1 /*
2 * Copyright (C) 2015 Michael Niedermayer <michaelni@gmx.at>
3 *
4 * This file is part of FFmpeg.
5 *
6 * FFmpeg is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2.1 of the License, or (at your option) any later version.
10 *
11 * FFmpeg is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Lesser General Public License for more details.
15 *
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with FFmpeg; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19 */
20
21 #include "swscale_internal.h"
22
ff_sws_alphablendaway(SwsContext * c,const uint8_t * src[],int srcStride[],int srcSliceY,int srcSliceH,uint8_t * dst[],int dstStride[])23 int ff_sws_alphablendaway(SwsContext *c, const uint8_t *src[],
24 int srcStride[], int srcSliceY, int srcSliceH,
25 uint8_t *dst[], int dstStride[])
26 {
27 const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(c->srcFormat);
28 int nb_components = desc->nb_components;
29 int plane, x, y;
30 int plane_count = isGray(c->srcFormat) ? 1 : 3;
31 int sixteen_bits = desc->comp[0].depth >= 9;
32 unsigned off = 1<<(desc->comp[0].depth - 1);
33 unsigned shift = desc->comp[0].depth;
34 unsigned max = (1<<shift) - 1;
35 int target_table[2][3];
36
37 for (plane = 0; plane < plane_count; plane++) {
38 int a = 0, b = 0;
39 if (c->alphablend == SWS_ALPHA_BLEND_CHECKERBOARD) {
40 a = (1<<(desc->comp[0].depth - 1))/2;
41 b = 3*(1<<(desc->comp[0].depth-1))/2;
42 }
43 target_table[0][plane] = plane && !(desc->flags & AV_PIX_FMT_FLAG_RGB) ? 1<<(desc->comp[0].depth - 1) : a;
44 target_table[1][plane] = plane && !(desc->flags & AV_PIX_FMT_FLAG_RGB) ? 1<<(desc->comp[0].depth - 1) : b;
45 }
46
47 av_assert0(plane_count == nb_components - 1);
48 if (desc->flags & AV_PIX_FMT_FLAG_PLANAR) {
49 for (plane = 0; plane < plane_count; plane++) {
50 int w = plane ? c->chrSrcW : c->srcW;
51 int x_subsample = plane ? desc->log2_chroma_w: 0;
52 int y_subsample = plane ? desc->log2_chroma_h: 0;
53 for (y = srcSliceY >> y_subsample; y < AV_CEIL_RSHIFT(srcSliceH, y_subsample); y++) {
54 if (x_subsample || y_subsample) {
55 int alpha;
56 unsigned u;
57 if (sixteen_bits) {
58 ptrdiff_t alpha_step = srcStride[plane_count] >> 1;
59 const uint16_t *s = (const uint16_t *)(src[plane ] + srcStride[plane ] * y);
60 const uint16_t *a = (const uint16_t *)(src[plane_count] + (srcStride[plane_count] * y << y_subsample));
61 uint16_t *d = ( uint16_t *)(dst[plane ] + dstStride[plane ] * y);
62 if ((!isBE(c->srcFormat)) == !HAVE_BIGENDIAN) {
63 for (x = 0; x < w; x++) {
64 if (y_subsample) {
65 alpha = (a[2*x] + a[2*x + 1] + 2 +
66 a[2*x + alpha_step] + a[2*x + alpha_step + 1]) >> 2;
67 } else
68 alpha = (a[2*x] + a[2*x + 1]) >> 1;
69 u = s[x]*alpha + target_table[((x^y)>>5)&1][plane]*(max-alpha) + off;
70 d[x] = av_clip((u + (u >> shift)) >> shift, 0, max);
71 }
72 } else {
73 for (x = 0; x < w; x++) {
74 if (y_subsample) {
75 alpha = (av_bswap16(a[2*x]) + av_bswap16(a[2*x + 1]) + 2 +
76 av_bswap16(a[2*x + alpha_step]) + av_bswap16(a[2*x + alpha_step + 1])) >> 2;
77 } else
78 alpha = (av_bswap16(a[2*x]) + av_bswap16(a[2*x + 1])) >> 1;
79 u = av_bswap16(s[x])*alpha + target_table[((x^y)>>5)&1][plane]*(max-alpha) + off;
80 d[x] = av_clip((u + (u >> shift)) >> shift, 0, max);
81 }
82 }
83 } else {
84 ptrdiff_t alpha_step = srcStride[plane_count];
85 const uint8_t *s = src[plane ] + srcStride[plane] * y;
86 const uint8_t *a = src[plane_count] + (srcStride[plane_count] * y << y_subsample);
87 uint8_t *d = dst[plane ] + dstStride[plane] * y;
88 for (x = 0; x < w; x++) {
89 if (y_subsample) {
90 alpha = (a[2*x] + a[2*x + 1] + 2 +
91 a[2*x + alpha_step] + a[2*x + alpha_step + 1]) >> 2;
92 } else
93 alpha = (a[2*x] + a[2*x + 1]) >> 1;
94 u = s[x]*alpha + target_table[((x^y)>>5)&1][plane]*(255-alpha) + 128;
95 d[x] = (257*u) >> 16;
96 }
97 }
98 } else {
99 if (sixteen_bits) {
100 const uint16_t *s = (const uint16_t *)(src[plane ] + srcStride[plane ] * y);
101 const uint16_t *a = (const uint16_t *)(src[plane_count] + srcStride[plane_count] * y);
102 uint16_t *d = ( uint16_t *)(dst[plane ] + dstStride[plane ] * y);
103 if ((!isBE(c->srcFormat)) == !HAVE_BIGENDIAN) {
104 for (x = 0; x < w; x++) {
105 unsigned u = s[x]*a[x] + target_table[((x^y)>>5)&1][plane]*(max-a[x]) + off;
106 d[x] = av_clip((u + (u >> shift)) >> shift, 0, max);
107 }
108 } else {
109 for (x = 0; x < w; x++) {
110 unsigned aswap =av_bswap16(a[x]);
111 unsigned u = av_bswap16(s[x])*aswap + target_table[((x^y)>>5)&1][plane]*(max-aswap) + off;
112 d[x] = av_clip((u + (u >> shift)) >> shift, 0, max);
113 }
114 }
115 } else {
116 const uint8_t *s = src[plane ] + srcStride[plane] * y;
117 const uint8_t *a = src[plane_count] + srcStride[plane_count] * y;
118 uint8_t *d = dst[plane ] + dstStride[plane] * y;
119 for (x = 0; x < w; x++) {
120 unsigned u = s[x]*a[x] + target_table[((x^y)>>5)&1][plane]*(255-a[x]) + 128;
121 d[x] = (257*u) >> 16;
122 }
123 }
124 }
125 }
126 }
127 } else {
128 int alpha_pos = desc->comp[plane_count].offset;
129 int w = c->srcW;
130 for (y = srcSliceY; y < srcSliceH; y++) {
131 if (sixteen_bits) {
132 const uint16_t *s = (const uint16_t *)(src[0] + srcStride[0] * y + 2*!alpha_pos);
133 const uint16_t *a = (const uint16_t *)(src[0] + srcStride[0] * y + alpha_pos);
134 uint16_t *d = ( uint16_t *)(dst[0] + dstStride[0] * y);
135 if ((!isBE(c->srcFormat)) == !HAVE_BIGENDIAN) {
136 for (x = 0; x < w; x++) {
137 for (plane = 0; plane < plane_count; plane++) {
138 int x_index = (plane_count + 1) * x;
139 unsigned u = s[x_index + plane]*a[x_index] + target_table[((x^y)>>5)&1][plane]*(max-a[x_index]) + off;
140 d[plane_count*x + plane] = av_clip((u + (u >> shift)) >> shift, 0, max);
141 }
142 }
143 } else {
144 for (x = 0; x < w; x++) {
145 for (plane = 0; plane < plane_count; plane++) {
146 int x_index = (plane_count + 1) * x;
147 unsigned aswap =av_bswap16(a[x_index]);
148 unsigned u = av_bswap16(s[x_index + plane])*aswap + target_table[((x^y)>>5)&1][plane]*(max-aswap) + off;
149 d[plane_count*x + plane] = av_clip((u + (u >> shift)) >> shift, 0, max);
150 }
151 }
152 }
153 } else {
154 const uint8_t *s = src[0] + srcStride[0] * y + !alpha_pos;
155 const uint8_t *a = src[0] + srcStride[0] * y + alpha_pos;
156 uint8_t *d = dst[0] + dstStride[0] * y;
157 for (x = 0; x < w; x++) {
158 for (plane = 0; plane < plane_count; plane++) {
159 int x_index = (plane_count + 1) * x;
160 unsigned u = s[x_index + plane]*a[x_index] + target_table[((x^y)>>5)&1][plane]*(255-a[x_index]) + 128;
161 d[plane_count*x + plane] = (257*u) >> 16;
162 }
163 }
164 }
165 }
166 }
167
168 return 0;
169 }
170