1/*
2 * pixel format descriptor
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#ifndef AVUTIL_PIXDESC_H
23#define AVUTIL_PIXDESC_H
24
25#include <inttypes.h>
26
27typedef struct AVComponentDescriptor{
28    uint16_t plane        :2;            ///< which of the 4 planes contains the component
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;
41    uint16_t shift        :3;            ///< number of least significant bits that must be shifted away to get the value
42    uint16_t depth_minus1 :4;            ///< number of bits in the component minus 1
43}AVComponentDescriptor;
44
45/**
46 * Descriptor that unambiguously describes how the bits of a pixel are
47 * stored in the up to 4 data planes of an image. It also stores the
48 * subsampling factors and number of components.
49 *
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.
53 */
54typedef struct AVPixFmtDescriptor{
55    const char *name;
56    uint8_t nb_components;      ///< The number of components each pixel has, (1-4)
57
58    /**
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.
63     * This value only refers to the chroma components.
64     */
65    uint8_t log2_chroma_w;      ///< chroma_width = -((-luma_width )>>log2_chroma_w)
66
67    /**
68     * Amount to shift the luma height right to find the chroma height.
69     * For YV12 this is 1 for example.
70     * chroma_height= -((-luma_height) >> log2_chroma_h)
71     * The note above is needed to ensure rounding up.
72     * This value only refers to the chroma components.
73     */
74    uint8_t log2_chroma_h;
75    uint8_t flags;
76
77    /**
78     * Parameters that describe how pixels are packed. If the format
79     * has chroma components, they must be stored in comp[1] and
80     * comp[2].
81     */
82    AVComponentDescriptor comp[4];
83}AVPixFmtDescriptor;
84
85#define PIX_FMT_BE        1 ///< Pixel format is big-endian.
86#define PIX_FMT_PAL       2 ///< Pixel format has a palette in data[1], values are indexes in this palette.
87#define PIX_FMT_BITSTREAM 4 ///< All values of a component are bit-wise packed end to end.
88#define PIX_FMT_HWACCEL   8 ///< Pixel format is an HW accelerated format.
89
90/**
91 * The array of all the pixel format descriptors.
92 */
93extern const AVPixFmtDescriptor av_pix_fmt_descriptors[];
94
95/**
96 * Reads a line from an image, and writes the values of the
97 * pixel format component c to dst.
98 *
99 * @param data the array containing the pointers to the planes of the image
100 * @param linesizes the array containing the linesizes of the image
101 * @param desc the pixel format descriptor for the image
102 * @param x the horizontal coordinate of the first pixel to read
103 * @param y the vertical coordinate of the first pixel to read
104 * @param w the width of the line to read, that is the number of
105 * values to write to dst
106 * @param read_pal_component if not zero and the format is a paletted
107 * format writes the values corresponding to the palette
108 * component c in data[1] to dst, rather than the palette indexes in
109 * data[0]. The behavior is undefined if the format is not paletted.
110 */
111void read_line(uint16_t *dst, const uint8_t *data[4], const int linesize[4],
112               const AVPixFmtDescriptor *desc, int x, int y, int c, int w, int read_pal_component);
113
114/**
115 * Writes the values from src to the pixel format component c of an
116 * image line.
117 *
118 * @param src array containing the values to write
119 * @param data the array containing the pointers to the planes of the
120 * image to write into. It is supposed to be zeroed.
121 * @param linesizes the array containing the linesizes of the image
122 * @param desc the pixel format descriptor for the image
123 * @param x the horizontal coordinate of the first pixel to write
124 * @param y the vertical coordinate of the first pixel to write
125 * @param w the width of the line to write, that is the number of
126 * values to write to the image line
127 */
128void write_line(const uint16_t *src, uint8_t *data[4], const int linesize[4],
129                const AVPixFmtDescriptor *desc, int x, int y, int c, int w);
130
131/**
132 * Returns the pixel format corresponding to name.
133 *
134 * If there is no pixel format with name name, then looks for a
135 * pixel format with the name corresponding to the native endian
136 * format of name.
137 * For example in a little-endian system, first looks for "gray16",
138 * then for "gray16le".
139 *
140 * Finally if no pixel format has been found, returns PIX_FMT_NONE.
141 */
142enum PixelFormat av_get_pix_fmt(const char *name);
143
144/**
145 * Returns the number of bits per pixel used by the pixel format
146 * described by pixdesc.
147 *
148 * The returned number of bits refers to the number of bits actually
149 * used for storing the pixel information, that is padding bits are
150 * not counted.
151 */
152int av_get_bits_per_pixel(const AVPixFmtDescriptor *pixdesc);
153
154#endif /* AVUTIL_PIXDESC_H */
155