Video parameter Interpretation

1, resolution (resolution)

Video resolution refers to the size or size of the image of the video imaging product, and its expression is: "horizontal pixels * vertical pixels." Common image resolutions are QCIF (176X144), CIF (352x288), D1 (704x576), 720P (1280x720), 1080P (1920*1080). The maximum resolution of camera imaging is determined by CCD or CMOS photosensitive device. Some cameras now support the modification of the resolution, which is produced by cutting the original image with the camera's own software.

2, Frame rate (Rate).

A frame is a static picture, continuous frames to form animation, such as movies. The number of frames we usually say is the number of frames that are transmitted in 1 seconds, usually with fps (Frames per Second). Each frame is a still image, the rapid and continuous display of frames to form the illusion of movement, restore the state of the object at that time. The offers high frame rate allows for smoother, more realistic animations. The greater the number of frames per second (fps), the smoother the actions displayed. In general, the image frame rate set to 25fps or 30fps is sufficient.

3, Code flow (Data Rate).

Code flow refers to the video image after coding compression in the unit time of data flow, also known as the code rate, video coding in the picture quality control of the most important part. At the same resolution, the smaller the compression ratio, the greater the rate of video image, the higher the picture quality.

The correlation between resolution, frame rate, and code flow can be shown in the following diagram :

         for still images, a higher image quality can be achieved with a lower stream of code, and a higher code flow is required for moving images. For example, for the 720P camera, the typical rate is: 2M, for indoor scenes, due to less moving objects, the speed is small, configure 2M code flow can meet the requirements; for the road monitoring scene, because of the speed of traffic flow, scene transformation is large, you may need to configure 4M code rate. In practical applications, we should be configured to change the code rate, so that it better adapt to the scene change