By PURPLELEC | 21 September 2023 | 0 Comments
Main functions of video surveillance capture card
Among the capture cards, image capture cards are mainly used for security monitoring. The main functions and technical indicators of video surveillance cards with PC as the hardware environment are:
interface
The interface of the video capture card includes the interface between the video and the PC and the interface with the analog video device. At present, PC video capture cards usually use a 32-bit PCI bus interface, which is inserted into the expansion slot of the PC motherboard to realize communication and data transmission between the capture card and the PC. The capture card must have at least one composite video interface (Video In) to connect to analog video equipment. High-performance capture cards generally have a composite video interface and an S-Video interface. General capture cards support both PAL and NTSC TV standards.
It should be noted that video capture cards generally do not have TV antenna interfaces and audio input interfaces. Video capture cards cannot be used to directly capture TV RF signals, and they cannot directly capture audio signals in analog videos. To collect audio, a sound card must be installed on the PC. The video capture card obtains digital audio through the sound card on the PC and synchronizes the audio with the collected digital video.
Function
On the PC, the video capture card can receive the analog video signal from the video input end, collect the signal, quantize it into a digital signal, and then compress and encode it into a digital video sequence. Most video capture cards have hardware compression functions. When capturing video signals, the video signals are first compressed on the card, and then the compressed video data is transmitted to the host through the PCI interface. General PC video capture cards use intra-frame compression algorithms to store digital videos into AVI files. Some high-end video capture cards can also directly convert the collected digital video data into MPEG-4 or H264 format files in real time.
Since the analog video input terminal can provide an uninterrupted source of information, the video capture card must capture each frame of the analog video sequence and transfer the data to the PC system before capturing the next frame of image. Therefore, the key to achieving real-time acquisition is the processing time required for each frame. If the processing time of each frame of video image exceeds the time between two adjacent frames, data loss will occur, that is, frame loss. The capture card first compresses the acquired video sequence and then stores it in the hard disk.
The first point is playback quality
The most important function in the security monitoring system is to play back historical videos. The playback image quality is one of the important performance indicators of the surveillance capture card. Genuine surveillance capture cards should achieve 10-bit ultra-high-definition D1 images. The images have no color distortion and no delay. The market It is difficult to achieve this effect by using a pirated surveillance capture card.
The second point is display resolution
As the resolution of monitoring acquisition cards in security monitoring systems is generally divided into display resolution and video recording resolution. The display resolution only refers to the display resolution of the WINDOWS system desktop. After the collection is implemented, the genuine capture card can reach a resolution of 704*576 when performing multi-screen splitting. When recording and broadcasting, the resolution can reach 352*288/320*240. This is a resolution that cannot be achieved by ordinary surveillance capture cards on the market, and it is even more impossible for pirated capture cards to achieve it. When recorded and played back by pirated capture cards, the pixel mosaic on the monitor is exposed, and the image quality is very poor.
The third point is remote monitoring
Remote monitoring is an essential function of monitoring acquisition cards, but many engineering companies still lack confidence in remote monitoring. Remote monitoring functions include: multi-screen monitoring, recording and playback, dynamic IP function, automatic connection function after power failure, remote control, remote configuration, status viewing, code stream adjustment, two-way voice intercom, alarm function, and multicast function Wait, the engineering company should test whether it has the above functions one by one, and at the same time observe the remote image quality, rather than just the smoothness.
The fourth point is frame rate
The number of frames per second (fps) or frame rate of the monitoring capture card indicates the number of times the graphics processor can update per second when processing the field. A high frame rate results in smoother, more realistic animations. Generally speaking, 100fps in P mode and 120fps in N mode is a very good effect. The pirated capture card only exceeds the frame rate of 75fps, which is far less than 100.
The fifth point is the function of the capture card
Generally speaking, the surveillance acquisition card must have the following functions: image collection, recording and remote transmission; collecting various alarm signals, realizing alarm linkage and transmitting them to the centralized control station monitoring center; controlling the movement of the pan/tilt and lens; controlling the switching of the matrix switcher video images. However, there is no way for the pirated surveillance capture cards on the market to completely achieve this.
The 7130 capture card is specially launched for video surveillance. It supports the standard DIRECT SHOW API for development and does not require secondary development. It can also provide secondary development SDK according to the needs of different customers. And can be applied to video webcasts, streaming media, video conferencing, etc. In the face of market demand and industry development, relying on a keen sense of smell and sensitive market insight, Tianchuang Hengda Digital Video Technology Development (Beijing) Co., Ltd. took the lead in applying intelligent video technology to surveillance acquisition cards. At present, 8 series, 9 series and AV series monitoring and acquisition cards have realized the application of intelligent functions (intelligent brightness adjustment, intelligent local amplification).
The main advantages of 8 series, 9 series and AV series monitoring and acquisition cards are:
The first point is that powerful data retrieval and analysis functions can provide fast response time and investigation time.
Second point, more effective surveillance – security operators only need to pay attention to relevant information
Third point, fast response time - millisecond alarm trigger response time
Fourth point, intelligent brightness adjustment, intelligent local amplification
The current intelligent video surveillance capture card is suitable for security monitoring in industries such as banks, postal and telecommunications, military, electric power, prisons, transportation, shopping malls, factories and government agencies.
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