Since Thomas Edison first invented the phonograph, the way music is stored and the equipment to play it back has significantly changed over the years. Originally the music was on a bulky physical format, i.e. the record. Then other methods came along including real-to-real, then cassette tapes and finally CDs. Each successor aimed to provide superior quality, ease-of-use or portability to the previous generation. The music industry ran into problems trying to bring in the successor to the Audio-CD, but ran into a format war between DVD-Audio and Super-Audio CD. However, consumers on the other hand stuck with CDs since most could not see what was wrong with CD to fork out for costly higher definition audio play equipment supporting DVD-Audio or Super-Audio CD.
As the original digital audio formats were uncompressed using PCM, they required a huge amount of storage capacity. The Moving Pictures Expert Group (MPEG) overcame this by developing an audio compression format that removes audio frequency bands that the average consumer cannot hear such as when combined with other audio frequencies, louder frequencies and so on. In 1992, their compression standard MPEG-1 Layer 3 (MP3) was introduced as part of the MPEG 1.0 standard. MP3 compresses audio down to around 1/10 its original size with little or no audible difference to the average consumer.
Later on in the 1990's when more users started going online and getting sufficiently fast PCs to handle the MP3 format, the birth of P2P file sharing networks had started, initially with the invention of Napster. While the majority of consumers were happy with this one codec, the music did not like it for one main reason - It did not support any copyright protection restrictive measures. As a result, the birth of other audio formats started aiming to provide superior quality or better compression than MP3 while supporting copyright anti-copy protection measures.
The main two battling are AAC as used by iTunes and WMA as used by Microsoft and WMA based music stores. While AAC does not natively support copy-restrictive measures, Apple encapsulated its own restrictive measures known as FairPlay. The music industry is aiming to promote these music stores, while on the other hand is on a losing battle with trying to discourage or prevent the use of file sharing networks.
While MP3 can easily be used for other purposes such as compressing audio samples and effects for games, interactive services and so on, it has one other drawback - Royalty charges. The OGG standard aimed to overcome the royalty issue when it first started in 1993 as an open-source project by the Xiph foundation. OGG actually covers several royalty free audio-compression formats, including Vorbis, FLAC and Squish. Vorbis aims to compete with MP3 with superior quality and no royalty charges for its use. However, as it does not have the same recognition and backing as MPEG, the gaming industry has been the only one to make any serious use of this audio codec. The reason the game industry chose it is that the codec does not cost them any royalty charges and their audio samples does not need copy-protection measures as what the music industry demands.
Over time, it will be interesting to see what compression codec ultimately wins. Sony is another recent contender that wants its ATRAC audio series to be become the mainstream format. They are one of the few companies to launch a portable digital audio player that lacks MP3 support in an aim to force its customers to switch over to its proprietary ATRAC3(plus) format. However, Sony's recent NW-HD1 has been criticised for only support Sony's proprietary format. Anyway, one thing that is for sure over time is that the sales of physical audio media will gradually be replaced little by little with online music downloads and streaming.
For the original rather lengthy story on the history
and progress of audio medium formats and codec's, see this article. Feel free to discuss and find out more about audio compression, software and hardware on our Audio Forum.
Source: IEEE Spectrum Online
