Re: [ARSCLIST] Lossy compression losing quality (was Re: [ARSCLIST] Pristine Audio and the Milllennials . . .)

[Don Cox <doncox@xxxxxxxxxxxxxx>]

On 10/12/07, Richard L. Hess wrote:

> At 02:36 PM 2007-12-10, Howard Friedman wrote:
> 
>> Does that mean that ripping CDA format files from a CD to MP3 format 
>> on my hard drive loses nothing?
> 
> Howard,
> 
> That is not copying a file, that is changing the file. The CDA format 
> is 44.1/16 uncompressed. You're compressing it when you make the MP3.
> 
> Copying a CDA to your hard drive would result in a WAV file of 44.1
> ks/s and 16 bit depth. That would be lossless except in extreme cases
> of poor readability which would normally fail, or at least be flagged,
> depending on your ripping tool. ExactAudioCopy.DE gives you an error
> report. I don't know what Windows Media Player does in that regard.
> 
> When you change the file format you lose something (unless you 
> upconvert). When you make analog copies, you lose something.
> 
Except that changing from WAV to AIFF or back loses nothing, as they are
almost identical.

> When most people say "copy a file" they mean from one carrier to 
> another in the same format, not migrating it to a different format.
> 
> That type of copying is transparent or it will fail (with the chance 
> of an undetectable error in something like 1 per Petabyte or 
> something along that order of magnitude 1 PB = 1,000,000 GB) For all 
> intents and purposes, copying a file will work or fail. If it fails, 
> it tells you.
> 
Except for copying over the Internet. It is possible to files to arrive
with small errors without warning - I sometimes see this in JPG image
files, where the colours break up after the error. In an audio file, you
would probably just get a click.


> If you're changing a file format from uncompressed to compressed, 
> that is changing the file format, not copying. You will lose quality. 
> When you uncompress and recompress an MP3 or JPEG file, you will lose 
> quality which is why these files are not used as input for editing.
> 

Regards
-- 
Don Cox
doncox@xxxxxxxxxxxxxx