Dolby Digital 5.1 => Pro-logic/II

A few questions as I am rather confused.

Using Headac3he

Under options-output chanels what is 2ch 4ch & 6ch.
I was under the impression for dolby Pro-logic 2 I need to select suround2 & 2Ch. ie 5.1 chan downmixed to 2 chanels, retaining 3/2 speaker config.

So what is 4ch & 6 ch mean as dolby prologic/II does not support 6 chan????
Does surround2 = prologic 2
& surround = prologic.?

Using DVD2AVI & dolby downmix

Does this make a dolby pro-logic compliant stream?
What happens if I dont use downmix? does this mean I only get the L&R chanels in the output wav?

cheers

No one knows this,

[vitualis]

If you choose to downmix, it will encode the stereo audio into a Dolby Surround compatible signal.

If you don't choose downmix, you end up with plain stereo.

"Prologic" and "Prologic 2" refer to the decoding method only. They decode the same thing (Dolby Surround encoded audio) but use more intellegent alogorithms (in Prologic2 compared to Prologic) to get better effects.

Read the tech documents at the Dolby website for more info.

Regards.

[Antonio S.]

vitualis:

I have a receiver that can decode Dolby Prologic II. Even when it converts a 2 analog channel material to 5.1 channels, the Dolby Surround material MUST be encoded for Dolby Prologic II. If not, it will not encode it correctly. As oppose to Dolby Prologic, Dolby Prologic II has the ability to have 2 diferent surround channels. I don't think tha the regular DOWNMIXING intended for Dolby Prologic will make any difference with Dolby Prologic II. All 5.1 information must be encoded as 2 channels only. Playing a Dolby suround material intended for Dolby Prologic will not make a significant improvement when deceded with Dolby Prologic II. Analog channels encoded for Dolby Prologic II rivals Dolby Digital 5.1, in a A B comparison it is very dificult to know the diference...

Antonio S.
http://www.antonio.owns.it

[W_Eagle]

Hello pal

vitualis:
Analog channels encoded for Dolby Prologic II rivals Dolby Digital 5.1, in a A B comparison it is very dificult to know the diference...

What software can downmix Dolby 5.1 wav (or other format) to Dolby prologic II?

Take care

[Antonio S.]

W_Eagle:

At this moment, I don't know of any DOWNMIXING program intended for Dolby Prologic II. As I read in the Dolby site some time ago, to encode Dolby suround for Dolby Prologic II requires a complex program to perform the job, and at this moment I don't think that you may find it FREEWARE. However most of the Dolby 2.0 Digital encountered in recent DVD movies is already encoded for Dolby Prologic II. Remember that to have the benefits of 5.1 chanels from Dolby suround, you must have a Dolby Prologic II decoder.

Antonio S.
http://www.antonio.owns.it

[W_Eagle]

Hello pal,

Thanks for the reply.
Yes, I'm quite aware that my system (standalone DVD/AV receiver) have to have Dolby Prologic II decoder in order for me to hear it ...
Is there any commercial or shareware software to decode Dolby Prologic II (that is - under US$1,000 )?

Take care

I guess no one knows this, and no one uses Headac3he.

Encoding pro-logic II if you read the guide on doom9.org it claims suround2 in headac3he is prologic II.
Back to my original ? what exactly is the 2,4,6 chan options?

??

[vitualis]

@ Antonio:

No, no, no!

It seems that no matter how many times I write this, people still don't get it.

Dolby Pro Logic and Dolby Pro Logic II refer to the decoding method ONLY.

They all DECODE Dolby Surround encoded material. You CANNOT matrix material specifically for Dolby Pro LogicII rather than Dolby Pro Logic.

From the Dolby website:

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).

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.

Pro Logic II is an advanced matrix decoder. DECODER.

It DECODES Dolby Surround encoded material. As per the above quote, it is smarter than Pro Logic I and can do some effects on standard stereo streams too.

Regards.

[martin]

hi i use soft encode 1.0 for5.1 takes long time to get use to it but its worth it hope this helps ps excelent results

[vitualis]

It should be noted that Soft Encode 5.1 actually encodes to Dolby Digital AC3 (or was it DTS?).

You can use neither on a VCD or SVCD.

Regards.