Navigation generally supports AVI, MPEG, MP4, etc. These three video formats are the most commonly supported, as are audio formats MP3, WMA, etc.

The common characteristics of audio file formats are: to play or process audio files in a computer, that is to say, the sound file needs to be converted from digital to analog. This process also consists of sampling and quantization. The lowest frequency of audible sound is from 20Hz to the highest frequency of 20KHZ. Human ears cannot hear sounds above 20KHz.

Therefore, the maximum bandwidth of the audio file format is 20KHZ, so the sampling rate needs to be between 40~50KHZ, and more quantization bits are required for each sample. The standard for audio digitization is 16 bits per sample -96dB signal-to-noise ratio, using linear pulse code modulation PCM, with each quantization step having equal length. This standard is used in the production of audio files.

Extended information:

One is the car trace monitoring function. As long as the encoded GPS receiving device is installed on the car, the car can pass the computer control center no matter where it travels. The electronic map indicates its location;

The other is the driving guide function. The car owner can store the electronic map of the traffic routes in various areas on a floppy disk. As long as the floppy disk is inserted into the car receiving device, it will display The screen will immediately display the traffic status of the area where the car is located. It can not only input the destination and pre-program the best driving route, but also accept instructions from the computer control center to select the route and direction of the car. .

Baidu Encyclopedia-Car Navigation