Finally I decoded QS recordings with Adobe Audition

[Lucanu]

Ok mandel....
I've tried your method.....visually speaking seems you have 2 mono files, front and left, there's a separation between the two above but no separation at all from left and right front, and left and right rear.

I used the same test file and I put in multitrack the results, yours and mine.

this is what comes from...

 

[Lucanu]

Now, as you can see, the test file has center front, left front, left front+left rear, left rear, center rear, right rear, right front+right rear, rear front.

The script I use is a little bit different and it's this (paste it if you think it's useful):

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 4181759 scaled 1848959 SR 44100
Freq: Off
Comment: Filters\Center Channel Extractor
cmd: {2A0B716A-4C11-4871-8C81-36BAB58A47B6}
1: 1
2: 8192
3: 0
4: 40
5: 6
6: 2
7: -48
8: 90
9: 0
10: 22050
11: 180
12: 904
13: 9
14: 4
15: 50
16: 0
17: 0
18: 0
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: Filters\Center Channel Extractor
cmd: {2A0B716A-4C11-4871-8C81-36BAB58A47B6}
1: 1
2: 8192
3: 0
4: 40
5: 6
6: 2
7: -48
8: 90
9: 0
10: 22050
11: 0
12: 904
13: 9
14: 4
15: 48
16: 0
17: 0
18: 0
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:

As intended at the start of 3ad you must have a front.wav and rear.wav in your c:\qs directory

Now, if you take a look at channel separation map for qs decoded material seems my script respects the graphic with same separation.

 

[Disclord]

Don't know if this info will help or not, but here goes:

For Sansui's QS with basic 2-channel stereo playback, Lt-Rt will have 7.7db of separation. When decoded, it's -3db all around with diagonally opposite channels being -20db or more down as Lucanu's graphic shows. The basic linear QS decode equations are:

Lf = Lt +.414Rt
Rf = Rt +.414Lt
Lb = -J(Lt - .414Rt)
Rb = J(Rt -.414Lt)

For variable matrix decoding, if you add to the sum of the two composite signals 2.41 times the DIFFERENCE between the two signals, then Lf will be totally separated from Rf. To extract Rf, you subtract 2.41 times the difference. If any back sounds are present, they will be increased 2.41 times.

The full equation for Lf extraction is:

(1.414Lf + 1.414Rf) + 2.41(.586Lf - .586Rf) =
1.414Lf +1.414Rf + 1.414Lf - 1.414Rf = 2.82Lf

The output from from the Lt channel now contains only the Lf with the original crosstalk from Rt cancelled out by the 2.41 coefficient.

For Lb extraction, the encoding is: jLb + j.414Rb.
The decoding is:

jLb + J.414Rb + jRb + j.414Lb +j.2.41Lb + jRb - j.2.41Rb - jLb = j2.82Lb
Or, simplified
(Lt - Rt) + 2.41(Lt + Rt)

Phase can be used to sense Front/Back since, in QS, the phase difference between the channels is directly proportional to the F/B ratio. It's 90 degrees when F/B ratio equals 1-to-1 and 180 degrees when all sounds are at back, no fronts.

As I said, I don't know if this info will be helpful or not since I have not tried PC based decoding, but perhaps one of you will be able to adapt it for improved QS decoding results.

Cheers!
Ty C.

 

[Lucanu]

This info is very helpful!
thanks Disclord!

 

[Lucanu]

Well....
I think I lost myself reading various versions, maths and calculating things....

This is Wendy Carlos' scheme for encoding/decoding qs material.

I think this is the real thing just because she released and mixed an album in quad, using the Qs matrix.

 

[Lucanu]

As you can see, in the decoding process, there's only two channels out of phase. Both taken from from Rt.
The -90° thing is applied just before output of the rear channels. That's why I don't understand the Qs decoding process....
There's a lot of difference according to others dematrix processes.

W.C. explains that for
Lf = .854LT+.354RT
Rf = .854RT+.354LT
Lb = -j(.854LT-.354RT)
Rb = -j(.354LT-.854RT)

 

[Disclord]

First of all, everyone needs to stop reading Wendy Carlos' site. Go to the patent database if you want correct information. Also, it dosen't matter if you are using a PC or not, you will NEVER EVER recover the original channels once they have been matrixed down to two. It's an impossibility. Only if a single source (or at most two) is present at once is it possible to completely recover the original signals - otherwise, the various channels will ALWAYS have crosstalk. The best way to decode would to be to figure out a variable dematrix with a phase or amplitude detector to detect the prominent (loudest) sound at any instant and enhance its directionality. QS, unlike SQ, needs both side-to-side and front-to-back directional enhancement.

Here's a Sansui-based diagram of QS encoding and decoding, along with the matrix notation of the channel content.

 

[Lucanu]

Thanks disclord...

btw I took a look yesterday to your website... VHD talking...

 

[Sonik Wiz]

First of all, everyone needs to stop reading Wendy Carlos' site. Go to the patent database if you want correct information.

Amen, Brother Ty.
All considerations so far have really over complicated the QS decoding method. It's a very simple add/subtract mix, exactly as I stated in my earlier post, with the 90 deg shiftt applied after this. The bigger question is , why bother? Simple QS decoding in and of itself is pretty dismal. I hope to offer some info soon that will do a good job of enhancing QS directionality as well as be applicable in Stereo to Surround (S2S) decoding.

And you are right on for the patent suggestion. Go to www.uspto.gov & search by keywords, inventor, company, etc. You will have to download a image viewer to read the diagrams.

BTW, nice diagrams you have there. Where'd ya get 'em from?

 

[Disclord]

Scotto-San,

I meant to credit you - or more exactly "Sonik Wiz-Circa 1984" but had a few cats demanding attention, thus forgetting and hit "Post Reply" before I remembered. All credit for the graphics go to you! Please forgive me - I did at least keep the MCS Review title in the graphic.

Here's an even better Patent Database - worldwide.
http://ep.espacenet.com/search97cgi/s97_cgi.exe?Action=FormGen&Template=ep/EN/home.hts

Use the Advanced search and you can search US only or US WO for US and WorldWide - All patents are viewable as PDF's - for free. It's what I do when I need to relax - or have a good laugh!

Ty C.

 

[Lucanu]

Ok....I surrend...

BTW, just a consideration

It's TRUE W.C. method is totally incorrect...
but
I consider a thing....
It's about channel extraction: the script is based on that calculating method, wrong, but works, or, as I think, works "better".
Can you explain how can this happen?
I consider only the "graphic" factor, because in general, there's a better channel separation (not so perfect, but still it works)...

I need only a few comments about that

thanks

@disclord & SonikWiz
Thanks for your help for finding great info about all this stuff

 

[Lucanu]

Tatataratataaaaaa....

Well, I'm a little crazy, as you can see, but I took a whole new way for decoding.
Theorically, there's more separation at all, and effectively it all sounds much better

this is the picture of the "classic" test file I use and the graphic results.

Now, I'm gonna explain how I did it:

Take your sample and save it as c:\qs\front.wav and c:\qs\rear.wav

1: go to front.wav
do a center channel extraction with the values of the picture ccefront.jpg.

do it again for other 3 times.
now go to effects/amplitude/pan-expand/ (take values from picture panex.jpg)

2: go to rear.wav
do a center channel extraction, same values but for (center) channel.
do it again for other 3 times.
phase shift left channel -90° and right channel +90°.
pan/expand with same values you had before.

and save all.

that's it.
decoqs.jpg is the picture of test file coded with this method.

 

[Lucanu]

This is the automated script for the stuff I mentioned before...

Collection: lucanu qs
Title: qs
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: P

Freq: Off
Comment: Filters\Center Channel Extractor
cmd: {2A0B716A-4C11-4871-8C81-36BAB58A47B6}
1: 1
2: 8192
3: 0
4: 40
5: 6
6: 2
7: -48
8: 90
9: 0
10: 22050
11: 180
12: 904
13: 9
14: 4
15: 50
16: 0
17: 0
18: 0
Freq: Off
Comment: Filters\Center Channel Extractor
cmd: {2A0B716A-4C11-4871-8C81-36BAB58A47B6}
1: 1
2: 8192
3: 0
4: 40
5: 6
6: 2
7: -48
8: 90
9: 0
10: 22050
11: 180
12: 904
13: 9
14: 4
15: 50
16: 0
17: 0
18: 0
Freq: Off
Comment: Filters\Center Channel Extractor
cmd: {2A0B716A-4C11-4871-8C81-36BAB58A47B6}
1: 1
2: 8192
3: 0
4: 40
5: 6
6: 2
7: -48
8: 90
9: 0
10: 22050
11: 180
12: 904
13: 9
14: 4
15: 50
16: 0
17: 0
18: 0
Freq: Off
Comment: Filters\Center Channel Extractor
cmd: {2A0B716A-4C11-4871-8C81-36BAB58A47B6}
1: 1
2: 8192
3: 0
4: 40
5: 6
6: 2
7: -48
8: 90
9: 0
10: 22050
11: 180
12: 904
13: 9
14: 4
15: 50
16: 0
17: 0
18: 0

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

Freq: Off
Comment: Filters\Center Channel Extractor
cmd: {2A0B716A-4C11-4871-8C81-36BAB58A47B6}
1: 1
2: 8192
3: 0
4: 40
5: 6
6: 2
7: -48
8: 90
9: 0
10: 22050
11: 0
12: 904
13: 9
14: 4
15: 48
16: 0
17: 0
18: 0
Freq: Off
Comment: Filters\Center Channel Extractor
cmd: {2A0B716A-4C11-4871-8C81-36BAB58A47B6}
1: 1
2: 8192
3: 0
4: 40
5: 6
6: 2
7: -48
8: 90
9: 0
10: 22050
11: 0
12: 904
13: 9
14: 4
15: 48
16: 0
17: 0
18: 0
Freq: Off
Comment: Filters\Center Channel Extractor
cmd: {2A0B716A-4C11-4871-8C81-36BAB58A47B6}
1: 1
2: 8192
3: 0
4: 40
5: 6
6: 2
7: -48
8: 90
9: 0
10: 22050
11: 0
12: 904
13: 9
14: 4
15: 48
16: 0
17: 0
18: 0
Freq: Off
Comment: Filters\Center Channel Extractor
cmd: {2A0B716A-4C11-4871-8C81-36BAB58A47B6}
1: 1
2: 8192
3: 0
4: 40
5: 6
6: 2
7: -48
8: 90
9: 0
10: 22050
11: 0
12: 904
13: 9
14: 4
15: 48
16: 0
17: 0
18: 0
Freq: Off
End:

p.s. I edited this post with a better script

 

[Lucanu]

Anyone tried it or no???

 

[Lucanu]

Someone will surely notice that finally I have my own Sansui and as you can imagine I've put in play some of my own recordings in Qs.
Tried the script first and listen to it, the I played back the originals into the Sansui qrx-7001 and.....

Surprise: :banana: the script decoding is nearly perfect, I should say it gets better results than Sansui (more channel separation).

You must have a C:\qs folder where to put the sample you have then save it to front.wav and rear.wav.
The script must be into the AA1.5 script folder.

This is the script I want to share with you.

 

[imploder]

Hi folks!
I was absent to this forum for a couple of months...
I am the guy who brought up the SQ decoding method...

The "logic" QS decoding is absolutely simple, believe me, I tested my method with testfiles from matrixquad and with my own records.

Taking the well known vector based schemes as basis and doing a "non-logic" decoding by mixing various files and helpfiles (I will not try to explain that step again....), the channels A' B' C' and D' come out. (A and D for back and B and C for front)

Look at them: Everyone contains a +90 or -90 degrees phase shifted SINGLE channel! So for example on A'(left back) there is contained B' (left front)...

Now the "logic" part:

This means simply that if the IN PHASE (!) material is removed with CCE at 0 degrees from each front and back stereo file and the remaining parts are shifted back in phase there will come out completely channel seperated stereo files.

The trick is: The former front file gets the back file and vice versa.

No crosstalk (exept limits of the source material)

Complete channel seperation can be done, because crosstalk caused by the downmixing was already avoided at the mixing (or should have been avoides, not all Quad recordings were high end...)

Rubbish in, rubbish out, of course.

So, Germany is close to Italy, hmm??

Greetings to all, keep Quad alive!

Imploder

 

[Lucanu]

In fact imploder, if you take a closer look to the script that isattached in the zip and look to the processes you'll see effectively that my method (at least the last one I posted) use only the CCE function, 0° for extract rears and 180° for the front.
Now because it can't be done aggressevely I decided to make the CCE extraction 4 times for front and 4 times for rear, because it sounded less watery. I could apply an aggressive process to the CCE limiting time and elaboration, but the result was horrible, so it's better to do it several times with more light values.

and yes, Germany is close to Italy, or better, is close to Sardinia (in summer there's 50% of italians and the rest germans)

 

[sam77aus]

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 .......................................etc.

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!

I do not have any QS encoded albums to test this out on, but this procedure seems to works very well at synthesizing a quad effect from a stereo source.

Samuel

 

[Lucanu]

It works if you apply a pan/expand effect before doing the qs script.
Another thing I missed....
When decoding is done you must apply a phase shift -90° for rear left and +90° for rear right.

 

[Q-Eight]

I've got one QS encoded LP, and I have the day off tomorrow! I will experiment.

I have to say, this PC decoder has changed the way I look at SQ. I always saw it as a cheap ploy that was thrown at the American Public. Let's call it the AMC Pacer of the audio world. Hearing it decoded on my computer gives me a newfound respect for the format. I guess this is what they'd HOPED it would sound like 30 years ago eh?

I've never heard a Tate but now I don't want one! LOL :banana: