[vorbis] MP3/Vorbis comparision

[al goldstein]

Frank:

You have made your point! Thanks for the results! Looking at your gifs,
I am more concerned with the fluctuations up to 2000kHz. But perhaps the
average of many runs would be much flatter.

I've noticed that the sound of the DAC from soundcards may be considerably
different. 

Cheers .......Al

On Tue, 11 Feb 2003, Frank Grotelueschen wrote:

> al goldstein wrote:
> >I may not be sensitive to changes of a few db above 10kHz.  I'm wondering
> >how the following tests would turn out. Record pink noise. Play it back as
> >wav file. Encode it in various ways and play it back. Look at these playbacks
> >througn a spectrum analyser. Now change your sound card and see how the
> >results change.
> 
> Ok
> 1. I've generated white (not pink!) noise, 5 sec long with -6dB level.
> 2. encoded this file with "oggenc" q3 up to q7
> 3. decoded them with "oggdec" back to wav.
> 4. made a frequency analysis over the uncompressed original and
>    frequancy analysis over the compressed and decompressed files.
> 
> Result:
> With quality 3, 4 and 5 an high frequency boost at 10 kHz and higher
> is clearly visible. Quality 6 and 7 are ok, frequency response is flat.
> 
> All files, wav, ogg, and gifs from frequency analysis are here:
> 
> http://home.t-online.de/home/520022073876/ogg01-whitenoise.zip
> 
> Filesize is around 5.1 MB.
> In the gifs, i have the marked the area with high freqquencies boost.
> 
> 
> Al:
> 
> Why i should change my sound card?
> I have testest all files with the SAME soundcard. The soundcard has
> nothing to do with the problems with ogg.
> 
> Frank
> 
> --- >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-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-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.