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When decoding coefficients, detect whether the block is DC-only, and take advantage of this knowledge to perform DC-only inverse transform. This is achieved by: - first, changing the 108x4 element modulo_three_table into a 108 element table (kind of base4), and accessing each value using mask and shifts. - then, checking low bits for 0 (as they represent the presence of higher frequency coefficients) Also provide x86 SIMD code for the DC-only inverse transform. Signed-off-by: Kostya Shishkov <kostya.shishkov@gmail.com>
41 lines
1.4 KiB
C
41 lines
1.4 KiB
C
/*
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* RV30/40 MMX/SSE2 optimizations
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* Copyright (C) 2012 Christophe Gisquet <christophe.gisquet@gmail.com>
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*
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* This file is part of Libav.
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*
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* Libav is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* Libav is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with Libav; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include "libavutil/cpu.h"
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#include "libavutil/x86_cpu.h"
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#include "libavcodec/dsputil.h"
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#include "libavcodec/rv34dsp.h"
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void ff_rv34_idct_dequant4x4_dc_mmx2(DCTELEM *block);
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void ff_rv34_idct_dequant4x4_dc_noround_mmx2(DCTELEM *block);
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av_cold void ff_rv34dsp_init_x86(RV34DSPContext* c, DSPContext *dsp)
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{
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#if HAVE_YASM
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int mm_flags = av_get_cpu_flags();
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if (mm_flags & AV_CPU_FLAG_MMX2) {
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c->rv34_inv_transform_dc_tab[0] = ff_rv34_idct_dequant4x4_dc_mmx2;
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c->rv34_inv_transform_dc_tab[1] = ff_rv34_idct_dequant4x4_dc_noround_mmx2;
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}
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#endif
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}
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