Analysis of the MP3 decoding algorithm principle.
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1: Introduction to the general structure of the MP3 codec
MP3 decoding process
Look dumbfounded, right? There are many concepts here that need to be explained one by one.
Bitstream: Bitstream is a content distribution protocol. It uses an efficient software distribution system and peer-to-peer technology to share large files (such as a movie or TV show) and allows each user to provide upload services as a network redistribution node. (Because no professional has studied this content, I will interpret it as a datum for now, and the internal content will have time to discuss.)
Synchronization and error checking – The transmission and synchronization of mp3 data streams are based on frames. A frame is the smallest format unit of MP3, it can no longer be divided. The header of each frame contains basic information about the current frame, including timing information. The timing information consists of ‘1’s containing 12 consecutive bits. The first step in the mp3 video decoding job is to synchronize the decoder with the input data stream. After starting the decoder, it can be done by looking for 12 consecutive bits of ‘1’s in the data. Once the synchronization information is obtained, the subsequent frame header information is: frame header information, which includes information such as sampling rate, padding bits, and bit rate.
Huffman decoding: You can understand it this way, I do a one to one correspondence between different data through a table and use this corresponding code to represent the original information, then the number with high frequency, I use the shortest possible code to represent Numbers that appear less frequently are represented by longer codes. This reduces the amount of content that the information represents. And after transmission, it can be restored according to this comparison code. Probably the beginning is this.
Reverse quantization is the reverse of the quantization process. If you want to understand this, you need to learn the quantization process.
