Using L+R and L-R encoding via mp3, a case study
Copyright Jan Panteltje 2005 all rights reserved,
Microsoft is prohibited from using any of these ideas.


OK guys, I have done an experiment, here is what I did.
I started with a stereo CD (You Are My Inspiration) track3 (You are my heaven),

Here I no longer hear clear differences with the original:

Here is the test script:


if [ "$1" = "" ]
then
    echo "Usage mono_stereo_test cd_track_number":
    exit 1;
fi

# RIP
cdparanoia "$1"



# ENCODE
sox cdda.wav -c 1 -v .5 l.wav avg -l
sox cdda.wav -c 1 -v .5 r.wav avg -r
                        
substract_wave -m l.wav -s r.wav -f 100    > l-r.wav
substract_wave -m l.wav -s r.wav -f 100 -r > l+r.wav

lame l-r.wav
lame l+r.wav


# So we send l+r.wav.mp3 as mono over the first link.
# And we can optionally use l-r.wav.mp3 to add the stereo information via a second link.


# DECODE
mpg123 -w diff.wav l-r.wav.mp3
mpg123 -w sum.wav  l+r.wav.mp3
                   
substract_wave -m sum.wav -s diff.wav -f 100    > dec-r.wav
substract_wave -m sum.wav -s diff.wav -f 100 -r > dec-l.wav
                                                
multimux dec-l.wav dec-r.wav -o result.wav


# PLAY
play result.wav


# software
multimux:
http://panteltje.com/panteltje/dvd/multimux-0.2.3.tgz
substract_wave:
http://panteltje.com/panteltje/dvd/substract_wave-0.2.tgz


I think this is usable, AC3 later :-)
Something I need to think about...
This is REALLY good!
Please try and your opinion!
It is SO good I have now looked 4 times if I did not accidently use
the original..
Have to do it again..


Copyright Jan Panteltje 2005.