Implement a write_line() function.
[libav.git] / libavcodec / pixdesc.h
CommitLineData
9b61d838 1/*
e0cffbe7 2 * pixel format descriptor
9b61d838
MN
3 * Copyright (c) 2009 Michael Niedermayer <michaelni@gmx.at>
4 *
5 * This file is part of FFmpeg.
6 *
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
11 *
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21
22#include <inttypes.h>
23
24#include "libavutil/intreadwrite.h"
084c7cc5 25#include "get_bits.h"
9b61d838
MN
26
27typedef struct AVComponentDescriptor{
28 uint16_t plane :2; ///< which of the 4 planes contains the component
21010f6b
SS
29
30 /**
31 * Number of elements between 2 horizontally consecutive pixels minus 1.
32 * Elements are bits for bitstream formats, bytes otherwise.
33 */
34 uint16_t step_minus1 :3;
35
36 /**
37 * Number of elements before the component of the first pixel plus 1.
38 * Elements are bits for bitstream formats, bytes otherwise.
39 */
40 uint16_t offset_plus1 :3;
78679783 41 uint16_t shift :3; ///< number of least significant bits that must be shifted away to get the value
9b61d838
MN
42 uint16_t depth_minus1 :4; ///< number of bits in the component minus 1
43}AVComponentDescriptor;
44
d3bcbf57 45/**
e0cffbe7 46 * Descriptor that unambiguously describes how the bits of a pixel are
d3bcbf57
MN
47 * stored in the up to 4 data planes of an image. It also stores the
48 * subsampling factors and number of components.
49 *
e0cffbe7
DB
50 * @note This is separate of the colorspace (RGB, YCbCr, YPbPr, JPEG-style YUV
51 * and all the YUV variants) AVPixFmtDescriptor just stores how values
52 * are stored not what these values represent.
d3bcbf57 53 */
9b61d838 54typedef struct AVPixFmtDescriptor{
1e896640 55 const char *name;
9b61d838
MN
56 uint8_t nb_channels; ///< The number of components each pixel has, (1-4)
57
58 /**
e0cffbe7
DB
59 * Amount to shift the luma width right to find the chroma width.
60 * For YV12 this is 1 for example.
61 * chroma_width = -((-luma_width) >> log2_chroma_w)
62 * The note above is needed to ensure rounding up.
9b61d838
MN
63 */
64 uint8_t log2_chroma_w; ///< chroma_width = -((-luma_width )>>log2_chroma_w)
65
66 /**
e0cffbe7
DB
67 * Amount to shift the luma height right to find the chroma height.
68 * For YV12 this is 1 for example.
69 * chroma_height= -((-luma_height) >> log2_chroma_h)
70 * The note above is needed to ensure rounding up.
9b61d838
MN
71 */
72 uint8_t log2_chroma_h;
73 uint8_t flags;
e0cffbe7 74 AVComponentDescriptor comp[4]; ///< parameters that describe how pixels are packed
9b61d838
MN
75}AVPixFmtDescriptor;
76
e0cffbe7 77#define PIX_FMT_BE 1 ///< big-endian
d3f76612 78#define PIX_FMT_PAL 2 ///< Pixel format has a palette in data[1], values are indexes in this palette.
e0cffbe7 79#define PIX_FMT_BITSTREAM 4 ///< All values of a component are bit-wise packed end to end.
9b61d838 80
d2863e72
SS
81/**
82 * The array of all the pixel format descriptors.
83 */
84extern const AVPixFmtDescriptor av_pix_fmt_descriptors[];
9b61d838 85
9b34899e
SS
86/**
87 * Reads a line from an image, and writes to \p dst the values of the
88 * pixel format component \p c.
89 *
90 * @param data the array containing the pointers to the planes of the image
91 * @param linesizes the array containing the linesizes of the image
92 * @param desc the pixel format descriptor for the image
93 * @param x the horizontal coordinate of the first pixel to read
94 * @param y the vertical coordinate of the first pixel to read
95 * @param w the width of the line to read, that is the number of
96 * values to write to \p dst
0a47f60a
SS
97 * @param read_pal_component if not zero and the format is a paletted
98 * format writes to \p dst the values corresponding to the palette
99 * component \p c in data[1], rather than the palette indexes in
100 * data[0]. The behavior is undefined if the format is not paletted.
9b34899e 101 */
0a47f60a
SS
102static inline void read_line(uint16_t *dst, const uint8_t *data[4], const int linesize[4],
103 const AVPixFmtDescriptor *desc, int x, int y, int c, int w, int read_pal_component)
9b61d838
MN
104{
105 AVComponentDescriptor comp= desc->comp[c];
106 int plane= comp.plane;
107 int depth= comp.depth_minus1+1;
108 int mask = (1<<depth)-1;
109 int shift= comp.shift;
110 int step = comp.step_minus1+1;
111 int flags= desc->flags;
9b61d838 112
c95dd8d3
SS
113 if (flags & PIX_FMT_BITSTREAM){
114 GetBitContext gb;
115 init_get_bits(&gb, data[plane] + y*linesize[plane], linesize[plane]*8);
116 skip_bits_long(&gb, x*step + comp.offset_plus1-1);
117
118 while(w--){
119 int val = show_bits(&gb, depth);
0a47f60a 120 if(read_pal_component)
c95dd8d3
SS
121 val= data[1][4*val + c];
122 skip_bits(&gb, step);
123 *dst++= val;
124 }
125 } else {
59b05350 126 const uint8_t *p = data[plane]+ y*linesize[plane] + x*step + comp.offset_plus1-1;
9b61d838 127
59b05350
SS
128 while(w--){
129 int val;
130 if(flags & PIX_FMT_BE) val= AV_RB16(p);
131 else val= AV_RL16(p);
132 val = (val>>shift) & mask;
0a47f60a 133 if(read_pal_component)
59b05350 134 val= data[1][4*val + c];
9b61d838 135 p+= step;
59b05350
SS
136 *dst++= val;
137 }
c95dd8d3 138 }
9b61d838 139}
9401d18f
SS
140
141/**
142 * Writes the values from src to the pixel format component c of an
143 * image line.
144 *
145 * @param src array containing the values to write
146 * @param data the array containing the pointers to the planes of the
147 * image to write into. It is supposed to be zeroed.
148 * @param linesizes the array containing the linesizes of the image
149 * @param desc the pixel format descriptor for the image
150 * @param x the horizontal coordinate of the first pixel to write
151 * @param y the vertical coordinate of the first pixel to write
152 * @param w the width of the line to write, that is the number of
153 * values to write to the image line
154 */
155static inline void write_line(const uint16_t *src, uint8_t *data[4], const int linesize[4],
156 const AVPixFmtDescriptor *desc, int x, int y, int c, int w)
157{
158 AVComponentDescriptor comp = desc->comp[c];
159 int plane = comp.plane;
160 int depth = comp.depth_minus1+1;
161 int step = comp.step_minus1+1;
162 int flags = desc->flags;
163
164 if (flags & PIX_FMT_BITSTREAM) {
165 int skip = x*step + comp.offset_plus1-1;
166 uint8_t *p = data[plane] + y*linesize[plane] + (skip>>3);
167 int shift = 8 - depth - (skip&7);
168
169 while (w--) {
170 *p |= *src++ << shift;
171 shift -= step;
172 p -= shift>>3;
173 shift &= 7;
174 }
175 } else {
176 int shift = comp.shift;
177 uint8_t *p = data[plane]+ y*linesize[plane] + x*step + comp.offset_plus1-1;
178
179 while (w--) {
180 if (flags & PIX_FMT_BE) {
181 uint16_t val = AV_RB16(p) | (*src++<<shift);
182 AV_WB16(p, val);
183 } else {
184 uint16_t val = AV_RL16(p) | (*src++<<shift);
185 AV_WL16(p, val);
186 }
187 p+= step;
188 }
189 }
190}