mirror of
https://github.com/librempeg/librempeg
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82 lines
2.2 KiB
C
82 lines
2.2 KiB
C
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/*
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* H.264/MPEG-4 Part 10 (Base profile) encoder.
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*
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* DSP functions
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*
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* Copyright (c) 2006 Expertisecentrum Digitale Media, UHasselt
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*
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* FFmpeg 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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* FFmpeg 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 FFmpeg; 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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/**
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* @file h264dsp.c
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* H.264 encoder related DSP utils
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*
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*/
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#include "dsputil.h"
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extern const uint8_t ff_div6[52];
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extern const uint8_t ff_rem6[52];
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#define H264_DCT_PART1(X) \
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a = block[0][X]+block[3][X]; \
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c = block[0][X]-block[3][X]; \
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b = block[1][X]+block[2][X]; \
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d = block[1][X]-block[2][X]; \
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pieces[0][X] = a+b; \
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pieces[2][X] = a-b; \
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pieces[1][X] = (c<<1)+d; \
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pieces[3][X] = c-(d<<1);
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#define H264_DCT_PART2(X) \
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a = pieces[X][0]+pieces[X][3]; \
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c = pieces[X][0]-pieces[X][3]; \
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b = pieces[X][1]+pieces[X][2]; \
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d = pieces[X][1]-pieces[X][2]; \
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block[0][X] = a+b; \
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block[2][X] = a-b; \
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block[1][X] = (c<<1)+d; \
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block[3][X] = c-(d<<1);
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/**
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* Transform the provided matrix using the H.264 modified DCT.
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* @note
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* we'll always work with transposed input blocks, to avoid having to make a
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* distinction between C and mmx implementations.
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*
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* @param block transposed input block
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*/
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static void h264_dct_c(DCTELEM block[4][4])
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{
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DCTELEM pieces[4][4];
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DCTELEM a, b, c, d;
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H264_DCT_PART1(0);
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H264_DCT_PART1(1);
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H264_DCT_PART1(2);
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H264_DCT_PART1(3);
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H264_DCT_PART2(0);
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H264_DCT_PART2(1);
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H264_DCT_PART2(2);
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H264_DCT_PART2(3);
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}
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void ff_h264dsp_init(DSPContext* c, AVCodecContext *avctx)
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{
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c->h264_dct = h264_dct_c;
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}
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