When you are ripping your music CDs to build a music library, you have many options when it comes to the choice of audio file formats. WAV, MP3, AAC, Apple Lossless, Flac, APE, Ogg and WMA are the more popular audio formats among others. The best practice is to narrow down the file format choice to one or two formats when you build your music library for ease of management.
Unfortunately there is no easy answer as to which is the best format, the choice is often subjective and depends a lot on the intent and usage of your music library.
### Keep A Lossless Copy
If you intend your music library as a replacement for the physical CDs, rip the audio into a lossless audio format. You can then keep the CDs away and never have to visit them again. But first let’s explain what is lossless format and the need for one.
WAV, Apple Lossless, Flac and APE (Monkey Audio) are example of lossless format. Lossless format are faithful representation of its source CD music without taken any content away. WAV is the first lossless format available, it is designed as a computer representation of the CD content, and is a non compressed format. A 3-minutes WAV file is about 40 to 60MB. Apple Lossless, Flac and APE are compressed format, which reduced the file size to about half of WAV file. One CD on compressed lossless format will take up about 200-300MB. You can store roughly about 850 CDs for a 250G storage.
Compared with lossy formats such as MP3 or AAC, which by design will filter off some music bits from the original source. For majority of us who has common ears, we are not able to hear the difference of a quality encoded high bitrate MP3 music from its original CD source. Lossy format also is designed to minimize storage, a 3-minutes MP3 takes about 6 to 8 MB using a high bitrate such as 320kbps during the conversion. The higher the bitrate, the bigger is the file and the closer it is to the original source. For MP3, most people will consider to encode using a bitrate of 192kbps or higher, or using the more optimized variable bitrate VBR if the encoder supports it. However lossy format is not meant to be used as a source for further audio conversion.
Let’s say you ripped the latest Green Day CD into MP3 files with high bitrate encoding. You then convert the MP3 files to WAV formats and burn it into CD. The resulting audio CD is a lesser copy of the original, as some audio data was being removed when you ripped the original CD songs into MP3. If you subsequently ripped the resulting audio CD again into MP3, the new set of MP3 will be worst than the first set of MP3.
We do not encourage using lossy formats such as MP3 or AAC as source for any conversion, at least for serious music listening.
If storage is not an issue, rip your CDs collection into a lossless format for a long lasting music library. You can use tool such as [Max](http://sbooth.org/Max/) to easily convert this lossless format to MP3 or AAC for its small file size. Using Max’s batch conversion, you can convert your library of 300G lossless music library to MP3 in one go. We would suggest keeping a main music library in a lossless format, and create a secondary library in MP3/AAC format for portability and wider player support.
### Which Lossless Format
We recommend [Flac](http://flac.sourceforge.net/) as the lossless format of choice. It is the most widely supported open source lossless format. WAV is not desirable due to its file size and the lack of id tagging support. The problem for Apple users is Flac is not supported by Apple. You can not use the format in iTunes, iPod and iPhone. Using a secondary MP3/AAC music library ‘solves’ this problem. Let’s hope we see Flac in future Apple product.
Apple fans might be tempted to use Apple Lossless. We do not like this format as much due mainly to its proprietary nature. Most encoder/decoder depends on Mac’s system module to provide Apple Lossless support. Outside of Mac, open source encoder/decoder was written based on reverse engineering work. This does not give us the confidence of 100% compatibility. There is yet any public documentation on Apple Lossless file format.
A small annoyance with Apple Lossless is the “.m4a” file extension. This is the same file extension used by iTunes Plus, which is basically a type of lossy AAC format. If you have both type of music files together, you can see where the confusion could come. You might wrongly use a lossy format as the source for your conversion.
### Which Lossy Format
MP3 is our lossy format of choice, for its industry standard position and the widest player support. We have nothing against AAC, which is the other lossy format for your consideration. AAC is supported by other vendors such as Sony and Nokia. AAC is meant to be a replacement for MP3 with a more efficient design. However modern MP3 encoder/decoder, cheap storage and Amazon’s support of using MP3 for its online music store makes it impossible for AAC to take over.
If you purchased music online, the audio file format is predetermined by the vendor: its AAC for iTunes and MP3 for Amazon.com. Both are lossy format. There is no online music store offering lossless audio at the moment. Please use the lossy file format as supplied and do not convert them to other format. For iTunes, we encourage you to purchase songs in iTunes Plus format which is DRM-free. The higher price is good price to pay for digital freedom, as you can use the files anywhere without the dependence of an DRM infrastructure.
To summarize, here is our best practice pointers on choosing the best file format for your music library:
1. Rip your music CDs to a lossless format (Flac) and a lossy format (MP3) for playback. You can rip your CD to both format at the same time using tool such as [Max](http://sbooth.org/Max/).
2. If you purchase online music, use the format as supplied.
3. Use only lossless format as the source for music file conversion.
4. Stay DRM-free.