pixdesc: Document the component order
[libav.git] / libavutil / pixdesc.h
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9b61d838 1/*
e0cffbe7 2 * pixel format descriptor
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3 * Copyright (c) 2009 Michael Niedermayer <michaelni@gmx.at>
4 *
2912e87a 5 * This file is part of Libav.
9b61d838 6 *
2912e87a 7 * Libav is free software; you can redistribute it and/or
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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 *
2912e87a 12 * Libav is distributed in the hope that it will be useful,
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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
2912e87a 18 * License along with Libav; if not, write to the Free Software
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19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21
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22#ifndef AVUTIL_PIXDESC_H
23#define AVUTIL_PIXDESC_H
5499a313 24
9b61d838 25#include <inttypes.h>
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26
27#include "attributes.h"
8f653e28 28#include "pixfmt.h"
9b61d838 29
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30typedef struct AVComponentDescriptor {
31 /**
32 * Which of the 4 planes contains the component.
33 */
6b3ef7f0 34 int plane;
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35
36 /**
2268db2c 37 * Number of elements between 2 horizontally consecutive pixels.
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38 * Elements are bits for bitstream formats, bytes otherwise.
39 */
2268db2c 40 int step;
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41
42 /**
2268db2c 43 * Number of elements before the component of the first pixel.
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44 * Elements are bits for bitstream formats, bytes otherwise.
45 */
2268db2c 46 int offset;
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47
48 /**
49 * Number of least significant bits that must be shifted away
50 * to get the value.
51 */
6b3ef7f0 52 int shift;
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53
54 /**
2268db2c 55 * Number of bits in the component.
b2e059a1 56 */
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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
b2e059a1 69} AVComponentDescriptor;
9b61d838 70
d3bcbf57 71/**
e0cffbe7 72 * Descriptor that unambiguously describes how the bits of a pixel are
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73 * stored in the up to 4 data planes of an image. It also stores the
74 * subsampling factors and number of components.
75 *
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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.
d3bcbf57 79 */
b2e059a1 80typedef struct AVPixFmtDescriptor {
1e896640 81 const char *name;
b2e059a1 82 uint8_t nb_components; ///< The number of components each pixel has, (1-4)
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83
84 /**
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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.
357561e7 89 * This value only refers to the chroma components.
9b61d838 90 */
b2e059a1 91 uint8_t log2_chroma_w; ///< chroma_width = -((-luma_width )>>log2_chroma_w)
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92
93 /**
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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.
357561e7 98 * This value only refers to the chroma components.
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99 */
100 uint8_t log2_chroma_h;
b8b5d827 101
102 /**
103 * Combination of AV_PIX_FMT_FLAG_... flags.
104 */
105 uint64_t flags;
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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].
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111 * If the format is RGB-like, the first component is R, followed
112 * by G and B.
113 *
114 * If the format is YUV-like, the first component is Y, followed
115 * by U and V.
116 *
117 * If present, the Alpha channel is always the last component.
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118 */
119 AVComponentDescriptor comp[4];
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120
121 /**
122 * Alternative comma-separated names.
123 */
124 const char *alias;
b2e059a1 125} AVPixFmtDescriptor;
9b61d838 126
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127/**
128 * Pixel format is big-endian.
129 */
130#define AV_PIX_FMT_FLAG_BE (1 << 0)
131/**
132 * Pixel format has a palette in data[1], values are indexes in this palette.
133 */
134#define AV_PIX_FMT_FLAG_PAL (1 << 1)
135/**
136 * All values of a component are bit-wise packed end to end.
137 */
138#define AV_PIX_FMT_FLAG_BITSTREAM (1 << 2)
139/**
140 * Pixel format is an HW accelerated format.
141 */
142#define AV_PIX_FMT_FLAG_HWACCEL (1 << 3)
143/**
144 * At least one pixel component is not in the first data plane.
145 */
146#define AV_PIX_FMT_FLAG_PLANAR (1 << 4)
147/**
148 * The pixel format contains RGB-like data (as opposed to YUV/grayscale).
149 */
150#define AV_PIX_FMT_FLAG_RGB (1 << 5)
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151/**
152 * The pixel format is "pseudo-paletted". This means that Libav treats it as
153 * paletted internally, but the palette is generated by the decoder and is not
154 * stored in the file.
155 */
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156#define AV_PIX_FMT_FLAG_PSEUDOPAL (1 << 6)
157/**
158 * The pixel format has an alpha channel.
159 */
160#define AV_PIX_FMT_FLAG_ALPHA (1 << 7)
cbe5a60c 161
9b34899e 162/**
49bd8e4b 163 * Read a line from an image, and write the values of the
351aff72 164 * pixel format component c to dst.
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165 *
166 * @param data the array containing the pointers to the planes of the image
9a58234f 167 * @param linesize the array containing the linesizes of the image
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168 * @param desc the pixel format descriptor for the image
169 * @param x the horizontal coordinate of the first pixel to read
170 * @param y the vertical coordinate of the first pixel to read
171 * @param w the width of the line to read, that is the number of
bf7e799c 172 * values to write to dst
0a47f60a 173 * @param read_pal_component if not zero and the format is a paletted
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174 * format writes the values corresponding to the palette
175 * component c in data[1] to dst, rather than the palette indexes in
0a47f60a 176 * data[0]. The behavior is undefined if the format is not paletted.
9b34899e 177 */
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178void av_read_image_line(uint16_t *dst, const uint8_t *data[4],
179 const int linesize[4], const AVPixFmtDescriptor *desc,
180 int x, int y, int c, int w, int read_pal_component);
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181
182/**
49bd8e4b 183 * Write the values from src to the pixel format component c of an
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184 * image line.
185 *
186 * @param src array containing the values to write
187 * @param data the array containing the pointers to the planes of the
188 * image to write into. It is supposed to be zeroed.
9a58234f 189 * @param linesize the array containing the linesizes of the image
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190 * @param desc the pixel format descriptor for the image
191 * @param x the horizontal coordinate of the first pixel to write
192 * @param y the vertical coordinate of the first pixel to write
193 * @param w the width of the line to write, that is the number of
194 * values to write to the image line
195 */
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196void av_write_image_line(const uint16_t *src, uint8_t *data[4],
197 const int linesize[4], const AVPixFmtDescriptor *desc,
198 int x, int y, int c, int w);
5499a313 199
5efccce2 200/**
49bd8e4b 201 * Return the pixel format corresponding to name.
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202 *
203 * If there is no pixel format with name name, then looks for a
204 * pixel format with the name corresponding to the native endian
205 * format of name.
206 * For example in a little-endian system, first looks for "gray16",
207 * then for "gray16le".
208 *
209 * Finally if no pixel format has been found, returns PIX_FMT_NONE.
210 */
716d413c 211enum AVPixelFormat av_get_pix_fmt(const char *name);
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212
213/**
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214 * Return the short name for a pixel format, NULL in case pix_fmt is
215 * unknown.
216 *
217 * @see av_get_pix_fmt(), av_get_pix_fmt_string()
218 */
716d413c 219const char *av_get_pix_fmt_name(enum AVPixelFormat pix_fmt);
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220
221/**
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222 * Print in buf the string corresponding to the pixel format with
223 * number pix_fmt, or an header if pix_fmt is negative.
224 *
225 * @param buf the buffer where to write the string
226 * @param buf_size the size of buf
227 * @param pix_fmt the number of the pixel format to print the
228 * corresponding info string, or a negative value to print the
229 * corresponding header.
230 */
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231char *av_get_pix_fmt_string(char *buf, int buf_size,
232 enum AVPixelFormat pix_fmt);
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233
234/**
49bd8e4b 235 * Return the number of bits per pixel used by the pixel format
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236 * described by pixdesc. Note that this is not the same as the number
237 * of bits per sample.
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238 *
239 * The returned number of bits refers to the number of bits actually
240 * used for storing the pixel information, that is padding bits are
241 * not counted.
242 */
243int av_get_bits_per_pixel(const AVPixFmtDescriptor *pixdesc);
244
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245/**
246 * @return a pixel format descriptor for provided pixel format or NULL if
247 * this pixel format is unknown.
248 */
249const AVPixFmtDescriptor *av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt);
250
251/**
252 * Iterate over all pixel format descriptors known to libavutil.
253 *
254 * @param prev previous descriptor. NULL to get the first descriptor.
255 *
256 * @return next descriptor or NULL after the last descriptor
257 */
258const AVPixFmtDescriptor *av_pix_fmt_desc_next(const AVPixFmtDescriptor *prev);
259
260/**
261 * @return an AVPixelFormat id described by desc, or AV_PIX_FMT_NONE if desc
262 * is not a valid pointer to a pixel format descriptor.
263 */
264enum AVPixelFormat av_pix_fmt_desc_get_id(const AVPixFmtDescriptor *desc);
265
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266/**
267 * Utility function to access log2_chroma_w log2_chroma_h from
268 * the pixel format AVPixFmtDescriptor.
269 *
270 * @param[in] pix_fmt the pixel format
271 * @param[out] h_shift store log2_chroma_h
272 * @param[out] v_shift store log2_chroma_w
273 *
274 * @return 0 on success, AVERROR(ENOSYS) on invalid or unknown pixel format
275 */
276int av_pix_fmt_get_chroma_sub_sample(enum AVPixelFormat pix_fmt,
277 int *h_shift, int *v_shift);
278
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279/**
280 * @return number of planes in pix_fmt, a negative AVERROR if pix_fmt is not a
281 * valid pixel format.
282 */
283int av_pix_fmt_count_planes(enum AVPixelFormat pix_fmt);
284
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285/**
286 * Utility function to swap the endianness of a pixel format.
287 *
288 * @param[in] pix_fmt the pixel format
289 *
290 * @return pixel format with swapped endianness if it exists,
291 * otherwise AV_PIX_FMT_NONE
292 */
293enum AVPixelFormat av_pix_fmt_swap_endianness(enum AVPixelFormat pix_fmt);
294
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295/**
296 * @return the name for provided color range or NULL if unknown.
297 */
298const char *av_color_range_name(enum AVColorRange range);
299
300/**
301 * @return the name for provided color primaries or NULL if unknown.
302 */
303const char *av_color_primaries_name(enum AVColorPrimaries primaries);
304
305/**
306 * @return the name for provided color transfer or NULL if unknown.
307 */
308const char *av_color_transfer_name(enum AVColorTransferCharacteristic transfer);
309
310/**
311 * @return the name for provided color space or NULL if unknown.
312 */
313const char *av_color_space_name(enum AVColorSpace space);
314
315/**
316 * @return the name for provided chroma location or NULL if unknown.
317 */
318const char *av_chroma_location_name(enum AVChromaLocation location);
319
51135d1d 320#endif /* AVUTIL_PIXDESC_H */