Audio file formats: a comparison
August 27, 2013 in digital music by Dan Gravell
Choosing an audio file format is of great importance to your music library. The choice comes into play at numerous times; when you download music you often get a choice of different formats, and when you rip CDs you can choose which format you rip to.
Making the choice between the numerous formats is pretty daunting for a novice. There are comparisons on Wikipedia but this may appear overly detailed. There are multiple ways of "measuring" the applicability of an audio format to your situation, but not all of them are objective or, indeed, measurable. So, instead, I decided to create a brief comparison of audio file formats by which their day-to-day attributes are shared.
What are these "day-to-day" attributes? They're general areas that are affected by your choice of audio format. Here I've chosen audio quality, flexibility, playability and storage cost.
- Audio quality
- The faithfulness of the audio playback achievable by playing the audio format
- Flexibility
- Once you have acquired the audio, how amenable to change and manipulation the audio file is
- Playability
- How broad a range of music players can play the format
- Storage cost
- How much space audio files in this format consume on your hard disk or NAS
Some audio file formats allow variability, for example MP3 allows different levels of audio quality. Where this is the case, a non-strict "average" possible value is assumed. Best case values would not be fair to assume, as normally such variability means that a choice in one area comes at a cost in another (for example, audio quality at the cost of extra storage space).
Each category is rated out of three, one being the lowest score, three the best.
| Format | Audio quality | Flexibility | Playability | Storage cost |
|---|---|---|---|---|
| Apple lossless | ★★★ | ★★★ | ★★ | ★★ |
| FLAC | ★★★ | ★★★ | ★ | ★★ |
| MP3 | ★ | ★ | ★★★ | ★★★ |
| MP4/AAC | ★ | ★ | ★★★ | ★★★ |
| Ogg vorbis | ★ | ★ | ★ | ★★★ |
| WAV | ★★★ | ★★ | ★★ | ★ |
| WMA (lossless) | ★★★ | ★★ | ★★ | ★★ |
| WMA (lossy) | ★ | ★ | ★★ | ★★★ |
In general, lossless formats should get full marks for flexibility, however WAV's poor tagging support means it loses out here; transcoding to different audio formats becomes more difficult to do completely, with full metadata. WMV is also marked down because of a history of violating user rights with DRM, and the continued control of the codec by Microsoft.
What's the conclusion? Well, sadly these ratings are loaded with a few caveats; the best audio file format for you is dependent on your circumstances.
One interesting conclusion from this table is that the greatest deviation in values between audio formats occur for the storage cost and playability areas. This might seem an academic analysis until you start really considering the person-to-person applicability of these ratings.
If you are an OS X user and wedded to the iTunes family of products, for example, then Apple Lossless appears a clear winner, but other people with different devices might go elsewhere. Given playability varies a lot, the more diverse music devices you have the more you have to adopt a "playable" audio format. This goes for those of the open-source bent (FLAC) as well as Apple users. If you have a lot of different devices, aim for a playable format.
This suggests to me that a future development of this table will be to extract out different usage scenarios, such as music devices used, and represent these in multiple different tables.
So which is best? For my own usage, FLAC is still preferred, but like all non trivial questions, the answer to this one is "it depends".
Thanks to Matt Reinbold for the image above.
