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Hydrogenaudio Forum => General Audio => Topic started by: Moitah on 2004-01-12 06:13:41

Title: Winamp "Center Cut" DSP Plugin released
Post by: Moitah on 2004-01-12 06:13:41
dsp_centercut is Winamp plugin that separates stereo audio into side and center channels. It's based on the "center cut" filter from VirtualDub. The algorithm's author, Avery Lee, describes it as follows:
Quote
The classic "vocal cut" filter, except that the output is stereo instead of mono. This is accomplished through FFT phase analysis; the output will have some warbling in it, but stereo separation is preserved.

Download: dsp_centercut.zip (http://www.moitah.net/download/latest/dsp_centercut.zip) (Binary and Source) - To use it, copy dsp_centercut.dll into your Winamp\Plugins directory and restart Winamp. Then go into Winamp's Preferences (CTRL+P) in the DSP/Effect Plug-ins section. Select "Center Cut v1.4.0" in the list, and you will see these options in the drop-down list below:Changes:
1.4.0 (2007-Jul-19)1.3.2 (2006-Jul-14)1.3.1 (2006-Jul-12)1.3.0 (2006-Jul-12)1.2.0 (2004-Mar-30)1.1.0 (2004-Jan-19)Known issues:  The buffer isn't cleared when the audio is stopped playing, so the next song you play will have a small bit of the previous song at the beginning.  I probably won't bother fixing this.

Enjoy
Title: Winamp "Center Cut" DSP Plugin released
Post by: Chun-Yu on 2004-01-12 13:33:04
Very intersting...I might create a foobar2000 DSP based on this
Title: Winamp "Center Cut" DSP Plugin released
Post by: neoufo51 on 2004-01-12 18:23:24
Quote
Very intersting...I might create a foobar2000 DSP based on this

OMG, we need a vocal remover of some kind for Foobar2000. Please go ahead and make it. It would be very much appreciated. 
Title: Winamp "Center Cut" DSP Plugin released
Post by: Moitah on 2004-01-12 18:28:06
I just discovered a bug that can cause this plugin to crash when switching between the options in the dropdown list.  I think I've found the problem and will try to fix it tonight.
Title: Winamp "Center Cut" DSP Plugin released
Post by: neoufo51 on 2004-01-12 18:42:56
This is BY FAR the most effective plugin with a vocal remover that I have ever used. Thanks for releasing this. We really need a Foobar2000 port for this though. I dunno if Moitah or Chun-Yu will do it, but either way, if one of you guys does a nice stable Foobar2000 version of this, a lot of people here on the forum are going to love you. 
Title: Winamp "Center Cut" DSP Plugin released
Post by: Moitah on 2004-01-12 19:06:15
I wouldn't say its very effective as a 'vocal remover', but it depends on the song obviously.  I use it because I think it sounds cool and sometimes you can hear stuff you've never noticed in the song.
Title: Winamp "Center Cut" DSP Plugin released
Post by: Chun-Yu on 2004-01-12 20:37:25
I'll do it later today, should be real simple.
Title: Winamp "Center Cut" DSP Plugin released
Post by: Moitah on 2004-01-12 20:51:42
I'm having a hard time finding the problem.  It doesn't help that I don't really know how to use the debugger .  If someone with more experience would like to help, it would be appreciated.  To reproduce the bug, I switch rapidly between the first 2 options in the dropdown list (the ones labeled "Center Cut - ") with the up/down arrow keys.  I can get it to happen pretty easily on my computer, but couldn't get it to happen on a different computer.
Title: Winamp "Center Cut" DSP Plugin released
Post by: Moitah on 2004-01-13 03:53:27
Here's some more detailed information I have discovered after a lot of testing:

This other computer I tried it on is running Winamp 2.80.  I copied the Winamp directory to my computer and ran it, and couldn't get the plugin to crash.  So maybe it's only with newer versions of Winamp (I can get it to crash on 2.90, 2.95, and 5.0).  Also, it seems like it's easiest to crash while playing FLAC and Monkey's Audio (I can get it to crash with MP3/Vorbis but it takes quite a bit longer).  I'm not sure why this is, but keep this in mind if you are trying to reproduce the problem.

Playing with the code, it appears that when the module type is changed in the dropdown list (switch between Side and Center... I don't think the Classic code crashes), the global variables are reset and the new module's "init" function is called WHILE the old module's "modifysamples" function is running.  When the old module's "modifysamples" function resumes, the global variables are different than when it started and I think the memory it allocated has been freed (causing an access violation when the memory is written to).

Any ideas?
Title: Winamp "Center Cut" DSP Plugin released
Post by: Chun-Yu on 2004-01-13 13:34:28
Update: I've got this working in foobar2000, but...as code for my experimental DSP plugin that runs C# code you enter :B  A real version that doesn't require .NET should come soon.  I'll probably release this C# component separately since it's kinda fun to use to experiment with an idea before implementing it as your own component.
Title: Winamp "Center Cut" DSP Plugin released
Post by: neoufo51 on 2004-01-16 13:10:55
Quote
Update: I've got this working in foobar2000, but...as code for my experimental DSP plugin that runs C# code you enter :B  A real version that doesn't require .NET should come soon.  I'll probably release this C# component separately since it's kinda fun to use to experiment with an idea before implementing it as your own component.

Nice, keep up the good work. Please make a thread for it on the Foobar forums when you are done. Looking very forward to this.
Title: Winamp "Center Cut" DSP Plugin released
Post by: Chun-Yu on 2004-01-16 13:20:03
Done: http://www.hydrogenaudio.org/forums/index....ST&f=33&t=17661 (http://www.hydrogenaudio.org/forums/index.php?act=ST&f=33&t=17661)
Title: Winamp "Center Cut" DSP Plugin released
Post by: Moitah on 2004-01-20 02:43:12
I finally found the problem !  It has been fixed in v1.1.0 (the download link has been updated in the first post).

Chun-Yu:  Good job on the foobar2000 plugin .  I used the code as a reference when updating mine to work with 8/16/24/32 bit samples.
Title: Winamp "Center Cut" DSP Plugin released
Post by: KurtCocain on 2004-01-20 21:47:59
Quote
Very intersting...I might create a foobar2000 DSP based on this

PLease do. Id be glad to have one for foobar2k
Title: Winamp "Center Cut" DSP Plugin released
Post by: Chun-Yu on 2004-01-20 22:15:38
 Please look 2 posts up from your post.
Title: Winamp "Center Cut" DSP Plugin released
Post by: M on 2004-01-21 16:52:40
Very interesting! After my humorously-flawed and tension-induced attempts (http://www.hydrogenaudio.org/show.php/showtopic/17267) to explain how something like this could be done, it's nice to learn that someone actually accomplished it! (... and to the few folks who congratulated me on the "Center Channel" that was causing my mental-aberrance, my wife's test proved otherwise. Phase-cancellation?  Ah well... we aren't quite ready for a child yet, anyway.)

  Just curious, but has anyone considered reworking this as a VST-based plugin? I don't know enough programming to do so myself, or I would have already tried it.

    - M.
Title: Winamp "Center Cut" DSP Plugin released
Post by: Moitah on 2004-03-31 05:26:27
Version 1.2.0 has been released, I've updated the first post.
Title: Winamp "Center Cut" DSP Plugin released
Post by: specise_8472 on 2004-04-01 05:32:33
Good work.
I have looked at the source and might have a go at a VST plugin.
Only problem is I code in a real language (Pascal)  , and so have to translate the gibberish into something usuable 
(Of course, all in good fun  )

If I get it up and running, I will add in my crosstalk cancel plugin before this one. Should make a lot of difference. And remove hopefully the echos from the removed vocals.

Anyway again, good work.

Don't Blame Me, I Only Work Here!
Title: Winamp "Center Cut" DSP Plugin released
Post by: Realtime on 2004-04-01 10:15:50
GREAT!
Know with larger FHT this become a very PRO plug-in! Good Work!

Only one thing: I've tested it very deeply but sometimes I hear some strange "click" in the processed waves (both in realtime and in disk-streamed wav).

It seems to me that sometimes exists some "gaps" between one buffer block and another because these little cracks are periodical (looking the wave I see some big level gap that of course produce cracks) and their occourrence vary with the size of the buffer: the larger the buffer, the longer are the time between one click and another.

You can download a test wave I've produced using Winamp5 with the Disk-Write plugin on a stereo film soundtrack (the anime Boogiepop Phantom) using the center-cut (Side-Stereo) processing.
Here'is the ORIGINAL (http://www.gianniricciardi.com/Download/Original.wav) and the PROCESSED (http://www.gianniricciardi.com/Download/Processed.wav) wav files at 48KHz-16bit-Stereo.
You can hear the cracks on the sonar-like sounds at the end of the file.

This is the only problem I've found on this plugin that in my opinion sounds very very very good! 
Title: Winamp "Center Cut" DSP Plugin released
Post by: clau23love on 2005-11-13 06:29:07
Moitah, congratulations for your work! I was looking for some years for such an application, but you actually built it!

I got vers. 1.20. I don't know how much this helps you, but, I believe the reason of crashing Winamp when switching "Sides" to "Center" is some kind of de-synchronization.

If you start Winamp in "center" mode, and then switch to "sides" mode, you'll note that music skips ahead with about a second. Maybe you should try to (somehow, I don't know), use the very same buffers for both of the two modes, "center" & "sides".

I believe there's a change in buffer size Winamp doesn't like when going from "center" to "sides". It doesn't always crash, since this is sort of a source material dependant.

Good luck!
Title: Winamp "Center Cut" DSP Plugin released
Post by: n3tfury on 2005-11-13 09:08:25
i just grabbed this too.  great work Moitah! 

(talk about bringing a thread back from the dead!)
Title: Winamp "Center Cut" DSP Plugin released
Post by: Moitah on 2005-11-15 04:38:53
Quote
Moitah, congratulations for your work! I was looking for some years for such an application, but you actually built it!

I got vers. 1.20. I don't know how much this helps you, but, I believe the reason of crashing Winamp when switching "Sides" to "Center" is some kind of de-synchronization.

If you start Winamp in "center" mode, and then switch to "sides" mode, you'll note that music skips ahead with about a second. Maybe you should try to (somehow, I don't know), use the very same buffers for both of the two modes, "center" & "sides".

I believe there's a change in buffer size Winamp doesn't like when going from "center" to "sides". It doesn't always crash, since this is sort of a source material dependant.

Good luck!
[{POST_SNAPBACK}][/a] (http://index.php?act=findpost&pid=341470")

The crashing is because Winamp's threading is buggy (it unloads your plugin from one thread while ModifySamples is still running in another).  There is a workaround in v1.2.0 which actually works pretty good but I guess not all the time.  I mentioned it on the Winamp forums a while back in hope of getting it fixed, but I don't think they care .

The skipping is because Winamp unloads/reloads the plugin when you switch between options in the dropdown list, so the buffer is cleared.  I could fix this by only having one option there, and switching between side/center in a GUI that comes up when you go into the plugin configuration.  This would fix the crashing problem when switching between side/center, but it might still crash when switching between different DSP plugins.  But I have never written any GUI in C++, and I haven't felt like learning how.

I actually have a C# version that I wrote, but haven't released it because I'm not happy with the other code that I wrote to host it, called DSPDotNet.  It doesn't have the problems you described, allows you to change the FHT window size in the GUI, has an option to use an algorithm modification made by Avery Lee in later versions of VirtualDub that usually makes the output sound crisper (though I have heard it mess up one sample), and also includes a fix discovered by myself recently to get rid of the clicking in the output (see [a href="http://forums.virtualdub.org/index.php?act=ST&f=2&t=10976]here[/url]).  I hope to fix it up sometime and release it, but I can't say when or if I will do it.  Screenshot:

(http://www.moitah.net/misc/ddn05.png)
Title: Winamp "Center Cut" DSP Plugin released
Post by: markanini on 2005-11-15 09:17:27
You wouldnt feel like porting your plugin to foobar2000? Chun-Yu ported v1.0 to foobar2000 but it would be nice to benefit from the improvements of the newer versions. Perhaps your waiting for the v0.9 SDK to be public first?
Title: Winamp "Center Cut" DSP Plugin released
Post by: Moitah on 2006-01-05 03:45:15
I am releasing a beta of my DSPDotNet project, it's a wrapper written in Managed C++ and C# to allow Winamp DSP plugins to be written in .NET languages.  I mentioned in my last post that I wasn't happy with it, so it has been completely rewritten .  You can download the binaries here (http://www.moitah.net/download/byversion/DSPDotNet-Beta1.zip).  Just unzip it to your Winamp\Plugins directory, making sure to preserve directory structure.  The .NET Framework 2.0 is required.

It includes my C# port of Center Cut.  Features over the C++ version are switching between side/center without gaps, a "new algorithm" option (something Avery changed in the code which may or may not improve quality depending on the song), changing window size (it will eat some samples when you do this), and a modification by myself to fix clicking that occurred in the output sometimes.  The Center Cut code is GPL of course, so here's (http://www.moitah.net/download/byversion/DDN_CenterCut-Beta1-Source.zip) the source for it.

I plan to release the main DSPDotNet code (GPL) when it's finished and documented.

BTW, this runs over 50% faster than the C++ version (both using window size of 8192), most likely because the way I coded the C++ version wasn't so great .
Title: Winamp "Center Cut" DSP Plugin released
Post by: markanini on 2006-01-05 06:56:03
Works and sounds great in Winamp!
Unfortunately crashes in foobar with Winamp DSP wrapper, but thats for another thread I guess.

Good work Moitah!
Title: Winamp "Center Cut" DSP Plugin released
Post by: Moitah on 2006-01-05 08:00:58
Quote
Works and sounds great in Winamp!
Unfortunately crashes in foobar with Winamp DSP wrapper, but thats for another thread I guess.

Good work Moitah!
[a href="index.php?act=findpost&pid=354701"][{POST_SNAPBACK}][/a]

Thanks .  Maybe I will test it sometime in foobar with the wrapper.

To answer your earlier question about a native foobar2000 version, the answer is no because I am not very comfortable coding in C++.  If anything, I would port DSPDotNet to foobar, but I don't think I'd be motivated to since I rarely use foobar.
Title: Winamp "Center Cut" DSP Plugin released
Post by: Moitah on 2006-01-05 08:28:54
@markanini: I just realized you're the same person who posted about a problem which you described as "buzzing", does this new version solve the problem?
Title: Winamp "Center Cut" DSP Plugin released
Post by: markanini on 2006-01-05 09:20:23
Quote
@markanini: I just realized you're the same person who posted about a problem which you described as "buzzing", does this new version solve the problem?
[a href="index.php?act=findpost&pid=354719"][{POST_SNAPBACK}][/a]

All gone
Title: Winamp "Center Cut" DSP Plugin released
Post by: Moitah on 2006-07-12 09:41:13
New version!

1.3.0 (2006-Jul-12):
dsp_centercut.zip (http://www.moitah.net/download/latest/dsp_centercut.zip) (Binary and Source)
Title: Winamp "Center Cut" DSP Plugin released
Post by: Moitah on 2006-07-12 19:59:54
Released 1.3.1 because I broke the "classic vocal remover" in 1.3.0 .
Title: Winamp "Center Cut" DSP Plugin released
Post by: pepoluan on 2006-07-12 20:10:22
Grrr... just as I finished downloading 1.3.0

Peace!
Title: Winamp "Center Cut" DSP Plugin released
Post by: Moitah on 2006-07-15 01:07:41
1.3.2 released, contains a quality tweak (doesn't make a big difference most of the time).
Title: Winamp "Center Cut" DSP Plugin released
Post by: scharfis_brain on 2006-07-24 21:16:41
Would it be possible to turn this vocal remover into a pretty effective Dolby Prologic I Decoder?

Center Cut - Sides (Stereo) -> to Left and Right
Center Cut - Center (Mono) -> to Center

The Surround information can be decoded by inverting the Left or the Right channel and then feed this kind of inverted stereo into the vocal remover in "Center Cut - Center (Mono)" Mode.


in summary this means:

+Lt & +Rt: Center Cut - Sides (Stereo) -> to Left and Right
+Lt & +Rt: Center Cut - Center (Mono) -> to Center
-Lt & +Rt: Center Cut - Center (Mono) -> to Surround

what du you think about it?
Title: Winamp "Center Cut" DSP Plugin released
Post by: Moitah on 2006-07-24 22:10:38
I don't have any material to try it on, nor do I have a surround sound setup.  You can try it yourself with the help of a sound editor to do the inversion and to combine the results into a 5 channel WAV.  If you use Winamp with the disk writer, make sure you restart Winamp or reload the DSP plugin (select "(none)" and then Center Cut again) to flush the buffer between runs, otherwise the outputted files won't be synchronized with each other.  Alternatively you could use the foobar2000 plugin (http://www.hydrogenaudio.org/forums/index.php?showtopic=46611) which doesn't have this problem, or Center Cut GUI (http://forums.virtualdub.org/index.php?act=ST&f=21&t=12627) (requires WAV input).  If you do it, let us know how it turns out.
Title: Winamp "Center Cut" DSP Plugin released
Post by: MedO on 2006-07-24 23:56:21
I'm very new to audio programming, so played around with your source to see what happens when I do this and that... I have a few hints, too.

There are a few unnecessary calculations in CenterCut_Run:

Code: [Select]
double cR, cI;
double A, B, C, D;

cR = lR + rR;
cI = lI + rI;

A = cR*cR + cI*cI;
B = -cR*(lR+rR)-cI*(lI+rI);
C = lR*rR+lI*rI;
D = B*B-4*A*C;

if (D>=0.0 && A>nodivbyzero) {
    double alpha = (-B-sqrt(D))/(2*A);

    cR*=alpha;
    cI*=alpha;
} else
    cR = cI = 0.0;


B is the same as -A, so you can replace the code with the following:

Code: [Select]
double cR, cI;
double A, C, D;

cR = lR + rR;
cI = lI + rI;

A = cR*cR + cI*cI;
C = lR*rR+lI*rI;
D = A*(A-4*C);

if (D>=0.0 && A>nodivbyzero) {
    double alpha = (A-sqrt(D))/(2*A);

    cR*=alpha;
    cI*=alpha;
} else
    cR = cI = 0.0;


Also, the bass is often in the middle with the voice, so you might try to set cI=cR=0 for i < (100*halfwindow/samplefreq) to keep the frequencies below 100 hz, or something like that.

I hope that was useful  .
Title: Winamp "Center Cut" DSP Plugin released
Post by: Moitah on 2006-07-25 00:32:47
B is the same as -A, so you can replace the code with the following: ...

Nice observation.  Originally cR and cI were calculated differently, I just changed it in v1.3.2 it based on a suggestion by Avery and didn't think to simplify it any further.

Also, the bass is often in the middle with the voice, so you might try to set cI=cR=0 for i < (100*halfwindow/samplefreq) to keep the frequencies below 100 hz, or something like that.

I tried the same thing a few days ago and it did sound good.  I'd like to have the option to do this in dsp_centercut, but I don't do GUI stuff in C++ .
Title: Winamp "Center Cut" DSP Plugin released
Post by: Iceman_jkh on 2006-09-19 06:23:05
Moitah,

This DSP is excellent!!!.. really sounds great!

Is there any news on whether its gonna come out in VST form?
I REALLY need this in VST form, but my programming skills arent even nearly up to it.

I'm debating whether I should learn how to do it - which will take forever - or can you tell me if a VST version is in progress at the moment?

Cheers
Ice
Title: Winamp "Center Cut" DSP Plugin released
Post by: Moitah on 2006-09-19 18:29:44
I don't plan on making a VST version.
Title: Winamp "Center Cut" DSP Plugin released
Post by: Iceman_jkh on 2006-10-03 13:58:48
Has anyone looked into writing a VST version of this program.. or is anyone currently doing it?

There are a few centre channel extractor VST's out there, but they leave a lot to be desired! Centre cut is the first one Ive found that actually produces passable results... and not just passable, but excellent!
Title: Winamp "Center Cut" DSP Plugin released
Post by: Moitah on 2007-07-19 18:45:17
1.4.0 released, adds ability to put the bass (< 200 Hz) in the side output and exclude it from the center.  This is useful if you're using the plugin for the purpose of vocal removal.
Title: Winamp "Center Cut" DSP Plugin released
Post by: Eliud on 2007-10-04 23:16:19
Could it theoretically be possible to run the plugin with the "Center Cut - Sides (Bass to Sides)" setting, save output to audio file, then run the plugin with the "Center Cut - Center (Bass to Sides)" setting, save output to audio file, THEN use audio editor to make a two channel file first with LEFT sides of both different output results placed on the left and right respectively, inverse phase ONE channel, and ADD some reverb or echo effect ONLY to the channel where the center channel was kept and see perhaps if the reverb added on this channel CANCELS OUT the reverb (with any luck!) of the output result of the other channel (the one with "Center Cut - Sides (Bass to Sides)" setting on) without drastically and negatively affecting the percussion and other instruments in the center where the vocals are... And having the same procedure done for the RIGHT processed channels, respectively. In other words, by doing this, you would have the LEFT PROCESSED channel and RIGHT PROCESSED channel with less reverberation as well, then combining the final results as a stereo audio file... having an almost 100% vocal free recording. Is this possible?

P.S. When one selects/highlights ONE channel in a sound editor, does the inserts applied to this channel ONLY affect this channel? The reason I'm asking is if this is the case, one can monitor in realtime the output result in MONO mode to HEAR how much reverb cancellation is happening in the final result for the respective channel being tweaked. Thanks. 
Title: Winamp "Center Cut" DSP Plugin released
Post by: vanmeter on 2010-02-13 23:12:30
I realize this is an old thread, but I've recently discovered this plug-in and have a question. I e-mailed moitah privately today from his site, but thought I'd ask here as well in case others have run into this as well.

I'm knocked out by how well this works with mono records recorded as stereo, extracting the center. Astounding...except that the audio occasionally has artifacts that sound like lower bit-rate mp3 compression, like the "underwater" sound, but only with certain source material.

Is this just part of the package with this kind of extraction, or is this possibly some winamp setup (input, etc.) problem? Processor speed perhaps? Just not sure what the problem might be. Thanks!
Title: Winamp "Center Cut" DSP Plugin released
Post by: DVDdoug on 2010-02-18 02:43:55
Quote
I'm knocked out by how well this works with mono records recorded as stereo, extracting the center.
If you like the effect, go ahead and use it, but this is not the best way to restore the original mono, if that's what you're trying to do.

If it's a stereo recording with identical left & right channels, you can simply choose one channel or the other,  mix them, or leave it as-is.  If you're talking about vinyl records, you can choose channel with the fewest clicks & pops.  Or, you can replace the defects on one channel with the good signal from the opposite channel.  (Wave Repair (http://www.delback.co.uk/wavrep/) can do this, and it often works very well with true-stereo records too!)

If it's simulated stereo, you can try mixing the channels, but phasing/timing differences between the channels can foul-up the result, so it's often best to leave it as-is.


Quote
Astounding...except that the audio occasionally has artifacts that sound like lower bit-rate mp3 compression, like the "underwater" sound, but only with certain source material.

I assume these are FFT (http://en.wikipedia.org/wiki/FFT) artifacts.    I don't believe it's related to processor speed, but it's possibly due to algorithm compromises designed to speed-up the processing so that it works in real time?
Title: Winamp "Center Cut" DSP Plugin released
Post by: Joe Bloggs on 2014-03-27 12:53:49
Sorry for resurrecting an old thread again, but I'd like to say that 10 years on this is still an awesome plugin!

I used this adapter for running this plugin on a VST host
http://forum.openmpt.org/index.php?topic=4102.0 (http://forum.openmpt.org/index.php?topic=4102.0)

Then made multiple copies of both the winamp plugin and the adapter plugin to hack this winamp plugin into running multiple instances on Live Professor

This allows me to split stereo recordings into left, center and right channels and apply individualized DSP processing to each channel.  This is just an example of what I've come up with:
(http://jodoforce.smugmug.com/Other/Equalization/i-JKTCmTc/0/O/3-channel%20stack.jpg)

There's two instances of Center Cut separating out the center and side music info, feeding two HRTF plugins and EQ plugins shaping the center and side music info differently.

Before when I used HRTF plugins to simulate speaker sound on headphones I found the resulting sound to always be unnatural and muffled.  Now with this virtual 3-channel setup I find the sound to be superior to unprocessed 2-channel headphone output in every way!
Title: Re: Winamp "Center Cut" DSP Plugin released
Post by: Rolf Taylor on 2020-11-07 14:50:24
Hello Folks,
I hope I don't annoy anyone posting to such an old thread. But my thoughts are indeed an extension of this one.

The stereo to 5.1 upmixer called "Penteo" is based on this center cut algorithm combined with a phase corrector algorithm by Hans Van Zutphen's "Tape Restore Live" azimuth corrector (this is divulged in John Henry Wheeler's Penteo patent). It makes good sense that phase (aka azimuth) correction would reduce the fuzziness sometimes heard with Center Cut.

I have heard quite a bit of Penteo Upmixed material and some of it is actually better than native 5.1 material. In fact some of the best 5.1 I have heard was upmixed using Penteo. Maintaining the original artistic soundstage image but spreading it across more speakers magically solves the "lost in the mix" problem that has always been the bain of sound mixers.

So, I am going in a couple of directions with this:

1) Has anyone played around with azimuth correction in conjunction with Center Cut? If not, I urge someone to try this.

2) Does anyone know how one goes about converting this type of computer code into DSP code that would run on a DSP platform? I have never written code for DSP, but my understanding is that it doesn't run normal computer languages like C++. But I could be wrong on that. Perhaps some sort of cross compiler would be used.

3) Back in the early days of Penteo they intended on selling real time hardware encoders. I like dedicated devices, so the idea of buying Pro-tools and the Penteo plug in, no matter the issue of cost, just isn't what I am looking for. Batch conversion might be an option, but real time seems like the best way to go, IMHO. Same problem with running plug-ins on Winamp. I guess I could go that route, but definitely not my preference.

4) I suppose processing files is another approach. Not sure of an efficient batch process to convert my large music library.

Here's where I am going with this. Ideally, these algorithms could be converted and made into a DSP plug in for something like the Analog Devices' ADAU1701 processor (e.g. some of the miniDSP and Dayton Audio products) could make pretty amazing open source hardware/software real time upmixer.

Ideas?

(An Aside). I have a reasonably modern AVR with both Dolby and DTS upmixers built in. None are more than "interesting". Penteo goes beyond that, but isn't available except as a plug in. Not sure why the AVR folks haven't done anything better. Perhaps it has to do with the "not invented here" effect. I can understand Dolby and DTS not wanting to use something that includes open source code, but why hasn't Dolby, Denon, or Onkyo done so (there is already open source code in many of their products)?

Reference Link

(Inventor of Penteo on open source components): https://www.quadraphonicquad.com/forums/threads/penteo-shocker.13838/

(more on center cut): http://www.virtualdub.org/blog/pivot/entry.php?id=102