ffmpeg | branch: master | Rémi Denis-Courmont <r...@remlab.net> | Sun May 12 19:26:29 2024 +0300| [d452db8410256550d500864ef7ba5917d6afc864] | committer: Rémi Denis-Courmont
lavc/vc1dsp: R-V V vc1_unescape_buffer Notes: - The loop is biased toward no unescaped bytes as that should be most common. - The input byte array is slid rather than the (8 times smaller) bit-mask, as RISC-V V does not provide a bit-mask (or bit-wise) slide instruction. - There are two comparisons with 0 per iteration, for the same reason. - In case of match, bytes are copied until the first match, and the loop is restarted after the escape byte. Vector compression (vcompress.vm) could discard all escape bytes but that is slower if escape bytes are rare. Further optimisations should be possible, e.g.: - processing 2 bytes fewer per iteration to get rid of a 2 slides, - taking a short cut if the input vector contains less than 2 zeroes. But this is a good starting point: T-Head C908: vc1dsp.vc1_unescape_buffer_c: 12749.5 vc1dsp.vc1_unescape_buffer_rvv_i32: 6009.0 SpacemiT X60: vc1dsp.vc1_unescape_buffer_c: 11038.0 vc1dsp.vc1_unescape_buffer_rvv_i32: 2061.0 > http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=d452db8410256550d500864ef7ba5917d6afc864 --- libavcodec/riscv/vc1dsp_init.c | 2 ++ libavcodec/riscv/vc1dsp_rvv.S | 53 ++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 55 insertions(+) diff --git a/libavcodec/riscv/vc1dsp_init.c b/libavcodec/riscv/vc1dsp_init.c index 8ef0c1f40f..f105a3a3c6 100644 --- a/libavcodec/riscv/vc1dsp_init.c +++ b/libavcodec/riscv/vc1dsp_init.c @@ -35,6 +35,7 @@ void ff_avg_pixels16x16_rvv(uint8_t *dst, const uint8_t *src, ptrdiff_t line_siz void ff_avg_pixels8x8_rvv(uint8_t *dst, const uint8_t *src, ptrdiff_t line_size, int rnd); int ff_startcode_find_candidate_rvb(const uint8_t *, int); int ff_startcode_find_candidate_rvv(const uint8_t *, int); +int ff_vc1_unescape_buffer_rvv(const uint8_t *, int, uint8_t *); av_cold void ff_vc1dsp_init_riscv(VC1DSPContext *dsp) { @@ -62,6 +63,7 @@ av_cold void ff_vc1dsp_init_riscv(VC1DSPContext *dsp) } } dsp->startcode_find_candidate = ff_startcode_find_candidate_rvv; + dsp->vc1_unescape_buffer = ff_vc1_unescape_buffer_rvv; } # endif #endif diff --git a/libavcodec/riscv/vc1dsp_rvv.S b/libavcodec/riscv/vc1dsp_rvv.S index 7c2b47f66c..1166f35cad 100644 --- a/libavcodec/riscv/vc1dsp_rvv.S +++ b/libavcodec/riscv/vc1dsp_rvv.S @@ -1,5 +1,6 @@ /* * Copyright (c) 2023 Institue of Software Chinese Academy of Sciences (ISCAS). + * Copyright (c) 2024 Rémi Denis-Courmont. * * This file is part of FFmpeg. * @@ -159,3 +160,55 @@ func ff_avg_pixels8x8_rvv, zve64x ret endfunc + +func ff_vc1_unescape_buffer_rvv, zve32x + vsetivli zero, 2, e8, m1, ta, ma + vmv.v.i v8, -1 + li t4, 1 + vmv.v.i v12, -1 + li t3, -1 + mv t5, a2 + blez a1, 3f +1: + vsetvli t0, a1, e8, m4, ta, ma + vle8.v v16, (a0) + vslideup.vi v8, v16, 2 + addi t0, t0, -1 # we cannot fully process the last element + vslideup.vi v12, v16, 1 + vslide1down.vx v20, v16, t3 + vsetvli zero, t0, e8, m4, ta, ma + vmseq.vi v0, v8, 0 + vmseq.vi v1, v12, 0 + vmseq.vi v2, v16, 3 + vmand.mm v0, v0, v1 + vmsltu.vi v3, v20, 4 + vmand.mm v0, v0, v2 + vmand.mm v0, v0, v3 + vfirst.m t2, v0 + bgez t2, 4f # found an escape byte? + + vse8.v v16, (a2) + addi t2, t0, -2 + add a2, a2, t0 +2: + vslidedown.vx v8, v16, t2 + sub a1, a1, t0 + vslidedown.vi v12, v8, 1 + add a0, a0, t0 + bgtu a1, t4, 1b // size > 1 + + lb t0, (a0) + sb t0, (a2) # copy last byte (cannot be escaped) + addi a2, a2, 1 +3: + sub a0, a2, t5 + ret +4: + vsetvli zero, t2, e8, m4, ta, ma + vse8.v v16, (a2) + addi t0, t2, 1 + add a2, a2, t2 + addi t2, t2, -1 + vsetvli zero, t0, e8, m4, ta, ma + j 2b +endfunc _______________________________________________ ffmpeg-cvslog mailing list ffmpeg-cvslog@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-cvslog To unsubscribe, visit link above, or email ffmpeg-cvslog-requ...@ffmpeg.org with subject "unsubscribe".
