Dolby Surround to 4 WAVs, Possible??

[mh2360]

Is it possible to extract the 4 channels (L, C, R, Sur) to separate .WAV files?

[mats.hogberg]

From what?

/Mats

[Kurt S]

There are 6 channels in Dolby 5.1 surround.
1 - Front Left
2 - Front Right
3 - Rear left
4 - Rear Right
5 - Center Channel
6 - Subwoofer

[dphirschler]

There's always the hard way. Record the line-outs from your DVD player to WAV files. You can do two at a time.


Darryl

[jimmalenko]

I'm sure headac3he can do it.

[Perro Grande]

If you have a valid AC3 file, you can use Besweet.

Set the AC3 as the input file, and set "6 Waves" as the output. It will produce the individual wave files.

[Baldrick]

It isn't possible using any software tool. It is only possible if it is 5.1 sound.

(Just dolby surround isn't 5.1)

[Perro Grande]

Yeah -- that's a good point, Baldrick...

You can't get something for nothing... What I said only applies if what you start with is a 5.1 Dolby Digital source in AC3 format.

Dolby Surround is, indeed, different than Dolby Digital. I'm not aware of any software that can create separate wave files from a Dolby Surround soundtrack...

Although that might be an interesting programming project for someone really into signal processing...

[mh2360]

The reason I asked is that a few older movies have only ever been released with a Dolby Surround/Pro-logic (DD 2.0) soundtrack. I was hoping the extract the channels and have a go at re-mixing a 5.1 soundtrack using something like Goldwave and encoding with Soft Encode. The LFE channel is easy enough to make. A bit of Stereo tweaking from the 1 rear channel to 2 channels for the rear. The L, C, R channels could probably be tweaked a little.

[wingnut]

Hmm,

I've been wondering about this for a while. A Dolby surround track is basically a stereo track with phase embedded extra channels, yes?

So a matrix decoder takes the stereo signal and does this

L R

---------------------- Matching signal ----------> Centre

---------------------- Phase embedded ---------> rears

Now, could a dsp routine be written to take a wave and work out the centre and rear channels and spit out two wave files then subtract this new centre channel from the left and right channels and spit those out as separate wave files too. At the same time the frequency rolled off lfe could be split off into another wave.

You could then load up soft encode or besweet or other flavour of ac3 encoder and pop out either a dolby digital 4.1 (l,r,c,rear+lfe) or duplicate the "rear" channel and make a 5.1 (l,r,c,lr,rr +LFE) file.

Not sure as to the complexity of doing that and digital audio manipulation is not a software area I've worked in but it's an idea for those of us that are archiving old laserdisk/vhs movies which have never/will never come out on dvd but carried a good dolby stereo mix.

Of course you could just make a dolby digital 2.0 soundtrack and leave the dolby stereo embedded .....

Cheers

Edz

[flaninacupboard]

Hmm,

Of course you could just make a dolby digital 2.0 soundtrack and leave the dolby stereo embedded .....

Now there's an idea

I see this question come up all the time, people should just leave alone and let their amp do the job it's designed for!

[kabanero]

Is it possible to extract the 4 channels (L, C, R, Sur) to separate .WAV files?

It isn't possible using any software tool. It is only possible if it is 5.1 sound.
(Just dolby surround isn't 5.1)

Yes, it is possible. I have done it.

... and encoding with Soft Encode.

mh2360,

If you have SoftEncode, open the program, click File..., Open..., choose the file type: AC3 (decode to PCM).

SoftEncoe will load your AC3 file as 2, 3, 4, 5, 6 (as many channels as you have inside that AC3) separate WAV tracks. Then you can save that as separate WAV files.

[flaninacupboard]

kabanero, we are NOT discussing AC3 or Dolby Digital, we are discussing Dolby Surround - this is entirely different.

[muskgrave]

i would like to second flannaginnanahannashinnanagans comment.
Theres no point in trying to take 2 channels and somehow tear them into 4 on your own. Thats the whole reason prologic is on your receiver. It gently smears what you would only tear up...if prologic is not on your receiver then you got it out of a cracker jack box and should flog yourself for coming on here and asking how to compensate...

dlv

[Eandtc]

My first post

I'm currently capturing the SW LDs with my Sony digital camcorder (video pass-through), and there's definitely pro-logic steering going on (I have the Logitech Z640 5.1 speaker system)

What I would like to do, however, is capture the LPCM soundtrack directly off the laserdisc and steer the soundtrack into 4 .wav's (L,C,R,S - possibly an LFE as well) so that I can make and remix a DD 5.1 soundtrack (i.e. better surround effects.)

Will Besweet do this? If I want to use Pro-Logic II, is there a program that will do this.

BTW, please don't tell me to run it through my receiver. I want to avoid unnecessary A/D conversions, and my reciever is nowhere next to my computer. Additionally, I don't want to record 2 channels at a time and have to re-sync the files on the computer. I'd like to do all this in the computer as much as possible.

Similarly, I don't want a 2.0 soundtrack, because these usually sound better in Pro-logic mode anyways. I'd rather just have a 5.1 soundtrack, so I don't have to switch modes.

[Perro Grande]

The surround sound steering you here when listening to SW on LD is the effect of ProLogic. There are only 2 channels in a ProLogic system, and the surround effect is gained via fun with phase shifting, etc.

That said...

I'm not aware of any software to produce discrete output from a ProLogic-encoded stereo soundtrack. BeSweet will not do it. The ProLogic encoding is preserved when you capture the soundtrack (either the analog or digital stereo tracks).

The conventional wisdom when ProLogic is the only "surround" mode available is to just capture the stereo signal and the prologic will follow along.

[Eandtc]

"The conventional wisdom when ProLogic is the only "surround" mode available is to just capture the stereo signal and the prologic will follow along."

But this ignores the fact that "something" has to create the 4 channels from two. If you listen to the soundtrack with a stereo reciever, you only hear two channels. If you have a Pro-logic/DD receiver but leave it in stereo mode, you only hear two channels.

Obviously, something in the receiver creates the other two channels. I simply want to recreate that process in my computer, rather than having the receiver do it.

That being said, it would appear I may have found an answer here.

[flaninacupboard]

If you search your way through the audio forum you will find plenty of discussion on dolby surround and pro-logic decoders. one in paticulr gives you the calculation you need to either encode or deocde surround signals, using something like cooledit or goldwave. it runs something like invert the right channel, subtract it from the left channel and you now have the surround channel. then you invert the left channel and subtract it from the right to get centre. if you search, you'll find it - it's all here.

[Perro Grande]

Obviously, something in the receiver creates the other two channels. I simply want to recreate that process in my computer, rather than having the receiver do it.

Yep -- the something is the Dolby Prologic decoder in your receiver which plays the necessary games with the phase, etc, that produces the four channel effect. There are, however, only two channels of information present. As you correctly pointed out, if you do not have ProLogic capabilities, you end up with Stereo.

I understand what you're trying to accomplish, and it certainly is possible to decode ProLogic with software. Some software-based DVD players can do it so the algorithms are out there. I'm not aware of any tools on this site that can do it automatically, though.

Again, though, I'm uncertain as to how much you're really going to gain in the process. The surround effects are going to have the same limited separation and frequency-response limitations as the original source unless you spend a LOT of time fiddling with them (and even then, I'm not sure how much could be done). It might end up being less time consuming to work backwards from a real 5.1 source (Special Edition) and edit it back to the original (a project I'm planning on trying here shortly).

[Eandtc]

What I am trying to get is 5 distinct soundtracks, so the conversion to 5.1 is easier. Since 2.0 usually comes out in mono, or at least less spacious than Pro-logic mode, I'm just trying to cut out the middle man. Also, my receiver doesn't do Pro-logic II, so I'm trying to recreate it in software.

I'm just willing to do a little extra work up front, so that the end product is easier to use. Rather than switch my receiver to pro-logic for the best soundtrack, I'm going to convert the prologic steering to a DD 5.1 soundtrack, which will work in regular DD mode everytime. I won't really "lose" anything - it'll be the same soundtrack in a better form.

BTW, I found this site: http://forum.doom9.org/showthread.php?s=&threadid=57736&perpage=20&pagenumber=1, and it works as advertised.

Pretty soon, I'll have Win2000 installed, and will be doing single-file captures of my LD's (30 GBs each). Then the real fun begins.