On 08/02/2016 08:40 AM, Paul B Mahol wrote: > On 8/2/16, Yue Shi Lai <y...@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). I have a properly implemented encoder with a FIR Hilbert transformer around, and since there is FFT now in FFmpeg, may investigate later if #4175 can be addressed. > There is already function that does accumulated multiplication IIRC no > need to use intrinsic, > i think is called fdsp->vector_fmac_scalar so use that instead of your > scale_accumulate. > See how its called in sofalizer filter: libavfilter/af_sofalizer.c > > Similar to pthread usage there is internal wrapper which should be used. I will include these together with other comments you may have. > Can't filter be made so it load kemar data from file instead hardcoded > into lavfi? It is possible and I will try a modification in that regard. Best wishes, Yue Shi Lai _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
