[FFmpeg-devel] [PATCHv2 1/2] lavc/h264dsp: R-V V 8-bit luma loop filter
Rémi Denis-Courmont
remi at remlab.net
Mon Jul 1 18:23:36 EEST 2024
T-Head C908 (cycles):
h264_h_loop_filter_luma_8bpp_c: 297.5
h264_h_loop_filter_luma_8bpp_rvv_i32: 369.2
h264_v_loop_filter_luma_8bpp_c: 862.7
h264_v_loop_filter_luma_8bpp_rvv_i32: 199.7
Performance in the horizontal scenario seems worse than scalar. x86
SSE2 and AVX optimisations are similarly affected. This is presumably
caused by unlucky inputs from checkasm, such that the C code
short-circuits almost all filter calculations.
Changes since version 1:
1) Multiplies rather than shuffles to extend the TC array.
2) Get rid of the weird MBAFF macros (as a consequence of (1)).
---
libavcodec/riscv/Makefile | 1 +
libavcodec/riscv/h264dsp_init.c | 13 ++-
libavcodec/riscv/h264dsp_rvv.S | 140 ++++++++++++++++++++++++++++++++
3 files changed, 153 insertions(+), 1 deletion(-)
create mode 100644 libavcodec/riscv/h264dsp_rvv.S
diff --git a/libavcodec/riscv/Makefile b/libavcodec/riscv/Makefile
index c180223141..a1510e8c6e 100644
--- a/libavcodec/riscv/Makefile
+++ b/libavcodec/riscv/Makefile
@@ -31,6 +31,7 @@ RVV-OBJS-$(CONFIG_H263DSP) += riscv/h263dsp_rvv.o
OBJS-$(CONFIG_H264CHROMA) += riscv/h264_chroma_init_riscv.o
RVV-OBJS-$(CONFIG_H264CHROMA) += riscv/h264_mc_chroma.o
OBJS-$(CONFIG_H264DSP) += riscv/h264dsp_init.o
+RVV-OBJS-$(CONFIG_H264DSP) += riscv/h264dsp_rvv.o
OBJS-$(CONFIG_HUFFYUV_DECODER) += riscv/huffyuvdsp_init.o
RVV-OBJS-$(CONFIG_HUFFYUV_DECODER) += riscv/huffyuvdsp_rvv.o
OBJS-$(CONFIG_IDCTDSP) += riscv/idctdsp_init.o
diff --git a/libavcodec/riscv/h264dsp_init.c b/libavcodec/riscv/h264dsp_init.c
index dbbf3db400..0d4d541992 100644
--- a/libavcodec/riscv/h264dsp_init.c
+++ b/libavcodec/riscv/h264dsp_init.c
@@ -24,8 +24,14 @@
#include "libavutil/attributes.h"
#include "libavutil/cpu.h"
+#include "libavutil/riscv/cpu.h"
#include "libavcodec/h264dsp.h"
+void ff_h264_v_loop_filter_luma_8_rvv(uint8_t *pix, ptrdiff_t stride,
+ int alpha, int beta, int8_t *tc0);
+void ff_h264_h_loop_filter_luma_8_rvv(uint8_t *pix, ptrdiff_t stride,
+ int alpha, int beta, int8_t *tc0);
+
extern int ff_startcode_find_candidate_rvb(const uint8_t *, int);
extern int ff_startcode_find_candidate_rvv(const uint8_t *, int);
@@ -38,8 +44,13 @@ av_cold void ff_h264dsp_init_riscv(H264DSPContext *dsp, const int bit_depth,
if (flags & AV_CPU_FLAG_RVB_BASIC)
dsp->startcode_find_candidate = ff_startcode_find_candidate_rvb;
# if HAVE_RVV
- if (flags & AV_CPU_FLAG_RVV_I32)
+ if (flags & AV_CPU_FLAG_RVV_I32) {
+ if (bit_depth == 8 && ff_rv_vlen_least(128)) {
+ dsp->h264_v_loop_filter_luma = ff_h264_v_loop_filter_luma_8_rvv;
+ dsp->h264_h_loop_filter_luma = ff_h264_h_loop_filter_luma_8_rvv;
+ }
dsp->startcode_find_candidate = ff_startcode_find_candidate_rvv;
+ }
# endif
#endif
}
diff --git a/libavcodec/riscv/h264dsp_rvv.S b/libavcodec/riscv/h264dsp_rvv.S
new file mode 100644
index 0000000000..77bf40db1f
--- /dev/null
+++ b/libavcodec/riscv/h264dsp_rvv.S
@@ -0,0 +1,140 @@
+/*
+ * Copyright © 2024 Rémi Denis-Courmont.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ * this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ * this list of conditions and the following disclaimer in the documentation
+ * and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "libavutil/riscv/asm.S"
+
+ .variant_cc ff_h264_loop_filter_luma_8_rvv
+func ff_h264_loop_filter_luma_8_rvv, zve32x
+ # p2: v8, p1: v9, p0: v10, q0: v11, q1: v12, q2: v13
+ # alpha: a2, beta: a3, tc_orig: v6
+ csrwi vxrm, 0
+ vaaddu.vv v14, v10, v11 # (p0 + q0 + 1) / 2
+ vwsubu.vv v16, v9, v12
+ vwaddu.vv v18, v8, v14
+ vwaddu.vv v20, v13, v14
+ vnsra.wi v24, v16, 2 # (p1 - q1) / 4
+ vnsrl.wi v14, v18, 1
+ vnsrl.wi v15, v20, 1
+ vneg.v v5, v6 # -tc_orig
+ vwsubu.vv v22, v11, v10 # q0 - p0
+ vwsubu.vv v18, v14, v9
+ vwsubu.vv v20, v15, v12
+ vwadd.wv v16, v22, v24
+ vmsge.vi v7, v6, 0 # tc_orig >= 0
+ vnclip.wi v14, v18, 0
+ vnclip.wi v15, v20, 0
+ vnclip.wi v16, v16, 1 # clip8((q0 - p0 + (p1 - q1) / 4 + 1) >> 1)
+ vmin.vv v14, v14, v6
+ vmin.vv v15, v15, v6
+ vmax.vv v14, v14, v5 # clip(p2 + ... - p1, +/-tc_orig)
+ vmax.vv v15, v15, v5 # clip(q2 + ... - q1, +/-tc_orig)
+ vwsubu.vv v20, v10, v11
+ vwsubu.vv v24, v9, v10
+ vwsubu.vv v26, v10, v9
+ vwsubu.vv v28, v12, v11
+ vwsubu.vv v30, v11, v12
+ vwsubu.vv v0, v8, v10
+ vwsubu.vv v2, v10, v8
+ vwsubu.vv v4, v13, v11
+ vwsubu.vv v18, v11, v13
+ vsetvli zero, zero, e16, m2, ta, ma
+ vmax.vv v20, v20, v22 # abs(p0 - q0)
+ vmax.vv v24, v24, v26 # abs(p1 - p0)
+ vmax.vv v28, v28, v30 # abs(q1 - q0)
+ vmax.vv v22, v0, v2 # abs(p2 - p0)
+ vmax.vv v26, v4, v18 # abs(q2 - q0)
+ vmslt.vx v1, v20, a2
+ vmslt.vx v2, v24, a3
+ vmand.mm v7, v7, v1
+ vmslt.vx v3, v28, a3
+ vmand.mm v7, v7, v2
+ vmslt.vx v0, v22, a3
+ vmand.mm v7, v7, v3 # whether to update p0 and q0
+ vmslt.vx v1, v26, a3
+ vmand.mm v0, v0, v7
+ vsetvli zero, zero, e8, m1, ta, mu
+ vadd.vi v6, v6, 1, v0.t # tc++
+ vadd.vv v9, v9, v14, v0.t # p1'
+ vmand.mm v0, v1, v7
+ vadd.vi v6, v6, 1, v0.t # tc++
+ vadd.vv v12, v12, v15, v0.t # q1'
+ vneg.v v5, v6 # -tc
+ vmin.vv v16, v16, v6
+ vwcvtu.x.x.v v18, v10
+ vmax.vv v16, v16, v5
+ vwcvtu.x.x.v v20, v11
+ vwadd.wv v18, v18, v16
+ vwsub.wv v20, v20, v16
+ vmmv.m v0, v7
+ vsetvli zero, zero, e16, m2, ta, ma
+ vmax.vx v18, v18, zero
+ vmax.vx v20, v20, zero
+ vsetvli zero, zero, e8, m1, ta, mu
+ vnclipu.wi v10, v18, 0, v0.t # p0'
+ vnclipu.wi v11, v20, 0, v0.t # q0'
+ jr t0
+endfunc
+
+func ff_h264_v_loop_filter_luma_8_rvv, zve32x
+ vsetivli zero, 4, e32, m1, ta, ma
+ vle8.v v4, (a4)
+ li t0, 0x01010101
+ vzext.vf4 v6, v4
+ sub t3, a0, a1
+ vmul.vx v6, v6, t0
+ vsetivli zero, 16, e8, m1, ta, ma
+ vle8.v v11, (a0)
+ sub t2, t3, a1
+ vid.v v0
+ vle8.v v10, (t3)
+ sub t1, t2, a1
+ vle8.v v9, (t2)
+ add t5, a0, a1
+ vle8.v v8, (t1)
+ add t6, t5, a1
+ vle8.v v12, (t5)
+ vle8.v v13, (t6)
+ jal t0, ff_h264_loop_filter_luma_8_rvv
+ vse8.v v9, (t2)
+ vse8.v v10, (t3)
+ vse8.v v11, (a0)
+ vse8.v v12, (t5)
+ ret
+endfunc
+
+func ff_h264_h_loop_filter_luma_8_rvv, zve32x
+ vsetivli zero, 4, e32, m1, ta, ma
+ vle8.v v4, (a4)
+ li t0, 0x01010101
+ vzext.vf4 v6, v4
+ addi a0, a0, -3
+ vmul.vx v6, v6, t0
+ vsetivli zero, 16, e8, m1, ta, ma
+ vlsseg6e8.v v8, (a0), a1
+ jal t0, ff_h264_loop_filter_luma_8_rvv
+ vssseg6e8.v v8, (a0), a1
+ ret
+endfunc
--
2.45.2
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