You've probably noticed audio files use extensions, things like .mp3 and .aac. For the layman, this is the file type used to store and process audio. Without talking your ear off or waffling on about technical specs, here's a no-nonsense list of the most commonly used audio formats (with a sprinkle of some pros and cons for good measure).
MP3 (MPREG Layer 3) - AKA Mr Universal
MP3 is by far the most widely accepted audio format that can be played on pretty much anything. Think of it as the "USB of audio formats". Although it's not the most advanced around in comparison to FLAC and other formats, it's adopted enough to be practically ubiquitous.
MP3 uses ID3 tags. Info about the track, like artist, album, and artwork can be stored as metadata (which is a handy way to compress and store info). When you upload MP3 files with ID3 tags, that stored info gets displayed automatically. For example, when uploading to Podcast.co you don't need to fill in the title or artist, but you can if you want.
To put it simply, if you plan on uploading your podcast, sharing it with others, or submitting it to directories, then MP3 is your best bet.
- Pros: Widely adopted and easy to use.
- Cons: Not as good as other audio formats in terms of compression and quality.
M4A/AAC (Advanced Audio Coding) - AKA The MP3 Killer
Designed to replace MP3 as the major audio format, AAC (also known as M4A) has an overall smaller file size and better audio quality. AAC can have either an .aac or .m4a file extension. In short, AAC is the actual audio encoding scheme (raw), while M4A is just the file extension (formatted).
Places like iTunes use AAC as the main type of audio format, while a lot of devices like iPhones and Androids now accept and play M4A files.
- Pros: Small file size, good quality, and becoming increasingly adopted as the next best audio format.
- Cons: Not as "main stream" as MP3.
WAV (Windows Wave) - AKA Raw Audio
WAV files are considered raw audio files, which contain the original recordings in all their glory. This means nothing is compressed which is ideal for editing purposes, the only downside is the files are huge!
It should go without saying, WAV files are not to be used on the web! If you're using WAV, say when editing your podcast, always compress to MP3. This ensures episodes are optimised for the web.
- Pros: Raw unaltered audio, useful for editing.
- Cons: Not for web use, need to be exported to another audio format.
WMA (Windows Audio Media) - AKA The Black Sheep
WMA is designed for Windows. If you're running on Mac, Linux, or anything else, then WMA just won't work without jumping through a few hoops. Don't export your podcast as a WMA file unless you have a specific use case for it.
- Pros: Windows friendly.
- Cons: Can't be used beyond Windows.
OGG (Vorbis) - AKA Open Source
Although not as popular as MP3, OGG is a bit better due to its ability to compress to a smaller file size. Similar to MP3, OGG allows for stored info using comments, which is handy for appending a title or artist.
Unlike other audio formats which have software patents, OGG is open source and for public use (as in, no one will come after you in a legal sense), making it widely adopted by software developers and the gaming community.
- Pros: Free to use without any legal issues and well supported online.
- Cons: Difficult to decode.
FLAC (Free Lossless Audio Codec) - AKA The Future
Similar to MP3, but lossless, meaning that audio is compressed in FLAC without any loss in quality (plus, the overall size is reduced). By far, this is probably the best way to handle audio. The only problem is at the moment it's not widely as adopted as say MP3 or WMA.
- Pros: A far better way to compress audio to a small file size, whilst keeping the overall audio quality.
- Cons: Not supported by a lot of mobile devices and online at the moment.