decoding dolby surround

[hypercube]

is there any software / guide to DECODE dolby surround, prologic and prologic II to WAV files ?

[kitty]

Have you tried a Google search?

[Nolonemo]

www.doom9.org

There's a plugin for BeSweet that will convert AC3 to WAV. Can't remember what it's called right now, but you'll see it.

[BJ_M]

you dont even need the plugin -- besweet will convert ac3 surround to wav .. as for prologic ... those are wav or mpa files to begin with so what do you want to convert ?

[hypercube]

I want to implement a dolby stereo DECODER.
as you know there is 1 encoding scheme called Dolby Stereo
and 3 decoding schemes called
Dolby Surround
Dolby Surround Prologic I
Dolby Surround Prologic II

I have some good equations for Dolby Surround, but not for Prologic I and II.

dear Nolonemo and BJ_M,
I want to DECODE dolby stereo, not to ENCODE.

[vitualis]

Good luck... but if you search the Dolby site, it would seem that Pro Logic decoding is very much hardware based...

I don't know if you'll be able to find a software simulation of it.

Regards.

[hypercube]

I heard that PanHandler can do this type of job. But must pay for it.


another solution may be to use Virtual Audio device like Total Recorder
with PowerDVD. I'm going to make some tests...

note:
Yes Prologic is mostly hardware based. (see Phillips chips like SAA7710T)
but software implementation is possible, like in Powerdvd...

[El Torro]

hmm, well i had a program for that Soft Encode 5.1
I could put surround 5.1 on WAV files, it could also convert AC3s to WAVs... But i can't seem to find it anymore, i lost it

[vitualis]

I am absolutely certain that Soft Encode does not DECODE Dolby Surround audio.

Regards.

[hypercube]

you're absolutly right.

El Torro,Nolonemo could you read what a say, please ?
I wan't to DECODE Dolby Stereo tracks
not to encode !

PowerDVD doesn't recognise TotalRecorder Virtual audio device.
I give up. This is too tricky.

Dolby equations are (simplified!) :

R = Rt
L = Lt
C = Rt+Lt
S = Rt-Lt

This is strange because R = Rt and L = Lt....

I need Dolby Stereo test files... does anyone know where
I can find some ?
(I mean real dolby stereo files, produced by real dolby stereo
encoder, not by freeware like BeSweet)

[flaninacupboard]

my advice to you, don't bother. i was umming and ahhing over this very problem. i discovered that a dvd burned with a dolby digital 2.0 track, that was originally a stereo dolby surround track, tripped my surround reciever into "Dolby Digital - Pro Logic" mode, giving me nice surround effects from a stereo file. hooray!

[hypercube]

Your track was originally a stereo dolby surround track, so, it's normal that
your surround reciever tripped into "Dolby Digital - Pro Logic" mode.
I'm not sure but there is a bit somewhere in AC3 bitstream saying "This Dolby digital stereo file can be decoded with dolby surround"...

I'm not sure to understand you. Do you mean that taking regular Stereo file into Dolby Prologic decoder sounds great ?

[hypercube]

Decoding prologic II should be possible using DirectShow filters from WinDVD 4 !!

First with Dolby Digital AC3:
Using Graphedit, I made some test:

AC3 file => AC3 PARSER => Intervideo Audio decoder
=> Intervideo Audio processor => WAV DEST => WAV FILE

check 6 Speakers in Intervideo Audio processor
The WAV FILE is Stereo, but in fact contain all channels samples.
(this only mean WAV DEST filter don't recognize properly 6 channels
as input, WAV DEST source code is public so it's not a problem...)


The Intervideo EXP DMO section contain
3 algorithm setup:
ICE, Prologic and Prologic II.
only ICE is enabled. this is the problem.

all other stuff should be resolved by programming.

[flaninacupboard]

no i mean a stereo "dolby surround" track from a laserdisc, which is cd standard pcm, recorded onto cd-r, then ripped onto the computer, and encoded as a dolby digital 2.0 file, when played on a dvd player, trips the surround amp into dolby digital - pro logic mode, which means any source that is stereo "dolby surround" will trip the amp. decoding it like that makes more sense than decoding it on the computer, and putting a 5.1 channel file on the disc, when you can use the amp to do it for you, and it'll undoubtedly do a better job! incidentally on an amp with pro-logic II, it should use dolby digital - pro logic II mode, although i have only noticed PII make a difference with much newer material (tv broadcasts) and things like the gamecube. get a copy of rogue leader and listen to the discrete 5.1 surround! clever!

[hypercube]

I don't have any Dolby prologic decoder. I want to convert
Dolby prologic II tracks from DVD to MPEG Multichannel.
nothing else

[flaninacupboard]

if you dont have a surround sound amplifier, whats the use of multichannel mpegs?

[hypercube]

Phillips DVD-762: internal dolby digital decoder & internal MPEG Mutlichannel decoder.

+

5.1 amplifier without any decoder inside

=
very good cheap system !

[lourenc2]

I am in the US and have had a hard time finding a dvd player that is multichannel mpeg compatible or a reasonably priced receiver. any suggestions as to where to look/

[hypercube]

don't know. I'm french. If you can, choose Phillips or Pioneer
look at my database on my website.

[flaninacupboard]

ahhhhhhhhhhhhhhhhhh, it all makes sense now!
if you can't find the software to do it you can always use a friends pro-logic reciever with pre-outs to record the four channels. if you use a standalone cd recorder you can have a cd-r with the right and left channels and a cd-r with front and rear. or use a minidisc recorder with lp2 and youll get 160mins of stereo(should be enough for a movie) on each disc, and newer ones have usb connections so you can download them onto your pc easily. if you dont have a firend with a reciever, here in the uk you can pick up pro logic amps dirt cheap, especially if they only have stereo inputs, because nobody wants them anymore. second hand units from technics and kenwood go for around £30 or so.

[hypercube]

the directX issue is more simple !