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Old 4th March 2002, 15:08   #1  |  Link
DarkAvenger
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@Midas: DS for DPL2 and possible bug in azid.dll 1.8

Hey Midas,

it would be great if you could add DS for DPL2 support in azid ("Surround2"?). Unfortunately you didn't reply to my mail, so I am trying it here:

According to my experiments (with help of "user/Anwender") you need to do following to get seperation for the rears with DPL2/CircleSurround/Logic7 amp:

The rears must be mixed down with a difference of 3db ie.

instead of mixing SR into Lt and Rt with -3db, I guess it needs to be done like -1.5db into Rt and -4.5db into Lt
same applies to SL: -1.5db into Lt and -4.5db into Rt.

Of course I am not sure about the absolute values (-4.5db and -1.5db), but I know that the difference should be at least 2db, best 3db. This downmix is still compatible with DPL, at least the speparation on the front axis seems to be good enough.

I could do this per hand, of course, but it would be much easier if you'd implement it, as it won't be hard for you, I guess.

bug of azid 1.8?

I am not if it is bufg or I am initilizing azid 1.8 incorrectly:

When trying a mono downmix (from a 5.1) source, the LFE is not downmixed. All other channels seem to be in the "center" mono channel. Could you verify this? (I am sure that with azid 1.7.1 this was even worse.)
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Old 4th March 2002, 17:09   #2  |  Link
DJ Bobo
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I thought that DPL2 was a pure playback technique, so what has Azid to do with it?!
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Old 4th March 2002, 18:19   #3  |  Link
DarkAvenger
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Basically yes, thats why I called it "DS for DPL2". In fact there are tracks which have been mixed to separetly control the surrounds and I found oout how, as I described above. So in order to make DPL2 work in the way you want, you have to probably downmix the way described, otherwise you will have a mono surround or two "guessed" surrounds - depending on the DPL2 mode (there are several).
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Old 4th March 2002, 19:32   #4  |  Link
DJ Bobo
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Ah, I understand now, its kinda of making the job for DPL2 easier what makes the result better, oh I see...
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Old 4th March 2002, 20:10   #5  |  Link
DarkAvenger
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Not really. It is nbot about making DPL2's jkob easier, it is about controlling DPL2's job..
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Old 9th March 2002, 11:08   #6  |  Link
Midas
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Hi,

First of all, what is DPL2? Is it something new from Dolby?

Secondly, Azid uses the standard DPL downmix recommended by the specs. I have tested it extensively, and Azid is compliant against DPL, but I dont know anyting about DPL2...

Last, yes the LFE is not mixed into the single center channel when decoding 1/0 (the easiest way for you guys to see this is to use the -M1 option). Whether this is a bug or not, can be discussed. Anyhow, I've added this to my bugs/todo list...

I have tested against a lot of standalone ac3-decoder in DVD-players. Most of them does not downmix the LFE channel, unless it is set in 5.1 mode.


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Old 9th March 2002, 12:34   #7  |  Link
DarkAvenger
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Yes it is something new (actually not sooo new). Just trust me, and please include it. As it is not hard to make a "Surround2" config, it would be greatly appreciated, if you do it. I don't have docs as well. It was a bit of (not real) "reverse" engineering and experiments. You can talk with "user", as well.

I know that your matrix for DS is 100% correct, but it doesn't make use of advanced capabilities of DPL2, which can seperate the rears, as I explained above.

As I said I am not sure about the factors. Maye -1.5db and -4.5db is correct, maybe 0db and -3db. I have to test further. But if you could mail me an experimental version, it could make things easier for me and "user" to find out the optimal values.

About that mono and LFE stuff: If the user doesn't want to downmix it, (s)he can still deselect it, so the current situation is not good when it is not *possible* to donmix the LFE at all.

Thx,

D A
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Old 9th March 2002, 17:37   #8  |  Link
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I don't know if this will help you guys at all but here is a link to the "Dolby Surround Pro Logic II Decoder Principles of Operation":

http://www.dolby.com/tech/l.wh.0007.PLIIops.html

I myself am a little confused over the whole format itself. It seems like is is a big improvement over Pro Logic, but is it backwards compatible with Pro Logic? Either way I hope that you can implement this Midas as I will hopefully be upgrading to a reciever with Pro Logic II this summer. Keep up the good work.
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Old 12th March 2002, 10:23   #9  |  Link
user
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DPL2 rocks !!!

http://www.hydrogenaudio.org/forums/...p?threadid=489


Here above you find my first experiences with DPL2 .

I must tell:

DPL2 is a great advance over old DPL !!!!

full compatible.

I would appreciate it, if Midas would develop his azid, so that it creates a DPL2 output instead of "old-fashioned" DPL.

I would suggest, that for the first time there could be the option to select, if you want a DPL or the DPL2 downmix, or a second azid, that is only able to do dpl2 downmix. (perhaps easier to test out, so that there are no bugs introduced in stable azid for dpl).

If you have once heard DPL2 coded music on eg. a Logic7- or a DPL2- decoder/receiver , you will be convinced forever.

Remember:

There is professional DPL2 coded CDDA, which sounds great, quite like 5.1 ac3. These music is easy to encode to mp3 eg. with keeping DPL2 information. Just use a bitrate of 128 and higher.
After I have heard my DPL2 CDDA, I dare to tell, that ac3 is a little bit obsolete, as you can provide 5 channels in a stereo wave....

Then I tested last week Dark Avengers / spacers test samples.

These samples give me hope, that one day you can downsample 5.1 ac3 to dpl2 wave, mp3, mp2, eg. via a new azid:



DA has done a great job.
The history:


His samples should contain only sounds for rear speakers. Rear left and right separated.

Even his first sample he sent to me, had got a separation of the rear channels, left and right. But the separation was weak, but clearly listenable.
Then he sent his second sample:
That was great, a very well separation between left and right rear channels.

I did some test:

Of course I switched my HK 5000 to old DPL only mode:

Then eg. all music (from my dpl2 CDDA stereoplay) sounds dull, flat, no separation between rear l,r. Reason of dullness:
Old dpl is limited to 7 or 8 kHz.
Switching to dpl2 is a great improvement.

The same I did with DA's samples:

In old dpl mode : no separation between rear left and right. But of course the test signal came only out of rear speakers.

in logic7 mode: separation between rear l, r

So I beg Midas for developing an azid which is able to downmix 5.1 ac3 to dpl2 stereo waves....

Many thanks !!!!!

Of course for already existing azid, too !!!!!!


P.S.:

I could sent to somebody lossless compressed waves (ape, monkeys audio) of:
fantastic dpl2 coded music
DA's test samples,
even HDCD, if there is interest, but HDCD is a different topic, look out at r3mix forum, test section.

Of course all samples just for testing !
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Old 15th March 2002, 09:28   #10  |  Link
user
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the DPL2 samples are published here:

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


@DA:

Are these the samples you wanted to get published ?

If you have some important more, you can send them to me, I will pass through to ff123.

Last edited by user; 15th March 2002 at 15:56.
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Old 15th March 2002, 10:05   #11  |  Link
LigH
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Excuse me asking that dumb question - what is *.ape, which player do I need? (Monkey audio?)
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Old 15th March 2002, 10:28   #12  |  Link
user
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yes, ape is Monkeys audio

yes. Or should I use another comprsseion format ?

Because monkeys audio is very useful even for transcoding eg. 256 kbit/s mp3 to 128 kbit/s mp3 with keeping ID3 tags of 256kbit source mp3, I use it.
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Old 15th March 2002, 10:42   #13  |  Link
DarkAvenger
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@user

Yeah, I guess so.
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Old 29th March 2002, 15:48   #14  |  Link
user
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@Midas

Hi Midas,

are you working on a DPL2 version of azid or is it already included in azid 1.8 ?
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Old 7th April 2002, 22:22   #15  |  Link
user
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new DPL2 samples at http://www.ff123.net/samples/dpl2/

Dolby Pro Logic 2 samples available !

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............


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

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

Last edited by user; 7th April 2002 at 22:25.
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