Audio Format Support
SongKong supports all popular audio formats, allowing you to tag your collection consistently whatever its origins. The full set of currently supported formats is Mp3, Mp4, M4a, M4p, Aiff, Aif, Aifc, Wav, Flac, Ogg and Wma. As new formats come along we will add support for these as well.
If you have a choice in the audio format to use they can be categorized into three groupings:
Below we summarize the history of these different audio formats in a loosely chronological order
Aiff and Wav Support
AIFF and WAV formats each provide an uncompressed lossless format for your audio equivalent to CD quality, whereas Flac and Apple Lossless provide a compressed lossless format. Both types can encode your audio without losing any of the original data. An uncompressed format does not need to be uncompressed during playback, which can potentially result in smoother playback but at the expense of larger file sizes, however with most hardware it is unlikely you could detect any difference in playback. To confuse matters a little it is now possible to store compressed lossless in Aiff (Aifc) and Wav files as well - but this is rarer and not part of the original specification.
Audio Interchange File Format (AIFF) was developed by Apple Inc. in 1988 and is most commonly used on Apple Mac systems. Waveform Audio File Format (WAV) is a Microsoft and IBM audio file format standard for storing an audio bitstream on PCs developed in 1991. Both are version of the Interchange File Format (IFF) format developed by Electronic Arts back in 1985.
Many applications neglect to support Aiff and Wav formats. Firstly because these formats were expected to die out and be replaced with newer formats; but although they are less prevalent then before this has not happened. Secondly originally there was no agreed way to store anything but the bare minimum of metadata, but now ID3v2 has become the defacto standard. This is the same format used by mp3 and allows SongKong to store all the metadata that SongKong finds such as artwork, composers, bpm and MusicBrainz and Discogs identifiers - not just the basic metadata such as artist and album
Mp3 was developed by the Fraunhofer Institute and released in 1993. It was the original lossy audio compression and because the file sizes were so much smaller than Aiff and Wav it much more suitable for downloading from the Internet and storing on your computer. The quality of mp3 is inferior to just about every other format but it stills make up the majority of many audio collections. Originally ID3v1 was created to store metadata in Mp3s but this was not adequate so ID3v2 was created. Three versions were created v22, v23 and v24, support for v22 and v24 is not as widepspread as for v23. SongKong let you save your metadata as v23 for backwards compatability or v24.
Mp4 and M4a Support
MP4 is a container format developed by Apple that can store audio and video. For SongKong we are only interested in Audio and .mp4 files usually store audio encoded in Advanced Audio Coding (AAC) format, this is an audio coding standard for lossy digital audio compression designed to be the successor of the MP3 format developed in 1997, AAC generally achieves better sound quality than MP3 at similar bit rates.
MP4 can also store Apple Lossless - this is Apples replacement for AIFF released in 2004. Like AIFF Apple Lossless doesn't throw away any details of the audio but it compresses the audio in a lossless way so the filesize is significantly smaller.
Mp4 files use a completely different way of storing metadata via atoms that is not well documented, so many tag editors do not support the mp4 format.
Windows Media Audio (wma) was Micosofts alternative to mp3s released in 1999. Subsequently there have been different version of Wma known as Wma Pro and Wma Lossless but they still use the .wma suffix and the same way of storing metadata.
OggVorbis is an open source alternative to Mp3s started in 1993, mainly because the Franhofer Institute had indicated it would start charge licensing fees for the MP3 audio format. The Ogg refers to the container format, and Vorbis refers to the actual audio encoding. The specification is publicly available and more easily understood. Instead of ID3v2 Ogg uses a new metadata format called Vorbis Comments, this was intended to be much simpler to use because it just consists of names and values, but unfortunately the full list of name and values has never been officially defined. Originally there was not a way to store binary data such as images but a solution has now been found.
Flac is an open source Lossless compression format, similar to Apple Lossless by Josh Coalson released in 2001. The specification is publicly available and more easily understood. Flac also uses Vorbis Comments for most of its metadata but uses a different way to store binary data such as images.