Without high-definition video compression, the video file is very large, which is not conducive to saving. Especially in video live broadcast, network conference, video monitoring, and distance education, you need to use video capture card to collect the signal of the video source equipment into the computer, then compress and encode the software, and finally become a video file that can be transmitted. So it is important to understand how video compression works and what factors it is related to.
Of course, for video beginners, many times will ask, why do you compress the video? The purpose of video compression is to reduce the video data rate while ensuring the visual effect as much as possible, so as to facilitate network transmission and preservation Otherwise, the uncompressed video file is very large, which is not conducive to preservation or transmission. There is a noun: video compression ratio. Video compression ratio generally refers to the ratio of the amount of data after compression to the amount of data before compression. Because video is a continuous static image, its compression coding algorithm has some common features with the compression coding algorithm of still images, but moving video also has its own characteristics, so its motion characteristics should also be considered when compressing to achieve High compression target.
The following is a brief introduction by Beijing Meifit technical staff on the factors related to high-definition video compression.
One is the format: the largest is AVI, which is nearly 10 times that of WMV, 15 times that of MPEG, etc. The smallest is FLV format. The basic ordering is AVI, WMV, MPEG-2, VOB, MP4, MOV, MPEG, RMVB, RM, FLV
The second is the video resolution: the larger the file, the larger.
The third is the bit rate of the video. The higher the file size, the larger the file size.
Then you know how to compress 8G video to about 3G ---- set the above three parameters.
Compressed so small, the quality of the video will be greatly reduced! This is inevitable, because the quality of the video is proportional to the video file size.
Of course, sharpness and resolution are not directly proportional. High-resolution movies may not be useful for every bit of data used for display; the avi format may not be very clear, and the mp4 format may not be unclear. Want to see a clear movie, one is to find a video with a clear original image and a low compression rate (some videos are large but not clear, often the original video that they process is not clear enough), and the second is to have a comparison Good display hardware.
At present, the high-definition video capture cards launched by Mefit are all in soft compression mode. After being captured into the computer through the video capture card, the software performs real-time compression processing. This mode has been widely used. Compared with the traditional hard compression capture card, the soft compression card has more advantages, mainly in low cost, comprehensive functions, and can achieve more functions with software. Therefore, the compatibility of soft compression capture cards is very important, which directly determines what software can be used by users, and the Mefit series HD video capture cards are directly compatible with the video software developed by the DirectShow standard, such as video conferences on the market , Webcast, P2P, switcher software, etc. are directly compatible, and even compatible with non-editing software Edius, providing a complete secondary development kit SDK to meet the needs of various video applications.