[FFmpeg-devel] [PATCH] [RFC] libavfilter HRTF/room acoustics filter [1/2]

[Michael Niedermayer]

On Tue, Aug 02, 2016 at 01:57:45PM -0700, Yue Shi Lai wrote:
> On 08/02/2016 08:40 AM, Paul B Mahol wrote:
> > On 8/2/16, Yue Shi Lai <ylai at users.sourceforge.net> wrote:
> >> - integrated matrix decoder (probably better suited as a separate filter)
> > 
> > This one does what?
> 
> This is an implementation of the steering or active matrix surround
> decoder (e.g. Quadraphonic or Dolby Surround). Implemented are 2-to-4, 5
> and 6 channels (the last one is to decode 5.1 into 7.1, either
> consumer-type 4 rear/surround or SDDS downmix with 5 front channels).
> Active matrix means that there is an active feed-back system suppressing
> cross talk for point sources (e.g. Tate DES and ProLogic). I take the
> statement from the users list
> (https://ffmpeg.org/pipermail/ffmpeg-user/2013-May/015091.html) still
> correct, there is no (even passive) matrix decoder in FFmpeg?
> 

> On a somewhat related matter: I was browsing through the matrix encoder
> in libavresample/audio_mix_matrix.c, and possibly rediscovered the bug
> in https://trac.ffmpeg.org/ticket/4175 . Also, the 5-channel coefficient
> seems to disagrees with Dolby (see the notes I wrote at some point while
> editing the Wikipedia section in
> https://en.wikipedia.org/wiki/Talk:Dolby_Pro_Logic#Source_of_the_DPLII_encoding_matrix.3F).

is this issue also affecting libswresample ?
if so i would be very interrested in a patch fixing it or i can
try to look into it myself ...

thx


[...]
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Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Freedom in capitalist society always remains about the same as it was in
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