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Lossy Audio Compression => Other Lossy Codecs => Topic started by: user on 2001-12-16 17:21:04

Title: Dolby Pro Logic 2
Post by: user on 2001-12-16 17:21:04

I tested DPL2 this weekend.

Fantastic surrounding.

Test materials:

CD (CDDA)  of German magazine "Stereoplay" with special songs which include DPL2 infos.

Eg. Erich Kunzel: Pink Panther and some more fantastic tracks.


harman kardon HK AVR 5000 ,

surround mode for decoding :Logic 7 (in aspect of functionality the same as DPL2 !)

a TYT 2000 clone: Grundig GDV 130 as (DVD) MP3 decoder / CD-Player

Sony DAT DTC 670 as digital & analogue reference (for A/B-comparisons : original wave / MP3 )

I encoded the waves to MP3 with dm-xtreme or alt-extreme, sorry cannot remember, if I had changed my settings and versions  already.....

My results:

It seems that MP3 copes with DPL2, probably with joint stereo, too.

MP3 joint stereo worked with DPL, that is a well known fact.
(I tested myself with special DPL songs, yes, I confirm that personally.... (if somebody should be interested in my opionion))

So as xtreme setting produced enough joint stereo frames in that test songs, I would confirm that phase information is kept well.

Well enough for DPL2 !!

That would be fine.

It would be even finer, if somebody (perhaps of Dolby company) would confirm that their DPL2 signals work really well with songs encoded to MP3, joint stereo.
Title: Dolby Pro Logic 2
Post by: SNYder on 2001-12-18 19:10:47
could u provide a link to a site on dpl2.  i never heard of it and would like to read up on it.
Title: Dolby Pro Logic 2
Post by: rjamorim on 2001-12-18 19:22:05
Maybe here...
http://www.dolby.com/tech/whtppr.html (http://www.dolby.com/tech/whtppr.html)

Take a look at Dolby's site.
Title: Dolby Pro Logic 2
Post by: user on 2001-12-19 16:05:57
main differences between Dolby pro logic and Dolby Pro logic 2:


4 independent channels/Speakers:
Left - Center  - Right
only one rear channel

So there is only a mono signal out of the 2 usual Rear speakers.
The rear channel (at least) is limited in frequency, I think only up to 7 or 8 kHz.

DPL 2:

5  independent channels:
left - center - right
rear left - rear right

And all channels have complete frequencies like CD, up to 20 kHz.

Both DPL/DPL2 informations are included in the normal stereo (wave) signal of eg. CDDA.
Even in the stereo analogue output.

I think it is coded by phase differences/informations.
Title: Dolby Pro Logic 2
Post by: user on 2001-12-19 16:12:40
But I want to tell you, that you do not need especially Dolby PL 2 decoders / amplifiers / receivers like Denon AVR 1802.

With Harman kardon , eg. my HK AVR 5000 ( or eg. 2000 , 3000, 4000, 5000, 7000) you have a very good decoder for DPL2 , too.

Logic 7 is able to decode phase informations, too.
It creates 5 separate channels, each with whole frequencies, too.

left - center - right
rear left - rear right

all at least  up to 20 kHz.

I think that HK uses same technique like Dolby, but was earlier and called it Logic 7.

Kenwood has a similar system, called "Circle surround", but I don't know, how good it is.
Title: Dolby Pro Logic 2
Post by: MaTTeR on 2001-12-20 21:27:03
Thanks for the testing man. I noticed the new PowerDVD XP 4.0 has the ability to decode DPL II. I've played around with it but no serious testing yet. It does work though
Title: Dolby Pro Logic 2
Post by: mikemikez on 2002-01-10 06:06:14

Yup, PowerDVD has indeed support for it... Just went and looked, it's in there..

So are you trying to say that a let's say 192KBit well encoded MP3 can contain 5 full frequency high quality channels of sound when using this?

Damn... That's nice

Title: Dolby Pro Logic 2
Post by: MaTTeR on 2002-01-10 06:37:40
Originally posted by mikemikez

So are you trying to say that a let's say 192KBit well encoded MP3 can contain 5 full frequency high quality channels of sound when using this?


Nope, currently were unable to have a multi-channel MP3 file:(  I'm finding that the new --alt-preset standard keeps the DPL information rather nicely though. Remember DPL is surround sound and not Dolby Digital (5.1).
Title: Dolby Pro Logic 2
Post by: AgentMil on 2002-01-10 09:08:29
This is very cool indeed. I have Dolby Pro Logic on one of my older system/amp, and found its performance to be very good. It looks like DPL2 looks like the best to gett surround out of audio CD's.

I think I will look for a combination amp that has DD5.1/DTS/DPL2, any suggestion?

Also does that mean MP3 can handle DPL2 encoded material and still faithfully, and at what bitrate does that fail?

Is DPL2 downward compatible with DPL encoded soundtracks?

Title: Dolby Pro Logic 2
Post by: johnicon on 2002-01-10 10:50:24
I think any stereo MP3 (be it j-stereo or "normal" stereo) that you encode using LAME will be compatible with DPL I & II.  Some MP3 codecs use a stero mode called intensity stereo when you use low enough bitrates (96 kbps, I think). IIRC intensity stereo destroys phase information, which DPL (or any matrix surround system, for that matter) needs to steer the signal.  So use LAME:)  DPL II is compatible with DPL I and any stereo source.  By the way, I'm looking at the Marantz SR-7200 or -8200...I don't know if they sell those models where you are.
Title: Dolby Pro Logic 2
Post by: MaTTeR on 2002-01-10 17:32:24
In my testing lately I found that bitrates below 128 destroys the phase information. More specifically the center channel is distorted and the sound is crackling and this is using joint stereo. I need to do some more testing though:)
Title: Dolby Pro Logic 2
Post by: 2Bdecided on 2002-01-11 10:12:09
Can someone summarize the difference between DPL and DPL2 please? I'd like to know how it works.

Title: Dolby Pro Logic 2
Post by: AgentMil on 2002-01-11 10:44:14
Hiya David,

I think someone pointed out www.dolby.com (http://www.dolby.com) for any information on DPL1 and DPL2.

But here is what I know:

1.) DPL and DPL2 uses matrix surround encoded stereo files, basically linked to phase changes in the stereo signal. I have DPL1 and can vouch that the thing actually works, and brilliantly at that. Although it is not like DD5.1

2.) DPL2 is trying to be DD5.1, as that all channels have now full bandwidth and thus will sound much nicer. On my DPL1 system the rear speakers are very fuzzy, like its has been muffled using a pillow.

3.) Both can work try to produce surround sound using a standard stereo signal, BUT I have been told this is not advised as the rear speakers can generally mess around with the signal in that the you will hear sounds coming from where it should not be. But with DPL encoded soundtracks the surround effect is amazing.

That is as far as my limited knowledge about DPL goes, I used to have alot of information about this as I used to be a Physics student, but now I study a completely different field. But visit www.dolby.com (http://www.dolby.com) I think they have a lot of white papers on their site.

Title: Dolby Pro Logic 2
Post by: user on 2002-03-15 09:32:07
http://www.ff123.net/samples/dpl2/ (http://www.ff123.net/samples/dpl2/)

DPL2 samples you find at ff123's.

The thread for developer of azid, so that users can downmix in (near ?!) future their 5.1 ac3 to DPL2 stereo waves:

http://forum.doom9.org/showthread.php?s=&threadid=19092 (http://forum.doom9.org/showthread.php?s=&threadid=19092)
Title: Dolby Pro Logic 2
Post by: user on 2002-04-08 01:43:39
[span style='font-size:18']Dolby Pro Logic 2        samples available ![/span]

http://www.ff123.net/samples/dpl2/ (http://www.ff123.net/samples/dpl2/)

Here you find all DPL2 samples (older ones created by Dark Avenger/spacer) and the new ones, named with DPL2 at beginning.
These ones are very pleasant to the ear....

from professional CDDA, especially coded in DPL2.
Source: Stereoplay 1/2002 CDDA.

I hope Dark Avenger tells Midas how he has created the DPL2 downmix.

Then I hope that Midas has time and fun to create a new azid version, perhaps first a test version which does only the DPL2 output.

Now everybody can check out/test, how compatible DPL2 waves are with his existing hifi-setup, eg. these DPL2 songs playing on pure stereo-hifi, or playing on "old" DPL-surround-stereo-hifi.
And playing on Logic7/DPL2/Circle-surround-hifi............

http://forum.doom9.org/showthread.php?s=&threadid=19092 (http://forum.doom9.org/showthread.php?s=&threadid=19092)
if you are convinced that DPl2 does well and tell it there.
So that Midas becomes convinced that the whole community wants it for downmixing 5.1 ac3 to stereo wave (Ogg, mp3, mp2 ...) , so that stereo wave contains 5 different independent full frequency channels, much much better than "old" Dolby Pro Logic Surround !

Additional there is a HDCD sample, but that is not important, of course.

http://www.ff123.net/samples/dpl2/ (http://www.ff123.net/samples/dpl2/)
Title: Dolby Pro Logic 2
Post by: user on 2002-04-08 15:10:02

perhaps it would be more suitable if this thread moves to test/technical.

Because people should try DPL2 samples on their different hifi-setups, stereo, "old" Dolby Pro Logic Surround hifi, and on Logic7/DPL2/Circle - surround hifi.

And they should post their experiences, eg. if a DPL2 coded wave sounds worse or well on stereo-hifi.
Or on DPL.
That DPL2 sounds very well on Logic7/DPL2 hifi is tested and proved, I would say, that is proven.
Perhaps somebody with Kenwoods Circle Surround should post his/her opinion.
Title: Dolby Pro Logic 2
Post by: user on 2002-05-02 09:54:53

Dark Avenger has implemented his DS2 knowledge into his program.

So now you can convert eg. your 5.1 ac3 to stereo wave with DS2 surround information,

which can be decoded by DPL2/Logic7/Circle surrround amps.
And PowerDVD 4.0, as I have heard...

So a lot people will benefit by DS2.
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