[FFmpeg-devel] [PATCH] swresample: reuse DSP functions from avutil
Paul B Mahol
onemda at gmail.com
Mon Jun 12 19:08:47 EEST 2023
On Wed, Jun 7, 2023 at 10:17 PM Michael Niedermayer <michael at niedermayer.cc>
wrote:
> On Wed, Jun 07, 2023 at 07:29:13PM +0200, Paul B Mahol wrote:
> > On Wed, Jun 7, 2023 at 6:01 PM Michael Niedermayer <
> michael at niedermayer.cc>
> > wrote:
> >
> > > On Wed, Jun 07, 2023 at 05:46:25PM +0200, Paul B Mahol wrote:
> > > > On Sat, May 13, 2023 at 3:09 AM Michael Niedermayer <
> > > michael at niedermayer.cc>
> > > > wrote:
> > > >
> > > > > On Fri, May 12, 2023 at 07:28:08PM +0200, Paul B Mahol wrote:
> > > > > > With fixed alignment requirements.
> > > > >
> > > > > > rematrix.c | 54
> > > > > ++++++++++++++++++++++++++++++++++++++++++++++++--
> > > > > > swresample.c | 5 ++++
> > > > > > swresample_internal.h | 2 +
> > > > > > 3 files changed, 59 insertions(+), 2 deletions(-)
> > > > > > 3b99c9eb2e2f1f17d1f306e37ddd7107405fede4
> > > > > 0001-swresample-reuse-DSP-functions-from-avutil.patch
> > > > > > From 771bc1414b737475bc42c7263fd7f21b4d9cc9b7 Mon Sep 17 00:00:00
> > > 2001
> > > > > > From: Paul B Mahol <onemda at gmail.com>
> > > > > > Date: Wed, 10 May 2023 15:41:01 +0200
> > > > > > Subject: [PATCH] swresample: reuse DSP functions from avutil
> > > > > >
> > > > > > Improves generic mixing dramatically.
> > > > > >
> > > > > > Signed-off-by: Paul B Mahol <onemda at gmail.com>
> > > > > > ---
> > > > > > libswresample/rematrix.c | 54
> > > +++++++++++++++++++++++++++--
> > > > > > libswresample/swresample.c | 5 +++
> > > > > > libswresample/swresample_internal.h | 2 ++
> > > > > > 3 files changed, 59 insertions(+), 2 deletions(-)
> > > > > >
> > > > > > diff --git a/libswresample/rematrix.c b/libswresample/rematrix.c
> > > > > > index 79e8a43eac..2133b0f90d 100644
> > > > > > --- a/libswresample/rematrix.c
> > > > > > +++ b/libswresample/rematrix.c
> > > > > > @@ -652,7 +652,32 @@ int swri_rematrix(SwrContext *s, AudioData
> *out,
> > > > > AudioData *in, int len, int mus
> > > > > > break;}
> > > > > > default:
> > > > > > if(s->int_sample_fmt == AV_SAMPLE_FMT_FLTP){
> > > > > > - for(i=0; i<len; i++){
> > > > > > + if (out->planar && in->planar)
> > > > > > + len1 = len & ~15;
> > > > > > + else
> > > > > > + len1 = 0;
> > > > > > + if ((intptr_t)out->ch[out_i] & 0x1f)
> > > > > > + len1 = 0;
> > > > > > + for (j = 0; j < s->matrix_ch[out_i][0] && len1
> > 0;
> > > > > j++) {
> > > > > > + in_i = s->matrix_ch[out_i][1+j];
> > > > > > + if ((intptr_t)in->ch[in_i] & 0x1f) {
> > > > > > + len1 = 0;
> > > > > > + break;
> > > > > > + }
> > > > > > + }
> > > > >
> > > > > Cant this be done outside the "inner" loop ?
> > > >
> > > >
> > > > Sure.
> > > >
> > > >
> > > >
> > > > >
> > > > >
> > > >
> > > > > also this produces some new NaN values
> > > > >
> > > > > @@ -91810,16 +91810,16 @@
> > > > > [e:0.246031 c:-nan max:0.988908] len: 936
> > > > > [e:0.247006 c:-nan max:0.988908] len: 936
> > > > > [e:0.247174 c:-nan max:0.988908] len: 936
> > > > > -[e:0.197683 c:0.773693 max:0.825360] len: 936
> > > > > -[e:0.192089 c:0.814010 max:0.820662] len: 936
> > > > > +[e:0.245992 c:0.031094 max:0.988908] len: 936
> > > > > +[e:0.246535 c:0.031025 max:0.988908] len: 936
> > > > > [e:0.013306 c:0.996638 max:0.037320] len: 32 F: 2
> > > > > [e:0.049179 c:0.909927 max:0.081071] len: 32 F: 2
> > > > > [e:0.159079 c:-nan max:0.299026] len: 32 F: 2
> > > > > [e:0.116819 c:-nan max:0.297598] len: 32 F: 2
> > > > > [e:0.159382 c:-nan max:0.299980] len: 32 F: 2
> > > > > [e:0.115993 c:-nan max:0.296648] len: 32 F: 2
> > > > > -[e:0.099115 c:0.996999 max:0.189015] len: 32 F: 2
> > > > > -[e:0.071657 c:0.998728 max:0.187209] len: 32 F: 2
> > > > > +[e:0.159577 c:-nan max:0.299503] len: 32 F: 2
> > > > > +[e:0.115367 c:-nan max:0.299503] len: 32 F: 2
> > > > >
> > > > >
> > > > Is that really important to you?
> > >
> > > The important part is not what the tool displays. But that this
> > > points to a worsening of the tested code (or a bug in the tool)
> > > The other numbers also seem to worsen by non trivial amounts
> > >
> >
> > Can you elaborate your reasoning. Otherwise I will not take this into
> > serious
> > account for very slow library wasting CPU cycles.
>
>
> if you do care that the output resembles the input then this from
> above should be concerning:
>
> > > > > -[e:0.197683 c:0.773693 max:0.825360] len: 936
> > > > > -[e:0.192089 c:0.814010 max:0.820662] len: 936
> > > > > +[e:0.245992 c:0.031094 max:0.988908] len: 936
> > > > > +[e:0.246535 c:0.031025 max:0.988908] len: 936
>
> before there is 0.81 correlation and afterwards there is
> 0.03 correlation
>
> I mean the tool is telling us, we go kind of from 81% similarity to 3%
> similarity
> if thats not a bug in the tool thats very odd
>
> The NaN could mean that the resampler turned a non zero signal into all
> zeros
> or a all zero signal into non zero. Or maybe it returned NaN directly. Not
> sure
> these are the only ways you get a NaN there
> If both signals are all zero the max difference would be 0 and its not.
>
> This tool tries to excercise corner cases, so if it changes theres a good
> chance theres either a new bug in a corner case or one fixed. I dont think
> this should be ignored.
>
The tool have not been touched for ages and is invalid and poorly designed.
Its results should not be considered seriously,
>
> thx
>
> [...]
> --
> Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
>
> Observe your enemies, for they first find out your faults. -- Antisthenes
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