Application of Internet Protocol Camera and H.264 Compression Technology

introduction

IP cameras in closed-circuit television systems (CCTV) transmit audio, video data, and control signals via Ethernet links using the Internet Protocol (IP). They have many advantages over traditional analog security cameras. Analog cameras typically transmit analog NTSC/PAL signals via coaxial cables. Unlike analog cameras, IP cameras support high-definition (HD) images, intelligent analysis, local video storage, and remote control.

Video compression technology is often used in IP cameras with image analysis, video encryption (to prevent hacker attacks), and the ability to package video data into Ethernet data. The compressed video data stream is sent to a hybrid digital video recorder (DVR) or network video recorder (NVR) for storage, playback, and display. IP network video surveillance systems allow security monitoring personnel to conduct remote monitoring, send pan/tilt/zoom (PTZ) commands over the IP network, and the control center can control security surveillance cameras across regions or multiple locations.

Low-power camera designs can be powered by Ethernet (PoE), eliminating the need for an additional power supply. By using the same cable to transmit data and power, PoE installations can greatly reduce wiring costs. In some cases, wireless networks (such as Wi-Fi?) can also replace Ethernet, making camera layout easier. This is especially important for home security cameras that do not yet offer Ethernet, when a "cloud computing" DVR is used instead of a physical DVR.

Multimedia Stream H.264 and Motion JPEG Compression Technology

Under the condition of equal image quality, the compression ratio of H.264 video compression standard is about twice that of the earlier MPEG-4 standard. In the H.264 standard, "high-end class" is defined as the highest video quality at the lowest bit rate, which is particularly suitable for applications such as video security monitoring. Coding schemes with shorter response time (latency) help to shorten the waiting time of security monitoring personnel. In addition, high-definition video encoding enables IP cameras to capture image details, such as facial features, car license plates, etc., to improve the image quality of security monitoring. Due to limited network bandwidth, the system is required to be able to encode/record one HD data stream through the local area network (LAN), and at the same time transmit a lower-definition image to the remote display through the wide area network (WAN).

Mobicam3 720p H.264/M-JPEG IP Camera Reference Design

In addition to H.264, many security surveillance systems also require backward compatibility with existing devices that do not support H.264. The Motion JPEG (M-JPEG) standard provides such systems with backward compatibility and the ability to capture high-definition, lossless images. In particular, it supports H.264 encoding for uninterrupted video recording while also capturing JPEG still images, which can be triggered by special events.

Image analysis

Image analysis is the process of analyzing video data and making decisions based on it. Software analysis functions can be used to take appropriate actions based on specific events without the need for input from security monitoring personnel. For example, if a camera detects that someone has crossed a secure area, an alarm signal can be issued. Image analysis functions include motion detection, tripwires, and image tracking. All of these functions need to be configured using an intuitive graphical user interface (GUI) in the PC-based security monitoring management software.

IP Camera Block Diagram

IP cameras need to be able to stream video data to multiple clients. For example, Maxim's IP camera reference design (Mobicam3) supports up to 16 clients and supports both the Real-time Transport Protocol (RTP) and the Real-time Streaming Protocol (RTSP). In addition, the reference design supports the following Ethernet protocols: HTTP, DHCP, SMTP, TCP/IP, UDP, TFTP, FTP, NTP, and UPnP?. The data stream can be encrypted using AES or SHA encryption technology.