libavcodec/h264dspenc.c

   1 /*
   2  * H.264/MPEG-4 Part 10 (Base profile) encoder.
   3  *
   4  * DSP functions
   5  *
   6  * Copyright (c) 2006 Expertisecentrum Digitale Media, UHasselt
   7  *
   8  * FFmpeg is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU Lesser General Public
  10  * License as published by the Free Software Foundation; either
  11  * version 2.1 of the License, or (at your option) any later version.
  12  *
  13  * FFmpeg is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16  * Lesser General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU Lesser General Public
  19  * License along with FFmpeg; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  21  */
  22
  23 /**
  24  * @file libavcodec/h264dspenc.c
  25  * H.264 encoder related DSP utils
  26  *
  27  */
  28
  29 #include "dsputil.h"
  30
  31 #define  H264_DCT_PART1(X) \
  32          a = block[0][X]+block[3][X]; \
  33          c = block[0][X]-block[3][X]; \
  34          b = block[1][X]+block[2][X]; \
  35          d = block[1][X]-block[2][X]; \
  36          pieces[0][X] = a+b; \
  37          pieces[2][X] = a-b; \
  38          pieces[1][X] = (c<<1)+d; \
  39          pieces[3][X] = c-(d<<1);
  40
  41 #define  H264_DCT_PART2(X) \
  42          a = pieces[X][0]+pieces[X][3]; \
  43          c = pieces[X][0]-pieces[X][3]; \
  44          b = pieces[X][1]+pieces[X][2]; \
  45          d = pieces[X][1]-pieces[X][2]; \
  46          block[0][X] = a+b; \
  47          block[2][X] = a-b; \
  48          block[1][X] = (c<<1)+d; \
  49          block[3][X] = c-(d<<1);
  50
  51 /**
  52  * Transform the provided matrix using the H.264 modified DCT.
  53  * @note
  54  * we'll always work with transposed input blocks, to avoid having to make a
  55  * distinction between C and mmx implementations.
  56  *
  57  * @param block transposed input block
  58  */
  59 static void h264_dct_c(DCTELEM block[4][4])
  60 {
  61     DCTELEM pieces[4][4];
  62     DCTELEM a, b, c, d;
  63
  64     H264_DCT_PART1(0);
  65     H264_DCT_PART1(1);
  66     H264_DCT_PART1(2);
  67     H264_DCT_PART1(3);
  68     H264_DCT_PART2(0);
  69     H264_DCT_PART2(1);
  70     H264_DCT_PART2(2);
  71     H264_DCT_PART2(3);
  72 }
  73
  74 void ff_h264dspenc_init(DSPContext* c, AVCodecContext *avctx)
  75 {
  76     c->h264_dct = h264_dct_c;
  77 }
  78