[studiorecorder] MP3 tests

  • From: "Neal Ewers" <neal.ewers@xxxxxxxxxxxxxx>
  • To: "Sr" <studiorecorder@xxxxxxxxxxxxx>
  • Date: Fri, 16 Jun 2006 13:08:40 -0500

Well, I have certainly learned some interesting things today.  

Results.

Studio recorder on a 1 hour file with white noise and various other high
quality sounds.  No VBR high quality, and in simple stereo and not joint
stereo.  Converted all files at 192 KBPS.
Time taken.  3 minutes 40 seconds.



Sound Forge with the same file, and the same settings except that I had
stereo set to joint.

Are you ready for this?  20 minutes and 23 seconds.  I then discovered
the error of my ways and set Sound Forge to simple stereo.  It still
took 20 minutes and 23 seconds.
The SF and SR files were within 3 KB of being the same size and I could
tell no difference in quality between them.

I then read Rob's message about very high quality MP3 conversion.  It
was way down at the bottom of the list and I didn't see it the first
time.  So, I cheated.  I used the same file in SR but only 10 minutes of
it and multiplied it by 6 to get 60 minutes.  When I got to 7 minutes on
the 10 minute file, times 6 or 42 minutes, I canceled the operation.
Rob, I think you're right.  If there is no significant difference, I
would remove it.  The question is, is there a difference.  Even if there
is, it ain't worth that long a time to convert in my opinion.

 

One question though.  Here is the definition of Joint stereo that Sound
Forge uses.  Rob, tell me if this is your understanding of this and if
it is needed on a file that is converted at 192 KBPS.  Sound forge does
some other additional processing as you will see in their description.

 

if 

 

Joint stereo

Select this radio button if you want the encoder to be able to 

take advantage of the similarity between the two channels of 

a stereo file. Joint stereo encoding is useful when you want 

to create a stereo file but require a relatively low bit rate.

When the radio button is selected, select or clear the 

Intensity stereo or MS (mid/side) stereo check boxes to 

indicate which encoding methods will be used. 

 

Intensity stereo

In this mode, the encoder can take advantage of the fact that 

the human ear does not distinguish location information for 

low frequencies as well as it does for higher frequencies. 

For high frequencies, magnitude and spatial information is 

encoded. For low frequencies, only magnitude and phase are 

encoded. 

 
These check boxes are not available in SF in normal stereo mode.
 
So, there you have it friends.
 
Neal Ewers
Ravenswood Productions
Local phone:  608-277-1995
Toll Free:  888-544-8332
Email:   <mailto:Neal.ewers@xxxxxxxxxxxxxx> Neal.ewers@xxxxxxxxxxxxxx
 <http://www.ravenswood.org/> http://www.ravenswood.org
 

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