ea84fd3c08288afc2cede6c37e605d99b3ac0811
[libav.git] / libavutil / pixdesc.h
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
27 #include "attributes.h"
28 #include "pixfmt.h"
29
30 typedef struct AVComponentDescriptor {
31 /**
32 * Which of the 4 planes contains the component.
33 */
34 int plane;
35
36 /**
37 * Number of elements between 2 horizontally consecutive pixels.
38 * Elements are bits for bitstream formats, bytes otherwise.
39 */
40 int step;
41
42 /**
43 * Number of elements before the component of the first pixel.
44 * Elements are bits for bitstream formats, bytes otherwise.
45 */
46 int offset;
47
48 /**
49 * Number of least significant bits that must be shifted away
50 * to get the value.
51 */
52 int shift;
53
54 /**
55 * Number of bits in the component.
56 */
57 int depth;
58
59 #if FF_API_PLUS1_MINUS1
60 /** deprecated, use step instead */
61 attribute_deprecated int step_minus1;
62
63 /** deprecated, use depth instead */
64 attribute_deprecated int depth_minus1;
65
66 /** deprecated, use offset instead */
67 attribute_deprecated int offset_plus1;
68 #endif
69 } AVComponentDescriptor;
70
71 /**
72 * Descriptor that unambiguously describes how the bits of a pixel are
73 * stored in the up to 4 data planes of an image. It also stores the
74 * subsampling factors and number of components.
75 *
76 * @note This is separate of the colorspace (RGB, YCbCr, YPbPr, JPEG-style YUV
77 * and all the YUV variants) AVPixFmtDescriptor just stores how values
78 * are stored not what these values represent.
79 */
80 typedef struct AVPixFmtDescriptor {
81 const char *name;
82 uint8_t nb_components; ///< The number of components each pixel has, (1-4)
83
84 /**
85 * Amount to shift the luma width right to find the chroma width.
86 * For YV12 this is 1 for example.
87 * chroma_width = -((-luma_width) >> log2_chroma_w)
88 * The note above is needed to ensure rounding up.
89 * This value only refers to the chroma components.
90 */
91 uint8_t log2_chroma_w; ///< chroma_width = -((-luma_width )>>log2_chroma_w)
92
93 /**
94 * Amount to shift the luma height right to find the chroma height.
95 * For YV12 this is 1 for example.
96 * chroma_height= -((-luma_height) >> log2_chroma_h)
97 * The note above is needed to ensure rounding up.
98 * This value only refers to the chroma components.
99 */
100 uint8_t log2_chroma_h;
101
102 /**
103 * Combination of AV_PIX_FMT_FLAG_... flags.
104 */
105 uint64_t flags;
106
107 /**
108 * Parameters that describe how pixels are packed. If the format
109 * has chroma components, they must be stored in comp[1] and
110 * comp[2].
111 */
112 AVComponentDescriptor comp[4];
113
114 /**
115 * Alternative comma-separated names.
116 */
117 const char *alias;
118 } AVPixFmtDescriptor;
119
120 /**
121 * Pixel format is big-endian.
122 */
123 #define AV_PIX_FMT_FLAG_BE (1 << 0)
124 /**
125 * Pixel format has a palette in data[1], values are indexes in this palette.
126 */
127 #define AV_PIX_FMT_FLAG_PAL (1 << 1)
128 /**
129 * All values of a component are bit-wise packed end to end.
130 */
131 #define AV_PIX_FMT_FLAG_BITSTREAM (1 << 2)
132 /**
133 * Pixel format is an HW accelerated format.
134 */
135 #define AV_PIX_FMT_FLAG_HWACCEL (1 << 3)
136 /**
137 * At least one pixel component is not in the first data plane.
138 */
139 #define AV_PIX_FMT_FLAG_PLANAR (1 << 4)
140 /**
141 * The pixel format contains RGB-like data (as opposed to YUV/grayscale).
142 */
143 #define AV_PIX_FMT_FLAG_RGB (1 << 5)
144 /**
145 * The pixel format is "pseudo-paletted". This means that Libav treats it as
146 * paletted internally, but the palette is generated by the decoder and is not
147 * stored in the file.
148 */
149 #define AV_PIX_FMT_FLAG_PSEUDOPAL (1 << 6)
150 /**
151 * The pixel format has an alpha channel.
152 */
153 #define AV_PIX_FMT_FLAG_ALPHA (1 << 7)
154
155 /**
156 * Read a line from an image, and write the values of the
157 * pixel format component c to dst.
158 *
159 * @param data the array containing the pointers to the planes of the image
160 * @param linesize the array containing the linesizes of the image
161 * @param desc the pixel format descriptor for the image
162 * @param x the horizontal coordinate of the first pixel to read
163 * @param y the vertical coordinate of the first pixel to read
164 * @param w the width of the line to read, that is the number of
165 * values to write to dst
166 * @param read_pal_component if not zero and the format is a paletted
167 * format writes the values corresponding to the palette
168 * component c in data[1] to dst, rather than the palette indexes in
169 * data[0]. The behavior is undefined if the format is not paletted.
170 */
171 void av_read_image_line(uint16_t *dst, const uint8_t *data[4],
172 const int linesize[4], const AVPixFmtDescriptor *desc,
173 int x, int y, int c, int w, int read_pal_component);
174
175 /**
176 * Write the values from src to the pixel format component c of an
177 * image line.
178 *
179 * @param src array containing the values to write
180 * @param data the array containing the pointers to the planes of the
181 * image to write into. It is supposed to be zeroed.
182 * @param linesize the array containing the linesizes of the image
183 * @param desc the pixel format descriptor for the image
184 * @param x the horizontal coordinate of the first pixel to write
185 * @param y the vertical coordinate of the first pixel to write
186 * @param w the width of the line to write, that is the number of
187 * values to write to the image line
188 */
189 void av_write_image_line(const uint16_t *src, uint8_t *data[4],
190 const int linesize[4], const AVPixFmtDescriptor *desc,
191 int x, int y, int c, int w);
192
193 /**
194 * Return the pixel format corresponding to name.
195 *
196 * If there is no pixel format with name name, then looks for a
197 * pixel format with the name corresponding to the native endian
198 * format of name.
199 * For example in a little-endian system, first looks for "gray16",
200 * then for "gray16le".
201 *
202 * Finally if no pixel format has been found, returns PIX_FMT_NONE.
203 */
204 enum AVPixelFormat av_get_pix_fmt(const char *name);
205
206 /**
207 * Return the short name for a pixel format, NULL in case pix_fmt is
208 * unknown.
209 *
210 * @see av_get_pix_fmt(), av_get_pix_fmt_string()
211 */
212 const char *av_get_pix_fmt_name(enum AVPixelFormat pix_fmt);
213
214 /**
215 * Print in buf the string corresponding to the pixel format with
216 * number pix_fmt, or an header if pix_fmt is negative.
217 *
218 * @param buf the buffer where to write the string
219 * @param buf_size the size of buf
220 * @param pix_fmt the number of the pixel format to print the
221 * corresponding info string, or a negative value to print the
222 * corresponding header.
223 */
224 char *av_get_pix_fmt_string(char *buf, int buf_size,
225 enum AVPixelFormat pix_fmt);
226
227 /**
228 * Return the number of bits per pixel used by the pixel format
229 * described by pixdesc. Note that this is not the same as the number
230 * of bits per sample.
231 *
232 * The returned number of bits refers to the number of bits actually
233 * used for storing the pixel information, that is padding bits are
234 * not counted.
235 */
236 int av_get_bits_per_pixel(const AVPixFmtDescriptor *pixdesc);
237
238 /**
239 * @return a pixel format descriptor for provided pixel format or NULL if
240 * this pixel format is unknown.
241 */
242 const AVPixFmtDescriptor *av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt);
243
244 /**
245 * Iterate over all pixel format descriptors known to libavutil.
246 *
247 * @param prev previous descriptor. NULL to get the first descriptor.
248 *
249 * @return next descriptor or NULL after the last descriptor
250 */
251 const AVPixFmtDescriptor *av_pix_fmt_desc_next(const AVPixFmtDescriptor *prev);
252
253 /**
254 * @return an AVPixelFormat id described by desc, or AV_PIX_FMT_NONE if desc
255 * is not a valid pointer to a pixel format descriptor.
256 */
257 enum AVPixelFormat av_pix_fmt_desc_get_id(const AVPixFmtDescriptor *desc);
258
259 /**
260 * Utility function to access log2_chroma_w log2_chroma_h from
261 * the pixel format AVPixFmtDescriptor.
262 *
263 * @param[in] pix_fmt the pixel format
264 * @param[out] h_shift store log2_chroma_h
265 * @param[out] v_shift store log2_chroma_w
266 *
267 * @return 0 on success, AVERROR(ENOSYS) on invalid or unknown pixel format
268 */
269 int av_pix_fmt_get_chroma_sub_sample(enum AVPixelFormat pix_fmt,
270 int *h_shift, int *v_shift);
271
272 /**
273 * @return number of planes in pix_fmt, a negative AVERROR if pix_fmt is not a
274 * valid pixel format.
275 */
276 int av_pix_fmt_count_planes(enum AVPixelFormat pix_fmt);
277
278 /**
279 * Utility function to swap the endianness of a pixel format.
280 *
281 * @param[in] pix_fmt the pixel format
282 *
283 * @return pixel format with swapped endianness if it exists,
284 * otherwise AV_PIX_FMT_NONE
285 */
286 enum AVPixelFormat av_pix_fmt_swap_endianness(enum AVPixelFormat pix_fmt);
287
288 /**
289 * @return the name for provided color range or NULL if unknown.
290 */
291 const char *av_color_range_name(enum AVColorRange range);
292
293 /**
294 * @return the name for provided color primaries or NULL if unknown.
295 */
296 const char *av_color_primaries_name(enum AVColorPrimaries primaries);
297
298 /**
299 * @return the name for provided color transfer or NULL if unknown.
300 */
301 const char *av_color_transfer_name(enum AVColorTransferCharacteristic transfer);
302
303 /**
304 * @return the name for provided color space or NULL if unknown.
305 */
306 const char *av_color_space_name(enum AVColorSpace space);
307
308 /**
309 * @return the name for provided chroma location or NULL if unknown.
310 */
311 const char *av_chroma_location_name(enum AVChromaLocation location);
312
313 #endif /* AVUTIL_PIXDESC_H */