7/11/2023 0 Comments Fraunhofer mp3 encoderTherefore,Īnother criterion by which the “futility” of sound is evaluated is a condition based on a characteristic of human hearing such as the inability of most people to distinguish signals that are below a certain power level, and this level is different for different frequency ranges. Much also depends on the strength of the signal. In addition, it must be taken into account that the hearing threshold of young people is much higher than that of older people and can easily exceed this average value. People are very diverse in their physiological characteristics. Despite the fact that this threshold is recognized as an elementary value and is included in all physics textbooks, this approach is incorrect. In this case, the threshold value, so to speak from fakto, is taken as a value equal to 16 kHz. What are the criteria for evaluating the “necessity” and “uselessness” of sounds? The vast majority of codecs emit sounds that are considered outside the threshold of human hearing. The lower the bit rate, the more difficult the quantization will be. “Unnecessary” elimination processes quantification. When the bandwidth (bitrate) is reduced to 256 kbs and less, the same algorithms come into play to eliminate “unnecessary” sounds that are based on the characteristics of the perception of sound by the human ear, the so-called “psychoacoustic model”. At the same time, the quality does not suffer at all, but the size is reduced only four times, that is, the compression ratio is the same as that of a normal filing cabinet that is why MP3 files are practically not compressed by normal file cabinets. With high quality MP3, and this is ~ 320 kbs bit rate, only mathematical compression algorithms are used to encode frames. And finally, if you couldn’t download the entire MP3 file from the internet, then that’s okay, you can still listen to music, only the player will get to the point where the connection was cut off and stop. Once the first frames are loaded into RAM memory or disk cache, the player starts playing them, while simultaneously loading new frames, thus achieving playback continuity. Second, it is this structural feature that makes MP3 a truly networked format. What are the benefits of this approach? First of all, the ability to rewind, as you can easily jump to an arbitrary frame and play the sound from this point. When played back, a sequence of frames decoded and produces a continuous sound from the recorded audio. Each of these frames is encoded separately with its own parameters and has a header in which these parameters are described. This means that the audio information during encoding is divided into equal parts of length, which are called frames. I will try to stop at this point in more detail.Īs said, MP3 is a streaming format. In addition to mathematical compression algorithms, this format also contains a very complex algorithm for removing unnecessary audio information, based on the psychological and physiological characteristics of the human body. Unlike conventional filing cabinets, which need to compress information in such a way that after file extraction not a single bit is changed, MP3 has slightly different goals. This format uses an extremely complex encoding algorithm. MP3 from the inside: psychophysiology of sound
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