Rus Articles Journal

How the figure ruined a copyright? Part 2. The squeezed sound of

Not only that artful programmers borrowed from the CD audiocompanies, so they also gave them very doubtful reciprocal “gift“ in the form of the MP3 format.

Mp3 (MPEG audio layer 3) scientists from the German institute Fraunhofer invented in 1994. But the true popularity of this format began after 19 - the summer programmer Justin Frankel invented for mp3 the special losing Winamp program. Thanks to that, as Winamp, and encoders for a MP3 were free, they with instantaneous velocity extended among users of computers without any advertizing campaign by the old everyday principle “It was pleasant - share with the friend“. Uncontrollable popularity of a new format forced to be given even monopolists from Microsoft, and today the MP3 loses any standard Windows player.

The main charm of a MP3 - files, certainly, is connected with their small sizes. So, on one compact - a disk instead of 74 min. uncompressed sounding it is possible to write down more than 11 hours of a MP3 - a soundtrack. In what way there is a compression?

the Situation is so. At the coding of the initial audiofile (which is submitted on CD - Audio in the form of the high-quality and “heavy“ wav format) in a MP3 unnecessary sound elements - generally those which are not perceived by a human ear are cut. Here both excess signals of close frequency, and those sounds which follow a loud signal belong (when sensitivity of an ear for a moment is weakened). Also the fact that rather narrow range - 1 - 4 kHz (range of the human speech) is of special value for our hearing is considered. The more sound elements “is cut out“, the easier received file.

Of course, it is necessary to pay for excessive “ease“. Therefore it is necessary to pay attention to quality of a MP3 - the file. It is defined by two indicators - bitrate and frequency of sampling.

Bitrate is a so-called capacity of a sound stream. It shows how many memory size is necessary for storage of 1 second of sound information. However bitrate characterizes only the total information value of a stream. Frequency range of a sound characterizes other indicator - sampling frequency . As we already wrote above, transforming an analog signal in digital, the computer does as if measurements (“selections“) of frequency characteristics of a sound through certain temporary intervals. Than more often “selections“ become, especially the “digital“ copy will turn out exact. Here sampling frequency also shows how many becomes measurements of an analog signal in a second. In the household media equipment sampling frequency usually makes 44,1 kHz (that is 44 100 measurements a second), in studio - 48 kHz.

Of course both characteristics are important for quality of a sound. But during creation of a musical mp3 - the file over sampling frequency usually experiment a little (frequency less than 44, 1 kHz considerably affect even quality of speech soundtracks). It is necessary to vary bitrate.

For speech soundtracks quite accepted also quality of 56 - 64 kbps can be. And here as minimum acceptable bitrate for musical files it is considered to be 128 kb a second. Of course, such bitrate provides only tolerable quality, but the file weighs at the same time very little. For example, 3 minutes of a sound in the MP3 format with bitrate of 128 kbps occupy about 2,8 MB while on a usual audiodisk - about 30 MB. The most possible bitrate of a MP3 - the file - 320 kbps - as prove tests, for average hearing is almost indistinguishable from the audiofile on CD while and here it less original by 5 - 6 times. You should not forget that quality of a MP3 depends not only on bitrate, but also on quality of the initial file, and also on the encoder.

Requirements to quality of a sound depend also on music type - if simple electronic the priest - music not bad obeys also in mp3, then sounding of a symphonic orchestra forces many music lovers to think of a vinyl record wistfully. Crucial importance has also quality of the sound-reproducing equipment. The shortcomings of a MP3 not noticeable on usual computer columns, become quite notable on the class Hi equipment - Fi.

There is one more interesting and effective method of compression of a sound - so-called VBR (variable bit rate) - compression with variable “floating“ bitrate. It when each separate fragment is coded with the most suitable bitrate. For example, one fragment of the file with smaller indicators - 112 kbps, another - 128 kbps, the third - 192 kbps. The successful combination of economy and quality is as a result reached.

A MP3 - not the only format of compression of a sound, though, certainly, the most known and widespread. Here it is possible to remember also ATRAC (the compression method which is thought up by Sony for minidisks), and wma (created Microsoft as alternative of a MP3), both AAC, and ogg (giving the best quality, than a MP3 at lower bitrates), and many others.

Capacity of sound carriers and capacity of the Internet grow and if was considered as standard bitrate as 128 kbps just five years ago, then now on the Internet the indicator from 192 kbps to 320 kbps dominates.

However, already now compression formats with losses (described above) are forced out by so-called Lossless - formats (FLAC, APE, WV, etc.) which are very popular with exacting music lovers today. These formats, of course, “are not so economical“ as a MP3. They compress initial CD - the file only half, but do it without all cuttings and losses for a sound. As a matter of fact, Lossless - formats are the same archivers (as well as well-known many zip and rar), only for audio. Therefore after a decompression of such format you receive the file COMPLETELY SIMILAR to the fact that was on CD - Audio - that is, in the qualitative and “heavy“ wav format. Besides there are programs playing Lossless - formats without preliminary decompression.

Now we will return to carriers. The main carrier of the squeezed audioformats became of flash - memory . The flash - memory is a memory semiconductor where data are stored on integrated chips. Data storage is non-volatile, very modest food is required only during record and reproduction. Transfer of information is made through USB - port. Data on such carrier can be stored steadily from 20 to 100 years.

But the main advantage a flash - memories that this carrier has no moving mechanical parts and consequently is less subject to wear is not afraid of pushes, dust and electromagnetic fields at all. If to add to it absolutely the tiny sizes, then becomes clear why “flash cards“ were widely used, first of all, in dictophones, mobile phones, digital cameras and, of course, in players.

Small, but at the same time capacious, a flash - memory was the successful and ruthless competitor of other “digital“ carriers. First of all, it began to bring out of use less and less successful TEMPORARY stores - whether it be a diskette or CD - RW. And since 2003 “flash cards“ in the union with the MP3 format began to force out actively and CD - players, having won a convincing victory today.

Write that the first mp3 - the player which went on sale was made in 1998 by the Korean company SaeHan. It had memory of only 32 MB (i.e. could contain about eight tracks with bitrate of 128 kbps) and cost 250 dollars.

Now the most popular mp3 - a player is iPod. One models use a flash - memory and are capable to contain to 16 GB of music. Others have the built-in hard drive (similar to computer) and their capacity reaches 160 GB! However at the same time they are more sensitive to blows and can easily will be damaged when falling.

Only relative high cost and commitment of the audiomarket to optical disks prevented - to memory to become a flash not only temporary, but also constant keepers of information.

However “flash cards“ promptly become cheaper, their capacity constantly grows and who knows whether they will become the main “digital“ carriers of the future.