What are the characteristics of digital audio technology in audio and video equipment?

Digital audio technology has the following characteristics:

(1) A lot of data

The amount of data of sound, image, video and animation is huge. The sampling frequency of 1min stereo is 44. 1 kHz, and the amount of data with quantization accuracy of 16 bits is about 10 MB, and it takes about 40 m to store a 4-Song Min of B; The storage capacity of 640x480 RGB color images is 900kB 1s (25 frames per second) and the video data is 22MB. A 650 MB CD can only store about 30 s video.

(2) There is a lot of redundancy in the data.

There is a lot of redundancy in massive data such as sound, image, video and animation. There is a great correlation between adjacent pixels of an image and between the front and back frames of a video sequence, and human ears and eyes have auditory and visual characteristics such as masking effect. Therefore, redundant information in data can be removed according to the inherent relationship of data, and the data volume can be reduced by compression coding.

(3) Large data storage capacity and high transmission efficiency.

Digital audio and video data is large, so it must be compressed and encoded during storage and transmission. After audio and video digital signals are compressed, 2-4 sets of standard definition television (SDTV) programs or a set of high definition television (HDTV) programs can be transmitted on the transmission channel of 6-8 MHz, and the storage capacity of the compressed DVD can reach 7-8CB.

(4) Easy to edit and process.

Traditional tapes need to rewind and fast-forward repeatedly when listening to a piece of music or watching a picture, and the editing process is also linear in sequence. Digital audio and video are different. It can be located instantly, organized in nonlinear logic, and can also use nonlinear editing software for special effects.

(5) The reliability of information transmission and storage is high.

Digital signals do not produce noise and distortion accumulation, and are easy to store, control and modify. Digital audio and video can be copied countless times without distortion, while analog audio and video signals will have an error accumulation every time they are transcribed, resulting in signal distortion. The quality of analog audio and video will decline after long-term storage, while digital audio and video can be stored for a long time without distortion.

(6) Effective information protection and copyright management

Digital audio and video can be easily combined with cryptography and authentication technology, which is convenient for information encryption/decryption and scrambling/descrambling. Suitable for professional applications (military, commercial and civil) or conditional access, video on demand, two-way interactive transmission and other applications.

(7) Extensible and easy to integrate with other digital devices.

Digital audio and video are easy to cooperate with other systems, integrate with other digital devices, and transmit on various communication channels and networks. Easy integration and mass production, good performance consistency and low cost. ruminate