Pro-logic II with DVD2SVCD++

[Hawk]

A couple of questions.(4)

1)Is pro-logic II only a decoding method or can you encode to optimise for Pro-logic II. As far as I can see Pro-logic II decodes the 3/2 config from a standard dolby surround encoded signal. from--
http://www.dolby.com

2)If you can encode for specifically for pro-logic II is this the surround 2 option in Headach3e & Be-sweet.

3)Does DVD2SVCD encode audio to take advantage of Pro-logic II.

4)Has anyone managed to get AC3 to work with SVCD?? I have searched the forum & found nothing.

[markrb]

Pro-Logic 2 is a decode method. BeSweet does have a surround2 downmix though in the newest version. Why don't you read the Besweet homepage or ask in the audio forum where DspGuru(author of Besweet) hangs out more if you want more specific info on it?
Be warned don't ask him about Headach3e, long history there.

5.1(AC-3) audio has been covered extensively. Basically the problem is only 2 or 3 Philips DVD players will play it. In short for SVCD the answer is no it won't work.

Read the stickies before asking it will save everyone much time, including you.
http://forum.doom9.org/showthread.php?s=&threadid=24155

Don't use the + or anything else to get attention. It is a forum rule violation(Rule 9).

Mark

[Hawk]

Can domeone who really knows what they are talking about please help me out here.
(and yes I have already searched the forum) & read many of the Docs at www.dolby.com.

[waldok]

Hi Hawk,

Dolby Prologic II is a decoding method that takes a "standard" stereo signal and artificially recreates 5 channels from it. Go to the www.dolby.com for more explanations. There is no encoding involved in DPL II, it's only a specific algorithm applied on the basic stereo signal.
As far as I am concerned, I have a Onkyo receiver that performs Dolby ProLogic II decoding. I use DVD2SVCD to encode movies in stereo sound, and at playback time, I just select DPL II Movie mode to create the illusion of 5 channels. Of course it is not as brilliant as real Dolby Digital or DTS, but it is quite impressive in some cases depending on the source.
It can even be surprising on old VHS...

Hope this helps.

Waldok

[waldok]

Sorry Hawk,

Next time I'll have a coffee before answering a post, or at least I'll read it with eyes opened...
You obviously already went to the dolby site.

Sorry.

Waldok.

[Hawk]

This is why I am a little confused with PLII.
If PLII is only a decoding method then why do we need surround 2?
Wouldnt the standard surround be enough if this was true?

[ux-3]

Sorry, but I get the impression, that hawk didn't read this stuff at www.dolby.com:

I quote their site:
Dolby Pro Logic is a matrix decoder that decodes the four channels of surround sound that have been encoded onto the stereo soundtracks of Dolby Surround program material such as VHS movies and TV shows. Dolby Surround is a matrix encoding process that in essence “folds” Left, Center, Right, and Surround channels onto stereo soundtracks. A Pro Logic decoder “unfolds” the four channels on playback (without a Pro Logic decoder, the encoded program plays in regular stereo).

So Prologic is the Decoder, whereas Dolby Surround is the encoding process. Same (almost) goes for PL2:
Dolby Pro Logic II is an advanced matrix decoder that derives five-channel surround (Left, Center, Right, Left Surround, and Right Surround) from any stereo program material, whether or not it has been specifically Dolby Surround encoded. On encoded material such as movie soundtracks, the sound is more like Dolby Digital 5.1 (see below), while on unencoded stereo material such as music CDs the effect is a wider, more involving soundfield. Among other improvements over Pro Logic, Pro Logic II provides two full-range surround channels, as opposed to Pro Logic’s single, limited-bandwidth surround channel.

This should settle the issue and explain thee need for a special encode in order to maximise the benefit from PL2.

Perhaps we should ask DSPGuru what difference the surround2 setting actually implies.

[Hawk]

UX3

Yes I did read the dolby site(very very carefully).
UX3 please read the whole thread, especially my last post.

Why do we need a new encoding method Surround 2 if it is only the decoding process that has changed?

[DSPguru]

Originally posted by Hawk
Can domeone who really knows what they are talking about please help me out here.
(and yes I have already searched the forum) & read many of the Docs at www.dolby.com. WTF ?!

[ux-3]

Well, a quick search in the forum suggested yields this:

Stereo means you'll get the L&R channels out of a 5.1 signal, with surround you'll get a 2ch signal that includes information taken from all 5.1 channels and can be decoded with Dolby ProLogic decoder to a surround channel back again. surround2 is a newer method to downmix the 5.1 signal into two channels in a way a Dolby Prologic II decoder can produce a more accurate reproduction of the original file.

Makes sense?

I can tell you from first hand experience that a surround encoded svcd at 128 will yield a _stereo_ rear signal when used with dpl2. However, when encoding with surround 2, the effect seems more pronounced at 192. Maybe I'm just wanting to think so...

[Hawk]

Thanks UX-3 for the infos, it kind of confirms what I was thinking that surround 2 is more optimised for PLII.

DSPGuru, dude instead of just correcting my bad english(danke), please could add some comments about PLII & surround 2 as I still am not 100% sure. Like I asked before in this thread

Why do we need a new encoding method Surround 2 if it is only the decoding process that has changed?

It seems to me that if the old surround was downmixing according to dolby specs we would not need a surround2 or am I missing something here?

by the way besweet is an excellent program!!

[waldok]

Well guys, here are my 2 cents

I've been producing SVCDs with DVD2SVCD and I can tell you that although I select 160kbs audio stereo only, the results when played back on my Onkyo TDXS 494 in dolby Prologic II movie mode are generally amazing '(sure depends on the quality of the initial audio track though).

I even can tell you that any standard stereo audio CD performs great when played back in DPLII music mode, although no surround of any kind was involved at cd creation time...

I don't really see how the encoding could be optimlized for DPL II decoding, so please, I'm curious to know if somebody can prove it other than by just saying "I find it better "

Waldok.:confused:

[DSPguru]

hi all! reply :
http://forum.doom9.org/showthread.php?s=&postid=188693#post188693
Originally posted by Hawk
DSPGuru, dude instead of just correcting my bad english(danke), please could add some comments about PLII & surround 2 as I still am not 100% sure. i guess it's a language problem, but it sure looks like total disrespect to my friend, mark.

Cheers,
Dg.

[markrb]

Not to heat up a flame war, but how is answering your question correctly not knowing what I am talking about?

Questions 1 and 4 were fully answered and a better/alternative source of info given for the other answers.

The rest was simply Moderator house keeping aka stating the rules.

A word of wisdom. Keep it friendly and you will get better answers. Try not to insult the moderation team or any member.

If my response came off rough that was not my intention. I merely was try to point out places to look for more complete info.

Mark

[waldok]

Mark,

I've been reading so many valuable posts from you that I sure know you know what you are talking about. I'm also pretty sure Hawk didn't mean YOU dont' know what you are talking about. You know, English is not my native language either so it is quite frequent that my written english might be interpreted in a wrong way and sometimes take another meaning for the reader. My feeling is Hawk was just asking for another expert about this issue, not implying you are not an expert. Like grandma said "two advices better than one"

Anyway, guys, let's keep this friendly, everybody is here to learn.

Cheers

:cool: Waldok :cool:

[Hawk]

Chill dudes no disrespect or insults were intended:sly:

DSPguru(or anyone else)- Can you help me with the following or can you point me in the direction of a detailed guide which can explain the following.

In the Bsweet GUI:-

Decode front/rear: with this I can select the speaker config e.g. 2/0
for dolby pro-logic/II +Surround2??

Input chanel Config
I guess this is where I select the input chanels I want to downmix to 2 chanels?
correct?



Output Chanel Config

Not really sure on this, If I am encoding from a 5.1 AC3 to Mpeg 1 layer 2 stream I can only select Left & Right? Correct??
Are the rest of the outputs for other format types which can handle more than 2 chanels eg wav, AC3 etc??



How is the LFE chanel handled when I downmix to 2 chanels , Is ít just split between the Left & right chanels?

+ there is a tiny bug in the Be-sweet GUI, the balloon which pops up over the acid window shows Dynamic compression=normal even when none is selected.
:scared: