Today, the term Mp3 is in the public domain. Everyone knows what it is, or at least everyone knows that it is something you hear. In fact, the MPEG-1 Layer III compression standard allows you to download the content of about ten albums onto one CD, while maintaining good sound quality. This is possible thanks to a compression algorithm that treats frequencies according to the psychoacoustic perception model, eliminating all those sounds of frequencies above 15,000 Hz, the maximum threshold that man can perceive.
It is a very poor description, but it should serve only as a theoretical starting point: Mp3 to be considered as a mode of operation that allows to fully exploit the spaces that were previously full of inaudible frequencies.
We must bear in mind, however, that there is not only this format. Sure it is the most renowned, but the choice is quite wide: Mp3 pro, Mpeg-2 AAC … The characteristics change from one case to another, but the only one that in my short experience in the field caught my attention was the Egg Vorbis. This new encoding format (already in common use under the name ogg files) launched by Xiph.org, has achieved the not inconsiderable goal of being counted as RC3, that is, the initial debugging phase has been passed and will soon be will become an official standard in the encoding of audio sources. But what does it get its name from? Ogg is nothing more than the name of the audio and video encoding and metadata format published by Xiph.org, while Vorbis is the specific name given to the encoding scheme developed to be contained in the Ogg suite. Instead, the logo derives from Norse mythology: it portrays Thor as he prepares to “compress” the serpent Jörmungandr with his trusty hammer Mjölnir. The serpent has a symbolic body in the form of a sinusoid, to represent a pure sound.
Having exhausted the most superficial descriptions, we can say that this is the technology of digital storage of audio tracks that is more directly opposed to other audio formats such as the mentioned Mp3, ect … Compared to the latter, it allows a better audio quality through lossy compression algorithms based on psychoacoustic research. More precisely, with the same quality, the file in Ogg takes up much less space, while it occupies the same space, the quality of the file encoded in Ogg is noticeably higher: a decidedly advantageous speech if we consider that always the files in Ogg can support a maximum of 256 discrete audio channels, versus two MP3 stereos. The remarkable performance of the Ogg format is certainly worthy of praise, but what I most wish to underline is its open source nature. Free understood not as free (SL can also be purchased) but as not subject to any type of patent and with the source code accessible to all. We know well what are the advantages of open source in terms of security, but in this case, we cannot help but observe that all the advantages mentioned above are the result of the collaboration created by the possibility that it offers everyone to observe and reshape the code source. : all those who felt and those who feel capable of making a contribution can do so. And this is the greatest strength of free software: it is as if, potentially, all of humanity is called to contribute to programming! Today, Ogg Vorbis is a fully open, non-confidential, patent and copyright free flat audio format; Can your contribution help us in the project to demolish the “prisons of ideas”? what are the Copirights; at the very least, it will allow us to hear much better.
As we can easily imagine, the world of Free Software is decidedly articulated and even if we want to circumscribe our discussion in the context of programs related to the “sensory” aspects? (audio, video …), surely we can consider other names besides the surely valid Ogg Vorbis.
Let’s consider, to stay on the subject of compression algorithms, the FLAC (Free Lossless Audio Codec). Beyond its open source nature, we must consider that it is a lossless code. This means that there is absolutely no data loss, as is the case with systems similar to the MP3 model, which eliminates all sounds above 20,000Hz. FLAC’s performance is comparable to Zip’s, but with two substantial differences: FLAC is specifically designed for audio, allowing for better sound performance.
