The stream processing technical analysis of the Network Camera

The stream processing technical analysis of the Network Camera


Analysis of network monitoring applications
Network infrastructure environment is one of the important factors for the good development of the network video surveillance market. At present, China's network video surveillance market, the lack of good network infrastructure environment, making network video surveillance, especially by certain obstacles to the application of HD IP Camera video.
HD IP Camera has been a qualitative leap in image clarity, but also to the network monitoring system has brought a series of questions:
Tight network bandwidth: the greater the resolution, ultra-high-definition transmission stream will increase, and increase the network bandwidth pressure;
· Storage space: the doubling of data traffic, increase the amount of storage, network storage pressure;
· Management platform hardware and software load intensified;
· Double construction costs.
Therefore, in the pursuit of high-definition network video surveillance equipment manufacturers proposed requirements to solve the above problems. Therefore, the need for the video stream processing and control technology to be constant development to respond to the problem of the high bandwidth, high capacity storage HD brought.
The development of video compression technology
In the field of video surveillance, video compression encoding format from the M-JPEG, H.263, MPEG4 to H.264 development, currently H.264 compression algorithm mainstream applications. The biggest advantage is that having a high data compression rate under the conditions of the same image quality of MPEG-4, H.264 compression ratio is 1.5-2 times. H.264 in having a high compression ratio also has a high-quality smooth image, and as such, after the H.264 compressed video data in the network during transmission require less bandwidth, and is also more economical, saves Users download time and data traffic.
Technically, H.264 concentrated the advantages of the previous standard, and absorb the experience accumulated in the standard-setting. Compared with H.263, MPEG4, H.264 did significantly reduce the bit rate can save up to 50% of the bit rate stream control. Now, there are more manufacturers of network video products with advanced H.264 compression algorithm.
Stream processing technology analysis
Even with advanced H.264 compression algorithm, HD 720P 3-4M stream HD 1080P 4-6M streams, still can not solve the problem of network, storage pressure, so there is a variety of streams approach.
Flow mode select function
General transmission of audio and video streaming, IP Camera the support stream selectable modes: audio and video streaming, pure video streaming, but also the camera supports audio-streaming mode. Depending on the demand for audio and video, select the appropriate flow mode, can greatly ease the pressure on the network, the storage pressure, lower investment costs.
Variety of coding techniques
HD IP Camera more supports three encoding technology, and that support JPEG/MPEG-4/H.264 three different compression formats, these three code stream can be set in accordance with the actual situation of the customer. Such as: lower stream H.264 video compression format D1 image transmitted to the remote real-time monitoring to the customer, while incoming megapixels, H.264 video compression format real-time image storage server for video, the other alarm transmission megapixels JPEG images, easy afterwards enlarged confirmed, looking for suspicious objects. Variety of coding techniques with applications, the same solution to ease the pressure on the network, storage pressure.
Dual-stream processing technology
Dual-stream, two stream that coexist in the IP Camera. The dual stream is achieved by separately encoded on the encoding side in two formats. A stream for network transmission, another stream for high-quality real-time storage, dual-stream at the same time take into account the local storage and remote network transmission to solve the bottleneck of network transmission. The realization of the dual-stream, lift, Kai the new page for local storage. Encoding, prior to storage, the flexibility to choose the size of the stream according to network bandwidth, and the coexistence of local HD storage and low stream transmission becomes possible.
Multi-stream processing technology
Relative to dual-stream, multi-stream output stream multiple choice, multiple clients to access the camera pre-set a good variety of streams. : 3,000,000 (15 frames / sec), 1080P (25 frames / sec), 720P (25 frames / sec) and D1 (25 frames / sec), and each client can be synchronized to receive pre-set stream. The technology is to be achieved in the environment of a variety of application needs, the cameras can provide multiple, independent streams selected simultaneously, and can also reduce the load on the network and pressure. Such as storage 3,000,000 smaller local Client Access 1080P, TV wall display with 720P, remote client access with D1 of Mobile Phone Users select CIF or QCIF resolution, no impact each other and can be sent simultaneously . In this way, we avoid the IP Camera is only one choice, only to meet the demand for high-definition monitors, and also saves storage space.
Various manufacturers of different multi-stream processing technology. Such as support for multiple concurrent stream video stream must be the same configuration parameters, modify any way stream configuration parameters, such as resolution, frame rate, all other stream configuration will change this and can not be truly multi-stream control. True multi-stream technology, a plurality of streams is completely independent of the configuration, may be to a different resolution, a different frame rate, the different compression ratio or by different coding methods, meanwhile, in a multi-stream performance support multiple concurrent resolution, full frame rate independent concurrent streams. The industry, there are manufacturers of network video products with the multi-stream processing technology alone.
Flow control mechanism
Processing multiple streams, Network Camera, configured independently for each video stream, to achieve good flow control mechanism, and also plays a very important role in the application. Stream Control contains variable stream, a constant stream mode and maximum flow limit.
· Variable stream, keep the video set configuration parameters, such as resolution, frame rate, bit rate of the video stream will change as the video content and fluctuate;
· Holding the video stream at a constant bit rate, the image quality and the code stream will be adjusted as the video content changes. Select an image quality priority, the user can also maintain a constant bit rate or frame rate priority;
· Maximum flow limit, allows the bit rate of the video stream fluctuate, but set a maximum defined threshold, when the bit rate reaches the maximum defined threshold, the corresponding reduction in the video image quality in order to keep the video stream does not exceed a set maximum threshold.
Visible for a true multi-stream technology provides a good chip processing support, and can provide a variety of flow control management mechanisms, in order to ensure network video products in actual use in the real availability and rationalization of the network video streams management, to better meet the needs of practical application.

In short, do a better stream processing and control to solve the problem of network storage pressure, in order to better meet the actual needs of the HD IP Camera video surveillance. Right now. Some security applications of network video products manufacturers H.264 compression algorithm and multi-stream processing technology is relatively mature, its network video products have been qualified for the needs of large high-definition network video surveillance system, and reduce overall customer input costs, while state-of-the-art The technology will also promote more large-scale application of the HD Network Camera video surveillance security industry.

Plug Play IP Camera HD IP Camera IP Camera Network Camera manufacturer :http://www.vstarcam.com