On Friday 04 January 2008 04:39, James Knott wrote:
> jdd wrote:
> > Carlos E. R. a écrit :
> >> ...
> >>>
> >>> wav (or flac) files are nearly losless
> >>
> >> Make that "completely losless".
> >
> > I know that's said, but I doubt it's real. Once wav file done, the
> > copy have no more problem, but I'm not sure that the wavs file made
> > by two different apps from the same track will be exactly the same.
> >
> > I don't think the real meaningfull content is different (the
> > music), but the beginning of the track, the inclusion or not of the
> > 2s silence track... all this is not clear (However I didn't
> > experiment this - yet)
> >
> > jdd
>
> Assuming they're using the same track, the .WAV files should be
> identical. The CD is already digital. It's a stream of data that
> shouldn't be changed, when copying to a file.
If the extraction is done digitally and all the media errors are
correctable, that's true. If the conversion is done from the analog
stream (very unlikely on modern CD drives), then there will be
variations in the quantization.
Keep in mind that there are two different kinds of error correction for
CDs. The kind used for data is very robust. The kind used for audio
sectors is much less so (and more of the bits on the sector are devoted
to audio sample data). Extraction ("ripping") software varies in how it
handles reported errors. Some try very hard (as in using retries) to
get error free data. Others take whatever they get.
As far as the FLAC compressions scheme, it is just as lossless as that
used by BZip2 or GZip or PKZIP. The data that comes out is precisely
(bit for bit) what went in.
Randall Schulz
--
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]
