English noun

Chinese noun
Saturation The intensity or purity of the color of a color image
Alarm volume Switch alarm signal Alarm Alarm
collector
Local display Video directly output and displayed by the encoding end Trigger
alarm output Conditionally output alarm signal
Serial port Serial interface
port number Protocol port address , an integer used to identify a process.
Contrast ratio. The ratio of screen brightness.
Multicast address. Address used for multicast.
Composite stream. Data stream containing video and audio compression. track
used to receive alarm and exception data.
This article refers to the route of the camera movement.
Loop-through output. This article refers to the one-to-one output of the input video signal.
Warning on the monitor. Display of alarm information on the monitor. This article specifically refers to the display of the alarm screen.
Decoder. The controller
recording delayAfter the set recording time is reached, the amount of time to be extended later.
Client A program that initiates communication to the server.
Brightness The relative lightness and darkness of the color image.
Code stream type. Compressed video data type, including video stream and composite stream.
The command is triggered by the command. Trigger the execution of a task.
Directory name refers to the file directory name, including the complete path.
Screen saver. This article refers to automatically turning off the screen display.
Upload center. Send alarm and abnormal data through the Ethernet port.
. Color difference component.
Sound warning. Notify by sound when alarming.
Video Loss Video input channel has video connection, but no video signal is received Video
Stream Compressed data stream containing only video
Video frame rate Frames per second
Image resolution Image size and dimensions, in pixels
Gateway is used to connect devices using different communication protocols Devices on two separate networks
Bit rate Bit rate type, upper limit of bit rate
Physical address Media access control address, also called MAC address
Cruise Movement path of the camera
Exception handling How to deal with exceptions
Motion detection Analyze whether there are changes in the video
Pre-recording time Pre-recording time before starting recording
Preset point Pre-set coordinates
Blocking alarm Alarm when a certain area is blocked
Cover Hiding a certain video area in the image

DCIF

We often call 2CIF (704*288, also called Half D1), compared with CIF (352*288), the resolution is doubled in the horizontal direction, but there is no change in the vertical direction, and the display ratio we are used to is 4:3, after horizontal and vertical scaling processing , which will lead to image imbalance.
Then we deinterlace the two odd and even HALF D1s to form a D1. After D1 is reduced by 3/4 horizontally and 2/3 vertically, it is converted into 528*384. The number of pixels of 528*384 is exactly CIF (352* 288) twice the number of pixels. In order to distinguish it from the commonly known 2CIF, we call it
DOUBLE CIF, or DCIF for short. Obviously, DCIF is more balanced in both horizontal and vertical directions than HalfD1, and has improved resolution in both horizontal and vertical directions compared to CIF. After testing a large number of video signals, based on the current video compression algorithm, DCIF (528*384) can well solve the problems of insufficient CIF clarity and too large a D1 code stream. Stable high-quality images can be obtained between 512K-1M bit rate.

H.264

There are two international standardization organizations responsible for video coding. One is the Video Code Expert Group (VCEG) under the International Telecommunications Union (ITUT), which promotes the development of video and audio coding technology; the other is the International Telecommunications Union (ITUT).Motion Picture Expert Group (MPEG) under the Standardization Organization (ISO)
promotes the widespread application of video and audio codecs.
After VCEG released the H.263 compression standard in 1997, it formulated the short-term development plan H.26N and the long-term development plan H.26L. After H.26N developed into H.263, it released the MPEG-4Sp version.
In the fourth quarter of 2001, when VCEG H.26L developed to TML9.0, MPEG and VCEG formed the Joint Video Coding Expert Group JVT to improve and improve the H.26L algorithm. VCEG released H.26L in May 2003. .264 compression standard; MPEG incorporated this technical specification into the MPEG-4 standard based on JVT’s modification of the H.26L compression algorithm, and released it as Part 10 of MPEG-4 (PART10). It is MPEG-4 AVC version. AVC versions of H.264 and MPEG-4. H.264 and MPEG-4 AVC represent the latest achievements of all mankind in video and audio coding and decoding.

FAT32

FAT32 is a file allocation table (FAT, the full name is File Allocation Table) with a cluster number byte table of 4 bytes (32 bits). Each cluster in the FAT32 partition format is fixed at 4KB, which greatly reduces the waste of disk space and improves disk utilization
.

The full English name of SMART

Self-Monitoring, Analysis and Reporting Technology. Its Chinese meaning is self-monitoring, analysis and reporting technology. This technology has been formally established in the ATA-3 standard, and all hard disk manufacturers also provide support for it. .
SMART technology can monitor magnetic heads, disks, motors, circuits, etc. The monitoring software on the host computer analyzes and compares the operation status of the monitored object with the historical records and preset safety values ​​of the monitored software. When an abnormality outside the safe value range occurs, When the situation arises, a warning can be automatically issued to the user. SMART technology can effectively predict potential hard drive failures and improve data security.

Dynamically adjust encoding parameters

The adjusted encoding parameters will take effect without starting or stopping recording or network transmission. In the surveillance system, for static surveillance scenes, methods can be used to reduce the resolution, image quality, bit rate and frame rate of the recording to keep the recording at a very low bit rate, and when the image changes, the resolution of the recording can be increased. , quality, bit rate and frame rate to achieve high-quality recording. Since the above parameters can be dynamically modified, the continuity of the image can be maintained without frequent switching of files, which not only meets the requirements for high image quality at critical moments, but also saves money. hard drive space and network bandwidth.

Resolution

The types of resolution include display resolution, image resolution and pixel resolution.
Display resolution refers to the largest display area on the screen in a specific display mode, expressed in horizontal and vertical pixels.
If the image resolution is greater than the display resolution, part of the image will not be displayed.
Pixel resolution refers to the ratio of the width to the length of a pixel. Different pixel aspect ratios will cause graphics distortion.
Commonly used image resolutions in digital surveillance:
PAL format: QCIF (1 7 4 * 1 4 4), CIF (3 5 2 * 2 8 8), 2CIF (704*288), DCIF (528*384), FULLD1 (704 *576)
NTSC format: QCIF (174*120), CIF (352*240), 2CIF (704*240), DCIF (528*320), FULL D1 (704*480)
Common display resolution of VGA monitor: 640* 480, 800*600, 1024*768, etc.

Face detection

is a technique for filtering out faces in images. Face detection is different from face recognition. The goal of face detection is: whether there are faces in the image, if so, how many there are, and where they are; while the goal of face recognition is: the faces that appear in the image. Whose face is it? Therefore, through face detection, a face recognition system can be realized, which can be applied in access control, attendance, security inspection (airports, conferences, large-scale cultural and sports activities), public security, urban monitoring and other occasions.

Dual stream
means that one channel of video outputs two independent streams through the video encoder. As shown in the figure,

the resolution, frame rate, bit rate and other parameters of the output stream can be set independently. The two generated code streams can meet different application requirements, such as one for hard disk storage and one for network transmission.

Watermark technology

refers to the use of signal processing methods to embed hidden marks in digital multimedia data. Such marks are usually invisible and can only be extracted through specially designed detectors, thus playing a protective role. Definition of watermark: The act of embedding information in a work imperceptibly. The watermark system consists of an embedder and a detector, as shown in the figure: the


embedder has two inputs: one is the information to be encoded as a watermark, and the other is the carrier work to embed the watermark. The output of the watermark embedder is usually transmitted and records. Input the watermark work output by the embedder into the watermark detector. Most detectors will try to detect whether the watermark exists, and if it exists, output the watermark spinning information.
The application of watermark technology in the field of surveillance: content certificate, which embeds signature information into the content to verify whether the content has been tampered with in the future. The content here refers to video materials. Most watermark applications can also be completed using other technologies. However, real watermarks have three advantages over other technologies:
Invisibility.
The watermark will not disappear when the work is displayed.
Watermarks undergo the same transformation as the work into which the watermark is embedded.

Transparent channel

is a technology that parses IP data packets and sends them directly to the serial port for judgment. In fact, it plays the role of extending the control distance of serial devices. IP networks can be used to control a variety of serial devices, such as control decoders, alarm hosts, access control, instrumentation and other serial devices. For users, they only see point-to-point transmission and do not need to care about the network transmission process, so it is called It is a serial port transparent channel.

File fragmentation

A file is scattered and recorded in discontinuous cluster numbers. The file contents in these discontinuous clusters are called file fragments. When the file contents in the hard disk are repeatedly deleted and written, file fragmentation is likely to occur, which will increase the seek delay and rotation delay of the hard disk, thus affecting the operating efficiency and service life of the hard disk.
If the files are predetermined and each file is pre-allocated with a consecutive cluster number, the generation of file fragmentation can be completely avoided.

Loop recording and non-loop recording

Loop recording refers to a recording method that automatically overwrites the original video data without replacing the hard drive when the program detects that all the hard disk space in the hard disk video recorder is full.
Acyclic recording refers to a recording method that stops recording when all the hard disk space in the hard disk video recorder is full. In this method, the hard disk must be replaced or the hard disk must be processed (recording data must be backed up and then formatted) before recording can continue.

Motion detection

is a technology that determines whether there are changes in the video scene by analyzing video images.
The movement of entities in the scene, changes in light and other factors are considered to have changed the scene.

Frame type

I (Intra code frame) frame is an intra-coded frame, P (Predicted frame) frame is a coded frame predicted forward based on I or adjacent P, and B (Bi-direction frame) frame is based on adjacent I, P or P, P frame calculation interpolation frame.