Astaria

Currently on the market are many kinds of DVR products. How to choose a most suitable hard disk video recorders, for many engineering companies have is a problem, especially the novice, it is impossible to start, select the hard disk video recorders, hard disk video recorders should be inspected in the way of image compression , image quality, real-time, network performance, stability and price, compression technology is the core of the hard disk recorder, select the compression method which is most critical. Here it is necessary to take into account the quality of images, but also take into account the image storage and transmission speed. The current video card hard drive appeared on the market are mainly compression M-JPE, wavelet algorithms, MPEG-1, H263, MPEG-4, H.264 and so on.1, M-JPEG is a JPEG-based still-image compression technology developed in the dyn abbotsford windows amic image compression technology, the drawback of low compression efficiency first, M-JPEG algorithm is based on the contents of each frame image compression, rather than the difference between adjacent frames to be compressed, thus creating a lot of redundant information is repeated storage, storage space occupied by the large per frame 8 – 20k bytes, it is best to do only 3k bytes per frame . Another point of difference is its real-time, in every way to ensure that all must be the premise of high-definition, it is difficult to complete real-time compression, and frame loss is serious, if the use of high compression ratio of the video quality will be seriously reduced. Tends to phase out such cards, but the price is cheap.2, the wavelet algorithm technology is to make the image signal in time domain and frequency domain resolution, while the highest resolution.