Sound file formats

Sound is a natural phenomenon and propagates through air vibrations, so we can say that it is only wave characteristics.

The task of converting sound into electronic form is to repeat all of these same wave characteristics. But the electronic signal converted into an ADC (analog-digital converter) is not analog and is recorded by short discrete values. Let them have a small interval between each other and be practically imperceptible, but we must always remember that it is only the emulation of a natural phenomenon called sound.

This recording is called pulse code modulation and is a sequential recording of discrete values. The length of the device, calculated in bits, indicates how many values ​​are taken simultaneously in a recorded sample. The higher the bit depth, the closer the sound will be to the original.

Any sound file can be presented (for your understanding) as a database. It has its own structure, the parameters of which are usually indicated in the file header. Next comes a structured list of values ​​for specific fields. Sometimes, instead of values, there are formulas to reduce file size.

RSM

PCM stands for Pulse Code Modulation, which stands for Pulse Code Modulation. Files with this extension are quite rare (I’ve only seen them in 3D Audio). But PCM is essential for all sound files. I wouldn’t say that this is a very inexpensive method of storing data on a disk, but I think you will never escape this, and modern hard drive volumes already allow you to ignore a couple of tens of megabytes.

DPCM

Research on economical storage of audio data on disk. If you come across this abbreviation, know that it is Differential PCM. This method is based on the quite justified idea that the calculations are much more cumbersome, compared to the fact that you can simply enter the difference values.

ADDPCM

Adaptive DPCM. Agree that by specifying only the difference values, there may be a problem with the fact that there are very small and very large values. As a result, no matter how super accurate the measurements are, there is still a distortion of reality. Therefore, a scalability factor has been added to the adaptive method.

Wav

The simplest discrete data storage. I would say direct. One of the file types in the RIFF family. In addition to the usual discrete values, bitness, number of channels, and volume level values, wav can contain many more parameters that you probably didn’t even know about. These are placemarks for timing, the total number of discrete values, the order of playing various parts of the sound file, and there is also a place for you to put text information there.

RIFF

Resource interchange file format. A single storage system for any structured data.

IFF

This storage technology is derived from the Amiga systems. Interchange file format. Almost the same as RIFF, only there are some nuances. Let’s start with the fact that the Amiga system is one of the first who started thinking about software-sampler emulation of musical instruments. As a result, the sound in this file is divided into two parts: what should sound at the beginning and the element of what follows at the beginning. That is, the beginning sounds once, then the second piece is repeated as many times as necessary, and the note can be played indefinitely.

MODIFICATION

The file contains a small sample of the sound that you can then use as a template for the instrument. Simply put, a sample stitched onto the synthesizer.

AIF or AIFF

Audio interchange file format. This format is common on Apple Macintosh and Silicon Graphics systems. Contains a combination of MOD and WAV.

AIFС or AIFF-С

The same AIFF, only with the specified compression parameters (compression).

AU

Again, the race to save space. The structure of the file is much simpler than in wav, but there is a method to encode the data. The files are very light, so they are quite widespread on the Internet. Most of the time you can find parameters * -Law 8 kHz – mono. But there are also 16-bit stereo files with frequencies of 22050 and 44100 Hz. This audio format is designed to work with audio on SUN, Linux, and FreeBCD production systems.