Digital music recording Part 4
Let’s take a look at the main audio file formats.
Mp3 appeared in 1992. With its high compression ratio and acceptable sound quality, it has become extremely popular and has become the de facto standard for storing music files. It is in this format that music files are recorded on portable players, so popular with young people. However, since the summer of 2002, mp3 has become a payment for programmers: for the right to include support for the format in their program, a license fee of 75 cents was established for each copy. To get a new and more advanced version of mp3 Pro, one had to pay $ 1.25 for each program. Naturally, the developers and users of the programs were extremely unhappy with this idea. In particular, mp3 support was not possible on open source operating systems like all Linux clones. Feeling they had had enough, the patent owners – the Fraunhofer Institute and Thomson Multimedia – were quick to declare that they were “misunderstood”, but, as in the old joke, “although spoons were found, the residue still remained.”
The unsuccessful and inflexible policy of patent holders has led to a sharp rise in the computing world of interest in other audio encoding formats, the first of which, of course, is WMA (Windows Media Audio) , created by Microsoft. It is based on the successful Voxware Audio Codec 4 technology, originally designed for speech encoding: Voxware 4 files retained 90 percent intelligibility at 64 Kbps, twice that of the competition.
The modified Voxware codec has become the WMA brand and now allows you to record music at 64 Kbps, similar in quality to mp3 at 128 Kbps. This means that for the same sound quality, a WMA file occupies half the size of a mp3 file. Experts believe that music recorded in WMA sounds “cleaner and more alive” than in mp3.
The most interesting and serious opponent of mp3 and WMA is the OGG (Ogg Vorbis Audio) format. The project started in 1993 under the name “Squish”. In English, this word has many meanings: jam, nonsense, and whining. It’s hard to say exactly what the authors had in mind, but some candy company said Squish was their trademark. I had to urgently change the name. No doubt, to avoid coincidences, he was chosen for being picky: the word “Vorbis” was taken from Terry Pratchett’s science fiction novel, and “Ogg” is a slang word for computer gamers, meaning “there is power. , does not matter!” ”
OGG is a free and open format. Its codec supports sample rates up to 48 kHz, bit rates up to 512 Kbps, up to 255 channels, allows text and graphic information to be stored in a file along with a composition, and sound is encoded at a variable rate. Since the stereo channels are encoded together, and not separately, the music that sounds on both channels is recorded not twice, but once, which makes the file very compact, its compression is 20-50% better than the mp3 and subjective sound quality is higher … The problem with Ogg Vorbis is that the whales of the computer business do not need a strong competitor and do not include its support in popular operating systems.
AAS. The full name is MPEG-2 AAC (Advanced Audio Coding). Developed by the Fraunhofer Institute and various commercial firms. It is based on the same mp3. The AAC was originally designed to support sample rates up to 96 kHz, and the maximum number of channels was increased from 2 to 48, taking into account future multi-channel formats such as today’s Dolby Digital. Due to the use of more complex algorithms, its encoders are significantly slower than in the case of mp3s, and the players also require more processor power. The best choices for 96Kbps AAC encoders deliver quality no worse, and sometimes even better, than 128Kbps mp3.
The AAC format allows the use of steganography techniques to embed so-called watermarks in the recorded sequence: author / artist names, copyright information, etc. Subsequently, the co-authors of the format independently created several versions of it, the most famous of which is Liquid Audio.
Until recently, Liquid Audio was considered the best in terms of playback quality and could claim to be the successor to mp3, but the creator of the format, Liquid Audio Company, followed an unsuccessful policy in its implementation.
VQF is a method and format developed by the Japanese company NTT and promoted mainly by the Japanese company Yamaha under the name SoundVQ.
