Released: DolbyProLogicII decoder that works! (proper channel separation)

[3dsnar]

With the new release of Aud-X (v. 1.2) we have lounched a DPLII decoder. I spent tens of hours in Matlab to figure out how to spearate all the channels properly, so I hope you will like the result.

In general (I think - please correct me if I'm wrong) there is no proper free software DPLII decoder available (i.e. the channels separation is not performed correctly). And Dolby does not publish anything on the decoding issue. Thus it is a bit
mysterious topic...
Therefore, I hope that our DPLII dec. algorithm will be of use for you.

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I was able to test the results on me, my wife and my friends and it seemed to be similarly effective, in terms of channel separation, as the original, hardware Dolby decoder.
All the tests were perfomed on the same HT amp.
Interestingly, they claimed that my algo sounds better in terms of linear distortions (the test noise played with the original DPLII decoder seemed to have distorted frequency characteristics...), but everyone must judge by his/her own...
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But, ofcourse opinion of all possible users is very interesting for me, so I could use some suggestions to improve this algo.
Here is a test sound for ya (maybe it will be useful).
http://forum.doom9.org/attachment.php?attachmentid=5562&d=1142231931
or check the attachement
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Just in case (probably for most readers this is more than obvious ), here are some details how to test the algorithm
and compare it to other existing ones.

To perform a comparison with the use of external hardware home theatre system, please do the following:
1) Select in Aud-X DS filter config PCM stream compatibility.
2) Select in Aud-X DS filter config SPDiF output. The decoded (to 5.1) stream will be encoded to AC3 (448 kbps), and sent to the external amp. And you will be able to listen to the results of our algorithm
3) Select stereo output in Aud-X filter to send the original stereo (DPLII downmix) to the external amp.
4) Select (in your amp) DPLII decoder.
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To perform a comparison with the use of other DS filters (e.g. FFDshow), please do the following:
1) To use other filters, please disable Aud-X (or disable PCM stream compatibility), and select the appropriate decoding option in the compared filter.
2) Enable PCM stream compatibility and use Aud-X 5.1 output
to decode the input DPLII downmix. Please make sure that the input stream is not already decoded to 6 channels by other filters, preceding Aud-X (there is an info in our decoder filter on the number of channels, or the type of the incoming stream).

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The channel order in the test file is
1) FL
2) FR
3) C
4) SL
5) SR

noise_dplii_dwmx.zip

[3dsnar]

Here is a speech 6 channel test file:
speech6chtest_dplii_dwmx.rar

And Aud-X DPLII backwards compatible sample:
audx-hghq-test.rar

[sohaibrazzaq]

This sounds very interesting.
Let me download this tool, will post comments after testing it.

[3dsnar]

OK, THX.
Please note.
DPLII is just a poor substitue of surround if compared to the digital formats,
such as DTS, DolbyDigital, or Aud-X, etc.
But there are plenty of movies with the DPLII sound, so I thought it would be nice to release a proper decoder for them