summaryrefslogtreecommitdiff
path: root/libavutil/pixdesc.h
blob: ca0722e1f4c2cdff532472fe59a4b4627deaf698 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
/*
 * pixel format descriptor
 * Copyright (c) 2009 Michael Niedermayer <michaelni@gmx.at>
 *
 * This file is part of FFmpeg.
 *
 * FFmpeg is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * FFmpeg is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with FFmpeg; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

#ifndef AVUTIL_PIXDESC_H
#define AVUTIL_PIXDESC_H

#include <inttypes.h>
#include "pixfmt.h"

typedef struct AVComponentDescriptor{
    uint16_t plane        :2;            ///< which of the 4 planes contains the component

    /**
     * Number of elements between 2 horizontally consecutive pixels minus 1.
     * Elements are bits for bitstream formats, bytes otherwise.
     */
    uint16_t step_minus1  :3;

    /**
     * Number of elements before the component of the first pixel plus 1.
     * Elements are bits for bitstream formats, bytes otherwise.
     */
    uint16_t offset_plus1 :3;
    uint16_t shift        :3;            ///< number of least significant bits that must be shifted away to get the value
    uint16_t depth_minus1 :4;            ///< number of bits in the component minus 1
}AVComponentDescriptor;

/**
 * Descriptor that unambiguously describes how the bits of a pixel are
 * stored in the up to 4 data planes of an image. It also stores the
 * subsampling factors and number of components.
 *
 * @note This is separate of the colorspace (RGB, YCbCr, YPbPr, JPEG-style YUV
 *       and all the YUV variants) AVPixFmtDescriptor just stores how values
 *       are stored not what these values represent.
 */
typedef struct AVPixFmtDescriptor{
    const char *name;
    uint8_t nb_components;      ///< The number of components each pixel has, (1-4)

    /**
     * Amount to shift the luma width right to find the chroma width.
     * For YV12 this is 1 for example.
     * chroma_width = -((-luma_width) >> log2_chroma_w)
     * The note above is needed to ensure rounding up.
     * This value only refers to the chroma components.
     */
    uint8_t log2_chroma_w;      ///< chroma_width = -((-luma_width )>>log2_chroma_w)

    /**
     * Amount to shift the luma height right to find the chroma height.
     * For YV12 this is 1 for example.
     * chroma_height= -((-luma_height) >> log2_chroma_h)
     * The note above is needed to ensure rounding up.
     * This value only refers to the chroma components.
     */
    uint8_t log2_chroma_h;
    uint8_t flags;

    /**
     * Parameters that describe how pixels are packed.
     * If the format has 2 or 4 components, then alpha is last.
     * If the format has 1 or 2 components, then luma is 0.
     * If the format has 3 or 4 components,
     * if the RGB flag is set then 0 is red, 1 is green and 2 is blue;
     * otherwise 0 is luma, 1 is chroma-U and 2 is chroma-V.
     */
    AVComponentDescriptor comp[4];
}AVPixFmtDescriptor;

#define PIX_FMT_BE        1 ///< Pixel format is big-endian.
#define PIX_FMT_PAL       2 ///< Pixel format has a palette in data[1], values are indexes in this palette.
#define PIX_FMT_BITSTREAM 4 ///< All values of a component are bit-wise packed end to end.
#define PIX_FMT_HWACCEL   8 ///< Pixel format is an HW accelerated format.
#define PIX_FMT_PLANAR   16 ///< At least one pixel component is not in the first data plane
#define PIX_FMT_RGB      32 ///< The pixel format contains RGB-like data (as opposed to YUV/grayscale)
/**
 * The pixel format is "pseudo-paletted". This means that FFmpeg treats it as
 * paletted internally, but the palette is generated by the decoder and is not
 * stored in the file.
 */
#define PIX_FMT_PSEUDOPAL 64

#define PIX_FMT_ALPHA   128 ///< The pixel format has an alpha channel


#if FF_API_PIX_FMT_DESC
/**
 * The array of all the pixel format descriptors.
 */
extern const AVPixFmtDescriptor av_pix_fmt_descriptors[];
#endif

/**
 * Read a line from an image, and write the values of the
 * pixel format component c to dst.
 *
 * @param data the array containing the pointers to the planes of the image
 * @param linesize the array containing the linesizes of the image
 * @param desc the pixel format descriptor for the image
 * @param x the horizontal coordinate of the first pixel to read
 * @param y the vertical coordinate of the first pixel to read
 * @param w the width of the line to read, that is the number of
 * values to write to dst
 * @param read_pal_component if not zero and the format is a paletted
 * format writes the values corresponding to the palette
 * component c in data[1] to dst, rather than the palette indexes in
 * data[0]. The behavior is undefined if the format is not paletted.
 */
void av_read_image_line(uint16_t *dst, const uint8_t *data[4], const int linesize[4],
                        const AVPixFmtDescriptor *desc, int x, int y, int c, int w, int read_pal_component);

/**
 * Write the values from src to the pixel format component c of an
 * image line.
 *
 * @param src array containing the values to write
 * @param data the array containing the pointers to the planes of the
 * image to write into. It is supposed to be zeroed.
 * @param linesize the array containing the linesizes of the image
 * @param desc the pixel format descriptor for the image
 * @param x the horizontal coordinate of the first pixel to write
 * @param y the vertical coordinate of the first pixel to write
 * @param w the width of the line to write, that is the number of
 * values to write to the image line
 */
void av_write_image_line(const uint16_t *src, uint8_t *data[4], const int linesize[4],
                         const AVPixFmtDescriptor *desc, int x, int y, int c, int w);

/**
 * Return the pixel format corresponding to name.
 *
 * If there is no pixel format with name name, then looks for a
 * pixel format with the name corresponding to the native endian
 * format of name.
 * For example in a little-endian system, first looks for "gray16",
 * then for "gray16le".
 *
 * Finally if no pixel format has been found, returns AV_PIX_FMT_NONE.
 */
enum AVPixelFormat av_get_pix_fmt(const char *name);

/**
 * Return the short name for a pixel format, NULL in case pix_fmt is
 * unknown.
 *
 * @see av_get_pix_fmt(), av_get_pix_fmt_string()
 */
const char *av_get_pix_fmt_name(enum AVPixelFormat pix_fmt);

/**
 * Print in buf the string corresponding to the pixel format with
 * number pix_fmt, or an header if pix_fmt is negative.
 *
 * @param buf the buffer where to write the string
 * @param buf_size the size of buf
 * @param pix_fmt the number of the pixel format to print the
 * corresponding info string, or a negative value to print the
 * corresponding header.
 */
char *av_get_pix_fmt_string (char *buf, int buf_size, enum AVPixelFormat pix_fmt);

/**
 * Return the number of bits per pixel used by the pixel format
 * described by pixdesc.
 *
 * The returned number of bits refers to the number of bits actually
 * used for storing the pixel information, that is padding bits are
 * not counted.
 */
int av_get_bits_per_pixel(const AVPixFmtDescriptor *pixdesc);

/**
 * Return the number of bits per pixel for the pixel format
 * described by pixdesc, including any padding or unused bits.
 */
int av_get_padded_bits_per_pixel(const AVPixFmtDescriptor *pixdesc);

/**
 * @return a pixel format descriptor for provided pixel format or NULL if
 * this pixel format is unknown.
 */
const AVPixFmtDescriptor *av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt);

/**
 * Iterate over all pixel format descriptors known to libavutil.
 *
 * @param prev previous descriptor. NULL to get the first descriptor.
 *
 * @return next descriptor or NULL after the last descriptor
 */
const AVPixFmtDescriptor *av_pix_fmt_desc_next(const AVPixFmtDescriptor *prev);

/**
 * @return an AVPixelFormat id described by desc, or AV_PIX_FMT_NONE if desc
 * is not a valid pointer to a pixel format descriptor.
 */
enum AVPixelFormat av_pix_fmt_desc_get_id(const AVPixFmtDescriptor *desc);

/**
 * Utility function to access log2_chroma_w log2_chroma_h from
 * the pixel format AVPixFmtDescriptor.
 *
 * See avcodec_get_chroma_sub_sample() for a function that asserts a
 * valid pixel format instead of returning an error code.
 * Its recommanded that you use avcodec_get_chroma_sub_sample unless
 * you do check the return code!
 *
 * @param[in]  pix_fmt the pixel format
 * @param[out] h_shift store log2_chroma_h
 * @param[out] v_shift store log2_chroma_w
 *
 * @return 0 on success, AVERROR(ENOSYS) on invalid or unknown pixel format
 */
int av_pix_fmt_get_chroma_sub_sample(enum AVPixelFormat pix_fmt,
                                     int *h_shift, int *v_shift);


#endif /* AVUTIL_PIXDESC_H */