libavcodec/lossless_videoencdsp.c

   1 /*
   2  * This file is part of FFmpeg.
   3  *
   4  * FFmpeg is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU Lesser General Public
   6  * License as published by the Free Software Foundation; either
   7  * version 2.1 of the License, or (at your option) any later version.
   8  *
   9  * FFmpeg is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * Lesser General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU Lesser General Public
  15  * License along with FFmpeg; if not, write to the Free Software
  16  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  17  */
  18
  19 #include "config.h"
  20 #include "libavutil/attributes.h"
  21 #include "libavutil/intreadwrite.h"
  22 #include "lossless_videoencdsp.h"
  23 #include "mathops.h"
  24
  25 #if HAVE_FAST_64BIT
  26 typedef uint64_t uint_native;
  27 #define READ   AV_RN64
  28 #define WRITE  AV_WN64
  29 #else
  30 typedef uint32_t uint_native;
  31 #define READ   AV_RN32
  32 #define WRITE  AV_WN32
  33 #endif
  34 // 0x7f7f7f7f or 0x7f7f7f7f7f7f7f7f or whatever, depending on the cpu's native arithmetic size
  35 #define pb_7f (~(uint_native)0 / 255 * 0x7f)
  36 #define pb_80 (~(uint_native)0 / 255 * 0x80)
  37
  38 static void diff_bytes_c(uint8_t *dst, const uint8_t *src1, const uint8_t *src2, intptr_t w)
  39 {
  40     long i;
  41
  42 #if !HAVE_FAST_UNALIGNED
  43     if (((uintptr_t)src1 | (uintptr_t)src2) & (sizeof(uint_native) - 1)) {
  44         for (i = 0; i + 7 < w; i += 8) {
  45             dst[i + 0] = src1[i + 0] - src2[i + 0];
  46             dst[i + 1] = src1[i + 1] - src2[i + 1];
  47             dst[i + 2] = src1[i + 2] - src2[i + 2];
  48             dst[i + 3] = src1[i + 3] - src2[i + 3];
  49             dst[i + 4] = src1[i + 4] - src2[i + 4];
  50             dst[i + 5] = src1[i + 5] - src2[i + 5];
  51             dst[i + 6] = src1[i + 6] - src2[i + 6];
  52             dst[i + 7] = src1[i + 7] - src2[i + 7];
  53         }
  54     } else
  55 #endif
  56     for (i = 0; i <= w - (int) sizeof(uint_native); i += sizeof(uint_native)) {
  57         uint_native a = READ(src1 + i);
  58         uint_native b = READ(src2 + i);
  59         WRITE(dst + i, ((a | pb_80) - (b & pb_7f)) ^ ((a ^ b ^ pb_80) & pb_80));
  60     }
  61     for (; i < w; i++)
  62         dst[i + 0] = src1[i + 0] - src2[i + 0];
  63 }
  64
  65 static void sub_median_pred_c(uint8_t *dst, const uint8_t *src1,
  66                               const uint8_t *src2, intptr_t w,
  67                               int *left, int *left_top)
  68 {
  69     int i;
  70     uint8_t l, lt;
  71
  72     l  = *left;
  73     lt = *left_top;
  74
  75     for (i = 0; i < w; i++) {
  76         const int pred = mid_pred(l, src1[i], (l + src1[i] - lt) & 0xFF);
  77         lt     = src1[i];
  78         l      = src2[i];
  79         dst[i] = l - pred;
  80     }
  81
  82     *left     = l;
  83     *left_top = lt;
  84 }
  85
  86 static void sub_left_predict_c(uint8_t *dst, const uint8_t *src,
  87                                ptrdiff_t stride, ptrdiff_t width, int height)
  88 {
  89     int i, j;
  90     uint8_t prev = 0x80; /* Set the initial value */
  91     for (j = 0; j < height; j++) {
  92         for (i = 0; i < width; i++) {
  93             *dst++ = src[i] - prev;
  94             prev   = src[i];
  95         }
  96         src += stride;
  97     }
  98 }
  99
 100 av_cold void ff_llvidencdsp_init(LLVidEncDSPContext *c)
 101 {
 102     c->diff_bytes      = diff_bytes_c;
 103     c->sub_median_pred = sub_median_pred_c;
 104     c->sub_left_predict = sub_left_predict_c;
 105
 106 #if ARCH_RISCV
 107     ff_llvidencdsp_init_riscv(c);
 108 #elif ARCH_X86
 109     ff_llvidencdsp_init_x86(c);
 110 #endif
 111 }