ffmpeg/libavcodec/h264dspenc.c

82 lines
2.3 KiB
C

/*
* H.264/MPEG-4 Part 10 (Base profile) encoder.
*
* DSP functions
*
* Copyright (c) 2006 Expertisecentrum Digitale Media, UHasselt
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/**
* @file h264dspenc.c
* H.264 encoder related DSP utils
*
*/
#include "dsputil.h"
extern const uint8_t ff_div6[52];
extern const uint8_t ff_rem6[52];
#define H264_DCT_PART1(X) \
a = block[0][X]+block[3][X]; \
c = block[0][X]-block[3][X]; \
b = block[1][X]+block[2][X]; \
d = block[1][X]-block[2][X]; \
pieces[0][X] = a+b; \
pieces[2][X] = a-b; \
pieces[1][X] = (c<<1)+d; \
pieces[3][X] = c-(d<<1);
#define H264_DCT_PART2(X) \
a = pieces[X][0]+pieces[X][3]; \
c = pieces[X][0]-pieces[X][3]; \
b = pieces[X][1]+pieces[X][2]; \
d = pieces[X][1]-pieces[X][2]; \
block[0][X] = a+b; \
block[2][X] = a-b; \
block[1][X] = (c<<1)+d; \
block[3][X] = c-(d<<1);
/**
* Transform the provided matrix using the H.264 modified DCT.
* @note
* we'll always work with transposed input blocks, to avoid having to make a
* distinction between C and mmx implementations.
*
* @param block transposed input block
*/
static void h264_dct_c(DCTELEM block[4][4])
{
DCTELEM pieces[4][4];
DCTELEM a, b, c, d;
H264_DCT_PART1(0);
H264_DCT_PART1(1);
H264_DCT_PART1(2);
H264_DCT_PART1(3);
H264_DCT_PART2(0);
H264_DCT_PART2(1);
H264_DCT_PART2(2);
H264_DCT_PART2(3);
}
void ff_h264dspenc_init(DSPContext* c, AVCodecContext *avctx)
{
c->h264_dct = h264_dct_c;
}