[vorbis-dev] audio analysis tool?

[Erik Stenborg]

I read about a tool from Fraunhofer here:
http://www.hydrogenaudio.org/index.php?act=ST&f=1&t=3382&hl=inverse+decoder&s=

I don't know if they have a working program or if it is just still in
research stage.

Hope that helps.

/Erik

On Wed, 6 Nov 2002, Eric Seppanen wrote:

> On Wed, Nov 06, 2002 at 02:13:39AM +0100, Segher Boessenkool wrote:
> > Eric Seppanen wrote:
> > > 
> > > I'm curious, does anyone know of a way to analyze a wave file to determine
> > > the quantity of information in it?  For example, given a particular .wav
> > > file, how can I find out if it's an original or was encoded to something
> > > lossy and back?
> > 
> > Just look at a spectrogram.  Big empty regions at the high frequencies
> > ==> lossy.  Lots of other features, too (it's not very hard to see which
> > codec you're looking at).
> 
> That's helpful, but I guess I was imagining that there might be some way 
> of quantifying how much data is there, for instance having a tool that 
> could look at an audio input and notice that it never seems to have more 
> than roughly 128kbps of information in it.
> 
> Since vorbis has quality settings, I figured it might be able to quantify 
> how much signal (not signal magnitude, but quantity of frequency data) is 
> coming in.
> 
> The other thing that occurs to me is that some codecs may "fake" 
> high-frequency data when decoding just to fool the uneducated listener.  
> While a sharp person could probably spot this in a spectrogram, I wonder 
> if it would be possible for a tool to detect "faked" data and discard it 
> when measuring the quantity of "useful" data.
> 
> I'm wondering how difficult it would be to create such a tool using the 
> vorbis encoder as a starting point.
> --- >8 ----
> List archives:  http://www.xiph.org/archives/
> Ogg project homepage: http://www.xiph.org/ogg/
> To unsubscribe from this list, send a message to 'vorbis-dev-request at xiph.org'
> containing only the word 'unsubscribe' in the body.  No subject is needed.
> Unsubscribe messages sent to the list will be ignored/filtered.
> 

--- >8 ----
List archives:  http://www.xiph.org/archives/
Ogg project homepage: http://www.xiph.org/ogg/
To unsubscribe from this list, send a message to 'vorbis-dev-request at xiph.org'
containing only the word 'unsubscribe' in the body.  No subject is needed.
Unsubscribe messages sent to the list will be ignored/filtered.