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When did mp3 music files first appear?

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When did mp3 music files first appear?

MPEG-1 Audio Layer 3, often referred to as MP3, is one of the most popular lossy compression and digital audio encoding formats today.

There is no noticeable drop in sound quality compared to the original uncompressed audio. It was invented and standardized in 1991 by a group of engineers at the Fraunhofer-Gesellschaft research organization in Erlangen, Germany.
MPEG-1 Audio Layer 3, often referred to as MP3, is one of the most popular lossy compression and digital audio encoding formats today. There is no noticeable drop in sound quality compared to the original uncompressed audio. It was invented and standardized in 1991 by a group of engineers at the Fraunhofer-Gesellschaft research organization in Erlangen, Germany.

The audio format supported by the MP3 player is not only MP3 format, but also WMA, WAV, MP3Pro, ASF, AAC and VQF, etc. The WMA format can reach CD quality when compressed to 64 kbps, and output is only half the size of the corresponding MP3 file. This is very important for models with only 32 MB of flash memory. WMA and RA formats are supported, which means FlashMemory space is almost doubled. If it’s hard, be sure to ask this question when purchasing.
Among all the music formats supported by MP3, the most common ones are MP3, WMA and WAV. Others are unpopular or too bulky to be practical.

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MP3 File Structure Analysis Part 2

Sounds in nature are very complex and waveforms are extremely complex.

Usually we use pulse code modulation coding, that is, PCM coding. PCM converts continuously changing analog signals into digital codes through three steps of sampling, quantizing, and encoding.

u Decode:

Reverse encoding process

1.1.2 Brief introduction of MP3
The full name of MP3 is MPEG Audio Layer 3. It is an efficient computer audio coding scheme. It converts audio files into smaller files with a .mp3 extension with a higher compression ratio, essentially maintaining the sound quality of the source file. MP3 is part of the ISO/MPEG standard,

The ISO/MPEG standard describes audio compression using a high performance perceptual coding scheme. This standard has been continuously updated to meet the pursuit of “high quality and low quality”. Three audio codec schemes, MPEG Layer1, Layer2 and Layer3, have been formed, respectively, corresponding to the three sound files MP1, MP2 and MP3

MPEG (Moving Picture Experts Group) is a group of moving picture experts under ISO. The MPEG standard it specifies is widely used in various multimedia. The MPEG standard includes video and audio standards. Audio standards have developed MPEG-1, MPEG -2, MPEG-2 ACC, MPEG-4. The MPEG-1 and MPEG-2 standards use the same family of Layer1, 2, 3 audio codecs, and most MP3s use the MPEG1 standard.

MP3 audio compression consists of two parts: encoding and decoding. Encoding is the process of converting the original signal to a level signal, and decoding is the reverse process. MP3 uses the PerceptualAudio Coding distortion algorithm. The frequency range of sound perceived by the human ear is 20 Hz to 20 kHz. MP3 cuts out a lot of redundant signals and irrelevant signals. The encoder transforms the original sound into the frequency domain through a mixed filter bank and uses a psychoacoustic model. to estimate that it may be only The perceived noise level is quantized and converted to Huffman coding to form an MP3 bit stream. The decoder is much simpler, its task is to extract the sound signal from the encoded spectral line components through inverse quantization and inverse transformation.

MP3 file data consists of multiple frames, and a frame is the smallest unit of an MP3 file. Each frame, in turn, consists of a frame header, additional information, and sound data. The playback time of each frame is 0.026 seconds and its duration varies with the bit rate. Some MP3 files have extra bytes at the end that contain description information for non-audio data.

MP3 file structure analysis

ü ID3:

Usually located in several bytes at the beginning or end of an mp3 file, it records the singer, title, album name, era, style, and other mp3 file information.

ID3 is divided into two versions, the V1 ID3 version is fixed at the end of the 128-word file section, it begins with the TAG character, if there is no ID3V1 information, it is considered that there is no ID3V1 information, the V2 ID3 version is found. at the beginning of mp3 and the length is variable.

ü Sampling rate:

The number of samples extracted from a continuous signal to form a discrete signal per second. It is expressed in Hertz (Hz). Sampling rate refers to the sampling frequency when converting an analog signal to a digital signal, i.e. how many points are sampled per unit of time. The higher the sample rate, the more realistic and natural the sound will be. On today’s major capture cards, the sample rate is generally divided into three levels: 22.05 KHz, 44.1 KHz, and 48 KHz. 22.05 KHz can only achieve the sound quality of FM radio, and 44.1 KHz is the theoretical limit of CD sound quality, and 48 KHz is more accurate.

ü Bit rate:

Bit rate refers to the number of bits (bits) transmitted per second. The unit is bps (bit per second). The higher the bit rate, the more information transmitted. In the audio and video fields, bit rate often translates to bit rate. The bit rate indicates how many bits per second the encoded (compressed) audio and video data should represent, and a bit is the smallest unit in binary. 0 or 1. The relationship between bitrate and audio and video compression is simply that the higher the bitrate, the better the quality of the audio and video, but the larger the encoded file; if the bitrate is lower, the situation is just the opposite.

Bit rate = sample rate * number of samples * number of channels

ü Bitrate/Stream/Bitrate:

It refers to the data stream used by audio and video files in a unit of time. The popular understanding is the sample rate, which is the most important part of quality control in audio and video encoding. Generally, the units we use are Kb/s and Mb/s. . Generally speaking, the higher the code stream, the lower the compression ratio and the higher the quality. The higher the code stream, the higher the sampling rate per unit time, the higher the data stream, the higher the accuracy, and the closer the processed file is to the original file.

ü Code:

From the point of view of information theory, the data that describes the source of information is the sum of the redundancy of information and data, namely: data = information + data redundancy. The audio signal has correlation in the time domain and the frequency domain, that is, there is data redundancy. Taking audio as the source, the essence of audio encoding is to reduce redundancy in the audio.

MP3 digital audio format

MP3 digital audio format

MP3 File Format

High-quality digitized audio requires a large amount of disk space.

mp3 file

Attempts to reduce the size of files using standard archivers (RAR, GZIP, etc.) do not generate significant gains due to the specificity of the sound data. However, it is possible to achieve a fairly significant level of compression of the audio information using special methods based on the analysis of the data structure and subsequent compression with some loss.

The real possibility of sound processing comparable in quality to existing analog examples did not appear until the late 1980s.

In 1988, the International Organization for Standardization (ISO) formed the MPEG (Moving Picture Experts Group) committee, whose main task is to develop standards for the encoding of moving pictures, sound and their combination. During the ten years of its existence, the committee has developed a series of norms on this subject. As a result, summarizing the extensive research in this area, several specific formats were recommended for storing data, which are excellent in quality of results and data flow.

There are currently three video storage standards: MPEG-1, MPEG-2, and MPEG-4.

Within the first two formats, there are also formats for storing audio information: Layer-1, Layer-2 and Layer-3. These three audio formats are defined for MPEG-1 and minor extensions are used in MPEG-2. The three formats are similar to each other, but use different levels of trade-off between compression and complexity.

Layer-1 is the simplest, it does not require significant compression costs, but it also provides a negligible compression ratio.

Layer-3 is the most time consuming and provides the best compression. Recently, this format has gained immense popularity. It is often called MP3. This name is associated with the extension of the audio files stored in this format.

The underlying idea behind all lossy audio compression techniques is to neglect the subtle details of the original sound that are beyond the reach of the human ear. Here several points can be highlighted.

Noise level . Sound compression is based on a simple fact: if a person is near a loud siren, they are unlikely to hear the conversation of the people who are nearby. And this happens not because a person pays close attention to a loud sound, but to a greater extent because the human ear actually misses out sounds that are in the same frequency range as a louder sound. This effect is called masking, it changes with the difference in volume and frequency of the sound.

The second point is the division of the audio frequency band into subbands, each of which is further processed separately. The encoding program extracts the loudest sounds in each band and uses this information to determine an acceptable noise level for that band. The best encoding programs also take into account the influence of adjacent bands. A very loud sound in one band can affect the masking effect and nearby bands.

Another point of the codification is the use of a psychoacoustic model based on the peculiarities of the human perception of sound. The compression used by this model is based on removing frequencies known to be inaudible, while more carefully preserving sounds that can be easily heard by the human ear. Unfortunately, there can be no exact mathematical formulas here.

The human perception of sound is a complex process, not fully understood, so the choice of compression methods is based on analyzing listening and comparing compressed sounds differently by teams of experts. But here there are practically limitless possibilities in the field of improving psychoacoustic models. Most of the existing algorithms to encode the human voice are based on the high predictability of said signal; Universal MPEG compression algorithms have tried to apply this technique with variable success.

Another compression technique is the use of so-called joint stereo. It is known that the human hearing aid can only determine the direction of the mid frequencies, the high and low sound, so to speak, separately from the source. This means that these background frequencies can be encoded into a mono signal. In addition to all this, compression uses the difference in the complexity of the flows in the channels.

Why mp3 is enough for you, but Lossless is not necessary

Why mp3 is enough for you, but Lossless is not necessary

mp3

Why mp3 is enough for you, but Lossless is not necessary
Did you finish the greenhouse? So you don’t need to lose, listen to high quality mp3.

Very often there are people who, in principle, despise compressed formats. You should not be guided by your opinion. The following mods that in the studio with a 90% probability will not hear the differences between compressed and uncompressed audio.

MP3 wasn’t invented just to reduce quality. It was developed by the Fraunchhofer Society, an association of applied research institutes in Germany. Later they came up with AAC, which could become the main compressed audio format … But it didn’t work.

Did you know that MP3 comes with variable (VBR) and constant (CBR) bit rate? The constant bit rate, due to the operation of the algorithm, is encoded each time as the first. Therefore, it can produce uneven quality, which means that not all sounds in this situation will be recorded in high quality.

Since MP3 has been around for a long time, it has many limitations. Bit width is 16-24 bits. The sample rate is represented by the following set of options: 8; 11,025; 12; sixteen; 22.05; 24; 32; 44.1; 48. The maximum bit rate does not exceed 320 kbps. The maximum number of channels is 2. But we are still talking about music, we still have to search for multi-channel recordings.

Now let’s see how MP3 is encoded. The illustration shows the time-frequency distribution of sound. Same recording: Audio CD, OGG file, MP3 well encoded. What we observe is that the pieces on the right and left almost completely coincide. This means that the MP3 file sounds almost the same as the original CD recording.

Human hearing and its limits – psychoacoustics

The fact is that the main task of the Fraunchhofer Society is the development of psychoacoustic models of human perception of sound. And here are many subtleties. The main thing is that we are not dolphins.

Second, there are certain restrictions on the number of sounds perceived simultaneously. A person cannot simultaneously hear more than 250 sounds of 24 ranges (in addition, the number of simultaneous sounds in the range is also quite small).

Third, the audible range is 16 Hz to 20 kHz and at the age of 60 it is reduced by almost half. Ideally, and during training (yes, you have to train it!).

All frequencies below 100 Hz are perceived not by the hearing cells, but … by the skin. Then the low waves are reflected in the ear canal; these waves are perceived as infrabass. (This is from the bone conduction area).
mp3_7_resize
Also, the number of cells that register acoustic waves is different for each one. But what is there? For each individual, their number in the right and left ear is different.

By the way, the perception of each ear is different. Change channels of your favorite song – get a new sound.

If you dig deeper, it turns out that each sound frequency is perceived only at a certain volume. When it is reached, the silence is replaced by a sharp and quite different sound. After that, a person can hear a lower sound of this frequency.

Digital audio formats: the MP3 phenomenon

Digital audio formats: the MP3 phenomenon

MP3 format

The MP3 music format (MPEG-1 Layer 3) is one of the most widely used digital audio formats in the world.

MP3 format MP3 format : An Overview

It is compatible with all portable and stationary audio devices. In May 2017, the developers of the format announced his “death”. On April 23, 2017, the Technicolor and Fraunhofer IIS licensed commercial program was canceled: the last patent included in the program expired, making the format standard in the public domain.
Can we say that the days of the most popular format are numbered? MP3 development began in the late 1980s at the Fraunhofer Institute for Integrated Circuits (IIS). In 1987, the University of Erlangen-Nuremberg and Fraunhofer IIS teamed up to work on the EU147 EUREKA Digital Audio Broadcasting (DAB) project. The first result of the alliance’s work was the LC-ATC codec, which made it possible to encode stereo music in real time.

The next step was the development of an optimal frequency domain (OCF) coding algorithm, which already had some of the characteristics of the future MP3 codec. For the first time, it is possible to encode music in good quality at 64 kbps for a mono signal. OCF was the beginning of the path towards standardization MPEG (Moving Picture Expert): an organization, responsible for the development and implementation of international standards for the compression and transmission of digital video and audio content.

In 1989, MPEG received 14 proposals for the implementation of an audio coding standard, so participants were invited to combine their developments. This led to the emergence of four potential candidates, including MUSICAM from the Institute for Broadcasting Technology IRT and Philips and ASPEC (Adaptive Spectral Perceptual Entropy Coding), which is the result of further enhancements to the OCF Fraunhofer IIS in addition to contributions from the University of Hannover in collaboration with AT&T and Thomson.

After extensive testing, MPEG proposed combining MUSICAM and ASPEC to create a family of three encoding methods: Level 1: a low-complexity version of MUSICAM; level 2 – MUSICAM codec; Level 3 (later called MP3): based on ASPEC. Technical development of the MPEG-1 standard was completed in December 1991. In 1994, Fraunhofer IIS introduced the world’s first MP3 encoder, the L3enc, and in 1995 the Fraunhofer researchers unanimously accepted “.mp3” as the file extension for MPEG Layer 3 [1].

Thanks to the compression algorithm used in the MP3 audio format, the size of the data required to reproduce the recording and ensure the quality of sound reproduction is significantly reduced to 10-12 times the original, depending on the recording bit rate. . Bit rate refers to the encoding / decoding rate of a digital audio stream; sound quality improves with increasing bit rate. The MP3 format has the following bit rates: 32 kbps (very low quality, acceptable only for voice), 96 kbps, 128 kbps (medium quality), 160 kbps, 192 kbps, 256 kbps, 320 kbps (maximum optimal quality). The principle of the compression algorithm is as follows: during the compression process, the audio codecs analyze the signals, focusing on the audible fragments, which are saved for later playback or transmission.

This rules out sounds beyond the perception range of the human ear (20 to 20,000 Hz). That is why MP3 is called lossy. There are three ways to encode MP3 files: constant bit rate (CBR), variable bit rate (VBR), and medium bit rate (ABR). CBR is the default encryption mode. In this mode, the bit rate is constant for the entire file. This means that each part of the MP3 file uses the same number of bits. Regardless of the complexity of a piece of music, the encoder uses the same bit rate, so the quality of the final file is variable.

Complex parts will be of lower quality than simpler ones. The main advantage of this mode is that the size of the final files does not change and can be accurately predicted. When encoding in VBR mode, the user selects the desired quality on a scale of 9 (lowest quality, highest distortion) to 0 (highest quality / lowest distortion). The codec then tries to maintain a certain quality throughout the file by choosing the optimal number of bits for each part of the audio recording. The main advantage is the ability to specify the level of quality to be achieved, but the significant disadvantage is the unpredictability of the final file size.

What format is suitable for my music?

Today, most of the music is listened to digitally. Or listen to your favorite songs directly through various streaming services or the files are dragged to your own mobile phone or laptop. In the second case in particular, it often happens that different music formats are used, each with its own advantages and disadvantages.

Music format

Because all music and sounds can be saved on devices in many different formats. Strictly speaking, these are audio formats that offer different sound quality and take up different amounts of storage space. Therefore, you will find below which audio format should be used and when.

Music File Formats

MP3 is well known

Anyone who has anything to do with digital music will be familiar with the MP3 format. Even the MP-3 player bears the name of this format in its day. Not surprisingly, MP3 is the most popular music format in the world. It is a lossy format that removes sounds that are inaudible to humans, so to speak, to reduce the size of the rest of the file. This means that, as a mere mortal, you won’t hear any difference in quality, but the file has gotten up to 90 percent smaller.

WAV is a proprietary Windows format

WAV is a Windows container format that saves music uncompressed. On the contrary, this means that a lot of storage space is required to save all the songs, radio plays, etc. on your devices. Therefore, this format is not recommended for large music collections.

But you can use a special program to convert your WAV files to MP3 in a few minutes and thus save and play them on all your devices without any problem. The software is free and can be used without any prior knowledge; check here.

ALAC is Apple’s music format

This format can also be saved as “.m4a” or “.m4p” and is the predominant music format in the iTunes Store. With the ALAC format, compression is lossless, ensuring that the final file has very high audio quality, but it also requires a relatively large amount of storage space. Also, files that end in “.m4p” have some copy protection measures, which is why this format is often used for commercial purposes.

Free formats like FLAC or Ogg-Vorbis

Ogg-Vorbis is an alternative audio format, which is a combination of current “Vorbis” music compression technology and the “.ogg” container. The advantage of this format is, among other things, that less storage space is used than with MP3 files and, at the same time, the quality is usually even better. However, the big problem is that the format is very little known and therefore only a few devices can reproduce this format.

With FLAC, the advantage is elsewhere. No major corporation has the threads in the background here. Therefore, there is no copy protection for any files. Furthermore, the format offers similar quality and also takes up little storage space. But even with this format, compatibility issues with many devices can quickly arise.

MP3 offers the best overall picture

It should be clear that MP3 has been the best audio format to use for years and still is today. Especially in private use, the advantages are enormous and no other format can match it. To do this, an overview again of the most important aspects of the MP3 format:

High quality
Low consumption of storage space.
Compatible with virtually any device
High level of consciousness

What is an MP3 file?

We start with one of the most common files in the world of computing, that is, the one with the name MP3.

MP3 files have been around for years and that is why their development is so widespread.

But what does an MP3 file represent in practice?

Well, an audio file in general is a sequence of numbers obtained by sampling the analog signal.

MP3

This sampling then responds to some parameters that are the frequency, measured in Khz and the resolution that is instead expressed in Bit.

The MP3 file is the most compressed form of an audio file, so to speak.

At the end of the day, you have to understand that the MP3 file manages to eliminate all the superfluous parts of the digital file of the sequence and the final sampling, exploiting some imperfections of the human body to be able to give you a clear and clean melody.

However, on the other hand, the MP3 file considerably reduces the quality of the reproduced sounds.

In fact, all the different nuances of a given melody boil down to the bone.

An MP3 is small in size from the point of view of memory, it must be seen as a kind of concentrate that gives you an appreciable final result but not one hundred percent complete.

In the most extreme cases, an MP3 file can reduce the original sounds and nuances of the music or melody by up to 90%.

However, these formats are highly appreciated and used because in addition to being practical and straightforward, they are now compatible with any technological device.

This means that you can always carry them with you and any product you have will be able to read an MP3 file.

Mp3 format

MP3 (in full version Moving Picture Expert Group-1/2 Audio Layer 3) is a lossy audio compression algorithm, developed by the MPEG group, capable of drastically reducing the amount of data needed to store a sound, while still be a reproduction. acceptably faithful to the original uncompressed file.

Mp3 Format

Data compression is carried out by eliminating all those sounds that are not perceived by the human auditory system. In fact, recordings in wav format contain much more information than our ear is capable of distinguishing: by removing too much information, it is possible to obtain size reductions of more than 10 times (compared to uncompressed wav format).

In practice, the mp3 format exploits the limits of our auditory system, limits that depend so much on the structure of our ear (not capable of perceiving frequencies above 20 kHz, but particularly sensitive to the intermediate range that goes from 700 Hz to around 6000 Hz) and the ways our brain perceives and interprets sounds. These perceptual limits are studied by psychoacoustics, a sector of psychology that deals with the perception of sounds.

A particularly important and exploited effect in mp3 compression is masking (masking), in which the perception (or less) of a sound is influenced by the presence of another sound. For example, conversation at a bus stop can become completely impossible if a noisy bus approaches: a weaker sound is “masked”, that is, made inaudible by the presence of a louder sound. Masking is all the more effective the closer the two sounds are to frequencies, since our auditory system is unable to discriminate sounds with very close frequencies.

As we have mentioned, mp3 compression is lossy type, that is, it causes irrecoverable data loss and consequently quality degradation. Mp3 encoding allows you to choose how much compression the compression should have, keeping in mind that higher compressions will always correspond to lower sound quality. The quality of mp3 compression is adjusted by a parameter called bitrate that specifies how many kbits the mp3 file should use for each second of recorded audio. There is also the possibility to vary the bit rate within a single mp3 file, using higher bit rates for some parts and lower bit rates for others (for example you can use a lower bit rate for the silent parts or that contain few instruments and use a higher bit rate for more complex parts).

The usable bit rate values are many (from 8 to 320 kbit / s) but 128 kbit / s is considered a good compromise between compression and quality. Knowing the bit rate, it is easy to calculate the size of an mp3 file, since it is enough to multiply this value by the duration of the recording.

MP3: analysis of an MP3

Different formats are used on the internet to let you listen to music. We will choose the MP3 format here.

On this page you will find all the help you need to listen to music on the internet and understand how it works. We answer the questions: What is MP3? Do radios use MP3? Why the MP3? Are record companies afraid of MP3? Mp3 is legal? How to listen and find an MP3? What is the future of MP3? Is the future of free MP3 in danger?

mp3 format

What is MP3?

MP3 (Mpeg-1 Audio Layer 3) is a destructive or compressed file format for data loss. A song deletes all data that may not be heard by the human ear. It is defined by ISO / IEC standards IS 11172-3 and IS 13818-3 and is recommended by the MPEG (Moving Pictures Experts Group).

mp3

The advantage of this format is that it can achieve a high compression rate in the sound file (for example, wav extension) without affecting the sound quality. The difference between the original sound of a compact disc and the compressed one in MP3 is inaudible. The compression speed is 1/12 (or even more than once, but in this case the quality is palpable), the files thus obtained have a really reasonable size:

Do radios use MP3?

This format is similar to the MiniDisc concept, but unlike DAT, MP3 works by deleting data. It is good to know that almost all radios currently use this format. All tubes are stored on a server and programming of the songs to be broadcast is done by computer. When the time comes, the computer searches for sound files with the extension .MP3 on the server and a decompression card automatically converts them into classic CD-quality sound files that are broadcast over the air. Now we can say goodbye to the old days when we were looking for vinyl records in the archives. It is a revolution in the world of radio!

Why the MP3?

Thanks to Mp3 it is now possible to store more than a hundred songs or more than a dozen albums on one blank recordable CD. Not long ago, it was not possible to play MP3 files only on computers, because playback requires real-time decompression that is not compatible with current audio CD playback devices. But given the possibilities this new format offers, Mp3 is on the rise with the public and manufacturers of computers and hi-fi equipment. Diamond Multimedia, famous for its graphics cards, designed the first MP3 player called “Rio”, which is barely bigger than a calling card !!! It allows you to store about 60 minutes of CD quality MP3 in the mass memory and about 9 hours of music if you choose the lowest quality. But many other models come out today with increasing capacity and lower costs … A DVD player in the living room is now also available and suitable for MP3 playback. The advantage is that you can create your own music compilation (MP3s are downloaded from the computer to the portable player through the serial port. Therefore, the songs can come from different sources (such as audio CDs or the Internet).

Are record companies afraid of MP3?

The arrival of Mp3 on the international market is likely to scare record companies, who think their profession will deteriorate and will probably disappear! We know that the copies were already possible with the cassette, the mini-disc and the CD … But it is true that the web is becoming a real database of illegal MP3s. Most artists believe that MP3 is a new way to publicize their works, especially since they can reach a wider audience via the Internet. The solution would be to pay Mp3 on the world network, according to record companies. We still don’t know when, but it is planned. Obviously, this format is not designed to be copy-protected. Many safe formats of comparable quality to MP3, such as “Liquid Audio”, are already offered, but less known, their future may not be very promising. The MP3 format raises the copyright problem as it can be downloaded for free on the internet, so there is some panic on the part of the music industry.