There are three commonly used decoders, one is a software decoder, the second is a hardware decoder, and the third is a wireless decoder. Normally, the decoder will not be used alone, but will be equipped with a specific encoder.
"Video decoding" is a kind of software decoder, mainly to help users restore digital and analog signals to the state before encoding, and this kind of decoder is often used for video and audio decoding.
The second is a hardware decoder. The common walkie-talkies in life are equipped with decoders. There are two kinds of walkie-talkies, one is an analog signal and the other is a digital signal. The security of the latter is higher than that of the former. But these two kinds of walkie-talkies all need encoders, receivers, and decoders to complete their work.
The last type is wireless decoders. In fact, many wireless networks and mobile networks use this type of equipment. Its modulation methods include GMSK, QAM, CPFSK, QPSK, etc. The common interface is RS-232 port, and this type of decoder There is a fixed working frequency range, and the application scenarios are extremely wide.
The function of the decoder is to "restore". Under normal circumstances, the decoder will not work independently. Whether it is a software decoder or a hardware decoder, there is a unique "compilation" standard. Take the software decoder as an example , When we use an encoder to encode a video, the video will be compiled according to the rules specified in advance. If we want to read the video, then we must use the corresponding decoder, and the encoding and decoding The methods are all unique.
The function of the hardware decoder is similar. Take the analog walkie-talkie as an example. When user A talks on the walkie-talkie, the built-in encoder of the walkie-talkie will convert the sound into a unique analog signal, and the walkie-talkie of user B will receive this simulation The signal is then restored to the sound we hear through the decoder, and this is the role of the hardware decoder.
Speaking of the function of a decoder, whether it is a software decoder, a hardware decoder or a wireless decoder, its function is actually to convert some special signals or files into routines that we can listen to, see, and use." style".
Let's take a simple example to illustrate. Suppose there are four students, they are Chinese A, British B, Japanese C, Japanese D, and Japanese C and D understand Chinese and the other English. If The Chinese A wants to communicate with the British B, so they need to rely on the Japanese C and D to convey it.
Chinese A speaks Chinese to Japanese C, while Japanese C speaks Japanese to Japanese D, and then Japanese D translates into English and tells British B. In this process, Japanese C acts as an encoder; Japanese C is responsible for editing Chinese into Japanese that Japanese D can understand. In order to make English B understandable, Japanese D translates Japanese into English. This is the function of the decoder.
On the market, decoders are needed for analog signals, digital signals, video, audio, and network signals.