1/*
2 * pixel format descriptor
3 * Copyright (c) 2009 Michael Niedermayer <michaelni@gmx.at>
4 *
5 * This file is part of Libav.
6 *
7 * Libav 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 * Libav 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 Libav; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21
22#ifndef AVUTIL_PIXDESC_H
23#define AVUTIL_PIXDESC_H
24
25#include <inttypes.h>
26#include "pixfmt.h"
27
28typedef struct AVComponentDescriptor{
29    uint16_t plane        :2;            ///< which of the 4 planes contains the component
30
31    /**
32     * Number of elements between 2 horizontally consecutive pixels minus 1.
33     * Elements are bits for bitstream formats, bytes otherwise.
34     */
35    uint16_t step_minus1  :3;
36
37    /**
38     * Number of elements before the component of the first pixel plus 1.
39     * Elements are bits for bitstream formats, bytes otherwise.
40     */
41    uint16_t offset_plus1 :3;
42    uint16_t shift        :3;            ///< number of least significant bits that must be shifted away to get the value
43    uint16_t depth_minus1 :4;            ///< number of bits in the component minus 1
44}AVComponentDescriptor;
45
46/**
47 * Descriptor that unambiguously describes how the bits of a pixel are
48 * stored in the up to 4 data planes of an image. It also stores the
49 * subsampling factors and number of components.
50 *
51 * @note This is separate of the colorspace (RGB, YCbCr, YPbPr, JPEG-style YUV
52 *       and all the YUV variants) AVPixFmtDescriptor just stores how values
53 *       are stored not what these values represent.
54 */
55typedef struct AVPixFmtDescriptor{
56    const char *name;
57    uint8_t nb_components;      ///< The number of components each pixel has, (1-4)
58
59    /**
60     * Amount to shift the luma width right to find the chroma width.
61     * For YV12 this is 1 for example.
62     * chroma_width = -((-luma_width) >> log2_chroma_w)
63     * The note above is needed to ensure rounding up.
64     * This value only refers to the chroma components.
65     */
66    uint8_t log2_chroma_w;      ///< chroma_width = -((-luma_width )>>log2_chroma_w)
67
68    /**
69     * Amount to shift the luma height right to find the chroma height.
70     * For YV12 this is 1 for example.
71     * chroma_height= -((-luma_height) >> log2_chroma_h)
72     * The note above is needed to ensure rounding up.
73     * This value only refers to the chroma components.
74     */
75    uint8_t log2_chroma_h;
76    uint8_t flags;
77
78    /**
79     * Parameters that describe how pixels are packed. If the format
80     * has chroma components, they must be stored in comp[1] and
81     * comp[2].
82     */
83    AVComponentDescriptor comp[4];
84}AVPixFmtDescriptor;
85
86#define PIX_FMT_BE        1 ///< Pixel format is big-endian.
87#define PIX_FMT_PAL       2 ///< Pixel format has a palette in data[1], values are indexes in this palette.
88#define PIX_FMT_BITSTREAM 4 ///< All values of a component are bit-wise packed end to end.
89#define PIX_FMT_HWACCEL   8 ///< Pixel format is an HW accelerated format.
90#define PIX_FMT_PLANAR   16 ///< At least one pixel component is not in the first data plane
91#define PIX_FMT_RGB      32 ///< The pixel format contains RGB-like data (as opposed to YUV/grayscale)
92
93/**
94 * The array of all the pixel format descriptors.
95 */
96extern const AVPixFmtDescriptor av_pix_fmt_descriptors[];
97
98/**
99 * Read a line from an image, and write the values of the
100 * pixel format component c to dst.
101 *
102 * @param data the array containing the pointers to the planes of the image
103 * @param linesize the array containing the linesizes of the image
104 * @param desc the pixel format descriptor for the image
105 * @param x the horizontal coordinate of the first pixel to read
106 * @param y the vertical coordinate of the first pixel to read
107 * @param w the width of the line to read, that is the number of
108 * values to write to dst
109 * @param read_pal_component if not zero and the format is a paletted
110 * format writes the values corresponding to the palette
111 * component c in data[1] to dst, rather than the palette indexes in
112 * data[0]. The behavior is undefined if the format is not paletted.
113 */
114void av_read_image_line(uint16_t *dst, const uint8_t *data[4], const int linesize[4],
115                        const AVPixFmtDescriptor *desc, int x, int y, int c, int w, int read_pal_component);
116
117/**
118 * Write the values from src to the pixel format component c of an
119 * image line.
120 *
121 * @param src array containing the values to write
122 * @param data the array containing the pointers to the planes of the
123 * image to write into. It is supposed to be zeroed.
124 * @param linesize the array containing the linesizes of the image
125 * @param desc the pixel format descriptor for the image
126 * @param x the horizontal coordinate of the first pixel to write
127 * @param y the vertical coordinate of the first pixel to write
128 * @param w the width of the line to write, that is the number of
129 * values to write to the image line
130 */
131void av_write_image_line(const uint16_t *src, uint8_t *data[4], const int linesize[4],
132                         const AVPixFmtDescriptor *desc, int x, int y, int c, int w);
133
134/**
135 * Return the pixel format corresponding to name.
136 *
137 * If there is no pixel format with name name, then looks for a
138 * pixel format with the name corresponding to the native endian
139 * format of name.
140 * For example in a little-endian system, first looks for "gray16",
141 * then for "gray16le".
142 *
143 * Finally if no pixel format has been found, returns PIX_FMT_NONE.
144 */
145enum PixelFormat av_get_pix_fmt(const char *name);
146
147/**
148 * Return the short name for a pixel format, NULL in case pix_fmt is
149 * unknown.
150 *
151 * @see av_get_pix_fmt(), av_get_pix_fmt_string()
152 */
153const char *av_get_pix_fmt_name(enum PixelFormat pix_fmt);
154
155/**
156 * Print in buf the string corresponding to the pixel format with
157 * number pix_fmt, or an header if pix_fmt is negative.
158 *
159 * @param buf the buffer where to write the string
160 * @param buf_size the size of buf
161 * @param pix_fmt the number of the pixel format to print the
162 * corresponding info string, or a negative value to print the
163 * corresponding header.
164 */
165char *av_get_pix_fmt_string (char *buf, int buf_size, enum PixelFormat pix_fmt);
166
167/**
168 * Return the number of bits per pixel used by the pixel format
169 * described by pixdesc.
170 *
171 * The returned number of bits refers to the number of bits actually
172 * used for storing the pixel information, that is padding bits are
173 * not counted.
174 */
175int av_get_bits_per_pixel(const AVPixFmtDescriptor *pixdesc);
176
177#endif /* AVUTIL_PIXDESC_H */
178