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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
27#include "attributes.h"
28#include "pixfmt.h"
29#include "version.h"
30
31typedef struct AVComponentDescriptor {
32 /**
33 * Which of the 4 planes contains the component.
34 */
35 int plane;
36
37 /**
38 * Number of elements between 2 horizontally consecutive pixels.
39 * Elements are bits for bitstream formats, bytes otherwise.
40 */
41 int step;
42
43 /**
44 * Number of elements before the component of the first pixel.
45 * Elements are bits for bitstream formats, bytes otherwise.
46 */
47 int offset;
48
49 /**
50 * Number of least significant bits that must be shifted away
51 * to get the value.
52 */
53 int shift;
54
55 /**
56 * Number of bits in the component.
57 */
58 int depth;
59
60#if FF_API_PLUS1_MINUS1
61 /** deprecated, use step instead */
62 attribute_deprecated int step_minus1;
63
64 /** deprecated, use depth instead */
65 attribute_deprecated int depth_minus1;
66
67 /** deprecated, use offset instead */
68 attribute_deprecated int offset_plus1;
69#endif
70} AVComponentDescriptor;
71
72/**
73 * Descriptor that unambiguously describes how the bits of a pixel are
74 * stored in the up to 4 data planes of an image. It also stores the
75 * subsampling factors and number of components.
76 *
77 * @note This is separate of the colorspace (RGB, YCbCr, YPbPr, JPEG-style YUV
78 * and all the YUV variants) AVPixFmtDescriptor just stores how values
79 * are stored not what these values represent.
80 */
81typedef struct AVPixFmtDescriptor {
82 const char *name;
83 uint8_t nb_components; ///< The number of components each pixel has, (1-4)
84
85 /**
86 * Amount to shift the luma width right to find the chroma width.
87 * For YV12 this is 1 for example.
88 * chroma_width = AV_CEIL_RSHIFT(luma_width, log2_chroma_w)
89 * The note above is needed to ensure rounding up.
90 * This value only refers to the chroma components.
91 */
92 uint8_t log2_chroma_w;
93
94 /**
95 * Amount to shift the luma height right to find the chroma height.
96 * For YV12 this is 1 for example.
97 * chroma_height= AV_CEIL_RSHIFT(luma_height, log2_chroma_h)
98 * The note above is needed to ensure rounding up.
99 * This value only refers to the chroma components.
100 */
101 uint8_t log2_chroma_h;
102
103 /**
104 * Combination of AV_PIX_FMT_FLAG_... flags.
105 */
106 uint64_t flags;
107
108 /**
109 * Parameters that describe how pixels are packed.
110 * If the format has 1 or 2 components, then luma is 0.
111 * If the format has 3 or 4 components:
112 * if the RGB flag is set then 0 is red, 1 is green and 2 is blue;
113 * otherwise 0 is luma, 1 is chroma-U and 2 is chroma-V.
114 *
115 * If present, the Alpha channel is always the last component.
116 */
117 AVComponentDescriptor comp[4];
118
119 /**
120 * Alternative comma-separated names.
121 */
122 const char *alias;
123} AVPixFmtDescriptor;
124
125/**
126 * Pixel format is big-endian.
127 */
128#define AV_PIX_FMT_FLAG_BE (1 << 0)
129/**
130 * Pixel format has a palette in data[1], values are indexes in this palette.
131 */
132#define AV_PIX_FMT_FLAG_PAL (1 << 1)
133/**
134 * All values of a component are bit-wise packed end to end.
135 */
136#define AV_PIX_FMT_FLAG_BITSTREAM (1 << 2)
137/**
138 * Pixel format is an HW accelerated format.
139 */
140#define AV_PIX_FMT_FLAG_HWACCEL (1 << 3)
141/**
142 * At least one pixel component is not in the first data plane.
143 */
144#define AV_PIX_FMT_FLAG_PLANAR (1 << 4)
145/**
146 * The pixel format contains RGB-like data (as opposed to YUV/grayscale).
147 */
148#define AV_PIX_FMT_FLAG_RGB (1 << 5)
149
150/**
151 * The pixel format is "pseudo-paletted". This means that it contains a
152 * fixed palette in the 2nd plane but the palette is fixed/constant for each
153 * PIX_FMT. This allows interpreting the data as if it was PAL8, which can
154 * in some cases be simpler. Or the data can be interpreted purely based on
155 * the pixel format without using the palette.
156 * An example of a pseudo-paletted format is AV_PIX_FMT_GRAY8
157 */
158#define AV_PIX_FMT_FLAG_PSEUDOPAL (1 << 6)
159
160/**
161 * The pixel format has an alpha channel. This is set on all formats that
162 * support alpha in some way. The exception is AV_PIX_FMT_PAL8, which can
163 * carry alpha as part of the palette. Details are explained in the
164 * AVPixelFormat enum, and are also encoded in the corresponding
165 * AVPixFmtDescriptor.
166 *
167 * The alpha is always straight, never pre-multiplied.
168 *
169 * If a codec or a filter does not support alpha, it should set all alpha to
170 * opaque, or use the equivalent pixel formats without alpha component, e.g.
171 * AV_PIX_FMT_RGB0 (or AV_PIX_FMT_RGB24 etc.) instead of AV_PIX_FMT_RGBA.
172 */
173#define AV_PIX_FMT_FLAG_ALPHA (1 << 7)
174
175/**
176 * The pixel format is following a Bayer pattern
177 */
178#define AV_PIX_FMT_FLAG_BAYER (1 << 8)
179
180/**
181 * Return the number of bits per pixel used by the pixel format
182 * described by pixdesc. Note that this is not the same as the number
183 * of bits per sample.
184 *
185 * The returned number of bits refers to the number of bits actually
186 * used for storing the pixel information, that is padding bits are
187 * not counted.
188 */
189int av_get_bits_per_pixel(const AVPixFmtDescriptor *pixdesc);
190
191/**
192 * Return the number of bits per pixel for the pixel format
193 * described by pixdesc, including any padding or unused bits.
194 */
195int av_get_padded_bits_per_pixel(const AVPixFmtDescriptor *pixdesc);
196
197/**
198 * @return a pixel format descriptor for provided pixel format or NULL if
199 * this pixel format is unknown.
200 */
201const AVPixFmtDescriptor *av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt);
202
203/**
204 * Iterate over all pixel format descriptors known to libavutil.
205 *
206 * @param prev previous descriptor. NULL to get the first descriptor.
207 *
208 * @return next descriptor or NULL after the last descriptor
209 */
210const AVPixFmtDescriptor *av_pix_fmt_desc_next(const AVPixFmtDescriptor *prev);
211
212/**
213 * @return an AVPixelFormat id described by desc, or AV_PIX_FMT_NONE if desc
214 * is not a valid pointer to a pixel format descriptor.
215 */
216enum AVPixelFormat av_pix_fmt_desc_get_id(const AVPixFmtDescriptor *desc);
217
218/**
219 * Utility function to access log2_chroma_w log2_chroma_h from
220 * the pixel format AVPixFmtDescriptor.
221 *
222 * See av_get_chroma_sub_sample() for a function that asserts a
223 * valid pixel format instead of returning an error code.
224 * Its recommended that you use avcodec_get_chroma_sub_sample unless
225 * you do check the return code!
226 *
227 * @param[in] pix_fmt the pixel format
228 * @param[out] h_shift store log2_chroma_w (horizontal/width shift)
229 * @param[out] v_shift store log2_chroma_h (vertical/height shift)
230 *
231 * @return 0 on success, AVERROR(ENOSYS) on invalid or unknown pixel format
232 */
233int av_pix_fmt_get_chroma_sub_sample(enum AVPixelFormat pix_fmt,
234 int *h_shift, int *v_shift);
235
236/**
237 * @return number of planes in pix_fmt, a negative AVERROR if pix_fmt is not a
238 * valid pixel format.
239 */
240int av_pix_fmt_count_planes(enum AVPixelFormat pix_fmt);
241
242/**
243 * @return the name for provided color range or NULL if unknown.
244 */
245const char *av_color_range_name(enum AVColorRange range);
246
247/**
248 * @return the name for provided color primaries or NULL if unknown.
249 */
250const char *av_color_primaries_name(enum AVColorPrimaries primaries);
251
252/**
253 * @return the name for provided color transfer or NULL if unknown.
254 */
255const char *av_color_transfer_name(enum AVColorTransferCharacteristic transfer);
256
257/**
258 * @return the name for provided color space or NULL if unknown.
259 */
260const char *av_color_space_name(enum AVColorSpace space);
261
262/**
263 * @return the name for provided chroma location or NULL if unknown.
264 */
265const char *av_chroma_location_name(enum AVChromaLocation location);
266
267/**
268 * Return the pixel format corresponding to name.
269 *
270 * If there is no pixel format with name name, then looks for a
271 * pixel format with the name corresponding to the native endian
272 * format of name.
273 * For example in a little-endian system, first looks for "gray16",
274 * then for "gray16le".
275 *
276 * Finally if no pixel format has been found, returns AV_PIX_FMT_NONE.
277 */
278enum AVPixelFormat av_get_pix_fmt(const char *name);
279
280/**
281 * Return the short name for a pixel format, NULL in case pix_fmt is
282 * unknown.
283 *
284 * @see av_get_pix_fmt(), av_get_pix_fmt_string()
285 */
286const char *av_get_pix_fmt_name(enum AVPixelFormat pix_fmt);
287
288/**
289 * Print in buf the string corresponding to the pixel format with
290 * number pix_fmt, or a header if pix_fmt is negative.
291 *
292 * @param buf the buffer where to write the string
293 * @param buf_size the size of buf
294 * @param pix_fmt the number of the pixel format to print the
295 * corresponding info string, or a negative value to print the
296 * corresponding header.
297 */
298char *av_get_pix_fmt_string(char *buf, int buf_size,
299 enum AVPixelFormat pix_fmt);
300
301/**
302 * Read a line from an image, and write the values of the
303 * pixel format component c to dst.
304 *
305 * @param data the array containing the pointers to the planes of the image
306 * @param linesize the array containing the linesizes of the image
307 * @param desc the pixel format descriptor for the image
308 * @param x the horizontal coordinate of the first pixel to read
309 * @param y the vertical coordinate of the first pixel to read
310 * @param w the width of the line to read, that is the number of
311 * values to write to dst
312 * @param read_pal_component if not zero and the format is a paletted
313 * format writes the values corresponding to the palette
314 * component c in data[1] to dst, rather than the palette indexes in
315 * data[0]. The behavior is undefined if the format is not paletted.
316 */
317void av_read_image_line(uint16_t *dst, const uint8_t *data[4],
318 const int linesize[4], const AVPixFmtDescriptor *desc,
319 int x, int y, int c, int w, int read_pal_component);
320
321/**
322 * Write the values from src to the pixel format component c of an
323 * image line.
324 *
325 * @param src array containing the values to write
326 * @param data the array containing the pointers to the planes of the
327 * image to write into. It is supposed to be zeroed.
328 * @param linesize the array containing the linesizes of the image
329 * @param desc the pixel format descriptor for the image
330 * @param x the horizontal coordinate of the first pixel to write
331 * @param y the vertical coordinate of the first pixel to write
332 * @param w the width of the line to write, that is the number of
333 * values to write to the image line
334 */
335void av_write_image_line(const uint16_t *src, uint8_t *data[4],
336 const int linesize[4], const AVPixFmtDescriptor *desc,
337 int x, int y, int c, int w);
338
339/**
340 * Utility function to swap the endianness of a pixel format.
341 *
342 * @param[in] pix_fmt the pixel format
343 *
344 * @return pixel format with swapped endianness if it exists,
345 * otherwise AV_PIX_FMT_NONE
346 */
347enum AVPixelFormat av_pix_fmt_swap_endianness(enum AVPixelFormat pix_fmt);
348
349#define FF_LOSS_RESOLUTION 0x0001 /**< loss due to resolution change */
350#define FF_LOSS_DEPTH 0x0002 /**< loss due to color depth change */
351#define FF_LOSS_COLORSPACE 0x0004 /**< loss due to color space conversion */
352#define FF_LOSS_ALPHA 0x0008 /**< loss of alpha bits */
353#define FF_LOSS_COLORQUANT 0x0010 /**< loss due to color quantization */
354#define FF_LOSS_CHROMA 0x0020 /**< loss of chroma (e.g. RGB to gray conversion) */
355
356/**
357 * Compute what kind of losses will occur when converting from one specific
358 * pixel format to another.
359 * When converting from one pixel format to another, information loss may occur.
360 * For example, when converting from RGB24 to GRAY, the color information will
361 * be lost. Similarly, other losses occur when converting from some formats to
362 * other formats. These losses can involve loss of chroma, but also loss of
363 * resolution, loss of color depth, loss due to the color space conversion, loss
364 * of the alpha bits or loss due to color quantization.
365 * av_get_fix_fmt_loss() informs you about the various types of losses
366 * which will occur when converting from one pixel format to another.
367 *
368 * @param[in] dst_pix_fmt destination pixel format
369 * @param[in] src_pix_fmt source pixel format
370 * @param[in] has_alpha Whether the source pixel format alpha channel is used.
371 * @return Combination of flags informing you what kind of losses will occur
372 * (maximum loss for an invalid dst_pix_fmt).
373 */
374int av_get_pix_fmt_loss(enum AVPixelFormat dst_pix_fmt,
375 enum AVPixelFormat src_pix_fmt,
376 int has_alpha);
377
378/**
379 * Compute what kind of losses will occur when converting from one specific
380 * pixel format to another.
381 * When converting from one pixel format to another, information loss may occur.
382 * For example, when converting from RGB24 to GRAY, the color information will
383 * be lost. Similarly, other losses occur when converting from some formats to
384 * other formats. These losses can involve loss of chroma, but also loss of
385 * resolution, loss of color depth, loss due to the color space conversion, loss
386 * of the alpha bits or loss due to color quantization.
387 * av_get_fix_fmt_loss() informs you about the various types of losses
388 * which will occur when converting from one pixel format to another.
389 *
390 * @param[in] dst_pix_fmt destination pixel format
391 * @param[in] src_pix_fmt source pixel format
392 * @param[in] has_alpha Whether the source pixel format alpha channel is used.
393 * @return Combination of flags informing you what kind of losses will occur
394 * (maximum loss for an invalid dst_pix_fmt).
395 */
396enum AVPixelFormat av_find_best_pix_fmt_of_2(enum AVPixelFormat dst_pix_fmt1, enum AVPixelFormat dst_pix_fmt2,
397 enum AVPixelFormat src_pix_fmt, int has_alpha, int *loss_ptr);
398
399#endif /* AVUTIL_PIXDESC_H */
400
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