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Brincadeira Music

When audio is digitized to be served electronically, it goes through a process called pulse-code modulation which consists of several phases:

  1. Its intensity is sampled some number of times per second; this is represented with the unit Hz (Hertz) or its SI multiples (often kHZ: "kilohertz", or thousands of samples per second). By the Nyquist–Shannon sampling theorem, a sample rate of N kHz can perfectly represent a sound with a frequency of at most N/2 kHz.

  2. This intensity is quantized to a certain number of bits per sample. This representation can be either integral or floating-point, but is typically linear and integral.

  3. The resulting waveform (typically in a WAV or AIFF container) is compressed using one of several coder-decoder algorithms (better known as codecs). These can either be lossy (which use psychoaccoustic models to throw away parts of the signal that they don't think humans can hear), or lossless (which are reversible transformations that when played perfectly reproduce the input signal).

CD Audio (immortalized in the Red Book standard) is uncompressed Linear PCM with 16 bits per sample and a sample rate of 44.1 kHz; this results in a stereo bit-rate of 1411.2 kbps.

Compression Formats

MP3
MPEG-1 Audio Layer III (or "mp3") is a lossy compression format originally developed to accompany digital video; it is the successor to the MP2 format used for stereo audio on DVDs. It provides a good balance of file size, decoding speed, and audio quality. The advent of cheap MP3 playback devices spurred the digital audio revolution of the 1990's, and it remains by far the most common audio format on the Internet. MP3 audio at or above 256kbps is generally indistinguishable from the original material.
Ogg Vorbis
Ogg Vorbis is a lossy compression format developed as a free and not-patent-encumbered alternative to MP3. It has very similar performance characteristics to MP3. It remains popular with Linux enthusiasts and on the Android platform, but has been losing ground since the patents on MP3 expired in 2017. Technically, Ogg is the name of the file format and Vorbis is the name of the codec. You can use this as a fun fact at parties.
AAC
MPEG-4 Part 14 (also known as the Advanced Audio Codec) is a natural successor to MP3. It is a lossy compression format which uses more advanced algorithms to obtain better quality in the same file-size (or the same quality in smaller files) relative to MP3. AAC is the default audio compression algorithm used for media in the Apple ecosystem, including all downloads from the iTunes Store (which are 256kbps stereo AAC files) and all system audio effects. Blind testing has shown that AAC files at or above 192 kbps are indistinguishable from the original material.
FLAC
The Free Lossless Audio Codec is a lossless compression format, which means that it is mathematically identical to the source file. It is very popular in the F/OSS communities.
Apple Lossless
Apple Lossless, or ALAC, is a lossless compression format for the Apple ecosystem. It is used to power the "lossless" mode of Apple Music.

All of our download pages include a selection of formats and recommendations on what to download. We recommend downloading the appropriate format for your device (usually AAC, Ogg Vorbis, or MP3), and listening to our tracks with a great pair of headphones or speakers.

What about sample rates and bit depths?

Typically, digital audio files are recorded at a sample rate of 44.1 kHz (which means that they can perfectly reproduce sounds at or below 22.05 kHz). While some platforms have started using higher sample rates (such as 96kHz or 192 kHz), there is no evidence that this results in better audio quality; human hearing typically only extends to between 15 and 20 kHz.

Audio is typically quantized with 16 bits of depth (this means that it can represent 65,536 distinct "loudness" values between the quietest and loudest sound). It's common to master audio at 24 or 32 bits, which allows for more overhead to prevent clipping. While, again, you may sometimes see "high definition" audio being served at 24 or 32 bits, blind testing has shown that humans cannot distinguish additional bit depth.

For more information, we recommend the excellent article 24/192 Music Downloads...and why they make no sense by Chris Montgomery (the original creator of Ogg Vorbis).