348bdc0195
The scaling filter with zero shift will give sub-sampling for 2x downsampling. Allow for a phase shift to get an averaging filter. Usage is for source scaling in 1 pass SVC mode for 1:2 downscale. Reduces aliasing in downsampled image. Keep the phase to 0/off for now. Change-Id: Ic547ea0748d151b675f877527e656407fcf4d51e
55 lines
2.2 KiB
C
55 lines
2.2 KiB
C
/*
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* Copyright (c) 2017 The WebM project authors. All Rights Reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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#include "./vp9_rtcd.h"
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#include "./vpx_dsp_rtcd.h"
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#include "./vpx_scale_rtcd.h"
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#include "vp9/common/vp9_blockd.h"
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#include "vpx_dsp/vpx_filter.h"
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#include "vpx_scale/yv12config.h"
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void vp9_scale_and_extend_frame_c(const YV12_BUFFER_CONFIG *src,
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YV12_BUFFER_CONFIG *dst, int phase_scaler) {
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const int src_w = src->y_crop_width;
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const int src_h = src->y_crop_height;
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const int dst_w = dst->y_crop_width;
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const int dst_h = dst->y_crop_height;
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const uint8_t *const srcs[3] = { src->y_buffer, src->u_buffer,
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src->v_buffer };
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const int src_strides[3] = { src->y_stride, src->uv_stride, src->uv_stride };
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uint8_t *const dsts[3] = { dst->y_buffer, dst->u_buffer, dst->v_buffer };
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const int dst_strides[3] = { dst->y_stride, dst->uv_stride, dst->uv_stride };
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const InterpKernel *const kernel = vp9_filter_kernels[EIGHTTAP];
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int x, y, i;
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for (i = 0; i < MAX_MB_PLANE; ++i) {
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const int factor = (i == 0 || i == 3 ? 1 : 2);
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const int src_stride = src_strides[i];
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const int dst_stride = dst_strides[i];
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for (y = 0; y < dst_h; y += 16) {
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const int y_q4 = y * (16 / factor) * src_h / dst_h + phase_scaler;
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for (x = 0; x < dst_w; x += 16) {
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const int x_q4 = x * (16 / factor) * src_w / dst_w + phase_scaler;
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const uint8_t *src_ptr = srcs[i] +
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(y / factor) * src_h / dst_h * src_stride +
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(x / factor) * src_w / dst_w;
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uint8_t *dst_ptr = dsts[i] + (y / factor) * dst_stride + (x / factor);
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vpx_scaled_2d(src_ptr, src_stride, dst_ptr, dst_stride,
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kernel[x_q4 & 0xf], 16 * src_w / dst_w,
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kernel[y_q4 & 0xf], 16 * src_h / dst_h, 16 / factor,
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16 / factor);
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}
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}
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}
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vpx_extend_frame_borders(dst);
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}
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