What about DirectShow filters included in WinDVD and PowerDVD (licensed from Dolby)? Honestly, the upmixing technique is so simple that it´s annoying to see that nobody has implemented it properly. LFE is not mentioned here since Dolby recommends not to use LFE in the DPLII downmixing. That only gives Lt - LtRt - Rt (and don´t even start with the Ls an Rs). That is NOT true Prologic (either I or II). They just end up creating a Center channel that is Lt + Rt while Lt and Rt are not touched. But no decoder I´ve tried has been able to achieve it properly. center) -> but also erase C form the source (Lc - C, and RC - C) -> L and R. LC and RC -> C is equal in both channels -> send C to another channel (i.e. "find whatever is in both channels and send it to another channel but also erase it form the source channels". Then, to retrieve C from Lt/Rt u will need to use a basic equation: The downmixing matrix for DPLII is very simple: In the Dolby website u can get all sorts of PDFs with the technical specs for their technology (like Dolby digital inner workings, DPLI/II matrixes, etc.).īut it isn´t even as hard as it may sound. Is the technical specification available to implement such a decoder properly?Ībsolutely. It involves channel phase shifting and phase cancellation techniques not implemented.
DOLBY PRO LOGIC II SOFTWARE
Keep in mind that DPLII decoding is done by hardware AC3 decoders, there is no codec or software that really provides true DPLII decoding, since the matrixes (as simple as they are) are not properly implemented yet by any software decoder. Ffdshow audio gives u the option to create your own upmixing and downmixing matrixes (as AC3filter does for AC3 and DTS streams). The AAC will be upmixed to 6-ch no matter what container u use as long as u have a way to perform matrix upmixing to the output (as ffdshow audio filter allows to). I`m not to familiar with PS, can`t help u there. Again, it may sound OK as stereo bu when apply matrix upmixing to the HE-AAC the sound will be damaged compared to the source. DPL is not compatible HE-AAC since HE-AAC severely alters the high range frequencies. I know that many will say that it sounds OK with 128 kbps but remember that it`s not about sounding OK as stereo but as a 6-channel upmix. The minimum bitrate should be the one that allows to properly maintain the stereo fields of the encoded AAC. Take care, John M.- DPLII downmixing does NOT decrease stereo quality When done right even this somewhat diverse implementation of equipment sounds good and proper. I have enough experience being in Classical, Jazz and Rock bands and I like what I hear, but I dont go overboard and my room is fairly good sized 21X12 and fully teated with sound absorbtion and refraction.
DOLBY PRO LOGIC II FULL
I find I have a great full lifelike sound regardless of what the pinheads say. Why let stuff get wasted, use it and if it is of no use then sell. In that setup the bluray front two channels go to the Vincent and the two surround channels go directly to the receiver for a 4.0 sound which is clabrated volume wise with my analog meter and it all sounds great.
DOLBY PRO LOGIC II PRO
Even though I could use Pro logic and all the decoding thats available I use this simple setup and also use it for my Bluray and flatscreen setup. They ,the speakers are set up well with the proper demensions and degrees that the pros exude about and are toed in and their seem to be no phase issues what so ever and the rear speakers are usually kept at a low volume and the sound is wonderful. I have 4 Def Tech 7000s and the front pair are powered by a Vincent 236II and the pre out from the Vincent goes into my NAD or Denon receivers, depending on mood and I have 4 channel stereo.
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