Dolby Digital EX question...

[wasp]

Hi!
I have got a disc which contain a Dolby Digital EX audio track (info from the booklet) but my stand alone receiver doesn't see it properly - by default decoding it as normal Dolby Digital string. I have heard that to proper automatic decode that kind of track I must have set a flag bit that inform decoder about EX audio stream. Does anybady know how can I set it? I have tried compare a few .IFO files (from my unproper decoded disc, and from proper working disc) and I haven't found any difrences in audio section...
?

[SeeMoreDigital]

You are not alone!

I have the same problem to with Dolby Digital EX DVD's. Some contain a flag, some don't.

However, I must be luckier than you because I am able to press a switch on my DSS amp and manually activate the rear centre speakers.

The same thing happens with DTS ES discrete and matrix DVD's too!

Just one of those things I guess.

Cheers

[mpucoder]

The flag is in the dolby digital stream, and is passed along to outboard decoders. But, the decoder must be one that can decode EX, or it ignores the flag.

DolbyDigital is also known as A/52, EX version is A/52a, spec is publicly available at ATSC website (http://www.atsc.org/standards.html)

[SeeMoreDigital]

Yea,

I came across a few web sites some time ago that listed many of the DolbyDigital EX DVD's. And identified which ones contained the necessary flag and which ones did'nt.

Let's hope there will be more that do... than don't, in the future!

Cheers

[maa]

Does anyone know if the AC3 format is protected by Dolby ?
I mean does every multichannel encoder come under the copyright or patent of Dolby Labs?
Seems an easy question but I've read that Dolby seems more concerned with the licencing of their TradeMark and not interseted in encoders as long as you don't call it Dolby. If you want to call it Dolby they seem to want to test the encoder for compliance or something.
Dolby doesn't apparently sell encoders so I assume you have to write your own.

Sourceforge.net has an Open Source 5.1 encoder so that can't be illeagal. Nero is offering a Dolby 2.0 encoder bundled with their 6.0 software and as a plugin for $24.-
Not sure if they are paying license fees for it though.

Anyone got the real info on this ?

[SeeMoreDigital]

DolbyDigital is just one of many multichannel formats. However, it is arguably the most famous of all the formats around.

All Dolby products are sold to manufacturers or consumers under licence. Even good old Dolby B, which can still be found on cassette player/recorders.

A few of the other multichannel formats are as follows: -
DTS (Digital Theatre Systems)
RMA (RealMediaAudio)
WMA (Windows Media Audio)
AAC (Advanced Audio Coding)
WAV - I've got some encodes with up to 8 channels
Mp3 - Yep, even Mp3 can have more than 2 channels

I'm sure other multichannel fans can add to this list with a vengeance!

Cheers

[Tuning]

Originally posted by SeeMoreDigital
A few of the other multichannel formats are as follows: -
WAV - I've got some encodes with up to 8 channels


Hi SeeMoreDigital,

I'm curious, how could a multichannel wav can be heared.
Although this is a utter newbie Q, please answer. :D
Thanks

[maa]

Thanks, but my question is aimed (well at least thats what I intended)at DVD and encoders that use the AC3 extension....

[mpucoder]

Like many technologies, publication of the specification does not mean the technology is public domain. You must obtain a license from Dolby for any commercial application (encoders, decoders, encoded streams), just like MPEG. For more information see the Dolby Digital (http://www.dolbylabs.com/digital/) page, which has pdf documents explaning licensing and tips for getting the most out of the format.

[maa]

Thanks,

well it seems a little unclear to me and others thats why I asked the question.


Making an encoder is ok.
Distributing it under GNU is ALSO ok (sourceforge)
Using it is - maybe - ok?
Saying its Dolby is NOT ok unless its approved and licenced - right ?


Dolby doesn't really answer this

[SeeMoreDigital]

Originally posted by Tuning
Hi SeeMoreDigital,

I'm curious, how could a multichannel wav can be heared.
Although this is a utter newbie Q, please answer. :D
Thanks I just open them using WMP9 and they play.

Having said that though. The more codecs and filters I install, often means that multi channel WAV files cannot be heard even though WMP9 plays them, ie the slide bar moves.

BeSweet generates them for use with other tools!

Cheers

[mpucoder]

@maa - that's about it. Just like MPEG, you can write encoders and decoders, distribute them freely, but the minute you turn a profit, they (MPEG-LA or DolbyLabs) want a piece of the pie. They (DVD LLC and DolbyLabs) also license their logos and trademarks, so AC3 or A/52 is the ATSC name for the format, but Dolby Digital is the trademarked name.

Using any encoder for yourself is fine, but, again, if a commercial product is the result, then a license is required for distribution of encoded material (not to mention other legal checks for included copyrighted material).

[maa]

Thanks mpucoder, thats exactly what I wanted to know :D

So:
The producer of a DVD using DD pays per DVD
(obvious)

A firm selling an encoder has to pay royalties too.
(less obvious unless registered and approved by Dolby)

[Stux]

Don't confuse a company looking the other way, to being legally allowed to do something.