[FFmpeg-devel] [PATCH 1/3] lavc/aarch64: Add neon implementation for pix_median_abs16
Hubert Mazur
hum at semihalf.com
Tue Sep 20 14:01:56 EEST 2022
Provide optimized implementation for pix_median_abs16 function.
Performance comparison tests are shown below.
- median_sad_0_c: 720.5
- median_sad_0_neon: 127.2
Benchmarks and tests run with checkasm tool on AWS Graviton 3.
Signed-off-by: Hubert Mazur <hum at semihalf.com>
---
libavcodec/aarch64/me_cmp_init_aarch64.c | 4 ++
libavcodec/aarch64/me_cmp_neon.S | 78 ++++++++++++++++++++++++
libavcodec/me_cmp.c | 5 +-
3 files changed, 85 insertions(+), 2 deletions(-)
diff --git a/libavcodec/aarch64/me_cmp_init_aarch64.c b/libavcodec/aarch64/me_cmp_init_aarch64.c
index ade3e9a4c1..fb51a833be 100644
--- a/libavcodec/aarch64/me_cmp_init_aarch64.c
+++ b/libavcodec/aarch64/me_cmp_init_aarch64.c
@@ -53,6 +53,8 @@ int nsse16_neon(int multiplier, const uint8_t *s, const uint8_t *s2,
ptrdiff_t stride, int h);
int nsse16_neon_wrapper(MpegEncContext *c, const uint8_t *s1, const uint8_t *s2,
ptrdiff_t stride, int h);
+int pix_median_abs16_neon(MpegEncContext *v, const uint8_t *pix1, const uint8_t *pix2,
+ ptrdiff_t stride, int h);
av_cold void ff_me_cmp_init_aarch64(MECmpContext *c, AVCodecContext *avctx)
{
@@ -78,6 +80,8 @@ av_cold void ff_me_cmp_init_aarch64(MECmpContext *c, AVCodecContext *avctx)
c->vsse[4] = vsse_intra16_neon;
c->nsse[0] = nsse16_neon_wrapper;
+
+ c->median_sad[0] = pix_median_abs16_neon;
}
}
diff --git a/libavcodec/aarch64/me_cmp_neon.S b/libavcodec/aarch64/me_cmp_neon.S
index f8998749a5..1e08d04869 100644
--- a/libavcodec/aarch64/me_cmp_neon.S
+++ b/libavcodec/aarch64/me_cmp_neon.S
@@ -969,3 +969,81 @@ function nsse16_neon, export=1
ret
endfunc
+
+function pix_median_abs16_neon, export=1
+ // x0 unused
+ // x1 uint8_t *pix1
+ // x2 uint8_t *pix2
+ // x3 ptrdiff_t stride
+ // w4 int h
+
+ ld1 {v2.16b}, [x1], x3
+ ld1 {v3.16b}, [x2], x3
+ movi v31.8h, #0
+ movi v16.8h, #0
+ ext v0.16b, v2.16b, v2.16b, #1
+ ext v1.16b, v3.16b, v3.16b, #1
+ usubl v28.8h, v2.8b, v3.8b
+ usubl2 v27.8h, v2.16b, v3.16b
+ usubl v26.8h, v0.8b, v1.8b
+ usubl2 v25.8h, v0.16b, v1.16b
+ sub w4, w4, #1 // we need to make h-1 iterations
+ saba v31.8h, v26.8h, v28.8h
+ saba v16.8h, v25.8h, v27.8h
+ mov h18, v28.h[0]
+ cmp w4, #1
+ sqabs h18, h18
+ movi v0.8h, #0
+
+ b.lt 2f
+1:
+
+ ld1 {v6.16b}, [x1], x3 // pix1 vector for V(j-1)
+ ld1 {v7.16b}, [x2], x3 // pix2 vector for V(j-1)
+ subs w4, w4, #1
+ ext v4.16b, v6.16b, v6.16b, #1 // pix1 vector for V(j)
+ ext v5.16b, v7.16b, v7.16b, #1 // pix2 vector for V(j)
+
+ // protected registers: v30, v29, v28, v27, v26, v25, v24, v23
+ // scratch registers: v22, v21, v20, v19, v17
+
+ // To find median of three values, calculate sum of them
+ // and subtract max and min value from it.
+ usubl v30.8h, v6.8b, v7.8b // V(j-1)
+ usubl2 v29.8h, v6.16b, v7.16b // V(j-1)
+ usubl v24.8h, v4.8b, v5.8b // V(j)
+ usubl2 v23.8h, v4.16b, v5.16b // V(j)
+ saba v0.8h, v30.8h, v28.8h
+ add v22.8h, v26.8h, v30.8h
+ smin v20.8h, v26.8h, v30.8h
+ add v21.8h, v25.8h, v29.8h
+ smax v19.8h, v26.8h, v30.8h
+ sub v22.8h, v22.8h, v28.8h
+ sub v21.8h, v21.8h, v27.8h
+ smin v17.8h, v19.8h, v22.8h
+ smin v22.8h, v25.8h, v29.8h
+ mov v28.16b, v30.16b
+ smax v20.8h, v20.8h, v17.8h // median values lower half
+ smax v19.8h, v25.8h, v29.8h
+ saba v31.8h, v24.8h, v20.8h
+ mov v27.16b, v29.16b
+ smin v19.8h, v19.8h, v21.8h
+ mov v26.16b, v24.16b
+ smax v17.8h, v22.8h, v19.8h // median values upper half
+ mov v25.16b, v23.16b
+ saba v16.8h, v23.8h, v17.8h
+
+ b.ne 1b
+
+2:
+ mov h17, v0.h[0]
+ ins v16.h[7], wzr
+ add d18, d18, d17
+ add v31.8h, v31.8h, v16.8h
+ uaddlv s17, v31.8h
+ add d18, d18, d17
+ fmov w0, s18
+
+ ret
+
+endfunc
diff --git a/libavcodec/me_cmp.c b/libavcodec/me_cmp.c
index 4242fbc6e4..e2f9f84b05 100644
--- a/libavcodec/me_cmp.c
+++ b/libavcodec/me_cmp.c
@@ -1048,6 +1048,9 @@ av_cold void ff_me_cmp_init(MECmpContext *c, AVCodecContext *avctx)
ff_dsputil_init_dwt(c);
#endif
+ c->median_sad[0] = pix_median_abs16_c;
+ c->median_sad[1] = pix_median_abs8_c;
+
#if ARCH_AARCH64
ff_me_cmp_init_aarch64(c, avctx);
#elif ARCH_ALPHA
@@ -1062,6 +1065,4 @@ av_cold void ff_me_cmp_init(MECmpContext *c, AVCodecContext *avctx)
ff_me_cmp_init_mips(c, avctx);
#endif
- c->median_sad[0] = pix_median_abs16_c;
- c->median_sad[1] = pix_median_abs8_c;
}
--
2.34.1
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