KISS, Audio Engineering

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Sawyer said on July 2nd, 2008 at 12:24 pm :

I’d say the biggest issue only having one format is the DRM lockdown that music vendors buy into. iTunes has done it for ages, using m4p, which is just AAC with a DRM wrapper. Microsoft has done it with protected WMA files. Fortunately, people with a lot of time on their hands have enabled us to crack the encryption with free tools and liberate the music into a free format. Proprietary formats will exist as long as consumers tolerate them. Rhapsody just announced an MP3 music store, joining the ranks of Amazon and a few other MP3 retailers. Their quality is greater than the AAC files purchased on iTunes, which could help tip the scales in their favor.

KISS, Audio Engineering

Since I am in a research lab dealing primarily with audio files, and since I recently read an op-ed about the uselessness of the multiplicity of proprietary and open source codecs, I’ve decided to do my own investigation.

Basically, there are three types of audio codecs, a codec (short for compression/decompression) any sort of program that can compress or decompress signal data, such as audio or video:

Uncompressed: using what is known as pulse-code modulation, the analog signal is sampled at regular time intervals and encoded to bits, and thus treats all forms of the signal in the same way: a span of silence is given the same amount of consideration as an orchestral piece occupying the same region of time.
Lossless: While more time-consuming than creating an uncompressed audio, lossless (such as FLAC) basically compressed those moments of silence while maintaining most of the integrity of the original audio. Since none of the original relevant audio signals are played around with, the original file can be recovered.
Lossy: Lossy takes advantage of the fact that the human ear has its limitations in discerning the fine acoustics of audio, such as higher frequencies (our ears are capable of hearing frequencies from approximately 20Hz to 20kHz). The original audio file cannot be recovered if it has been compressed to a lossy format.

The following table lists the six most popular formats:

File type	Description
mp3	MPEG-1 Audio Layer 3, perceptual audio coding and psychoacoustic, lossy compression
wav	Waveform audio, uncompressed audio in pulse-code modulation format, native to Windows. Basically “naive” encoding where silence and sound is encoded using the same number of bits.
ogg	More correctly referred as Ogg Vorbis, or Vorbis. Open source, lossy audio codec, designed as successor to mp3.
flac	Free Lossless Audio Codec, open-source lossless audio data compression with information from audio stream.
aiff	Audio Interchange File Format, uncompressed big-endian pulse-code modulation, native to Apple Macintosh, akin to wav for Windows.
aac	Advanced Audio Coding, standardized, lossy compression and encoding, default audio format for Apple iTunes, Sony’s PlayStation 3, Nintendo’s Wii, designed as successor to mp3.

Why are there so many formats? No doubt each of the companies involved in their development hoped that their format would outlast its competitors as the format of choice by the masses. No doubt mp3 has performed remarkably in that area, primarily because of a careful compromise between audio quality and file size. At this point it would take a market revolution of sorts in order for the masses to accept another form- forcing users to adopt it (like Apple’s favorite .aac) particularly due to the popularity of mp3 players (imagine instead referring to it as the aac player?) Because of the simultaneous emergence of so many codecs, hardware needs to be configured in order to decompress and allow for playback - cause for many a headache.

Why not keep it simple, audio engineers, and just have one audio file format for each of the types?

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