/* * This file is part of Libav. * * Libav 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. * * Libav 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 Libav; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ #include <stdint.h> #include "libavutil/attributes.h" #include "libavutil/common.h" #include "config.h" #include "h263dsp.h" const uint8_t ff_h263_loop_filter_strength[32] = { 0, 1, 1, 2, 2, 3, 3, 4, 4, 4, 5, 5, 6, 6, 7, 7, 7, 8, 8, 8, 9, 9, 9, 10, 10, 10, 11, 11, 11, 12, 12, 12 }; static void h263_h_loop_filter_c(uint8_t *src, int stride, int qscale) { int y; const int strength = ff_h263_loop_filter_strength[qscale]; for (y = 0; y < 8; y++) { int d1, d2, ad1; int p0 = src[y * stride - 2]; int p1 = src[y * stride - 1]; int p2 = src[y * stride + 0]; int p3 = src[y * stride + 1]; int d = (p0 - p3 + 4 * (p2 - p1)) / 8; if (d < -2 * strength) d1 = 0; else if (d < -strength) d1 = -2 * strength - d; else if (d < strength) d1 = d; else if (d < 2 * strength) d1 = 2 * strength - d; else d1 = 0; p1 += d1; p2 -= d1; if (p1 & 256) p1 = ~(p1 >> 31); if (p2 & 256) p2 = ~(p2 >> 31); src[y * stride - 1] = p1; src[y * stride + 0] = p2; ad1 = FFABS(d1) >> 1; d2 = av_clip((p0 - p3) / 4, -ad1, ad1); src[y * stride - 2] = p0 - d2; src[y * stride + 1] = p3 + d2; } } static void h263_v_loop_filter_c(uint8_t *src, int stride, int qscale) { int x; const int strength = ff_h263_loop_filter_strength[qscale]; for (x = 0; x < 8; x++) { int d1, d2, ad1; int p0 = src[x - 2 * stride]; int p1 = src[x - 1 * stride]; int p2 = src[x + 0 * stride]; int p3 = src[x + 1 * stride]; int d = (p0 - p3 + 4 * (p2 - p1)) / 8; if (d < -2 * strength) d1 = 0; else if (d < -strength) d1 = -2 * strength - d; else if (d < strength) d1 = d; else if (d < 2 * strength) d1 = 2 * strength - d; else d1 = 0; p1 += d1; p2 -= d1; if (p1 & 256) p1 = ~(p1 >> 31); if (p2 & 256) p2 = ~(p2 >> 31); src[x - 1 * stride] = p1; src[x + 0 * stride] = p2; ad1 = FFABS(d1) >> 1; d2 = av_clip((p0 - p3) / 4, -ad1, ad1); src[x - 2 * stride] = p0 - d2; src[x + stride] = p3 + d2; } } av_cold void ff_h263dsp_init(H263DSPContext *ctx) { ctx->h263_h_loop_filter = h263_h_loop_filter_c; ctx->h263_v_loop_filter = h263_v_loop_filter_c; if (ARCH_X86) ff_h263dsp_init_x86(ctx); }