Analysis of compression format for audio and video development

Network Camera and audio and video development as a new type of network applications, to adapt to the requirements of network transmission will inevitably become an important factor in product development, and this one of the video image technology has become the key. In the current Chinese network cameras and audio and video development products market, all kinds of compression technology, and each has advantages, providing users with a large choice of space. the anychat audio and video development platform uses the mainstream audio and video codec of H. Now small compilation of several video compression format for comparative analysis:

JPEG , M-jpeg

a considerable part of the domestic and foreign network cameras and audio and video development are using JPEG , Motion-jpeg compression technology, JPEG , M-jpeg the use of intra-frame compression, the image is clear and stable, suitable for video editing, and can be flexibly set the video definition and the number of compressed frames per channel. In addition, because of its compressed format can read a single screen, so can be arbitrary splicing, especially for the use of security forensics.

Wavelettransform

wavelet transform also belongs to the intra-frame compression technology, because this compression method removes the high-frequency components of the image, only the single-frame image signal, especially for the occasion of frequent screen changes, and the compression ratio has been improved, so also by some network cameras and audio and video development adopted, for example, BOSCH Launch of NetCam-4 series of digital Network cameras, Shenzhen Association good production NETCAM series of network cameras.

H.263

h.263 is a more mature standard, it is the inter-frame prediction and Transformation Coding hybrid algorithm, compression is relatively high, especially for low-bandwidth transmission activity video. The use of h.263 technology to produce network-based products, its cost is relatively moderate, soft / hardware-rich, suitable for centralized monitoring of a large number of demand, such as Shenzhen University Institute of Communication Technology Development of SF - Network Camera and SF-20 Audio and video development, Shenzhen Xin Wen Ding development of W750 audio and video development and w74gm network cameras are used in this compression technology.

MPEG-4

MPEG-4the focus is to solve the problem of low-bandwidth audio and video transmission,164KHZon the bandwidth,MPEG-4average can be transmitted5-7Frame/seconds. AdoptMPEG-4compression technology, network-based products can use a low-bandwidth network, such asPSTN,ISDN,ADSLand so on, greatly saves the network expense. In addition,MPEG-4the highest resolution is up to720x576, closeDVDThe picture effect, based on the image compression mode, determines that the moving object can be guaranteed to have good sharpness. MPEG-4all these advantages make it become one of the most important trends in the development of network product manufacturers.

In addition, some of the manufacturers are also using mpeg-1,mpeg-2 compression format, in addition, some manufacturers also use a variety of compression technology combination of ways, for example, some foreign network cameras, the compression method is MPEG-4, with the JPEG in combination, you can see JPEG still images, the use of MPEG-4 advanced compression enables high-quality, dynamic images to be transmitted on low bandwidth.

      throughout these compression techniques, although mpeg-4 with its good image compression performance, can support very low bandwidth to meet the quality of video conferencing, and thus become the future of network-based product development mainstream direction, but in the current market applications, the mpeg-4 for the time being, the reason is not yet dominant, mainly because although mpeg-4 International standards for mpeg-4 The algorithm is open, so vendors are fragmented, mixed, for the subsequent development of the two has a serious impact, in addition, mpeg - 4 In the image quality also needs to be improved, in the complex network environment, the data flows in the large time easily causes the data loss.

on the other hand, so many kinds of compression technology, but also allow users in the purchase of network cameras and audio and video development, there is a lot of trouble, some users require network transmission to achieve real-time, some require high image quality, and some require back-end storage system capacity is large enough ... .. for network-based products, the network transmission rate, image quality and system storage capacity are closely related to the compression method used by the products, and the three are restricted to each other, so it is difficult to achieve the most ideal state at the same time, only from the three to seek a balance point, that the user's own real real needs. Many manufacturers recommend that users in the choice of network cameras and audio and video development, the first should be clear about the system's existing resources, as well as the actual effect of the system to achieve.

Analysis of compression format for audio and video development