What audio formats do you need? Part 2
Hence, mankind started looking for a way to reduce file size without reducing sample rate and bit depth.
Compression with loss of sound quality
As a result of the research, it was found that human perception “skips” some sounds and their individual components, and if they are removed from the sound stream, the listener will not notice anything. Thanks to an algorithm that discards the “unnecessary”, it was possible to achieve impressive file size compression rates: 10 times and more! However, it turned out that the human brain “is not dumb” and understands that something is wrong with sound. Lossy compression gives a flatter, “cardboard” sound, lost transparency, sound details, a sense of space.
The bit rate, which is set by the creator of the sound file, plays an important role. For lossy compression, the higher the bit rate, the better the sound quality, but also the larger the file size. About 15 years ago, most music listeners were satisfied with the bit rate of MP3 files – 128-192 kbps (ten times) compression. Recently, there has been a tendency to prefer higher bit rates (256-320 kbps) or other formats (.ogg, .opus). Advanced compression algorithms use a variable bit rate: more bits are allocated for more complex musical pieces and less for lighter pieces, maintaining more or less the same quality at different moments of the sound.
Lossless compression
To avoid quality degradation, lossless audio compression methods have been developed as an alternative to lossy compression. Such compression is similar to archiving: when the data is packed into an archive, a file in zip, rar, etc. format, the size of which is smaller than the original data. It can then be unpacked and the original data will be accurately restored to the last bit. But conventional archiving methods produce very little compression of the audio data. Therefore, special algorithms for sound began to be developed, based on the idea of ​​predictability, self-similarity of sound waves. These algorithms usually compress a file 2 to 3 times. The resulting file size is larger than lossy compression, but still fully retains the original quality.
Lossless audio files (such as .flac) can be played without first unpacking – the audio player unzips the file during playback (the same is true for lossy files, however).
Unlike “lossy” formats, the bit rate isn’t that important here: it changes all the time depending on how much you’ve managed to compress a particular piece of sound, and of course it doesn’t affect the quality.
Audio file formats
To reiterate our original thesis, you only need four audio formats for all possible purposes. Consider them!
mp3
The most popular audio format with the worst sound quality. Lossy compression format.
As a step?
mp3 is historically the first audio compression format. It appeared and spread in those distant times, when the memory of computers was scarce and the Internet was accessed by telephone calls. Digital sound as such was still a novelty and existed alongside analog cassettes. The alternative to mp3 was just uncompressed sound (wav …), which takes up large amounts of data. Users were inspired by the very ability to burn all of their favorite artist’s albums to CD-ROM or send a song via email. At the time, undemanding consumers paid no heed to the voices of skeptics. So mp3 soon became the most widely used audio storage format.
[“I don’t hear the difference between mp3 and non-mp3 quality.” ]
.mp3
Advantage:
– Support for the maximum number of programs and devices
– Small file size
Disadvantages:
– Poor sound quality
– Limited technical capabilities
What to use for:
to listen to “drafts”, for preliminary screenings, “fast” delivery of demos over the Internet, rehearsals, official purposes, for voice recording
flac
flac is a lossless audio compression format, the most popular among its “siblings”. Compresses the file size, depending on the complexity of the audio information, between 1.4 and 4 times (the bit rate varies from 350 to 1010 kbps). Its prevalence was facilitated by open source code, which made it possible to create a large number of programs that work with it on all operating systems. Flac spread it so widely that even “brontosaurs” like Apple and Microsoft resigned themselves to its existence.
