[vorbis] never encodes same twice?

[Segher Boessenkool]

Karol Pietrzak wrote:
> 
> Hello.
> As the subject of my email states, I've noticed that oggenc
> never encodes the same twice.  i.e., encoding the same file
> twice, using the same settings and same OS, never results in
> identical files (checked using 'diff').  I know that a randomly
> generated serial number is put it, but it gets better: a diff (-

The CRC is different as well.

> a -u0)  between these two encodings is ~120KiB.  Umm... why?
> Should the diff be around 1KiB, at the most?

Try

cmp -l | wc -l

instead (this gives you the number of different bytes).

> 
> Also, I've compiled by own libao, libogg, etc. (in Linux 2.4.17)
> and one of the files I've encoded using these utils has a
> bitrate 2 bits lower than the same track encoded in Windows 95.
> Why is this?  Is there some way to find out whether my compiler

Different compiler, different rounding errors.

> (gcc 2.95.3) is creating degenerate ogg files, reminiscent of
> the recent RedHat compiler bug posted on vorbis.com?

Use the source, Luke!  Or just listen to it...  if it sounds right
to you, there's no problem (for you, at least).

<p>Segher

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