What encoder to use?
If you don't want to loose any audio information you need a lossless audio format. Beside flac there are others like shorten or monkey, which may be available for your distro. The down side is that the compression rates will be low and hardly any commercial device can play these files.
Between the audio formats which do lose information due to data compression according their psychoacustic model, mp3 and ogg are the most common. ogg may today have a slight advantage over mp3 in audio quality on lower bit rates (up to 128 kbps), but above that rate the differences become less important, as both encoders produce very good audio quality.
In short:
flac
+ lossless compression
+ free
+ very good audio quality (lossless)
- low compression rate (probably only around 2.x)
- hardware player support not existing (afaik)
ogg
- loss of audio information (amount depends on final bit rate)
+ free
+ good to very good (high bit rates) audio quality
+ high compression rate (depending on resulting audio quality)
- poor hardware player support
mp3
- loss of audio information (amount depends on final bit rate)
o 'not so' free, lame comes for free with most distros but there are license issues
+ good to very good (high bit rates) audio quality, though slightly lower at lower bit rates compared to ogg
+ high compression rate (depending on resulting audio quality)
+ good hardware player support
As mentioned before, mp3 and ogg both are audio formats with which you will lose sound information in the end. You cannot revert back to the original once you have the mp3/ogg files. You can create wav files of these and even burn them back onto a CD to play them on a CD-Player (while DVD-players usually can play both, wav and mp3, mostly not ogg) but the wav files generated from a mp3 or ogg will not be as good as the original. In reality, depending on your HiFi system and the compression rate you chose when creating the mp3s/oggs, you might not even hear a difference. However, if you do not want to lose any sound information but still want to compress your wave files, you should take a look into flac, shorten or monkey. But these encoders will not compress much better than the factor of 2.x .
Until you are not the absolute enthusiast you will most likely decide between ogg and mp3. Go for
ogg - if you want to listening to the music only via your computer or a computer based music server and/or you already have one of the few ogg playing players.
mp3 - if you want to listen to your music on other devices as well, like standard DVD players, portable players (USB stick, flash card, HD) or special car stereos. Today, early 2005, most of these devices only support the mp3 format.
Qualitywise both audio formats should be just fine, depending the compression rate you choose. For mp3 (and most likely ogg too) a bit rate of 128 kbps results in a compression rate of 11 compared to the original wav file which is stored on the CD. That might be good during travel but is not sufficient for a good home HiFi stereo system. 192 kbps is a good compromise even for you HiFi system in your living room. This would give you a compression rate of 7.3 .
Already years ago experts were not able to differentiate a 256 kbps mp3 from the CD original and that was in a blind test with a HiFi system which you might never be able to affort. :-) That still will reduce the storage space of the original wav by the factor of 5.5 , quite nice. On most modern systems you can as well use variable bit rate. Here the encoder varies the bit rate depending the complexity of the music according to its psychoacoustic model (wow :-) ). The lame setting '--preset extreme' generates a file with a VBR (variable bit rate in opposite to CBR, constant bit rate) of 224 to 256 kbps, depending the complexity of the music. This will compress the original by a factor up to 6.3 and will play on nearly everything currently on the market.
Unless you have an extremly expensive equipment (we are talking of thousands of Euros or US Dollars) and an extremly well trained ear, you will most likely not hear a difference to the maximum possible CBR rate of 320 kbps, just beleave me. Even that would still result in a compression rate of 4.4 . By the way, the setting '--preset extreme' will infact use 320 kbps for complex music parts while compressing less complex music much higher to achieve the average bit rate of 224 to 256 kbps.
A short list of audio quality parameters and resulting compression rates for lame (mp3s) (check lame --help for more):
'--preset extreme' = 224 to 256 kbps VBR, compression rate up to 6.3 . Uses up to 320 kbps for complex music parts and way less for less complex parts of the song. Good enough for high quality home HiFi systems. First choice!
'--preset extreme -b 256 = 256 kbps CBR, compression rate around 5.5 . Uses always 256 kbps for complex and not so complex music parts of the song. Some older players need CBRs. Good enough for high quality home HiFi systems.
'-h' = 128 kbps CBR joint stereo, compression rate about 11 . 128 kbps for all parts of the song. Good enough for kids music, portable players and, well, car stereos. Not good enough for better home Hifi systems, though.
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