On Fri, May 26, 2017 at 10:04:40PM +0200, Paul B Mahol wrote: > On 5/26/17, Michael Niedermayer <mich...@niedermayer.cc> wrote: > > On Fri, May 26, 2017 at 06:54:33PM +0200, Paul B Mahol wrote: > >> On 5/26/17, Michael Niedermayer <mich...@niedermayer.cc> wrote: > >> > On Fri, May 26, 2017 at 01:11:38PM +0200, Paul B Mahol wrote: > >> >> On 5/26/17, Nicolas George <geo...@nsup.org> wrote: > >> >> > Le septidi 7 prairial, an CCXXV, Paul B Mahol a ecrit : > >> >> >> > This belongs in libswresample > >> >> >> No it does not. > >> >> > > >> >> > I think it does too. > >> >> > >> >> You want to link libswresample with libavcodec? > >> > > >> > While this question was directed at nicolas ... > >> > > >> > I dont think audio upmix code should depend on a lib of encoders and > >> > decoders (libavcodec) > >> > No matter if the upmix code would be in libavfilter or libswresample > >> > > >> > I belive a temporary dependancy would be ok, if there is intend to > >> > factor/move things to remove the dependancy in the future. > >> > > >> > But IMO libavcodec is the wrong place to export generic FFT > >> > functionality. > >> > We need FFTs in codecs, we need them in filters, we need them in > >> > swresample (the soxr resampler we support also uses a FFT internally) > >> > > >> > Also moving FFT to a different lib should be quite easy compared to > >> > other ugly dependancies we have (as in snow motion estimation, which > >> > is not as easy to move. none the less none of these ugly dependancies > >> > should be there except temporary) > >> > > > >> This code does upmixing, and there could by myriad variants of upmixing. > > > > This is true for any format convertion or more genericaly for anything. > > there are always many ways to do something. > > > > the way FFmpeg is modularized is that we have a lib for audio format > > convertion, resampling, rematrixing including upmixing and > > downmixing, ... > > > > > >> > >> Having it in libswresample is flawed design. > >> > >> So I will not do the transitions. > >> > >> If you still object to leave it as it is, in lavfi. You will need to take > >> care of the necessary changes by yourself. > > > > Do you agree that we need a part of code and API that does > > audio format convertion, amongth it upmixing and downmixing ? > > Something thats used by default > > > > if you agree on the need of such code, why would it be flawed design > > to add a improved upmixing implementation in there so it gets used ? > > (be that by default or users choice of what to use by default or > > by specific choice for a specific instance) > > > > I want the best and most correct code to be used. > > I dont want to object or demand anything. I belive though that putting > > upmixing code in 2 different places and 2 different libs will give us > > headaches in the future > > Why is pan filter not part of libswresample? It does upmixing and downmixing. > Therefore it should be in libswresample by your logic.
libswresample supports what pan does through the C API
pan in libavfilter provides a convenient way to access the same
functionality through a filtergraph description string
>
> Why is stereotools not part of libswresample?
>
> Why is volume not part of libswresample?
same as with pan
>
> Hey why not put there ambisonics decoder too?
>
> Or equalizer?
>
> Why is eq filter not part of libswscale?
>
> Or any damn A->A or V->V filter?
This is becoming increasingly specific and outside the scope these
libs.
>
> Besides the surround filter is not "correct". There is no "correct"
> way to do upmixing.
>
> Consider mono upmixing, which is just spreading different bands to
> different channels,
> do you want that too in libswresample?
>
> What about synthesizers (we have anoisesrc) but I plan to add
> wavetable, do you want that
> in libswresample too?
You misunderstand me i think.
The filter patch you posted is descibed by you in the patch as:
+@section surround
+Apply audio surround upmix filter.
+
+This filter allows to produce multichannel output from stereo audio stream.
+
+The filter accepts the following options:
That is not a special case or something that falls outside the scope.
(which is what you argue about above with listing other filters)
this is a description of a generic stereo upmix.
In fact this very description could be used for the stereo upmix code
in swresample
[...]
--
Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
If a bugfix only changes things apparently unrelated to the bug with no
further explanation, that is a good sign that the bugfix is wrong.
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