Am Mo., 3. Juli 2023 um 10:27 Uhr schrieb John Cox <j...@kynesim.co.uk>:
> On Mon, 3 Jul 2023 00:12:46 +0300 (EEST), you wrote:
>
> >On Sun, 2 Jul 2023, Thomas Mundt wrote:
> >
> >> Am So., 2. Juli 2023 um 14:34 Uhr schrieb John Cox <j...@kynesim.co.uk>:
> >> Add an optional filter_line3 to the available optimisations.
> >>
> >> filter_line3 is equivalent to filter_line, memcpy, filter_line
> >>
> >> filter_line shares quite a number of loads and some calculations
> >> in
> >> common with its next iteration and testing shows that using
> >> aarch64
> >> neon filter_line3s performance is 30% better than two
> >> filter_lines
> >> and a memcpy.
> >>
> >> Signed-off-by: John Cox <j...@kynesim.co.uk>
> >> ---
> >> libavfilter/bwdif.h | 7 +++++++
> >> libavfilter/vf_bwdif.c | 31 +++++++++++++++++++++++++++++++
> >> 2 files changed, 38 insertions(+)
> >>
> >> diff --git a/libavfilter/bwdif.h b/libavfilter/bwdif.h
> >> index cce99953f3..496cec72ef 100644
> >> --- a/libavfilter/bwdif.h
> >> +++ b/libavfilter/bwdif.h
> >> @@ -35,6 +35,9 @@ typedef struct BWDIFContext {
> >> void (*filter_edge)(void *dst, void *prev, void *cur, void
> >> *next,
> >> int w, int prefs, int mrefs, int
> >> prefs2, int mrefs2,
> >> int parity, int clip_max, int spat);
> >> + void (*filter_line3)(void *dst, int dstride,
> >> + const void *prev, const void *cur,
> >> const void *next, int prefs,
> >> + int w, int parity, int clip_max);
> >> } BWDIFContext;
> >>
> >> void ff_bwdif_init_filter_line(BWDIFContext *bwdif, int
> >> bit_depth);
> >> @@ -53,4 +56,8 @@ void ff_bwdif_filter_line_c(void *dst1, void
> >> *prev1, void *cur1, void *next1,
> >> int prefs3, int mrefs3, int prefs4,
> >> int mrefs4,
> >> int parity, int clip_max);
> >>
> >> +void ff_bwdif_filter_line3_c(void * dst1, int d_stride,
> >> + const void * prev1, const void *
> >> cur1, const void * next1, int s_stride,
> >> + int w, int parity, int clip_max);
> >> +
> >> #endif /* AVFILTER_BWDIF_H */
> >> diff --git a/libavfilter/vf_bwdif.c b/libavfilter/vf_bwdif.c
> >> index 26349da1fd..52bc676cf8 100644
> >> --- a/libavfilter/vf_bwdif.c
> >> +++ b/libavfilter/vf_bwdif.c
> >> @@ -150,6 +150,31 @@ void ff_bwdif_filter_line_c(void *dst1,
> >> void *prev1, void *cur1, void *next1,
> >> FILTER2()
> >> }
> >>
> >> +#define NEXT_LINE()\
> >> + dst += d_stride; \
> >> + prev += prefs; \
> >> + cur += prefs; \
> >> + next += prefs;
> >> +
> >> +void ff_bwdif_filter_line3_c(void * dst1, int d_stride,
> >> + const void * prev1, const void *
> >> cur1, const void * next1, int s_stride,
> >> + int w, int parity, int clip_max)
> >> +{
> >> + const int prefs = s_stride;
> >> + uint8_t * dst = dst1;
> >> + const uint8_t * prev = prev1;
> >> + const uint8_t * cur = cur1;
> >> + const uint8_t * next = next1;
> >> +
> >> + ff_bwdif_filter_line_c(dst, (void*)prev, (void*)cur,
> >> (void*)next, w,
> >> + prefs, -prefs, prefs * 2, - prefs *
> >> 2, prefs * 3, -prefs * 3, prefs * 4, -prefs * 4, parity,
> >> clip_max);
> >> + NEXT_LINE();
> >> + memcpy(dst, cur, w);
> >> + NEXT_LINE();
> >> + ff_bwdif_filter_line_c(dst, (void*)prev, (void*)cur,
> >> (void*)next, w,
> >> + prefs, -prefs, prefs * 2, - prefs *
> >> 2, prefs * 3, -prefs * 3, prefs * 4, -prefs * 4, parity,
> >> clip_max);
> >> +}
> >> +
> >> void ff_bwdif_filter_edge_c(void *dst1, void *prev1, void
> >> *cur1, void *next1,
> >> int w, int prefs, int mrefs, int
> >> prefs2, int mrefs2,
> >> int parity, int clip_max, int spat)
> >> @@ -244,6 +269,11 @@ static int filter_slice(AVFilterContext
> >> *ctx, void *arg, int jobnr, int nb_jobs)
> >> refs << 1, -(refs << 1),
> >> td->parity ^ td->tff, clip_max,
> >> (y < 2) || ((y + 3) > td->h) ? 0
> >> : 1);
> >> + } else if (s->filter_line3 && y + 2 < slice_end &&
> >> y + 6 < td->h) {
> >> + s->filter_line3(dst,
> >> td->frame->linesize[td->plane],
> >> + prev, cur, next, linesize,
> >> td->w,
> >> + td->parity ^ td->tff,
> >> clip_max);
> >> + y += 2;
> >> } else {
> >> s->filter_line(dst, prev, cur, next, td->w,
> >> refs, -refs, refs << 1, -(refs
> >> << 1),
> >>
> >>
> >> Maybe I'm missing something, but doesn't this kick out most of the x86
> SIMD
> >> optimization because there is no filter_line3?
> >
> >It looks to me like it doesn't; it adds a new optional function pointer,
> >but the reference C function isn't set. So by default (and on x86)
> >filter_line3 is null, and the old assembly optimized codepaths are used.
> >But if an architecture does implement filter_line3, that's used instead
> of
> >filter_line.
>
> Indeed - that is both the intent and what appears to occur when I test
> it. I'd have made the C line3 function call down to line if I had any
> context that allowed it but passing a real context seemed against the
> spirit of nearly all the asm optimisations.
>
You´re right. Thanks.
_______________________________________________
ffmpeg-devel mailing list
ffmpeg-devel@ffmpeg.org
https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
To unsubscribe, visit link above, or email
ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
