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AUDIO FILES

ENGLISH VERSION THANKS TO GOOGLE TRANSLATE, ORIGINALLY MADE IN ITALIAN (must be optimized)

The times when we had accounts with various tape formats are now completely disappeared.
Today the life of a sound engineer or artist is, is entrusted entirely to the files.
Files in English means archive file and, as you can imagine, sources prior to digital, paper for the most part.
The computers that we use today instead of machinery, dealing only to create, store, manage and process files.

Similarly to the real world, analog, the virtual world, namely the parallel digital universe is subject to its rules that allow him to exist.
To better understand the digital environment should be somewhat ‘more aware of our; few of us, although sapendolo, you realize that a library, the mobile takes our books, can play its role because there is a force in Nature (called Gravity) without which not only books but even the furniture itself, floating in midair, ergo: without the force of gravity, the library does not work.
Still in metaphor we must bear in mind that books are also made of sheets obtained from the trees and they exist thanks to light, the food, rain, air, etc. And so on.
Similarly, the digital universe requires rules pseudo-natural to work.
The biosphere is the operating system and the ecosystem from Digital Audio Workstation …

PCM AUDIO FILE NOT COMPRESSED

Technical parameters:

FREQUENCY OF SAMPLING

The sampling frequency, expressed in Hz, although it may be that in some audio editor operated freely in cuts usually uses standard: 44.1, 48, 88.2, 96 or 192 kHz. The choice of which format to adopt is dictated by the technical characteristics of the sound card and quality requirements, the more high frequency and better quality (frequency response wider and less aliasing effect). The CD using 44.1kHz. Each time the sampling rate doubles, will also doubled the space occupied by the audio file.

RESOLUTION

The resolution is expressed in bits: the standards used are 16 and 24. Generally prefers to work a 24-bit because the resolution increases considerably: from 65,536 step, 16-bit to even 16,777,216, 24 bits. It should be noted that for the same period a 24-bit file will be 50% larger than a 16-bit file.

Chunk

To speak of this additional parameter we need to make a comparison: if our audio files (but applies to all other file types) were a book, this parameter would be represented from that, necessarily, must list the content pages. It ‘clear that more pages will have the index may have more chapters to the book.
Let’s go back to digital: This index is the Chunk. The Chunk is an area of the file (usually the head) that contains information on file, (there are also chunks of text where the parameters are written as the author’s name or the location of the original file on line timecode, etc.).. All audio files take a chunk to 32 digits (bits) which limits the length but a 4GB, usually more than enough, but in special cases this dimension could be limiting and that is the Sonic Foundry has developed the Wave64 format, which uses a chunk of 64 digits (bits), with the clear purpose do the maximum size limit.

LITTLE-BIG ENDIAN E-ENDIAN

Apple’s processors use a system to sort the Byte-called BIG ENDIAN, while IBM-compatible processors, Windows, using a system called little-endian. We enter a po ‘more on technical.
And ‘know that 8 bits are a Byte, a 16-bit file is then formed by Byte 2, the first Byte is said Least Significant Byte (LSB) and the second Most Significant Byte (MSB); processors working following order belong to little-endian system, those who prefer the MSB all’LSB instead belong to big-endian.
In practical terms if I had scanned the figure “16” with the system I ENDIAN LITTLE-this sequence of bits: “00000000-00010000” while with the system I ENDIAN BIG-this other: “00010000-00000000”. If at this point share the files on systems without an appropriate conversion, we would have a severely wrong because the initial value of “16” would be interpreted as “4096”!
If you happen to import an audio file format wrong, you know already a sound level which can be the result. From here all the controversy the incompatibility between Mac and PC.
The AIFF file and follow the order SD2 BIG-ENDIAN, the Wave, including all derivatives, the little-endian.

MAIN FORMATS

AIFF (extension. Aif) this format very popular in the Mac environment, is the proprietary format of Apple, is little used by Windows users. AIFF means Audio Interchange File Format (File Format for the Audio Interchange). Like the Wave if in a Stereo 44.1kHz and 16bit you can write directly in Red Book on CD Audio. Similarly, the BWF can contain text information and positioning.

WAVE: (extension. Wav) this format is the world’s PC as the AIFF format is that Macintosh. They are virtually equivalent if we exclude the fact that one follows the format Little Endian and the other Big Endian. There is in compressed format but for normal audio applications is used only in non-compressed by a loss of quality. The various compression formats depend on the CODEC installed and activated nell’ACM (Audio Compression Manager, managing audio compression) of Windows.

BROADCAST WAVE FILE: (extension. BWF) as can be understood by the name has the same content of an audio file Wave but is expanded by a series of information concerning the positioning timecode original date and time of creation, and the author of the file and so on. As is aimed at job training, differently from all’AIFF Wave and similarly, has not compressed formats.

SONY WAVE 64: (extension. W64), even this format, developed by Sonic Foundry (later acquired by Sony Pictures Digital), is almost similar to the Wave, except that it uses a chunk composed of 64 digits (bits) instead of the usual 32, could well exceed the limit of 4,294,967,296 bytes (4 GB) imposed by a chunk to 32 digits. Since not many DAW support it has no reason to be used only in anticipation of a really long record.

SOUND DESIGNER II: (extension. Sd2) This format, once widespread in Mac, has been gradually disappearing. Like the Wave if in a Stereo 44.1kHz and 16bit you can write directly in Red Book on CD Audio. Similarly, the BWF can contain text information and positioning.

During a digital recording through any Digital Audio Workstation (in most cases a computer with a recording software Audio / MIDI) real-time file on our hard drives in most common formats: AIFF, BWF, and Wave W64 that we already employed in the same category.

Every DAW software has the need to memorize the location of each and every file its amendment, level, pan-pot, fade or cut, automation or even more specific settings of the plugin used and where to andarli find, to name a fraction. These settings are written on a separate file, usually saved in the same folder or the other in a nearby area immediately, the format of which is owner said.

The format owner owes its name to its limited compatibility with other DAW, because each has a proper, and is so exclusive that even versions of the same software tangible older, often are not compatible! It should be recalled that in the owner files are saved all the MIDI events, if it allows the DAW recording.

Although the practice more used to exchange work between incompatible DAW is to export each track in an audio file by itself so long as the duration of the session, and possibly a MIDI file format 1 with the party played by external tools or virtual companies and associations have invested in achieving a specific standard for interchange:

AAF, stands for Advanced Authoring Format, allows you to export the metadata (the information so position. An audio file) on the fade and automation, plus some information on changes made not destructive.

AES31, the symbol AES is obviously that of ‘Audio Engineering Society who has given directives to maintain the metadata during the interchange between different platforms and via network. It is based on sound BWF.

OMF, stands for Open Media Framework (Interchange), was given birth by Digidesign in order to make interchangeable Protools sessions with other professional DAW, also relies on the management of metadata for audio files. It can also export in a format that uses a single file, enormous, which also includes audio files.

Open TL, is an interchange format developed by Tascam for their systems of hard-disk recording then extended to DAW computer.

At present no one has yet clearly prevailed over the other and in some DAW can be found all those formats. We recommend, however, even before the export, to see which ones are present in DAW destination.

– Alex Picciafuochi on behalf of http://www.smap.it