[FFmpeg-devel] [RFC] DXVA2 decoding and FFmpeg

[wm4]

On Mon, 15 Jun 2015 17:55:35 +0200
Stefano Sabatini <stefasab at gmail.com> wrote:

> On date Monday 2015-06-15 11:56:13 +0200, Stefano Sabatini encoded:
> [...]
> > From 3a75ef1e86360cd6f30b8e550307404d0d1c1dba Mon Sep 17 00:00:00 2001
> > From: Stefano Sabatini <stefasab at gmail.com>
> > Date: Mon, 15 Jun 2015 11:02:50 +0200
> > Subject: [PATCH] lavu/mem: add av_memcpynt() function with x86 optimizations
> > 
> > Assembly based on code from vlc dxva2.c, commit 62107e56 by Laurent Aimar
> > <fenrir at videolan.org>.
> > 
> > TODO: bump minor, update APIchanges
> > ---
> >  libavutil/mem.c          |  9 +++++
> >  libavutil/mem.h          | 14 ++++++++
> >  libavutil/mem_internal.h | 26 +++++++++++++++
> >  libavutil/x86/Makefile   |  1 +
> >  libavutil/x86/mem.c      | 85 ++++++++++++++++++++++++++++++++++++++++++++++++
> >  5 files changed, 135 insertions(+)
> >  create mode 100644 libavutil/mem_internal.h
> >  create mode 100644 libavutil/x86/mem.c
> > 
> > diff --git a/libavutil/mem.c b/libavutil/mem.c
> > index da291fb..0e1eb01 100644
> > --- a/libavutil/mem.c
> > +++ b/libavutil/mem.c
> > @@ -42,6 +42,7 @@
> >  #include "dynarray.h"
> >  #include "intreadwrite.h"
> >  #include "mem.h"
> > +#include "mem_internal.h"
> >  
> >  #ifdef MALLOC_PREFIX
> >  
> > @@ -515,3 +516,11 @@ void av_fast_malloc(void *ptr, unsigned int *size, size_t min_size)
> >      ff_fast_malloc(ptr, size, min_size, 0);
> >  }
> >  
> > +void av_memcpynt(void *dst, const void *src, size_t size, int cpu_flags)
> > +{
> > +#if ARCH_X86
> > +    ff_memcpynt_x86(dst, src, size, cpu_flags);
> > +#else
> > +    memcpy(dst, src, size, cpu_flags);
> > +#endif
> > +}
> 
> Alternatively, what about something like:
> 
> av_memcpynt_fn av_memcpynt_get_fn(void);
> 
> modeled after av_pixelutils_get_sad_fn()? This would skip the need for
> a wrapper calling the right function.

I don't see much value in this, unless determining the right function
causes too much overhead.