75 lines
3.4 KiB
C
75 lines
3.4 KiB
C
/*
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* Copyright (C) 2015 Michael Niedermayer <michaelni@gmx.at>
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include "swscale_internal.h"
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int ff_sws_alphablendaway(SwsContext *c, const uint8_t *src[],
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int srcStride[], int srcSliceY, int srcSliceH,
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uint8_t *dst[], int dstStride[])
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{
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const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(c->srcFormat);
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int nb_components = desc->nb_components;
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int plane, x, y;
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int plane_count = isGray(c->srcFormat) ? 1 : 3;
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int sixteen_bits = desc->comp[0].depth_minus1 >= 8;
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unsigned off = 1<<desc->comp[0].depth_minus1;
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unsigned shift = desc->comp[0].depth_minus1 + 1;
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unsigned max = (1<<shift) - 1;
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av_assert0(plane_count == nb_components - 1);
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if (desc->flags & AV_PIX_FMT_FLAG_PLANAR) {
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for (plane = 0; plane < plane_count; plane++) {
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int w = plane ? c->chrSrcW : c->srcW;
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int y_subsample = plane ? desc->log2_chroma_h: 0;
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for (y = srcSliceY >> y_subsample; y < FF_CEIL_RSHIFT(srcSliceH, y_subsample); y++) {
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if (sixteen_bits) {
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const uint16_t *s = src[plane ] + srcStride[plane] * y;
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const uint16_t *a = src[plane_count] + srcStride[plane_count] * y;
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uint16_t *d = dst[plane ] + dstStride[plane] * y;
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unsigned target = plane && !(desc->flags & AV_PIX_FMT_FLAG_RGB) ? 1<<desc->comp[0].depth_minus1 : 0;
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if ((!isBE(c->dstFormat)) == !HAVE_BIGENDIAN) {
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for (x = 0; x < w; x++) {
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unsigned u = s[x]*a[x] + target*(max-a[x]) + off;
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d[x] = av_clip((u + (u >> shift)) >> shift, 0, max);
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}
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} else {
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for (x = 0; x < w; x++) {
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unsigned aswap =av_bswap16(a[x]);
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unsigned u = av_bswap16(s[x])*aswap + target*(max-aswap) + off;
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d[x] = av_clip((u + (u >> shift)) >> shift, 0, max);
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}
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}
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} else {
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const uint8_t *s = src[plane ] + srcStride[plane] * y;
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const uint8_t *a = src[plane_count] + srcStride[plane_count] * y;
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uint8_t *d = dst[plane ] + dstStride[plane] * y;
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unsigned target = plane && !(desc->flags & AV_PIX_FMT_FLAG_RGB) ? 128 : 0;
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for (x = 0; x < w; x++) {
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unsigned u = s[x]*a[x] + target*(255-a[x]) + 128;
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d[x] = (257*u) >> 16;
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}
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}
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}
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}
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}
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return 0;
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}
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