Finally I decoded QS recordings with Adobe Audition

[Lucanu]

I tried different ways for decode some Qs material I own.
Now I've found th way to do it with Adobe Audition.
The inspiration has been taken from the thread about SQ decoding in AA.

Sorry, no scripts (I just can't do it....)

convert your sample to 32-bit 44.100
save it as front.wav
save it as rear.wav
open both

(this is front qs decoding)
go to front.wav
select only left channel
amplify it at -1.371 dB
select only right channel
amplify it at -9 dB
cut (ctrl+x) right channel
select left channel only
mix paste from clipboard into left channel
copy to new
go back to front.wav
undo all
select only left channel
amplify it at -9 dB
select only right channel
amplify it at -1.371 dB
select only left channel
cut (ctrl+x) it
select only right channel
mix paste from clipboard into it
go to front (2)
select both channels
cut it
go to front.wav
select left only
mix paste from clipboard
save front.wav

(this is rear qs decoding)
go to rear.wav
select only left channel
amplify it at -1.371 dB
select only right channel
amplify it at -9 dB
in the effects menu select invert
cut (ctrl+x) right channel
select left channel only
mix paste from clipboard into left channel
copy to new
go back to rear.wav
undo all
select only left channel
amplify it at -9 dB
select only right channel
amplify it at -1.371 dB
in the effects menu select invert
select left channel only
cut it
select right channel only
mix paste into it from clipboard
go to right (2)
select left channel only
cut it
go to rear.wav
select left channel only
mix paste from clipboard
select both channels
in the effects menu choos graphic phase shifter
select -90 degrees with 65536 FFT
save it


now you've got you front and rear channels decoded in Qs.

The procedure is directly taken from the Wendy Carlos Qs chart decoding
It's been tested with Qs material and with QsTones.mp3 and decodes pretty well.

Have fun!

 

[Scottmoose]

Ah. A nice, simple proceedure then.

I jest -in all seriousness now, many thanks for all the effort (considerable I'm sure) and I shall try it out right now. I suspect I won't be alone either...
All the best
Scott

 

[Sonik Wiz]

Hello Lucanu!

Lools like you’re trying to do simple QS decoding without any separation enhancement, right? It can be done much easier. Start by going into AA Channel Mixer & making two new presets.

Preset 1:
New Left Channel
Left = 92
Right =38

New Right Channel
Right = 92
Left =38
Click ADD & save this as QS FRONT DECODE

Preset 2:
New Left Channel
Left =92
Right = -38

New Right Channel
Left = -38
Right =92
Click ADD & save this as QS REAR DECODE

Apply these presets respectively to the front & rear wav files as you have described creating. Apply 90 degree phase appropriately to the rear channels. There ya go.

Question & Suggestion:
Do you plan on using this technique for decoding QS & playing back from yourPC? If that’s the case consider WINDVD that has PL 2 built into it. It will play files also & PL2 does a much better job of decoding QS than simple method as described above.


Scott

 

[Lucanu]

Yes Scott (Sonic Wiz ), it's the simplest way for decoding QS. BTW, I think there's a "natural" separation between the front and rear channels, if you test it with the QStest.mp3 in the Sq decoding thread you will notice a great separation.

For your enhancement there's a little problem with your solution: rear right channels are out of phase with rear left channels. Notice that the left channel is NEVER out of phase. Then you have to mix toghether the left and right channel in both cases, front and rear.
Take a closer look in the Wendy Carlos' scheme for Qs encoding.

As I know there's is no logical trick in Qs as it was for Sq, so I thought there was no need for any enhancement.

Thanks for your support!!

 

[Lucanu]

Ok, I made the script.

First of all create a directory in C:\qs
open AA, select the sample you want to decode and save it as c:\qs\front.wav and c:\qs rear.wav

Now this is the script.
Copy it and save it as qsdecoding.scp in your script directory of AA.

Collection: qsdecoding
Title: QsDecoding by Lucanu
Description:
Mode: 2
Undo: 1

Selected: none at 0 scaled 1848960 SR 44100
Freq: Off
cmd: Channel Both

Selected: none at 0 scaled 1848960 SR 44100
Freq: Off
cmd: Command 1100
1: C:\qs\front.wav
2: s

Selected: 0 to 1848959 scaled 1848960 SR 44100
Freq: Off
Comment: Amplitude\Amplify/Fade
cmd: {03EA5F5A-8046-4D8F-95E0-4387A5A4289D}
1: 0.853985
2: 0.854083
3: 0.853985
4: 0.854083
5: 1
6: 0
7: 0
8: 0
9: 1
10: 1
11: 0
12: 0
13: 0
14: 0

Freq: Off
cmd: Copy
1: 0

Freq: Off
cmd: Undo

Freq: Off
Comment: Amplitude\Amplify/Fade
cmd: {03EA5F5A-8046-4D8F-95E0-4387A5A4289D}
1: 0.354814
2: 0.354814
3: 0.354814
4: 0.354814
5: 1
6: 0
7: 0
8: 0
9: 1
10: 1
11: 0
12: 0
13: 0
14: 0

Freq: Off
Comment: Amplitude\Channel Mixer
cmd: {4EB62A8D-32F7-4515-8C90-919A17A50EE5}
1: 0
2: 1
3: 1
4: 0
5: 0
6: 0
7: 0

Freq: Off
cmd: Paste Special
1: 1
2: 1
3: 3
4: 1
5: 0
6: 0
7:
8: 0
9: 0

Freq: Off
cmd: Command 1100
1: C:\qs\rear.wav
2: s

Freq: Off
Comment: Amplitude\Amplify/Fade
cmd: {03EA5F5A-8046-4D8F-95E0-4387A5A4289D}
1: 0.853985
2: 0.854083
3: 0.853985
4: 0.854083
5: 1
6: 0
7: 0
8: 0
9: 1
10: 1
11: 0
12: 0
13: 0
14: 0

Freq: Off
cmd: Channel Right

Freq: Off
cmd: Command 3100

Freq: Off
cmd: Channel Both

Freq: Off
cmd: Copy
1: 0

Freq: Off
cmd: Channel Right

Freq: Off
cmd: Undo

Freq: Off
cmd: Channel Both

Freq: Off
cmd: Undo

Freq: Off
Comment: Amplitude\Amplify/Fade
cmd: {03EA5F5A-8046-4D8F-95E0-4387A5A4289D}
1: 0.354814
2: 0.354814
3: 0.354814
4: 0.354814
5: 1
6: 0
7: 0
8: 0
9: 1
10: 1
11: 0
12: 0
13: 0
14: 0

Freq: Off
cmd: Channel Right

Freq: Off
cmd: Command 3100

Freq: Off
cmd: Channel Both

Freq: Off
Comment: Amplitude\Channel Mixer
cmd: {4EB62A8D-32F7-4515-8C90-919A17A50EE5}
1: 0
2: 1
3: 1
4: 0
5: 0
6: 0
7: 0

Freq: Off
cmd: Paste Special
1: 1
2: 1
3: 3
4: 1
5: 0
6: 0
7:
8: 0
9: 0

Freq: Off
Comment: Filters\Graphic Phase Shifter
cmd: {FC0778B7-D686-4B7C-B40F-5F112504D8CC}
1: 262144
2: 2
3: 0
4: 900
5: 4096
6: 900
7: 1
8: 0
9: -180
10: 180
11: 3

Freq: Off
End:

Ciao!

 

[Lucanu]

p.s. you have to change the value "Selected: none at 0 scaled 1848960 SR 44100
" to a big one. So you can select entire wave, depending on how big is it.

 

[Disclord]

What are the separation values for PC decoded QS and SQ? Reason I ask is, since the format is a 4-2-4 matrix, the channels can NEVER be fully recovered. The Identity Matrix (the inverse of the encode) will decode to the stated fixed matrix values, with limited separation, but to go beyond that requires time-varying dematrixing. Thus, a 4x4 matrix multiply, which each channels dematrix equations varying based on directional predominance. No fixed solution will suffice since you can't solve for four unknowns with only two linear equations.

Cheers!
Ty C.

 

[mandel]

The approaches above achieve the same separation as passive hardware decoders which, loosely speaking, is 3db. 'logic' decoders 'directional predominance' improves this, but with the risk of 'pumping'.

The techniques discussed in this thread:
https://www.quadraphonicquad.com/forums/showthread.php?t=4633
allow full recovery via phase analysis, limited only by issues such as vinyls inherent crosstalk and imperfect stereo balance. The only downside is it takes a lot of processing power to do this.

 

[winopener]

The approaches above achieve the same separation as passive hardware decoders which, loosely speaking, is 3db. 'logic' decoders 'directional predominance' improves this, but with the risk of 'pumping'.

Could be intresting to apply the same "logic" part developed for the SQ method to the QS-decoded files and see what happens.

 

[mandel]

Check the sticky, you've already been begged

Also, as i mentioned a while back it's possible to do passive SQ/QS decoding on the fly in windows media player.

 

[Lucanu]

I tried to make the logical system applied in the sq decoding script .
The result is somehow identical to "non-logical". So I thought it was no useful.

One trick is that you have to normalize 80% both channel without select the "normalize L/R equally) function.

In this way you can recover the balance output of a non-perfect alignement of your turntable.
Another way for decoding SQ and QS is Plogue Bidule which has a good decoding system.
As I own a Sound Blaster Audigy I can decode on the fly with ASIO. The results are very good both in SQ and QS.

 

[Lucanu]

Ok, that' s a new logic trick

Before start the script take the front.wav and do a center channel extraction with values of surround (180 degrees), full spectrum, -48 dB center channel level, discrimination 100. This will remove directly the center surround from front speakers. Save front.wav
Go to rear.wav, do center channel extraction but with center value (0 degrees). This will remove the center front channel from the rear speakers completely. Save rear.wav
Now run the script mentioned before.

The decoded files played very well. I don't have music material encoded in Qs but the results are more "surround" than before.

Make some tests.

Ciao

 

[mandel]

The more I look at it, the more I wonder if a complete extraction of each channel isn't possible with QS.
Looking at SQ:
Lt = Lf + [-90]0.707LR + 0.707RR
Rt = Rf + [180]0.707LR + [90]0.707RR
The rear channels are on a +90 and -90 phase difference. The centre extract can remove them individually. With QS both the rears are on a 180 degree pan and aren't balanced between the channels. If a complete extraction is possible its going to be by a different approach...

 

[mandel]

After another hours work, I may have reached the opposite conclusion. Can somebody do one of the following two things for me.
a) Provide me with some proper QS test-tones
b) Confirm that the following mp3 is encoded into QS correctly: http://www.arafel.org.uk/~mandel/mixdown.mp3
Thanks...

 

[Lucanu]

Hey!!! is that you voice mandel????

I'll try to answer to your questions...

a) the qs test tone is available at this link http://www.grizwald.plus.com/quad/QSTones.mp3
(I work on that to see how it's been decoded....remember they are 5 secs of front center, front left+rear left, rear left, rear center, rear right, front right+rear right, front right)

b) I'll check it out

 

[Lucanu]

Ok, tested. Your sample seems to be Qs decoded....

 

[Lucanu]

About channel separation of my Qs decoding, there's a -3db between fl/fr and rl/rr, but with center channel extractor it's -40db total front/total rear.

 

[mandel]

Yep, my voice

I have found an approach that can essentially completely decode that QS sample I made. However it has a tendancy to drop information that lies in between the channels. More on this after more playing about today.

 

[Lucanu]

ok mandel....let us know....

 

[mandel]

Here is my method:

Start by entering a new centre channel extractor preset (these are rough values and need improvement)
Center level: 23dB
Crossover: 50
Phase Disc: 7
Spec: 80%
Amplitude Disc: 10
Amplitude Band Width: 20
FFT: 8192
Overlays: 6
---------------------
Import your QS encoded file.
Convert to 32db for high quality results.
Attenuate by 3db.
Attenuate LEFT channel by 7.67dB and save as left.wav
Undo left channel attenuation
Attenuate RIGHT channel by 7.67dB and save as right.wav

Reopen left.wav
Run centre channel extractor with Get Audio Phased At: Center
Run Channel Mixer with preset 'Full Mix'
Use Convert Sample Type to make mono file
Save as left_front.wav

Reopen left.wav
Run centre channel extractor with Get Audio Phased At: Surround
Use Graphic Phase shifter to shift:
LEFT channel -90 degrees
RIGHT channel + 90 degrees
Run Channel Mixer with preset 'Full Mix'
Use Convert Sample Type to make mono file
Save as left_rear.wav

Reopen right.wav
Run centre channel extractor with Get Audio Phased At: Center
Run Channel Mixer with preset 'Full Mix'
Use Convert Sample Type to make mono file
Save as right_front.wav

Reopen right.wav
Run centre channel extractor with Get Audio Phased At: Surround
Use Graphic Phase shifter to shift:
LEFT channel -90 degrees
RIGHT channel + 90 degrees
Run Channel Mixer with preset 'Full Mix'
Use Convert Sample Type to make mono file
Save as right_rear.wav

Import 4 mono wavs into DTS encoder, or whatever you use to make playable quad files.

I've used this on QS encoded mp3s of On The Run and The Great Gig In The Sky, and the results are pretty good