[FFmpeg-devel] [PATCH 08/15] avfilter/vf_bwdif: Add neon for filter_edge

[Martin Storsjö]

On Thu, 29 Jun 2023, John Cox wrote:

> Signed-off-by: John Cox <jc at kynesim.co.uk>
> ---
> libavfilter/aarch64/vf_bwdif_init_aarch64.c |  20 ++++
> libavfilter/aarch64/vf_bwdif_neon.S         | 104 ++++++++++++++++++++
> 2 files changed, 124 insertions(+)
>
> diff --git a/libavfilter/aarch64/vf_bwdif_init_aarch64.c b/libavfilter/aarch64/vf_bwdif_init_aarch64.c
> index 3ffaa07ab3..e75cf2f204 100644
> --- a/libavfilter/aarch64/vf_bwdif_init_aarch64.c
> +++ b/libavfilter/aarch64/vf_bwdif_init_aarch64.c
> @@ -24,10 +24,29 @@
> #include "libavfilter/bwdif.h"
> #include "libavutil/aarch64/cpu.h"
>
> +void ff_bwdif_filter_edge_neon(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);
> +
> void ff_bwdif_filter_intra_neon(void *dst1, void *cur1, int w, int prefs, int mrefs,
>                                 int prefs3, int mrefs3, int parity, int clip_max);
>
>
> +static void filter_edge_helper(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)
> +{
> +    const int w0 = clip_max != 255 ? 0 : w & ~15;
> +
> +    ff_bwdif_filter_edge_neon(dst1, prev1, cur1, next1, w0, prefs, mrefs, prefs2, mrefs2,
> +                              parity, clip_max, spat);
> +
> +    if (w0 < w)
> +        ff_bwdif_filter_edge_c((char *)dst1 + w0, (char *)prev1 + w0, (char *)cur1 + w0, (char *)next1 + w0,
> +                               w - w0, prefs, mrefs, prefs2, mrefs2,
> +                               parity, clip_max, spat);
> +}
> +
> static void filter_intra_helper(void *dst1, void *cur1, int w, int prefs, int mrefs,
>                                 int prefs3, int mrefs3, int parity, int clip_max)
> {
> @@ -52,5 +71,6 @@ ff_bwdif_init_aarch64(BWDIFContext *s, int bit_depth)
>         return;
>
>     s->filter_intra = filter_intra_helper;
> +    s->filter_edge  = filter_edge_helper;
> }
>
> diff --git a/libavfilter/aarch64/vf_bwdif_neon.S b/libavfilter/aarch64/vf_bwdif_neon.S
> index 6c5d1598f4..a33b235882 100644
> --- a/libavfilter/aarch64/vf_bwdif_neon.S
> +++ b/libavfilter/aarch64/vf_bwdif_neon.S
> @@ -128,6 +128,110 @@ coeffs:
>         .hword          5570, 3801, 1016, -3801         // hf[0] = v0.h[2], -hf[1] = v0.h[5]
>         .hword          5077, 981                       // sp[0] = v0.h[6]
>
> +// ============================================================================
> +//
> +// void ff_bwdif_filter_edge_neon(
> +//      void *dst1,     // x0
> +//      void *prev1,    // x1
> +//      void *cur1,     // x2
> +//      void *next1,    // x3
> +//      int w,          // w4
> +//      int prefs,      // w5
> +//      int mrefs,      // w6
> +//      int prefs2,     // w7
> +//      int mrefs2,     // [sp, #0]
> +//      int parity,     // [sp, #8]
> +//      int clip_max,   // [sp, #16]  unused
> +//      int spat);      // [sp, #24]

This doesn't hold for macOS targets (and the checkasm tests fail on that 
platform).

On macOS, arguments that aren't passed in registers but on the stack, are 
tightly packed. So since parity is 32 bit and mrefs2 also was 32 bit, 
parity is available at [sp, #4].

Therefore, it's usually simplest for portability reasons, to pass any 
arguments after the first 8, as intptr_t or ptrdiff_t, as that makes them 
consistent across platforms.

// Martin