This guide is especially for lay users who are not familiar with the process of a Music/Audio CD backup. A lot of information is available on the internet, the most notable being Hydrogen Audio. The document is intended for non technical readers, so I am not going to describe any technical details, but just link to them, so if you are interested you can read it further. I would encourage you to read and understand this page before you stray on to any of the links in this blog post. So you purchased a music CD, and you want to back it up or play it on your music player or phone or some which way…As you would know it by now, you are supposed to “rip” it to mp3 so you can play it on your other device.
In a NUTSHELL if you want to make a ‘perfect’ copy of your CD to your computer, then you would “rip” that and store the music in .flac format. The flac format may not be supported by most dedicated music players, but will yield the smallest file size for a 100% lossless encode of the music.
The music on the CD is stored in Audio Tracks, and the standard was devised very long long ago, hence it is not easily possible to “image”or directly copy an audio CD directly like one can do for a VCD/DVD/ etc… One hence has to “rip” each of the tracks. The format of the music stored on the CD is what is called “PCM”, more details can be read on wikipedia at Red Book CD Standard. The closest PC/computer based file standard for this format is what is usually known as “.wav” files which store the PCM format. If you rip a CD to wav files, the total size of the .wav files is roughly the same as the total data size of the CD. The format is the most “pure” copy if you ripped it correctly without errors, with the draw back of it being relatively “large” in terms of size.
As of 2011, there are 3 very popular format to store music in viz.
- .mp3 (MPEG1/2-Audio Layer3),
- .flac (Free Lossless Audio Codec)
- .aac (Advanced Audio Coding)
You probably know only 1. mp3 and aac are what they call “lossy” formats in which the original quality of the music/audio is sacrificed for reducing the size of the music file. mp3 is the older standard and aac is the more current standard if you happen to read the links in detail. The aac usually gives better quality at the same file size compared to the mp3. flac is what they call a “lossless audio codec” which means the exact audio quality is maintained in this type of format. This format is also very much current, so one gets a much smaller file than the original .wav (about half the size), but still larger than the aac/mp3 files.
If you want to make a “backup” of your CD to your computer, then there are 2 steps.
- RIP the CD correctly to a .wav file
- convert the .wav file to .flac (or any other lossless format/ flac being the most popular one)
Once you have a backup, then you can archive those files on a high capacity disk like DVD,Blu-ray as data or on a USB hard drive or some other form of storage.Most computer media players will play the .flac files directly.
If you want to play the music on other devices like IPOD, a cell Phone, or the cheap media players, then you should use the .flac files you saved/archived and create whatever format works best for your device, like mp3/aac/3gp etc,and copy it to those devices. There is no need to archive/backup these formats as they are not the perfect quality, you should just copy them to the devices so that you can listen to them.
The audio CD format is one of the oldest format on Disk media, hence it does not have very good automatic correction etc built into it. Usually audio CD’s develop scratches or defects due to storage and handling, and when one RIPS the audio from the CD its not a very perfect job, as compared to one of the newer formats like DVD or BluRay. The results also depend on the manufacturer and model of the CD drive… etc…If one wants to have “very good” quality of RIPS then one has to use special software to do a good job or recovering the music from the CD.
- Software(Free for personal use/GPL) …
The BEST software for RIPPING is “Exact Audio Copy”. It is however available only for Windows OS.
On Linux/Ubuntu, the BEST software is “rubyripper”.
On MacOSX, the BEST software is “XLD (X Lossless Decoder)”.
Both Linux and MacOSX softwares use the package/tools from ““cdparanoia” with some additional stuff.
For FLAC, there is no such thing as Quality, as it is only the BEST quality which is saved.
For MP3, 96Kbps is supposed to be FM-stereo-Radio quality, 128Kbps is supposed to be almost CD quality, though some would say 160+Kbps is CD quality. I have seen people calling 320+Kbps as “lossless” but note that this format is always lossy, no matter what bit-rate you choose.
For AAC, there is a lot of debate but the thumb rule is 96kbps VBR is about the same as almost CD quality (128Kbps in mp3) and 256Kbps VBR is considered almost like lossless.
There are 2 types of bit-rates, CBR=> Constant Bit Rate and VBR => Variable Bit Rate (sometimes also referred to as ABR =. Average Bit Rate). In the former (CBR) the whole audio is compressed at a fixed bit-rate, whereas in the latter the bit-rate varies throughout the audio, so eg, silence zones get more compressed and other more musical zones get a little less compressed, etc.. yielding a smaller file for the same listening quality. We usually use VBR/ABR today with both mp3 and aac.