Brief comparison of common Audio Formats

Do you love music? Ever wondered how digital music is saved on our smartphones / music players? What are the popular audio formats and how do they compare in terms of quality and file size? Read on to find out!

Uncompressed Audio

This refers to audio files directly ripped from a music CD, without applying any kind of compression i.e. it has the same quality as the original CD source. Common container formats include:

  1. Wave Audio ( .wav ) : This is the default uncompressed audio storage format on Windows. Audio files are saved with a bitrate of 1411kbps with a sampling rate of 44.1kHz.
  2. Audio Interchange File Format ( .aiff / .aif ) : This is the default uncompressed audio storage format on Mac OS . Audio files are saved with a sampling rate of 44.1kHz.

Since these are directly ripped from CD, they are very high quality audio formats, much better than the common mp3s. On the other hand due to no applied compression, they occupy lots of space : 50-60 MB per track on an average.

Lossless Compression

These are files which have the same audio quality as uncompressed audio, but are smaller in size due to applied compression ( akin to zip files in Windows, which compress the content without any loss of data ). Common formats include:

  1. Free Lossless Audio Codec ( .flac ) : It’s the most widely used lossless audio codec, due to similar quality yet smaller file size than uncompressed audio formats. The best part is that it’s free and open source and hence always open to enhancement by the developer community.
  2. Apple Lossless Audio Codec ( .m4a ) : This is Apple’s answer to lossless compression, with widespread support on Apple devices but not so much elsewhere. The compression level is similar to flac, though encoding speed may be lower in some cases.

Due to the lossless compression applied, these files are roughly half the size of uncompressed audio while maintaining the same audio quality, which makes these formats a good choice for archiving purposes.

All lossless formats are inter-convertible without any loss of audio quality.

Lossy Compression

These are files which are compressed to reduce the file size resulting in the loss of data from the original file. Intelligent compression algorithms try to make the file sound similar to the original but due to the loss of data these just don’t have similar quality to the lossless audio formats. On the plus side, these occupy much less space compared to the lossless audio formats and hence are much more popular and in use. Common formats include :

  1. MPEG Audio Layer-3 ( .mp3 ) : By far the most popular and the most supported audio file format, the good ol’ mp3 is now showing it’s age. Even though it is still good, better formats such as AAC are now slowly replacing it. These have bitrates ranging from 32 kbps (Lowest quality) to 320 kbps (Highest quality). This codec is still under active development, so an mp3 file encoded from the same source with the same settings in 2015 will sound better than a file encoded in 2000, due to advancements in compression techniques.
  2. Advanced Audio Coding ( .m4a / .aac ) : Designed to be the successor of the mp3 file format, this format is slowly gaining popularity, mainly supported by by Apple as their default codec for iTunes music. It has better compression efficiency than the mp3 codec, such that a 256 kbps AAC and a 320 kbps mp3 file sound similar and so it can reduce file size while maintaining similar quality or keep the file size same while giving better quality than mp3 files. AAC has widespread support among recent devices, though it can’t compete with mp3 in terms of compatibility.
  3. Windows Media Audio ( .wma ) : Microsoft’s answer to lossy compression, WMA was conceived as competitor to mp3 and other popular formats back in the day. However, it could not gain much traction in terms of popularity or compatibility. Even so, it is still supported by all versions of Windows and most modern music players. Blind tests in 2006 have shown that Windows Media Audio Pro can sound as good as AAC at similar bitrates but is nowhere as popular.
  4. Vorbis (.ogg ) : The major advantage of this format is that it’s open source and patent free so encoding in Vorbis format is hassle-free. It has been used as the audio codec of choice for encoding the soundtrack of many popular video games. In terms of quality, it is identical to AAC at higher bitrates. At low bitrates however, it display certain characteristic noise artifacts which may ruin the audio experience.

The best encoder for mp3 currently is LAME, while good quality AAC encodes use Nero AAC or iTunes AAC.

Transcoding from on lossy format to another or from a lossy format to lossless results in degradation of quality as the maximum achievable quality is that of the source file which in this case is a lossy format itself.

Conclusion

At the end of the day, its always audio quality vs file size and codec compatibility and AAC wins hands down. It’s better than mp3 and approaches flac at higher bitrates while still maintaining manageable file sizes. On the other hand, if storage space is not an issue, flac is the best choice as in addition to being lossless, it is slowly gaining more support and can be played on more and more devices.

Ways to download AAC / FLAC music :

  1. iTunes (mp3 / AAC)
  2. Chiasenhac (mp3 / AAC / FLAC)
  3. Torrents

-Animesh

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