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Supported audio formats

Fission has native support for editing six of the most popular audio formats: MP3, AAC, Apple Lossless, FLAC, AIFF, and WAV. Editing of these formats with Fission is always done losslessly.

Fission also has support for importing a large number of less common formats. See the current list of supported formats below.

Selecting an Audio Format

First, if you're unsure what audio format to save to, MP3 is likely a very safe bet. It will provide a very small audio file which can be played almost anywhere.

If you don't want to lose any quality but still wish to save disk space or bandwidth when transferring the file, Apple Lossless is a good choice for use with Apple devices. For lossless files which will play anywhere, AIFF or WAV are your best options.

Finally, if you can avoid switching audio formats entirely (by simply saving, instead of exporting), you'll prevent quality loss from occurring. That said, transcoding between formats is certainly fine when a specific file format is required, and quality loss caused by transcoding is generally not problematic.

For more information on each specific audio format, read below.

MP3

MP3 is the most popular format for audio compression, making it the most universal file type; MP3 files can be played almost anywhere. Because MP3 files are compressed lossily, some audio quality may be lost when they're created. However, the files are also very compact, using only a small amount of disk space.

The Variable Bit Rate (VBR) option for MP3 files allows the software to dynamically adjust the bitrate of the encoding, saving disk space without any additional quality loss. Modern MP3 encoding is largely done with VBR.

AAC

Though not as universal as MP3, AAC is another well-known format for audio compression. AAC files play well on devices made by Apple, including the Mac and iOS devices. Like MP3, AAC files are compressed lossily, meaning some audio quality may be lost when they're created. AAC files are generally even more compact than MP3, using less disk space for the same level of quality.

The High-Efficiency (HE-AAC) option for AAC files allows the software to compress encoding even further, to save disk space without additional quality loss. HE-AAC is limited to low bitrates (24 - 80 kbps) and a compatible player is needed to play the audio back optimally.

Apple Lossless

As you might expect, the Apple Lossless format was created by Apple. It's a lossless compression format, which means that even though the files are shrunk down in size, no audio quality is lost. Though they are compressed to around half the size of uncompressed AIFF/WAV files, these files will still be quite large. They'll play on all iOS devices and in Apple Music, as well as in many applications on the Mac.

FLAC

FLAC is an open competitor to Apple Lossless. Like Apple Lossless, it offers lossless compression, creating large files of around half the size of uncompressed AIFF/WAV files but losing no quality. FLAC is a popular format for web distribution of lossless audio. Unfortunately, playback of FLAC files is not as well supported as other formats. Fission makes it easy to convert files out of the FLAC format, if you desire.

AIFF/WAV

AIFF and WAV are twin uncompressed audio formats, which generally work identically. While AIFF was once used largely on the Mac platform and WAV used largely on Windows, they're now each compatible on both platforms. These files have no compression, so they're enormously large, but as with Apple Lossless and FLAC, no quality is lost. AIFF and WAV files will play in almost any audio player.