[vorbis] A killer clip

[Forever shall I be.]

On Tue, Jul 31, 2001 at 02:30:23PM -0700, Benjamin Flanders wrote:
> I don't know much about why the sample sounds so bad
> when encoded but I encoded it with lame vbr and ogg
> and I want to say is lame sounds good,  but this isn't
> what we want is it?  Lame doesn't have any of the
> annoying high pitch sound in it, none, this isn't true
> to the original sound clip.
> Ogg, though introduces some very bad artifacts,
> actually does encode the sound.  So my question is, if
> you put in a low pass filter, do attenuation, etc...
> will this cut out the sound like lame (not wanted) or
> just stop the artifacts from being produced (perfect
> world)?
> 
> I bow to Ogg's almighty presence
> ben
> 

They're not really artifacts..

The issue isn't really with the encoder algo, it's the fact
that the ogg vorbis encoder doesn't (yet) know where the
highest and lowest possible values are, so it goes past them
if it thinks it will sound the same -- this causes clipping,
which makes it have the pops.  bump it down about 2dB and it
will sound fine..

As for lame, the lowpass filter is killing lame.. you can
encode the sample with -h -k, and it will sound ok (note that
lame does understand where the min and max values are)

Hopefully Monty will make the vorbis encoder understand where
the min/max values are, but only time will tell :)


-- 
Zinx Verituse

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