[vorbis] encoding bitrates, different machines...

[Hugo van der Merwe]

> > I found I have ripped the same CD twice with different machines. Cannot 
> > remember when, why, or how, but anyway. I've been using jack, here is 
> > relevant output: [...]
> 
> Did you compared ripped tracks to see if they where identical ?
> If you rip the same track with the same CD reader several times and
> you compare them you'll found they're all different each other. This
> happens with almost all IDE CDs. Even my Plextor (SCSI) sometimes
> misses a bit here and there, but it usually works fine.

Actually, I'm thinking I probably reencoded from the same set of wav's,
I've recently discovered that I've got 4 CD's where I did this. I think
it was because I was using an old jack that did not yet support tagging
oggs after it had created them, so I sommer decided to reencode... thus,
it looks to me like one must have been -b, the other -q. There are very
significant size differences, but nominal rates are the same. Thus I 
think it was -b vs -q.

Odd thing is that one of the 4 CD's I double encoded like this actually
has smaller files with what I think was -b settings. OK, could be "hard
to encode, thus -q does large files", but both the "-q" and "-b" files
are <128k. I.e. the "-b" files could have been larger, for better
quality, and still be 128k.

Maybe I should do some -b encodings to see what kind of bitrates one 
gets. (I want to know if the rates I quoted in previous email could 
possibly be -b.)

> btw, I tried to encode the same track with the same machine 4 times. The
> encoded files had the same size, but cmp -l showed many different bytes.
> Strange.

The same wave, or just the same track? I believe that often a ripped
track might not start or end at exactly the same place after successive
rippings, and then you get longer/shorter silences at the ends of the
track.

Hugo

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