and teaching. It integrates a variety of computer software and hardware technologies, involving image processing, artificial intelligence and other fields. Video image acquisition card is an important part of machine vision system. Its main function is to collect the video data output by the camera in real time and provide a high-speed interface with the PC. Video capture card is an indispensable hardware device for video processing, video digitization and post-production of digital video editing. Through the video capture card, we can transfer the video signal shot by the camera from the video tape to the computer, and use the relevant video editing software to edit the digital video signal later, such as cutting the picture, adding ytterbium, subtitles and sound effects, setting the transition effect, adding various video special effects, etc. Finally, the edited video signal is converted into standard VCD, DVD and online streaming media format, which is convenient for dissemination and preservation.
Edit this video capture.
Capture analog video
1, capture analog video 1) Establish a video capture card that simulates the video capture environment.
Connect analog video sources (such as video cameras, video cameras, video recorders, VCD players, DVD players, etc.). ) With MPC (or Apple PowerMac) equipped with video capture card, a hardware environment for analog video capture is formed. 2) Install audio-visual X2, audio-visual acquisition and other video acquisition software. 3) Video Capture ① Set the video source to be used. 2) Play the video from the video source device. 3) Video capture is completed by video capture software.
Capture digital video
2. Collecting digital video Collecting digital video means using the IEEE 1394 interface that can connect DV video signals to complete the function of collecting DV signals shot by digital cameras to the multimedia computer system. First, establish the hardware environment, including wireless transmission system. Install the IEEE 394(FireWire or i.Link) interface card and connect the DV camera with the connecting cable. Note that the two ends of the DV cable have different interfaces. One end is a 4-pin port connected to a digital camera, and the other end is a 6-pin port connected to an IEEE 1394 acquisition card. Optional mixers, external speakers, video processing software and other software and hardware for adjusting the sound output of DV cameras need to be installed or selected.
Edit the system requirements in this paragraph.
At present, the video acquisition card is synchronized with video acquisition and compression, which means that the video stream is compressed into MPG format files when it enters the computer. This process requires the computer to have a high-speed CPU, a large enough memory, a high-speed hard disk and a smooth system bus ... the computing power of the CPU is enough to meet our requirements. The motherboard suggests choosing a control chip with RAID cascade function, because it can greatly speed up the data storage speed of the hard disk. However, the multi-core ultra-large capacity hard disk is basically enough for video shooting. Now the price of memory has basically plummeted to the bottom. Buying a brand of memory can provide enough memory bandwidth and capacity to capture images and convert data. The hard disk is the key to this configuration. It needs not only large capacity, but also fast storage speed. The minimum cache is 2M, which can be realized by ordinary hard disk. Of course, the larger the capacity, the better. Graphics card is not so important in video acquisition, so you can choose a general AGP card with a size of more than 32M. A sound card is generally enough for an ordinary family, and other things are generally unnecessary.
Edit the technical indicators of this paragraph.
According to different applications, different applicable environments and different technical indicators, there are various video capture cards at present. From the performance parameters of PCI-ETC2 102 video capture card, we can conclude the main functions and technical indicators of the video capture card with PC as the hardware environment:
Engagement/interface
The interface of video capture card includes the interface between video and PC and the interface with analog video equipment. At present, the video capture card usually adopts 32-bit PCI bus interface and is inserted into the expansion slot of PC motherboard to realize the communication and data transmission between the capture card and PC. The acquisition card must have at least one composite video interface (video input) to connect analog video equipment. High-performance acquisition cards generally have a composite video interface and an S-video interface. Universal acquisition card supports PAL and NTSC TV systems. Note: The previous TV card was not a video capture card. Image acquisition card generally has no TV antenna interface and audio input interface, so it can't directly collect TV RF signals or audio signals in analog video. There is also the previous image acquisition card (which has no real-time acquisition performance of audio and video signals) to collect sound, and a sound card must be installed on the PC. The image acquisition card obtains digital sound through the sound card on the PC, and synchronizes the sound with the collected digital video.
function
The analog video signal from the video input terminal can be received on a PC through a video acquisition card, and the signal is collected, quantized into a digital signal, and then compressed and encoded into a digital video sequence. Most video capture cards have the function of hardware compression. When collecting video signal, the video signal is compressed on the card first, and then the compressed video data is transmitted to the upper computer through PCI interface. General capture cards use intra-frame compression algorithm to store digitized video into AVI files. Some high-end video capture cards (hard cards) can directly compress the collected digital video data into MPEG- 1 files in real time.
Frame loss phenomenon
Because the analog video input terminal can provide uninterrupted information source, the video acquisition card should collect each frame of image in the analog video sequence and transmit these data to the PC system before collecting the next frame of image. Therefore, the key to real-time acquisition is the processing time required for each frame. If the processing time of each video image exceeds the interval between two adjacent frames, there will be data loss, that is, frame loss. The acquisition card compresses the obtained video sequence first, and then stores it in the hard disk, which means that the acquisition and compression of the video sequence are completed together, which saves the inconvenience of re-compression. Different grades of acquisition cards have different acquisition quality and compression performance.
drive
Video capture card driver: Video capture cards are generally equipped with hardware drivers to realize PC control and data communication. There are different drivers according to the operating system environment required by different acquisition cards. Only when the acquisition card is inserted into the expansion slot of PC motherboard and the driver is installed correctly can it work normally. However, some current video capture cards are very compatible, and basically do not need to install additional drivers, but also have general video capture card drivers.
debut
Video capture card application (editing software): the capture card is generally equipped with an acquisition application to control and operate the acquisition process. There are also some general acquisition programs. Digital video editing software, such as the latest version of audio and video X2, also has the functions of acquisition, editing, format conversion and recording. It is used in conjunction with the hardware of the acquisition card, that is, it can only be used after the hardware of the acquisition card is installed and driven normally. Of course, the current acquisition card basically supports common video editing software and non-editing software.
Edit the basic type of this paragraph.
Soft compression card and hard compression card.
Soft compression card, also known as video acquisition card, is mainly composed of video acquisition chip with 1 or above, peripheral components and circuits. The video acquisition card of this circuit
The structure is simpler than hard compression. This card is only responsible for collecting video, and video compression, decompression and other video processing are all realized by CPU operation. The basic principle of soft compression video capture card: the analog video signal of camera is input to DVR card, and the analog signal is converted into digital signal by video capture chip, and then directly or through PCI bridge chip, and then transmitted to memory and graphics card. The CPU executes the compression algorithm in DVR software, and the huge video signal is compressed and stored in the hard disk. Hard compression card is also called video capture compression card, which is different from soft compression card in that it adds video compression and decompression. Video compression is not handled by computer CPU, but by a DSP chip. The basic principle of hard compressed video capture card: the analog video signal of the camera is input to DVR card, and the video capture chip converts the analog signal into digital signal, and then transmits it to the temporary storage area of the card. Then, the video compression chip on the card executes the compression algorithm to compress the huge video signal. Finally, these compressed signals enter PCI directly or through the PCI bridge chip and are stored in the hard disk. As far as video compression ability is concerned, hard compression is better than soft compression. Soft compression card uses CPU for compression, which consumes computer resources. Reasonable computer configuration is the key to the long-term stable operation of soft compression DVR. There are many kinds of video capture cards, but for amateurs who don't have a lot of commercial video capture and processing, a cheap video capture card without hardware compression function, or a TV card and 3D image card with acquisition function, can be fully competent. As long as you work hard on the software, you can get the same processing results as the high-end expensive video capture card. Of course, it will take you more time in the later film and television file production process. The video capture software that comes with cheap or comprehensive cards is usually too simple, especially in the real-time file storage engine. The results of video capture and processing directly using these simple capture software are usually not satisfactory.
Analog acquisition card and digital acquisition card
From the interface between video signal source and acquisition card, video acquisition card can be divided into two categories: one is analog acquisition card, and the other is digital acquisition card. Analog acquisition card collects analog video signals into PC through AV or S terminals, thus converting analog signals into digital signals. Video signal sources can come from analog cameras, TV signals, analog video recorders, etc. Digital acquisition card collects digital video signals in digital-to-digital form through IEEE 1394 digital interface, and its video signal source mainly comes from digital equipment such as DV (Digital Camera). An important difference between analog capture card and digital capture card is that digital capture card can ensure that the video signal is not lost in the process of acquisition, and can obtain the same effect as the original video source, while analog capture card will cause a certain degree of video signal loss. Someone once made a vivid analogy: analog acquisition is similar to flipping a video tape with a video recorder, and the copied sub-band is always not as clear as the master tape. If the tape is used again, the effect will be worse; Digital collection is like copying a data file with a computer. No matter how many times it is copied, the copied file is exactly the same as the original file, and there is no difference. Two-in-one acquisition card refers to digital analog acquisition card and AV+DV acquisition card. Digital input and output, analog interface input (DV/AV/S-video), full interface board.
External acquisition box and built-in acquisition card
External USB video capture card and built-in PCI interface video receiving card. T30 1 Professional USB Video Capture Card
These two things have their own advantages and disadvantages. If the funds are insufficient, it is recommended that you choose the built-in PCI video receiving card. For plug-in cards, it is recommended to use PCI interface. At the same time, it also has the following advantages: first, the price is definitely much cheaper than the outside; Secondly, it does not occupy external desktop space. At present, there are too many peripherals on the computer desk, and it is annoying to put too many; Thirdly, the built-in graphics card does not need an external power supply, which not only saves the position of the power plug, but also reduces the clutter caused by too many power connection lines, and can also avoid the video quality degradation caused by the unstable mains voltage; Fourthly, most of the built-in video receiving cards can multitask under Windows system. The weakness of the built-in graphics card is that it is vulnerable to electromagnetic interference from internal components of the computer, which leads to the decline of playback quality; Installing the card is more troublesome than external connection, and the chassis needs to be disassembled before installation. It is also easy to conflict with other computer equipment when installing drivers or software. The external acquisition card has obvious advantages, and its external performance is more stable than the built-in video receiving card. Need an external dedicated power supply, but also occupy a parallel port on the computer, which will cause a lot of inconvenience to friends who have connected more peripherals.
Edit the selection point of this paragraph.
Clarify the purpose of purchase
1. There are many types of video capture cards, which may be produced by different manufacturers, and each type of video capture card focuses on a specific function. Therefore, we'd better be clear about the purpose of buying a video capture card before buying it, and pay attention to its practicality when buying a graphics card.
Universal type
2. According to its structure, video capture card can be divided into built-in and external formats. External graphics card, also called video receiving box, is a relatively independent device, and most of them can work independently of the computer host. That is to say, you can receive video information with the video receiving box without turning on the computer and running software. In addition, AV terminal and S terminal input, multi-function remote control, multi-channel video switching and so on are provided. The installation and operation of external video box is relatively simple, more like using a household appliance, and the viewing clarity of external products is often better than that of built-in products. In addition to the standard video receiving function, the built-in graphics card often provides different degrees of video capture function, which can convert the captured dynamic/static video signals into data streams. Video card with video capture function can not only receive video information, but also cooperate with analog camera to form a visual communication system.
price
3. Choosing the purchase price Next, the appropriate price level should be determined according to the use requirements and whether the funds are sufficient. Generally speaking, video capture cards always cooperate with computers and post-production equipment to form a system. In the same system, the quality indicators of all kinds of equipment must be consistent with each other. If the equipment with inconsistent indexes is selected, the final result will only reach the lowest index, so the money spent on the equipment with high indexes will be wasted.
capture effect
4. Choosing a capture effect Choosing a video capture card with good capture effect is definitely the pursuit of users. Users can choose an ordinary video capture card or a simple graphics card according to their own needs. When buying a graphics card, you should carefully check the video input/output interface, and provide S-video terminals in addition to ordinary RCA terminals. In terms of capture effect, it is best to choose a product whose dynamic capture effect is closer to the nominal 30 frames/second or 25 frames/second, in which the distortion of color, brightness and contrast of the captured image should be minimized.
resolution ratio
5. Choosing the resolution The resolution of the video capture card is inseparable from the connected computer. If we want to get some high-quality video pictures through the video capture card, we should pay attention to the resolution of the video capture card when playing dynamic video. The higher the resolution, the better. If you want to achieve high-definition effect, it is recommended to use hdmi acquisition card. No matter how bad the TV card is, it can't be less than 300×200, which is the resolution standard that ordinary TV can achieve. Now VGA HD acquisition card can collect1920x1440x60hz VGA signal line by line. Of course, in order to make the graphics card have the most perfect demonstration effect, I suggest you adjust the resolution of your computer to the same as the video capture card you bought.
Progressive speed of walking in unison
6. Video format If we buy a video card mainly for video editing, then we should pay attention to the video format that can be transmitted after the image is collected by the acquisition card. Some video capture cards can only be saved as AVI and have no image compression function. In order to adapt to the editing of video information in various formats, it has high resolution, can be saved as various images, and has the function of image compression.
function
7. Selection function Nowadays, video capture cards have more and more functions and become more and more perfect. Usually, an ordinary video capture card has only a few functions, so we don't need to be new and complete when buying, as long as it is practical. You use a notebook computer and want to use it for some professional video processing, then you can choose an external graphics card for the audio-visual notebook special acquisition card.
Other details
8. Pay attention to other details After considering the above main aspects, we can also compare some details, such as whether the video capture card provides automatic search and storage, and whether it provides manual assistance. When the graphics card is working, it is also very important to reproduce clear and low-distortion TV pictures on the computer screen. Some graphics cards have obvious flicker and blurred images, so try to test them on the computer when buying. Video capture cards are generally equipped with hardware drivers to realize the control and data communication between PC and capture card, so it is necessary to randomly check whether there is a driver disk. In addition, it is necessary to carefully check the types of video jacks supported and owned on the graphics card. In addition to the standard closed-circuit television jack, AV video, audio input/output jack, high-definition digital S-video jack, etc. It should also be provided to facilitate the connection with other audio and video equipment (such as DVD players, speakers, etc.). ). Of course, if you think you won't use these other audio and video ports in the future, you can ignore them. After all, the price of products without these sockets will be relatively cheaper. In addition, whether you can receive the supplementary channel of cable TV is also a problem to be considered, which is related to the characteristics of the tuner used in the product and cannot be compensated by the acquired software. Finally, when buying, you should ask the dealer about the function of the product, and you should also carefully look at whether what is introduced in the manual is consistent with what the dealer said.
use
9. Use of video capture card Generally speaking, it is very simple to collect DV with video capture card. When the acquisition card system is installed, the driver will be automatically installed, and then the DV will be connected to the input end of the computer's 1394 video acquisition card with 1394 cable, and then the audio and video will be installed. This is the simplest acquisition software, and the latest version is audio and video X2. Then, mpeg software, select Capture, and select the device as your DV player. Click the Collect button to collect.
Edit the installation instructions in this paragraph.
Note: When starting the software, please check whether the VGA cable is connected correctly and whether the VGA acquisition card has VGA signal.
Functional performance
High-speed analog-to-digital conversion of VGA signal up to 32 bits is adopted to ensure that the shot picture is high-definition and smooth, close to the original signal. Real-time sampling, acquisition and analog-to-digital conversion of VGA signal. The sampling bandwidth can reach 600MHz, and the maximum support is 1280* 1024*60Hz. Displaying video, text, pictures and web pages can ensure clarity, continuity and stability. Support the acquisition of VGA output signals such as desktops, notebooks and physical booths. Adaptive VGA signal sources with different resolutions and refresh rates.
install driver
Insert VGA- acquisition card into PCI slot of PC, and prompt to install driver when starting. Copy the newVGACapture folder from the CD to the hard disk, select the newVGACapture folder where the driver is located, and install the driver. After installing the driver, it will be displayed as: vgacap in Windows Device Manager. Then in the newVGACapture folder, click reg.bat, and the registration is successful. Restart the machine and you can use the VGA card. This card supports DirectShow SDK and VC SDK, and can be re-developed. Supports output in formats such as RGB24, RGB32 and YUY2.
application program
1. supports software such as Windows Media 9 encoder and amcap. Possible problems and solutions: 1. No source. Please check whether the VGA signal source is properly connected to the VGA card. The VGA cable should be provided by us (one end is a needle and the other end is a hole). The port of the pin on the card is the VGA input port, and the port of the hole is the VGA output port. You can't use a thread with needles at both ends. 2.amcap has no display option-> Preview prompt cannot set the frame rate of capture to select capture-> Set the frame rate, and check Use Frame Rate.
Hardware installation
Insert VGA acquisition card into PCI slot of PC, and fix the interface braid on the card. There are two interfaces on the braid, one is VGA IN (connected to the input of VGA signal source) and the other is VGA out (connected to the loop output of VGA signal source).
Detailed steps
Disconnect the power supply of the host and the wires that need to be disconnected, open the side baffle of the host, and you will see the largest board inside, that is, the motherboard. There will be milky white (mostly) slots at the bottom of the motherboard (there will be five in the big board and three in the small board), which is the PCI slot. Insert the acquisition card into any PCI slot. If other cards are already installed in the PCI slot, it is best to separate one slot from this card. Fix the acquisition card with screws. Install the baffle on the host side and connect the corresponding wiring and the host power supply. Boot, if your card is 1394, WIN XP system, then the system will automatically identify the card, if not, put the CD attached to the card into the CD-ROM drive, and install the drivers and some programs needed by the card. Right-click my computer, left-click Properties, left-click the Hardware tab, and left-click the Device Manager tab to see if there is a yellow question mark. If there is no yellow question mark, the acquisition card is installed correctly and can be used. If there is a yellow question mark, it means that the acquisition card is not installed correctly or the driver is not installed correctly, or there are other problems. After solving the above problems, the acquisition card can work. It is recommended that you read the instructions of the acquisition card before using it.
Edit the application scope of this paragraph.
Video capture cards are widely used in security monitoring, educational courseware recording, large screen splicing, multimedia recording, conference recording, virtual studio, virtual reality, security X-ray machine, radar image signal, VDR recorder, medical X-ray machine, endoscope, CT machine, gastrointestinal machine, colposcopy, industrial detection, intelligent transportation, medical imaging, industrial monitoring, instruments, machine vision and other fields. The video system composed of video hardware such as video acquisition card and interactive electronic whiteboard is often used for image acquisition/image analysis and processing/video conference/digital monitoring. Government: telecommuting meetings, government procurement meetings, remote statistics and collaboration, government bidding meetings, personnel recruitment and assessment, mass government consultation, letters and visits, public health command finance: financial working meetings, remote customer service, office meetings, e-commerce, remote consultation, operation guidance, roadshows, remote recruitment and training enterprises: enterprise regular meetings, remote business negotiations, collaborative office, remote recruitment and agency. Technical seminar, administrative office, internal training and study, branch meeting, remote customer service, remote monitoring and medical treatment: remote consultation, remote medical consultation, remote medical exchange education: multimedia teaching video live broadcast, network education and training, remote counseling, examination room monitoring, parents' meeting, academic exchange in different places, remote teaching and observation class of public security law, military: remote meeting, remote coordinated operational command, remote police command, remote interrogation, remote prison visit, etc.