Million HD boarded the security monitoring application stage. Do you understand HD? The following million HD videos from the camera, transmission, storage to display, take you to understand the composition of millions of high-definition monitoring system:
Q: What is 720P? What is 1080P?
A: 720P, 1080P is the format standard of the highest-level HD digital television set by the Society of Motion Picture and Television Engineers (SMPTE). The effective display format of 720P is: 1280×720, the number of pixels reaches 921,600, and the effective display format of 1080P is: 1920 ×1080, the number of pixels reached 2.0736 million. SMPTE (American Film and Television Engineering Association) divides the digital HDTV digital television scanning lines into 1080P, 1080I, and 720P (i is interlace, meaning interlaced, p is Progressive, line by line). 720P, 1080P is a display format that achieves resolutions of 1280×720 and 1920×1080 under progressive scan. It is a fusion of digital cinema imaging technology and computer technology. We often say that the 720P HD camera or 1080P HD camera is a camera that can output 720P or 1080P resolution images through a series of processes such as video capture, encoding, compression, and decoding according to this standard.
Q: What are the effective pixels of the HD camera?
A: The number of pixels of a digital camera/camera includes Effective Pixels and Maximum Pixels. The difference from the maximum pixel is that the effective pixel number refers to the pixel value that actually participates in photographic imaging, and the highest pixel value is the real pixel of the photosensitive device. This data usually includes the non-imaging portion of the photosensitive device, and the effective pixel is the photosensitive device. The pixel value that really participates in the photosensitive part is often much smaller than the maximum pixel value. Therefore, the digital camera/camera can obtain the largest picture pixel, which is a valid pixel, with the same pixel area.
At present, the nominal pixel value of many digital video cameras/cameras is often the largest pixel, not the effective pixel. In addition, at the same time, the same photosensitive device uses different effective pixels when shooting video and taking pictures. Generally, the effective pixels used when shooting video are much smaller than the effective pixels used when taking pictures.
Q: How to identify the performance of HD IP cameras? (How can a nominal 720P/1080P camera identify the merits)
A: The high-definition video camera belongs to the emerging field of video surveillance. At present, there is no unified inspection and test standard in China. Therefore, although high-definition cameras are also labeled as 720P or 1080P, the visual sense gap is very obvious. We can roughly determine the advantages and disadvantages of HD IP cameras with the following five points.
1. Sharpness test You can easily determine the sharpness of a high-definition camera by using an ordinary video image sharpness (line number) test card. This method can directly distinguish the sharpness of an image by the naked eye. In general, HDTV 720P camera test card indicators can clearly distinguish TV lines larger than 800TVL, while poor HD cameras have a lower index, and the image There is jitter or flash.
2. Dynamic Range Test The gray level data of high-definition images can be easily determined by ordinary video image gray scale test cards.
3, color reproduction through the color test card or the naked eye to determine the degree of color reproduction of high-definition video images. Generally, a good HD IP camera has a very high degree of reduction, and it can achieve a very realistic reduction effect.
4. The suppression of noise in the case of the same signal to noise ratio is one of the important indicators for measuring the performance of high-definition IP cameras. The bright processing and noise suppression on the screen directly determine the image quality effect. Many low-end cameras can only output more clear images in an ideal state of 100 Lux or more, and adapt to changes in light environment. Poor, strong or low-light environments have no effective means of suppressing noise and cannot guarantee image quality. In this case, the HD image is meaningless. We call it pseudo-HD.
5, image encoding compression algorithm IP high-definition camera for image encoding compression algorithm's good and bad is also one of the important indicators that directly affect the performance of the camera, the current market for high-definition camera video image encoding compression processing chip is divided into DSP chip ASIC Chips of two kinds of carriers, both have their merits, DSP chip function is relatively flexible, the development cycle is short, but the coding efficiency is low, and the cost is high. The ASIC chip has a relatively fixed application of functions and a long development cycle, but the coding efficiency is high, and the cost is low after mass use. No matter what kind of carrier is needed, a good video encoding compression algorithm is needed. A good algorithm can reduce the video stream and storage capacity as much as possible while ensuring the quality and clarity of the image. Poor IP high-definition cameras often produce mosaics or water ripples under large amounts of activity, which directly affects video image quality.
Q: How to store high-definition images?
A: Different from the traditional digital video recorder (DVR), a high-definition image storage device does not require image compression because it directly inputs digital video images. Instead, it only needs to store digital video image data. In addition, it also needs to support the management of IP high-definition cameras, network services, rights management, Web services and other back-end network services and application support. Currently, NVR devices have a variety of product configurations according to different usage requirements, including distributed NVRs and centralized NVR storage systems.
Q: What is 720P? What is 1080P?
A: 720P, 1080P is the format standard of the highest-level HD digital television set by the Society of Motion Picture and Television Engineers (SMPTE). The effective display format of 720P is: 1280×720, the number of pixels reaches 921,600, and the effective display format of 1080P is: 1920 ×1080, the number of pixels reached 2.0736 million. SMPTE (American Film and Television Engineering Association) divides the digital HDTV digital television scanning lines into 1080P, 1080I, and 720P (i is interlace, meaning interlaced, p is Progressive, line by line). 720P, 1080P is a display format that achieves resolutions of 1280×720 and 1920×1080 under progressive scan. It is a fusion of digital cinema imaging technology and computer technology. We often say that the 720P HD camera or 1080P HD camera is a camera that can output 720P or 1080P resolution images through a series of processes such as video capture, encoding, compression, and decoding according to this standard.
Q: What are the effective pixels of the HD camera?
A: The number of pixels of a digital camera/camera includes Effective Pixels and Maximum Pixels. The difference from the maximum pixel is that the effective pixel number refers to the pixel value that actually participates in photographic imaging, and the highest pixel value is the real pixel of the photosensitive device. This data usually includes the non-imaging portion of the photosensitive device, and the effective pixel is the photosensitive device. The pixel value that really participates in the photosensitive part is often much smaller than the maximum pixel value. Therefore, the digital camera/camera can obtain the largest picture pixel, which is a valid pixel, with the same pixel area.
At present, the nominal pixel value of many digital video cameras/cameras is often the largest pixel, not the effective pixel. In addition, at the same time, the same photosensitive device uses different effective pixels when shooting video and taking pictures. Generally, the effective pixels used when shooting video are much smaller than the effective pixels used when taking pictures.
Q: How to identify the performance of HD IP cameras? (How can a nominal 720P/1080P camera identify the merits)
A: The high-definition video camera belongs to the emerging field of video surveillance. At present, there is no unified inspection and test standard in China. Therefore, although high-definition cameras are also labeled as 720P or 1080P, the visual sense gap is very obvious. We can roughly determine the advantages and disadvantages of HD IP cameras with the following five points.
1. Sharpness test You can easily determine the sharpness of a high-definition camera by using an ordinary video image sharpness (line number) test card. This method can directly distinguish the sharpness of an image by the naked eye. In general, HDTV 720P camera test card indicators can clearly distinguish TV lines larger than 800TVL, while poor HD cameras have a lower index, and the image There is jitter or flash.
2. Dynamic Range Test The gray level data of high-definition images can be easily determined by ordinary video image gray scale test cards.
3, color reproduction through the color test card or the naked eye to determine the degree of color reproduction of high-definition video images. Generally, a good HD IP camera has a very high degree of reduction, and it can achieve a very realistic reduction effect.
4. The suppression of noise in the case of the same signal to noise ratio is one of the important indicators for measuring the performance of high-definition IP cameras. The bright processing and noise suppression on the screen directly determine the image quality effect. Many low-end cameras can only output more clear images in an ideal state of 100 Lux or more, and adapt to changes in light environment. Poor, strong or low-light environments have no effective means of suppressing noise and cannot guarantee image quality. In this case, the HD image is meaningless. We call it pseudo-HD.
5, image encoding compression algorithm IP high-definition camera for image encoding compression algorithm's good and bad is also one of the important indicators that directly affect the performance of the camera, the current market for high-definition camera video image encoding compression processing chip is divided into DSP chip ASIC Chips of two kinds of carriers, both have their merits, DSP chip function is relatively flexible, the development cycle is short, but the coding efficiency is low, and the cost is high. The ASIC chip has a relatively fixed application of functions and a long development cycle, but the coding efficiency is high, and the cost is low after mass use. No matter what kind of carrier is needed, a good video encoding compression algorithm is needed. A good algorithm can reduce the video stream and storage capacity as much as possible while ensuring the quality and clarity of the image. Poor IP high-definition cameras often produce mosaics or water ripples under large amounts of activity, which directly affects video image quality.
Q: How to store high-definition images?
A: Different from the traditional digital video recorder (DVR), a high-definition image storage device does not require image compression because it directly inputs digital video images. Instead, it only needs to store digital video image data. In addition, it also needs to support the management of IP high-definition cameras, network services, rights management, Web services and other back-end network services and application support. Currently, NVR devices have a variety of product configurations according to different usage requirements, including distributed NVRs and centralized NVR storage systems.
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