[FFmpeg-devel] [PATCH v8 14/18] swscale/ops_memcpy: add 'memcpy' backend for plane->plane copies

[Niklas Haas]

On Sun, 13 Jul 2025 19:04:21 +0200 Alexander Strasser via ffmpeg-devel <ffmpeg-devel at ffmpeg.org> wrote:
> On 2025-07-12 12:44 +0200, Niklas Haas wrote:
> > From: Niklas Haas <git at haasn.dev>
> >
> > Provides a generic fast path for any operation list that can be decomposed
> > into a series of memcpy and memset operations.
> >
> > 25% faster than the x86 backend for yuv444p -> yuva444p
> > 33% faster than the x86 backend for gray -> yuvj444p
> > ---
> >  libswscale/Makefile     |   1 +
> >  libswscale/ops.c        |   2 +
> >  libswscale/ops_memcpy.c | 132 ++++++++++++++++++++++++++++++++++++++++
> >  3 files changed, 135 insertions(+)
> >  create mode 100644 libswscale/ops_memcpy.c
> >
> > diff --git a/libswscale/Makefile b/libswscale/Makefile
> > index d3cb7bc555..0fed799542 100644
> > --- a/libswscale/Makefile
> > +++ b/libswscale/Makefile
> > @@ -18,6 +18,7 @@ OBJS = alphablend.o                                     \
> >         ops.o                                            \
> >         ops_backend.o                                    \
> >         ops_chain.o                                      \
> > +       ops_memcpy.o                                     \
> >         ops_optimizer.o                                  \
> >         options.o                                        \
> >         output.o                                         \
> > diff --git a/libswscale/ops.c b/libswscale/ops.c
> > index 2d8f9e6084..76423f631e 100644
> > --- a/libswscale/ops.c
> > +++ b/libswscale/ops.c
> > @@ -28,8 +28,10 @@
> >  #include "ops_internal.h"
> >
> >  extern SwsOpBackend backend_c;
> > +extern SwsOpBackend backend_murder;
> >
> >  const SwsOpBackend * const ff_sws_op_backends[] = {
> > +    &backend_murder,
> >      &backend_c,
> >      NULL
> >  };
> > diff --git a/libswscale/ops_memcpy.c b/libswscale/ops_memcpy.c
> > new file mode 100644
> > index 0000000000..ef4784faa4
> > --- /dev/null
> > +++ b/libswscale/ops_memcpy.c
> [...]
> > +
> > +SwsOpBackend backend_murder = {
> > +    .name    = "memcpy",
> > +    .compile = compile,
> > +};
>
> Is this intentional?
> While everything is name `memcpy` the variables are namend `_murder`?

It's an (IMO) harmless joke. I can remove it if you'd prefer.

>
>
>   Alexander
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