MP3 file format

MP3 file format

Mp3 file format
Mp3 file format

Introduction:
MP3 file format

Mp3 file format
Mp3 file format

1. Overview:
MP3 files are made up of frames, and frames are the smallest unit of MP3 files. The full name of MP3 must be MPEG1 Layer 3 audio files. MPEG
(Motion Picture Experts Group) translates into Chinese as Moving Picture Experts Group, and refers specifically to moving video and audio compression standards.
MPEG1 standard, also known as MPEG audio layer, which is divided into three layers based on compression quality and encoding complexity, namely,
Layer-1, Layer2 and Layer3, which correspond to the three sound files of MP1, MP2 and MP3 respectively, and use different
levels of audio files according to different purposes. The higher the MPEG audio encoding level, the more complex the encoder and the higher the compression ratio. The compression ratios of MP1 and MP2 are 4:1 and
6:1-8:1 respectively, while the compression ratio of MP3 is as high as 10:1-8:1. 12:1, meaning one minute of CD-quality music requires 10MB
of storage space without compression, but only about 1 MB after MP3 compression encoding. However, MP3 uses a lossy compression method for audio signals. To reduce
sound distortion, MP3 adopts “sensory coding technology”, that is, it first analyzes the frequency spectrum of audio files during encoding, and then uses filters to filter the
noise . levels. Then the remaining bits are spread and arranged by means of quantization, and finally an MP3 file with a higher compression ratio is formed, and the
compressed file can achieve a sound effect closer to the original sound source during playback.
2. The whole structure of
MP3 files: MP3 files are roughly divided into three parts: TAG_V2 (ID3V2), Frame, TAG_V1 (ID3V1)
ID3V2 contains information like author, composer, album, etc. The length is not fixed, which expands the information volume of ID3V1.
A series of frames, the number is determined by the size of the file and the length of the frame. The length of each frame of the
frame
may not be fixed or fixed, and is determined by the bitrate
.
Each table is divided into two parts: table header and data entity Header of data.
frame
Record the bit rate, sample rate, version and other information of mp3, and each frame is independent of each other The frame
ID3V1 contains information like author, composer, album, etc., and the length is 128BYTE . 3. MP3 FRAME format: each FRAME has a FRAMEHEADER frame header, the length is 4BYTE (32 bits), there may be two CRC check bytes after the frame header, the existence of these two bytes depends on the FRAMEHEADER information If bit 16 is 0, there is no checksum after the frame header, and if it is 1, there is a checksum. The checksum length is 2 bytes, followed by the FRAMEHEADER, followed by the frame entity data. The format is as follows: FRAMEHEADER CRC (free) MAIN_DATA 4 BYTE 0 OR 2 BYTE The length is calculated from frame header 1. The format of the FRAMEHEADER frame header is as follows: AAAAAAAA AAABCCD EEEEFFGH IIJJKLMM

Advantages and disadvantages of MP3 technology.

In the internet age, MP3 has become a de facto standard for digital audio files. Napster’s popular peer-to-peer application allowed music lovers to exchange MP3 files so they could get songs without paying for it. This article is written to guarantee the pros and cons of MP3, to help you decide whether to convert your existing music files to MP3 in a different format or not.

mp3 advantages

Advantages of MP3

The advantage of MP3 is the high quality. The quality of an MP3 file is determined by the bit rate. Flow is measured in kilobits per second. The bit rate of an MP3 file can range from 8 kbps to 320 kbps. You should keep your songs at 160 kbps if you don’t really like them and don’t put them at the top of your list of mp3 players. Keep your songs at 192 kbps if you like them a bit. Use 256 kbps for the songs you like. And use 320 kbps for your all-time favorite songs. Regardless, even an 320kbps MP3 doesn’t sound as good as the song’s WAV file version. But a 320kbps MP3 takes up four times less space than a WAV file. To use an analogy, an MP3 file is a WAV file, which is a JPEG image of a BMP image.

Problems

The second advantage is that it can be played on many types of devices, such as CD players and Apple iPods. You can also play MP3 files with multimedia players such as Winamp, Windows Media Player or QuickTime. The third advantage of MP3 is ID3 tags. The ID3 tag of an MP3 file stores the artist name, song title, year, and genre. You can also create your own playlists.

Another advantage of MP3 is that encoding is simple. It is easy to rip audio CDs and burn as easily as regular MP3 CD-Rs. The encoding speed is also very fast, but it also depends on the speed of the CD player. Producing MP3 files takes very little time. You can use lossless audio compression if you have a lot of free disk space and lossy audio compression if you have little free disk space. The MP3 LAME encoders are free and open source, so that everyone can contribute to their development.

Another plus of MP3 is that the layout is simple. MP3 can be downloaded from HTTP or FTP sites. You can also distribute MP3 files through portable storage devices such as USB flash drives. You can also buy MP3s from online music stores such as iTunes and eMusic.

You can also use a server to distribute these files. Listening to it in MP3 uses an M3U playlist format such as (which means MP3 URL) or PLS. MP3 streaming is also used by internet radio stations. You can integrate MP3 streams with a Flash player. You may have different rates for dial-up and broadband connections. MP3 audio is not stored on your hard drive.

MP3 problems

A disadvantage of MP3 is that it takes up a lot of storage space. Since an MP3 file generally takes up to 5 megabytes (MB) of disk space, the number of files it can store is limited. Due to the relatively large size of an MP3 file, the slow file can also be downloaded if you have a slow internet connection.

Another problem is that the song can jump to random places. This happens especially if you have a slow computer and use multiple programs that load the processor at the same time. It is technically not free. You also need an MP3 decoder if you want to convert MP3 audio files to WAV format. The MP3 format has very little security available. For example, people who used the Morpheus file sharing service had their computers accessible to hackers.

Another limitation is that this file is not the best fidelity format for audio files. Other audio formats, such as Ogg Vorbis and Advanced Audio Coding (AAC), are superior in quality to MP3. AAC is the format used in the Apple iTunes player. However, MP3 is still the most popular audio format in the world.

The pros and cons of MP3, which I just mentioned will help you make a good decision before downloading music next time.