Audiobook Formats and File Types: Which One is Best?

YOU ARE READING: Audiobook Formats and File Types: Which One is Best? AT PhebinhvanhocEN

The audiobook file that you should use the most is mp3, but there are many other types of formats that you should know, such as flac.

Audio is growing faster than e-books or print books. That means that to increase your audiobook sales, you need to have a solid understanding of the technical requirements of audio.

You are reading: Audio books file format

While there are many audio formats, used by a wide variety of businesses, there is really only one audiobook file format that you should master, with a few others that are useful to know.

and we’ll break each one down in this post.

audiobook file types

When it comes to audiobooks and audio file types, there are a lot of formats out there, but only a few are relevant to audiobook creators.

we’ll take a look at each type, but know that the only ones you really need to worry about are mp3, wav, and flac.

lossy compressed audio formats

The term “lossy” means that the audio has gone through a compression process. this significantly reduces the size of the audio file, but may result in a loss of quality.

Still, it’s common to use them as audiobooks, and acx recommends mp3 as the primary file format.

so let’s take a look at each of the lossy compressed audio formats for audiobooks.

mp3

By far the most popular (possibly of any file type) is the mp3 (.mp3). mp3 uses its audio coding compression to remove a lot of superfluous data that most of us don’t listen to anyway. stands for mpeg audio layer 3, with layer 3 being its own unique encoding scheme.

An mp3 file is the most common lossy audio format, and although the quality drops slightly, vocals still come through without much loss. this means that mp3 audiobooks will not be much different than higher quality formats.

aax

you may see an aax file if you find the actual files of your audible audiobooks. aax was an audiobook format developed by audible using an mpeg-4 wrapper that also allowed encrypting the file with drm.

this is not a type of file you need to worry about creating. audible does the transfer for you, but it’s worth knowing that it exists and that this is what audible uses to deliver its audiobook files to readers.

m4a/m4b

the compressed format that apple uses, like audible uses aax, is m4a or m4b.

this is also the format used for apple store music. m4a is more common for music, and the m4b file is more common for audiobooks and podcasts, as it allows for additional metadata such as bookmarks, which m4a does not.

aac

aac stands for advanced audio coding and is actually a superior form of compression compared to mp3. the sound quality is much better.

However, aac has never caught on in the same way as mp3, at least for most consumers. That said, it’s a common format used by a variety of companies, including YouTube, the iTunes library, most smart devices, and consoles.

m4p

m4ps is simply a version of aac that includes digital rights management. It was originally built by Apple for the iTunes Music Store. like aac, the sound quality is generally better.

ogg

ogg is a kind of digital container that contains vorbis files. vorbis files are open source, unlike most other file types we looked at. it’s also a superior form of audio compression and quality.

That said, it’s a file type that has had some trouble competing with the mp3 and aacs of the world, so it’s often overlooked.

wma

wma stands for windows media audio, and there are both lossy and lossless formats for it.

If you use a windows machine, you are probably familiar with it as it was developed by microsoft and is commonly used in their operating systems. That said, it’s not used much on non-microsoft devices, and doesn’t really offer any benefits that an aac or ogg doesn’t.

lossless compressed audio formats

While lossy files are compressed to significantly reduce file size, sacrificing some quality in the process, “lossless” files use a compression method that is not as effective at reducing file size, but maintains all audio quality.

there are one or two of these that you should be aware of when creating your audiobook. so let’s take a look.

flac

flac is widely regarded as the most superior form of lossless compressed audio, and it’s no wonder why.

flac stands for free lossless audio codec. it’s an open source file, which means there are no intellectual property issues, and its compression is almost as good as an mp3, but without sacrificing any quality.

is one of the formats accepted by findaway voices, and you will see it appear more and more.

wave

wav is one of the most popular audio file types. it’s an old format, but despite this, it’s still widely used and superior to many formats.

wav files do not sacrifice quality at all, although they are much larger than a lossy compressed file. Just like audiobooks, even if they were produced as wav, they are likely to be converted to a lossy format when the listener gets their hands on an audiobook.

alaca

apple lossless audio codec (alac) is apple’s proprietary file format for high-quality audio.

Although originally exclusive to Apple, it became open source and royalty-free in 2011. However, it is still widely used by Apple, with the exclusion of some superior files such as flac.

Like others on this list, it doesn’t sacrifice quality, but compression isn’t as good as flac.

wma

wait, didn’t we talk about this already?

yes, wma has lossy and lossless format. both use the same extension.

While this is a common format with windows, it’s not one you should use for audiobooks. the software is proprietary and has limited hardware support. it is also the worst in terms of compression efficiency.

so it’s best to stick to flac or wav for your lossless files.

what is the best format?

When it comes to adapting your kindle ebook for audiobook listeners, there are really only a few formats you should use.

For lossy formatting, mp3 and aac are best. aac is the best in terms of compression space saving and quality. however, mp3 is so widely used at the moment that you will have a better chance of successfully submitting your mp3 audiobook in this format.

For lossless formatting, the best options are flac and wav. the latter is much more common, but flac is easily the superior file type. and for starters, a lot of people are starting to accept flac files, including search voices.

acx/audio presentation requirements

We know all the different formats, but what exactly do we need to submit our book to acx?

acx has a number of different requirements for its audiobooks, but the audiobook format is relatively simple.

According to acx’s own website, they want an mp3 file with a constant bitrate of 192kbps (or higher) at 44.1khz.

what does this mean?

Bitrate is a measure of the quality of mp3s. a high bitrate will result in a higher quality mp3 file, but will also result in a larger file size.

mp3 range tends to be between 96 and 320 kbps. the acx/audible requirements put it in the middle of that range. it can go louder, but audible notes that this probably won’t result in a discernible increase in quality for listeners.

in other words, just send an mp3 at 192 kbps and you’ll be fine.

you can see more of their audio requirements on their website.

audio requirements for findaway voices

while acx is largely considered the gold standard when it comes to producing audiobooks, findaway voices is another major powerhouse to consider.

findaway voices work with a wide variety of editors, so if your audio is good enough for findaway voices, it should be good enough for everyone.

just like acx, findaway accepts mp3 files at 192 kbps or higher. however, they also accept flac files. the sample rate is also 44.1 kHz.

then if you want to send the best possible quality you can do it with search voices via flac files.

Most of the other audio requirements for findaway are the same as for acx.

the end result

Audiobooks have come a long way, but the best formats to use them are still the most basic: mp3 format or flac format.

While you may want to work with wav files when working with your audiobook’s narrator, you’ll eventually need to convert those files to play in an mp3 player.

then once you deliver the files to acx, findaway voices or wherever you send your files, they will be converted into all the appropriate files to deliver to the listener. We hope this article has helped. let us know if you have anything you would add. we love to hear from our readers.

Other content