/* * Copyright (c) 2013 The WebM project authors. All Rights Reserved. * * Use of this source code is governed by a BSD-style license * that can be found in the LICENSE file in the root of the source * tree. An additional intellectual property rights grant can be found * in the file PATENTS. All contributing project authors may * be found in the AUTHORS file in the root of the source tree. */ #include <assert.h> #include <string.h> #include "./vpx_config.h" #include "./vpx_dsp_rtcd.h" #include "vpx/vpx_integer.h" #include "vpx_dsp/vpx_convolve.h" #include "vpx_dsp/vpx_dsp_common.h" #include "vpx_dsp/vpx_filter.h" #include "vpx_ports/mem.h" static void convolve_horiz(const uint8_t *src, ptrdiff_t src_stride, uint8_t *dst, ptrdiff_t dst_stride, const InterpKernel *x_filters, int x0_q4, int x_step_q4, int w, int h) { int x, y; src -= SUBPEL_TAPS / 2 - 1; for (y = 0; y < h; ++y) { int x_q4 = x0_q4; for (x = 0; x < w; ++x) { const uint8_t *const src_x = &src[x_q4 >> SUBPEL_BITS]; const int16_t *const x_filter = x_filters[x_q4 & SUBPEL_MASK]; int k, sum = 0; for (k = 0; k < SUBPEL_TAPS; ++k) sum += src_x[k] * x_filter[k]; dst[x] = clip_pixel(ROUND_POWER_OF_TWO(sum, FILTER_BITS)); x_q4 += x_step_q4; } src += src_stride; dst += dst_stride; } } static void convolve_avg_horiz(const uint8_t *src, ptrdiff_t src_stride, uint8_t *dst, ptrdiff_t dst_stride, const InterpKernel *x_filters, int x0_q4, int x_step_q4, int w, int h) { int x, y; src -= SUBPEL_TAPS / 2 - 1; for (y = 0; y < h; ++y) { int x_q4 = x0_q4; for (x = 0; x < w; ++x) { const uint8_t *const src_x = &src[x_q4 >> SUBPEL_BITS]; const int16_t *const x_filter = x_filters[x_q4 & SUBPEL_MASK]; int k, sum = 0; for (k = 0; k < SUBPEL_TAPS; ++k) sum += src_x[k] * x_filter[k]; dst[x] = ROUND_POWER_OF_TWO(dst[x] + clip_pixel(ROUND_POWER_OF_TWO(sum, FILTER_BITS)), 1); x_q4 += x_step_q4; } src += src_stride; dst += dst_stride; } } static void convolve_vert(const uint8_t *src, ptrdiff_t src_stride, uint8_t *dst, ptrdiff_t dst_stride, const InterpKernel *y_filters, int y0_q4, int y_step_q4, int w, int h) { int x, y; src -= src_stride * (SUBPEL_TAPS / 2 - 1); for (x = 0; x < w; ++x) { int y_q4 = y0_q4; for (y = 0; y < h; ++y) { const unsigned char *src_y = &src[(y_q4 >> SUBPEL_BITS) * src_stride]; const int16_t *const y_filter = y_filters[y_q4 & SUBPEL_MASK]; int k, sum = 0; for (k = 0; k < SUBPEL_TAPS; ++k) sum += src_y[k * src_stride] * y_filter[k]; dst[y * dst_stride] = clip_pixel(ROUND_POWER_OF_TWO(sum, FILTER_BITS)); y_q4 += y_step_q4; } ++src; ++dst; } } static void convolve_avg_vert(const uint8_t *src, ptrdiff_t src_stride, uint8_t *dst, ptrdiff_t dst_stride, const InterpKernel *y_filters, int y0_q4, int y_step_q4, int w, int h) { int x, y; src -= src_stride * (SUBPEL_TAPS / 2 - 1); for (x = 0; x < w; ++x) { int y_q4 = y0_q4; for (y = 0; y < h; ++y) { const unsigned char *src_y = &src[(y_q4 >> SUBPEL_BITS) * src_stride]; const int16_t *const y_filter = y_filters[y_q4 & SUBPEL_MASK]; int k, sum = 0; for (k = 0; k < SUBPEL_TAPS; ++k) sum += src_y[k * src_stride] * y_filter[k]; dst[y * dst_stride] = ROUND_POWER_OF_TWO(dst[y * dst_stride] + clip_pixel(ROUND_POWER_OF_TWO(sum, FILTER_BITS)), 1); y_q4 += y_step_q4; } ++src; ++dst; } } static void convolve(const uint8_t *src, ptrdiff_t src_stride, uint8_t *dst, ptrdiff_t dst_stride, const InterpKernel *const x_filters, int x0_q4, int x_step_q4, const InterpKernel *const y_filters, int y0_q4, int y_step_q4, int w, int h) { // Note: Fixed size intermediate buffer, temp, places limits on parameters. // 2d filtering proceeds in 2 steps: // (1) Interpolate horizontally into an intermediate buffer, temp. // (2) Interpolate temp vertically to derive the sub-pixel result. // Deriving the maximum number of rows in the temp buffer (135): // --Smallest scaling factor is x1/2 ==> y_step_q4 = 32 (Normative). // --Largest block size is 64x64 pixels. // --64 rows in the downscaled frame span a distance of (64 - 1) * 32 in the // original frame (in 1/16th pixel units). // --Must round-up because block may be located at sub-pixel position. // --Require an additional SUBPEL_TAPS rows for the 8-tap filter tails. // --((64 - 1) * 32 + 15) >> 4 + 8 = 135. uint8_t temp[135 * 64]; int intermediate_height = (((h - 1) * y_step_q4 + y0_q4) >> SUBPEL_BITS) + SUBPEL_TAPS; assert(w <= 64); assert(h <= 64); assert(y_step_q4 <= 32); assert(x_step_q4 <= 32); convolve_horiz(src - src_stride * (SUBPEL_TAPS / 2 - 1), src_stride, temp, 64, x_filters, x0_q4, x_step_q4, w, intermediate_height); convolve_vert(temp + 64 * (SUBPEL_TAPS / 2 - 1), 64, dst, dst_stride, y_filters, y0_q4, y_step_q4, w, h); } static const InterpKernel *get_filter_base(const int16_t *filter) { // NOTE: This assumes that the filter table is 256-byte aligned. // TODO(agrange) Modify to make independent of table alignment. return (const InterpKernel *)(((intptr_t)filter) & ~((intptr_t)0xFF)); } static int get_filter_offset(const int16_t *f, const InterpKernel *base) { return (int)((const InterpKernel *)(intptr_t)f - base); } void vpx_convolve8_horiz_c(const uint8_t *src, ptrdiff_t src_stride, uint8_t *dst, ptrdiff_t dst_stride, const int16_t *filter_x, int x_step_q4, const int16_t *filter_y, int y_step_q4, int w, int h) { const InterpKernel *const filters_x = get_filter_base(filter_x); const int x0_q4 = get_filter_offset(filter_x, filters_x); (void)filter_y; (void)y_step_q4; convolve_horiz(src, src_stride, dst, dst_stride, filters_x, x0_q4, x_step_q4, w, h); } void vpx_convolve8_avg_horiz_c(const uint8_t *src, ptrdiff_t src_stride, uint8_t *dst, ptrdiff_t dst_stride, const int16_t *filter_x, int x_step_q4, const int16_t *filter_y, int y_step_q4, int w, int h) { const InterpKernel *const filters_x = get_filter_base(filter_x); const int x0_q4 = get_filter_offset(filter_x, filters_x); (void)filter_y; (void)y_step_q4; convolve_avg_horiz(src, src_stride, dst, dst_stride, filters_x, x0_q4, x_step_q4, w, h); } void vpx_convolve8_vert_c(const uint8_t *src, ptrdiff_t src_stride, uint8_t *dst, ptrdiff_t dst_stride, const int16_t *filter_x, int x_step_q4, const int16_t *filter_y, int y_step_q4, int w, int h) { const InterpKernel *const filters_y = get_filter_base(filter_y); const int y0_q4 = get_filter_offset(filter_y, filters_y); (void)filter_x; (void)x_step_q4; convolve_vert(src, src_stride, dst, dst_stride, filters_y, y0_q4, y_step_q4, w, h); } void vpx_convolve8_avg_vert_c(const uint8_t *src, ptrdiff_t src_stride, uint8_t *dst, ptrdiff_t dst_stride, const int16_t *filter_x, int x_step_q4, const int16_t *filter_y, int y_step_q4, int w, int h) { const InterpKernel *const filters_y = get_filter_base(filter_y); const int y0_q4 = get_filter_offset(filter_y, filters_y); (void)filter_x; (void)x_step_q4; convolve_avg_vert(src, src_stride, dst, dst_stride, filters_y, y0_q4, y_step_q4, w, h); } void vpx_convolve8_c(const uint8_t *src, ptrdiff_t src_stride, uint8_t *dst, ptrdiff_t dst_stride, const int16_t *filter_x, int x_step_q4, const int16_t *filter_y, int y_step_q4, int w, int h) { const InterpKernel *const filters_x = get_filter_base(filter_x); const int x0_q4 = get_filter_offset(filter_x, filters_x); const InterpKernel *const filters_y = get_filter_base(filter_y); const int y0_q4 = get_filter_offset(filter_y, filters_y); convolve(src, src_stride, dst, dst_stride, filters_x, x0_q4, x_step_q4, filters_y, y0_q4, y_step_q4, w, h); } void vpx_convolve8_avg_c(const uint8_t *src, ptrdiff_t src_stride, uint8_t *dst, ptrdiff_t dst_stride, const int16_t *filter_x, int x_step_q4, const int16_t *filter_y, int y_step_q4, int w, int h) { /* Fixed size intermediate buffer places limits on parameters. */ DECLARE_ALIGNED(16, uint8_t, temp[64 * 64]); assert(w <= 64); assert(h <= 64); vpx_convolve8_c(src, src_stride, temp, 64, filter_x, x_step_q4, filter_y, y_step_q4, w, h); vpx_convolve_avg_c(temp, 64, dst, dst_stride, NULL, 0, NULL, 0, w, h); } void vpx_convolve_copy_c(const uint8_t *src, ptrdiff_t src_stride, uint8_t *dst, ptrdiff_t dst_stride, const int16_t *filter_x, int filter_x_stride, const int16_t *filter_y, int filter_y_stride, int w, int h) { int r; (void)filter_x; (void)filter_x_stride; (void)filter_y; (void)filter_y_stride; for (r = h; r > 0; --r) { memcpy(dst, src, w); src += src_stride; dst += dst_stride; } } void vpx_convolve_avg_c(const uint8_t *src, ptrdiff_t src_stride, uint8_t *dst, ptrdiff_t dst_stride, const int16_t *filter_x, int filter_x_stride, const int16_t *filter_y, int filter_y_stride, int w, int h) { int x, y; (void)filter_x; (void)filter_x_stride; (void)filter_y; (void)filter_y_stride; for (y = 0; y < h; ++y) { for (x = 0; x < w; ++x) dst[x] = ROUND_POWER_OF_TWO(dst[x] + src[x], 1); src += src_stride; dst += dst_stride; } } void vpx_scaled_horiz_c(const uint8_t *src, ptrdiff_t src_stride, uint8_t *dst, ptrdiff_t dst_stride, const int16_t *filter_x, int x_step_q4, const int16_t *filter_y, int y_step_q4, int w, int h) { vpx_convolve8_horiz_c(src, src_stride, dst, dst_stride, filter_x, x_step_q4, filter_y, y_step_q4, w, h); } void vpx_scaled_vert_c(const uint8_t *src, ptrdiff_t src_stride, uint8_t *dst, ptrdiff_t dst_stride, const int16_t *filter_x, int x_step_q4, const int16_t *filter_y, int y_step_q4, int w, int h) { vpx_convolve8_vert_c(src, src_stride, dst, dst_stride, filter_x, x_step_q4, filter_y, y_step_q4, w, h); } void vpx_scaled_2d_c(const uint8_t *src, ptrdiff_t src_stride, uint8_t *dst, ptrdiff_t dst_stride, const int16_t *filter_x, int x_step_q4, const int16_t *filter_y, int y_step_q4, int w, int h) { vpx_convolve8_c(src, src_stride, dst, dst_stride, filter_x, x_step_q4, filter_y, y_step_q4, w, h); } void vpx_scaled_avg_horiz_c(const uint8_t *src, ptrdiff_t src_stride, uint8_t *dst, ptrdiff_t dst_stride, const int16_t *filter_x, int x_step_q4, const int16_t *filter_y, int y_step_q4, int w, int h) { vpx_convolve8_avg_horiz_c(src, src_stride, dst, dst_stride, filter_x, x_step_q4, filter_y, y_step_q4, w, h); } void vpx_scaled_avg_vert_c(const uint8_t *src, ptrdiff_t src_stride, uint8_t *dst, ptrdiff_t dst_stride, const int16_t *filter_x, int x_step_q4, const int16_t *filter_y, int y_step_q4, int w, int h) { vpx_convolve8_avg_vert_c(src, src_stride, dst, dst_stride, filter_x, x_step_q4, filter_y, y_step_q4, w, h); } void vpx_scaled_avg_2d_c(const uint8_t *src, ptrdiff_t src_stride, uint8_t *dst, ptrdiff_t dst_stride, const int16_t *filter_x, int x_step_q4, const int16_t *filter_y, int y_step_q4, int w, int h) { vpx_convolve8_avg_c(src, src_stride, dst, dst_stride, filter_x, x_step_q4, filter_y, y_step_q4, w, h); } #if CONFIG_VP9_HIGHBITDEPTH static void highbd_convolve_horiz(const uint8_t *src8, ptrdiff_t src_stride, uint8_t *dst8, ptrdiff_t dst_stride, const InterpKernel *x_filters, int x0_q4, int x_step_q4, int w, int h, int bd) { int x, y; uint16_t *src = CONVERT_TO_SHORTPTR(src8); uint16_t *dst = CONVERT_TO_SHORTPTR(dst8); src -= SUBPEL_TAPS / 2 - 1; for (y = 0; y < h; ++y) { int x_q4 = x0_q4; for (x = 0; x < w; ++x) { const uint16_t *const src_x = &src[x_q4 >> SUBPEL_BITS]; const int16_t *const x_filter = x_filters[x_q4 & SUBPEL_MASK]; int k, sum = 0; for (k = 0; k < SUBPEL_TAPS; ++k) sum += src_x[k] * x_filter[k]; dst[x] = clip_pixel_highbd(ROUND_POWER_OF_TWO(sum, FILTER_BITS), bd); x_q4 += x_step_q4; } src += src_stride; dst += dst_stride; } } static void highbd_convolve_avg_horiz(const uint8_t *src8, ptrdiff_t src_stride, uint8_t *dst8, ptrdiff_t dst_stride, const InterpKernel *x_filters, int x0_q4, int x_step_q4, int w, int h, int bd) { int x, y; uint16_t *src = CONVERT_TO_SHORTPTR(src8); uint16_t *dst = CONVERT_TO_SHORTPTR(dst8); src -= SUBPEL_TAPS / 2 - 1; for (y = 0; y < h; ++y) { int x_q4 = x0_q4; for (x = 0; x < w; ++x) { const uint16_t *const src_x = &src[x_q4 >> SUBPEL_BITS]; const int16_t *const x_filter = x_filters[x_q4 & SUBPEL_MASK]; int k, sum = 0; for (k = 0; k < SUBPEL_TAPS; ++k) sum += src_x[k] * x_filter[k]; dst[x] = ROUND_POWER_OF_TWO(dst[x] + clip_pixel_highbd(ROUND_POWER_OF_TWO(sum, FILTER_BITS), bd), 1); x_q4 += x_step_q4; } src += src_stride; dst += dst_stride; } } static void highbd_convolve_vert(const uint8_t *src8, ptrdiff_t src_stride, uint8_t *dst8, ptrdiff_t dst_stride, const InterpKernel *y_filters, int y0_q4, int y_step_q4, int w, int h, int bd) { int x, y; uint16_t *src = CONVERT_TO_SHORTPTR(src8); uint16_t *dst = CONVERT_TO_SHORTPTR(dst8); src -= src_stride * (SUBPEL_TAPS / 2 - 1); for (x = 0; x < w; ++x) { int y_q4 = y0_q4; for (y = 0; y < h; ++y) { const uint16_t *src_y = &src[(y_q4 >> SUBPEL_BITS) * src_stride]; const int16_t *const y_filter = y_filters[y_q4 & SUBPEL_MASK]; int k, sum = 0; for (k = 0; k < SUBPEL_TAPS; ++k) sum += src_y[k * src_stride] * y_filter[k]; dst[y * dst_stride] = clip_pixel_highbd( ROUND_POWER_OF_TWO(sum, FILTER_BITS), bd); y_q4 += y_step_q4; } ++src; ++dst; } } static void highbd_convolve_avg_vert(const uint8_t *src8, ptrdiff_t src_stride, uint8_t *dst8, ptrdiff_t dst_stride, const InterpKernel *y_filters, int y0_q4, int y_step_q4, int w, int h, int bd) { int x, y; uint16_t *src = CONVERT_TO_SHORTPTR(src8); uint16_t *dst = CONVERT_TO_SHORTPTR(dst8); src -= src_stride * (SUBPEL_TAPS / 2 - 1); for (x = 0; x < w; ++x) { int y_q4 = y0_q4; for (y = 0; y < h; ++y) { const uint16_t *src_y = &src[(y_q4 >> SUBPEL_BITS) * src_stride]; const int16_t *const y_filter = y_filters[y_q4 & SUBPEL_MASK]; int k, sum = 0; for (k = 0; k < SUBPEL_TAPS; ++k) sum += src_y[k * src_stride] * y_filter[k]; dst[y * dst_stride] = ROUND_POWER_OF_TWO(dst[y * dst_stride] + clip_pixel_highbd(ROUND_POWER_OF_TWO(sum, FILTER_BITS), bd), 1); y_q4 += y_step_q4; } ++src; ++dst; } } static void highbd_convolve(const uint8_t *src, ptrdiff_t src_stride, uint8_t *dst, ptrdiff_t dst_stride, const InterpKernel *const x_filters, int x0_q4, int x_step_q4, const InterpKernel *const y_filters, int y0_q4, int y_step_q4, int w, int h, int bd) { // Note: Fixed size intermediate buffer, temp, places limits on parameters. // 2d filtering proceeds in 2 steps: // (1) Interpolate horizontally into an intermediate buffer, temp. // (2) Interpolate temp vertically to derive the sub-pixel result. // Deriving the maximum number of rows in the temp buffer (135): // --Smallest scaling factor is x1/2 ==> y_step_q4 = 32 (Normative). // --Largest block size is 64x64 pixels. // --64 rows in the downscaled frame span a distance of (64 - 1) * 32 in the // original frame (in 1/16th pixel units). // --Must round-up because block may be located at sub-pixel position. // --Require an additional SUBPEL_TAPS rows for the 8-tap filter tails. // --((64 - 1) * 32 + 15) >> 4 + 8 = 135. uint16_t temp[64 * 135]; int intermediate_height = (((h - 1) * y_step_q4 + y0_q4) >> SUBPEL_BITS) + SUBPEL_TAPS; assert(w <= 64); assert(h <= 64); assert(y_step_q4 <= 32); assert(x_step_q4 <= 32); highbd_convolve_horiz(src - src_stride * (SUBPEL_TAPS / 2 - 1), src_stride, CONVERT_TO_BYTEPTR(temp), 64, x_filters, x0_q4, x_step_q4, w, intermediate_height, bd); highbd_convolve_vert(CONVERT_TO_BYTEPTR(temp) + 64 * (SUBPEL_TAPS / 2 - 1), 64, dst, dst_stride, y_filters, y0_q4, y_step_q4, w, h, bd); } void vpx_highbd_convolve8_horiz_c(const uint8_t *src, ptrdiff_t src_stride, uint8_t *dst, ptrdiff_t dst_stride, const int16_t *filter_x, int x_step_q4, const int16_t *filter_y, int y_step_q4, int w, int h, int bd) { const InterpKernel *const filters_x = get_filter_base(filter_x); const int x0_q4 = get_filter_offset(filter_x, filters_x); (void)filter_y; (void)y_step_q4; highbd_convolve_horiz(src, src_stride, dst, dst_stride, filters_x, x0_q4, x_step_q4, w, h, bd); } void vpx_highbd_convolve8_avg_horiz_c(const uint8_t *src, ptrdiff_t src_stride, uint8_t *dst, ptrdiff_t dst_stride, const int16_t *filter_x, int x_step_q4, const int16_t *filter_y, int y_step_q4, int w, int h, int bd) { const InterpKernel *const filters_x = get_filter_base(filter_x); const int x0_q4 = get_filter_offset(filter_x, filters_x); (void)filter_y; (void)y_step_q4; highbd_convolve_avg_horiz(src, src_stride, dst, dst_stride, filters_x, x0_q4, x_step_q4, w, h, bd); } void vpx_highbd_convolve8_vert_c(const uint8_t *src, ptrdiff_t src_stride, uint8_t *dst, ptrdiff_t dst_stride, const int16_t *filter_x, int x_step_q4, const int16_t *filter_y, int y_step_q4, int w, int h, int bd) { const InterpKernel *const filters_y = get_filter_base(filter_y); const int y0_q4 = get_filter_offset(filter_y, filters_y); (void)filter_x; (void)x_step_q4; highbd_convolve_vert(src, src_stride, dst, dst_stride, filters_y, y0_q4, y_step_q4, w, h, bd); } void vpx_highbd_convolve8_avg_vert_c(const uint8_t *src, ptrdiff_t src_stride, uint8_t *dst, ptrdiff_t dst_stride, const int16_t *filter_x, int x_step_q4, const int16_t *filter_y, int y_step_q4, int w, int h, int bd) { const InterpKernel *const filters_y = get_filter_base(filter_y); const int y0_q4 = get_filter_offset(filter_y, filters_y); (void)filter_x; (void)x_step_q4; highbd_convolve_avg_vert(src, src_stride, dst, dst_stride, filters_y, y0_q4, y_step_q4, w, h, bd); } void vpx_highbd_convolve8_c(const uint8_t *src, ptrdiff_t src_stride, uint8_t *dst, ptrdiff_t dst_stride, const int16_t *filter_x, int x_step_q4, const int16_t *filter_y, int y_step_q4, int w, int h, int bd) { const InterpKernel *const filters_x = get_filter_base(filter_x); const int x0_q4 = get_filter_offset(filter_x, filters_x); const InterpKernel *const filters_y = get_filter_base(filter_y); const int y0_q4 = get_filter_offset(filter_y, filters_y); highbd_convolve(src, src_stride, dst, dst_stride, filters_x, x0_q4, x_step_q4, filters_y, y0_q4, y_step_q4, w, h, bd); } void vpx_highbd_convolve8_avg_c(const uint8_t *src, ptrdiff_t src_stride, uint8_t *dst, ptrdiff_t dst_stride, const int16_t *filter_x, int x_step_q4, const int16_t *filter_y, int y_step_q4, int w, int h, int bd) { // Fixed size intermediate buffer places limits on parameters. DECLARE_ALIGNED(16, uint16_t, temp[64 * 64]); assert(w <= 64); assert(h <= 64); vpx_highbd_convolve8_c(src, src_stride, CONVERT_TO_BYTEPTR(temp), 64, filter_x, x_step_q4, filter_y, y_step_q4, w, h, bd); vpx_highbd_convolve_avg_c(CONVERT_TO_BYTEPTR(temp), 64, dst, dst_stride, NULL, 0, NULL, 0, w, h, bd); } void vpx_highbd_convolve_copy_c(const uint8_t *src8, ptrdiff_t src_stride, uint8_t *dst8, ptrdiff_t dst_stride, const int16_t *filter_x, int filter_x_stride, const int16_t *filter_y, int filter_y_stride, int w, int h, int bd) { int r; uint16_t *src = CONVERT_TO_SHORTPTR(src8); uint16_t *dst = CONVERT_TO_SHORTPTR(dst8); (void)filter_x; (void)filter_y; (void)filter_x_stride; (void)filter_y_stride; (void)bd; for (r = h; r > 0; --r) { memcpy(dst, src, w * sizeof(uint16_t)); src += src_stride; dst += dst_stride; } } void vpx_highbd_convolve_avg_c(const uint8_t *src8, ptrdiff_t src_stride, uint8_t *dst8, ptrdiff_t dst_stride, const int16_t *filter_x, int filter_x_stride, const int16_t *filter_y, int filter_y_stride, int w, int h, int bd) { int x, y; uint16_t *src = CONVERT_TO_SHORTPTR(src8); uint16_t *dst = CONVERT_TO_SHORTPTR(dst8); (void)filter_x; (void)filter_y; (void)filter_x_stride; (void)filter_y_stride; (void)bd; for (y = 0; y < h; ++y) { for (x = 0; x < w; ++x) { dst[x] = ROUND_POWER_OF_TWO(dst[x] + src[x], 1); } src += src_stride; dst += dst_stride; } } #endif