Zune Boards - View Single Post - Comparision of lossless vs lossy audio file compression

roebeet · 07-03-2009, 08:06 AM

I'm writing up this quick tutorial, as I did not see one in the past via a ZB search. I've seen a few posts about file conversions, so I figured I'd explain the in's and out's of music conversion, for the uninitiated.

There are two types of audio compression: lossy and lossless. "Lossy" (WMA, MP3, AAC) basically means that data is removed, forever, to decrease the file size. And the bitrate will control just how much of that data is removed. "Lossless", on the other hand, retains all the original data. Lossless can be uncompressed (example: CD-Audio or PCM WAV) or it can be compressed (FLAC, WMA-L, ALAC, APE) similar to how a ZIP file works.

With that in mind, the general rule of thumb is that a lossy file shouldn't be transcoded to another lossy (or even lossless) format, as the data is already lost. Transcoding to lossy again further degrades the data, and transcoding to lossless is just a waste of space - once the data is lost, you cannot get it back.

As for the sound quality of a lossy file vs lossless, that is an endless argument. Some people cannot hear an audible difference, and others claim that they can. I personally can hear differences between 160kbps WMA's / 192kbps MP3's vs. FLAC, but the differences are minute. And with V0 MP3's, it's almost impossible to detect.

What I do right now is archive my CD's into FLAC format, and then transcode them to LAME V1 MP3 for usage in my various devices (a good trade-off of SQ vs file size). As storage sizes increase and prices decrease, I fully expect that I will be using a lossless format eventually.... perhaps in five years, is my best guess.

07-03-2009, 08:06 AM	#1 (permalink)
roebeet Zune Freak Join Date: Sep 2008 Location: Pennsylvania, USA Posts: 1,023	Comparision of lossless vs lossy audio file compression I'm writing up this quick tutorial, as I did not see one in the past via a ZB search. I've seen a few posts about file conversions, so I figured I'd explain the in's and out's of music conversion, for the uninitiated. There are two types of audio compression: lossy and lossless. "Lossy" (WMA, MP3, AAC) basically means that data is removed, forever, to decrease the file size. And the bitrate will control just how much of that data is removed. "Lossless", on the other hand, retains all the original data. Lossless can be uncompressed (example: CD-Audio or PCM WAV) or it can be compressed (FLAC, WMA-L, ALAC, APE) similar to how a ZIP file works. With that in mind, the general rule of thumb is that a lossy file shouldn't be transcoded to another lossy (or even lossless) format, as the data is already lost. Transcoding to lossy again further degrades the data, and transcoding to lossless is just a waste of space - once the data is lost, you cannot get it back. As for the sound quality of a lossy file vs lossless, that is an endless argument. Some people cannot hear an audible difference, and others claim that they can. I personally can hear differences between 160kbps WMA's / 192kbps MP3's vs. FLAC, but the differences are minute. And with V0 MP3's, it's almost impossible to detect. What I do right now is archive my CD's into FLAC format, and then transcode them to LAME V1 MP3 for usage in my various devices (a good trade-off of SQ vs file size). As storage sizes increase and prices decrease, I fully expect that I will be using a lossless format eventually.... perhaps in five years, is my best guess. __________________ Last edited by roebeet; 07-03-2009 at 08:11 AM.