FFmpeg
pixdesc.h
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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 
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;
59 
60 /**
61  * Descriptor that unambiguously describes how the bits of a pixel are
62  * stored in the up to 4 data planes of an image. It also stores the
63  * subsampling factors and number of components.
64  *
65  * @note This is separate of the colorspace (RGB, YCbCr, YPbPr, JPEG-style YUV
66  * and all the YUV variants) AVPixFmtDescriptor just stores how values
67  * are stored not what these values represent.
68  */
69 typedef struct AVPixFmtDescriptor {
70  const char *name;
71  uint8_t nb_components; ///< The number of components each pixel has, (1-4)
72 
73  /**
74  * Amount to shift the luma width right to find the chroma width.
75  * For YV12 this is 1 for example.
76  * chroma_width = AV_CEIL_RSHIFT(luma_width, log2_chroma_w)
77  * The note above is needed to ensure rounding up.
78  * This value only refers to the chroma components.
79  */
80  uint8_t log2_chroma_w;
81 
82  /**
83  * Amount to shift the luma height right to find the chroma height.
84  * For YV12 this is 1 for example.
85  * chroma_height= AV_CEIL_RSHIFT(luma_height, log2_chroma_h)
86  * The note above is needed to ensure rounding up.
87  * This value only refers to the chroma components.
88  */
89  uint8_t log2_chroma_h;
90 
91  /**
92  * Combination of AV_PIX_FMT_FLAG_... flags.
93  */
94  uint64_t flags;
95 
96  /**
97  * Parameters that describe how pixels are packed.
98  * If the format has 1 or 2 components, then luma is 0.
99  * If the format has 3 or 4 components:
100  * if the RGB flag is set then 0 is red, 1 is green and 2 is blue;
101  * otherwise 0 is luma, 1 is chroma-U and 2 is chroma-V.
102  *
103  * If present, the Alpha channel is always the last component.
104  */
106 
107  /**
108  * Alternative comma-separated names.
109  */
110  const char *alias;
112 
113 /**
114  * Pixel format is big-endian.
115  */
116 #define AV_PIX_FMT_FLAG_BE (1 << 0)
117 /**
118  * Pixel format has a palette in data[1], values are indexes in this palette.
119  */
120 #define AV_PIX_FMT_FLAG_PAL (1 << 1)
121 /**
122  * All values of a component are bit-wise packed end to end.
123  */
124 #define AV_PIX_FMT_FLAG_BITSTREAM (1 << 2)
125 /**
126  * Pixel format is an HW accelerated format.
127  */
128 #define AV_PIX_FMT_FLAG_HWACCEL (1 << 3)
129 /**
130  * At least one pixel component is not in the first data plane.
131  */
132 #define AV_PIX_FMT_FLAG_PLANAR (1 << 4)
133 /**
134  * The pixel format contains RGB-like data (as opposed to YUV/grayscale).
135  */
136 #define AV_PIX_FMT_FLAG_RGB (1 << 5)
137 
138 /**
139  * The pixel format has an alpha channel. This is set on all formats that
140  * support alpha in some way, including AV_PIX_FMT_PAL8. The alpha is always
141  * straight, never pre-multiplied.
142  *
143  * If a codec or a filter does not support alpha, it should set all alpha to
144  * opaque, or use the equivalent pixel formats without alpha component, e.g.
145  * AV_PIX_FMT_RGB0 (or AV_PIX_FMT_RGB24 etc.) instead of AV_PIX_FMT_RGBA.
146  */
147 #define AV_PIX_FMT_FLAG_ALPHA (1 << 7)
148 
149 /**
150  * The pixel format is following a Bayer pattern
151  */
152 #define AV_PIX_FMT_FLAG_BAYER (1 << 8)
153 
154 /**
155  * The pixel format contains IEEE-754 floating point values. Precision (double,
156  * single, or half) should be determined by the pixel size (64, 32, or 16 bits).
157  */
158 #define AV_PIX_FMT_FLAG_FLOAT (1 << 9)
159 
160 /**
161  * Return the number of bits per pixel used by the pixel format
162  * described by pixdesc. Note that this is not the same as the number
163  * of bits per sample.
164  *
165  * The returned number of bits refers to the number of bits actually
166  * used for storing the pixel information, that is padding bits are
167  * not counted.
168  */
169 int av_get_bits_per_pixel(const AVPixFmtDescriptor *pixdesc);
170 
171 /**
172  * Return the number of bits per pixel for the pixel format
173  * described by pixdesc, including any padding or unused bits.
174  */
176 
177 /**
178  * @return a pixel format descriptor for provided pixel format or NULL if
179  * this pixel format is unknown.
180  */
182 
183 /**
184  * Iterate over all pixel format descriptors known to libavutil.
185  *
186  * @param prev previous descriptor. NULL to get the first descriptor.
187  *
188  * @return next descriptor or NULL after the last descriptor
189  */
191 
192 /**
193  * @return an AVPixelFormat id described by desc, or AV_PIX_FMT_NONE if desc
194  * is not a valid pointer to a pixel format descriptor.
195  */
197 
198 /**
199  * Utility function to access log2_chroma_w log2_chroma_h from
200  * the pixel format AVPixFmtDescriptor.
201  *
202  * @param[in] pix_fmt the pixel format
203  * @param[out] h_shift store log2_chroma_w (horizontal/width shift)
204  * @param[out] v_shift store log2_chroma_h (vertical/height shift)
205  *
206  * @return 0 on success, AVERROR(ENOSYS) on invalid or unknown pixel format
207  */
209  int *h_shift, int *v_shift);
210 
211 /**
212  * @return number of planes in pix_fmt, a negative AVERROR if pix_fmt is not a
213  * valid pixel format.
214  */
216 
217 /**
218  * @return the name for provided color range or NULL if unknown.
219  */
220 const char *av_color_range_name(enum AVColorRange range);
221 
222 /**
223  * @return the AVColorRange value for name or an AVError if not found.
224  */
225 int av_color_range_from_name(const char *name);
226 
227 /**
228  * @return the name for provided color primaries or NULL if unknown.
229  */
230 const char *av_color_primaries_name(enum AVColorPrimaries primaries);
231 
232 /**
233  * @return the AVColorPrimaries value for name or an AVError if not found.
234  */
235 int av_color_primaries_from_name(const char *name);
236 
237 /**
238  * @return the name for provided color transfer or NULL if unknown.
239  */
240 const char *av_color_transfer_name(enum AVColorTransferCharacteristic transfer);
241 
242 /**
243  * @return the AVColorTransferCharacteristic value for name or an AVError if not found.
244  */
245 int av_color_transfer_from_name(const char *name);
246 
247 /**
248  * @return the name for provided color space or NULL if unknown.
249  */
250 const char *av_color_space_name(enum AVColorSpace space);
251 
252 /**
253  * @return the AVColorSpace value for name or an AVError if not found.
254  */
255 int av_color_space_from_name(const char *name);
256 
257 /**
258  * @return the name for provided chroma location or NULL if unknown.
259  */
260 const char *av_chroma_location_name(enum AVChromaLocation location);
261 
262 /**
263  * @return the AVChromaLocation value for name or an AVError if not found.
264  */
265 int av_chroma_location_from_name(const char *name);
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  */
278 enum 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  */
286 const 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  */
298 char *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  * @param dst_element_size size of elements in dst array (2 or 4 byte)
317  */
318 void av_read_image_line2(void *dst, const uint8_t *data[4],
319  const int linesize[4], const AVPixFmtDescriptor *desc,
320  int x, int y, int c, int w, int read_pal_component,
321  int dst_element_size);
322 
323 void av_read_image_line(uint16_t *dst, const uint8_t *data[4],
324  const int linesize[4], const AVPixFmtDescriptor *desc,
325  int x, int y, int c, int w, int read_pal_component);
326 
327 /**
328  * Write the values from src to the pixel format component c of an
329  * image line.
330  *
331  * @param src array containing the values to write
332  * @param data the array containing the pointers to the planes of the
333  * image to write into. It is supposed to be zeroed.
334  * @param linesize the array containing the linesizes of the image
335  * @param desc the pixel format descriptor for the image
336  * @param x the horizontal coordinate of the first pixel to write
337  * @param y the vertical coordinate of the first pixel to write
338  * @param w the width of the line to write, that is the number of
339  * values to write to the image line
340  * @param src_element_size size of elements in src array (2 or 4 byte)
341  */
342 void av_write_image_line2(const void *src, uint8_t *data[4],
343  const int linesize[4], const AVPixFmtDescriptor *desc,
344  int x, int y, int c, int w, int src_element_size);
345 
346 void av_write_image_line(const uint16_t *src, uint8_t *data[4],
347  const int linesize[4], const AVPixFmtDescriptor *desc,
348  int x, int y, int c, int w);
349 
350 /**
351  * Utility function to swap the endianness of a pixel format.
352  *
353  * @param[in] pix_fmt the pixel format
354  *
355  * @return pixel format with swapped endianness if it exists,
356  * otherwise AV_PIX_FMT_NONE
357  */
359 
360 #define FF_LOSS_RESOLUTION 0x0001 /**< loss due to resolution change */
361 #define FF_LOSS_DEPTH 0x0002 /**< loss due to color depth change */
362 #define FF_LOSS_COLORSPACE 0x0004 /**< loss due to color space conversion */
363 #define FF_LOSS_ALPHA 0x0008 /**< loss of alpha bits */
364 #define FF_LOSS_COLORQUANT 0x0010 /**< loss due to color quantization */
365 #define FF_LOSS_CHROMA 0x0020 /**< loss of chroma (e.g. RGB to gray conversion) */
366 
367 /**
368  * Compute what kind of losses will occur when converting from one specific
369  * pixel format to another.
370  * When converting from one pixel format to another, information loss may occur.
371  * For example, when converting from RGB24 to GRAY, the color information will
372  * be lost. Similarly, other losses occur when converting from some formats to
373  * other formats. These losses can involve loss of chroma, but also loss of
374  * resolution, loss of color depth, loss due to the color space conversion, loss
375  * of the alpha bits or loss due to color quantization.
376  * av_get_fix_fmt_loss() informs you about the various types of losses
377  * which will occur when converting from one pixel format to another.
378  *
379  * @param[in] dst_pix_fmt destination pixel format
380  * @param[in] src_pix_fmt source pixel format
381  * @param[in] has_alpha Whether the source pixel format alpha channel is used.
382  * @return Combination of flags informing you what kind of losses will occur
383  * (maximum loss for an invalid dst_pix_fmt).
384  */
385 int av_get_pix_fmt_loss(enum AVPixelFormat dst_pix_fmt,
386  enum AVPixelFormat src_pix_fmt,
387  int has_alpha);
388 
389 /**
390  * Compute what kind of losses will occur when converting from one specific
391  * pixel format to another.
392  * When converting from one pixel format to another, information loss may occur.
393  * For example, when converting from RGB24 to GRAY, the color information will
394  * be lost. Similarly, other losses occur when converting from some formats to
395  * other formats. These losses can involve loss of chroma, but also loss of
396  * resolution, loss of color depth, loss due to the color space conversion, loss
397  * of the alpha bits or loss due to color quantization.
398  * av_get_fix_fmt_loss() informs you about the various types of losses
399  * which will occur when converting from one pixel format to another.
400  *
401  * @param[in] dst_pix_fmt destination pixel format
402  * @param[in] src_pix_fmt source pixel format
403  * @param[in] has_alpha Whether the source pixel format alpha channel is used.
404  * @return Combination of flags informing you what kind of losses will occur
405  * (maximum loss for an invalid dst_pix_fmt).
406  */
407 enum AVPixelFormat av_find_best_pix_fmt_of_2(enum AVPixelFormat dst_pix_fmt1, enum AVPixelFormat dst_pix_fmt2,
408  enum AVPixelFormat src_pix_fmt, int has_alpha, int *loss_ptr);
409 
410 #endif /* AVUTIL_PIXDESC_H */
AVPixelFormat
AVPixelFormat
Pixel format.
Definition: pixfmt.h:64
name
it s the only field you need to keep assuming you have a context There is some magic you don t need to care about around this just let it vf default minimum maximum flags name is the option name
Definition: writing_filters.txt:88
space
Undefined Behavior In the C some operations are like signed integer dereferencing freed accessing outside allocated space
Definition: undefined.txt:4
AVColorTransferCharacteristic
AVColorTransferCharacteristic
Color Transfer Characteristic.
Definition: pixfmt.h:476
av_write_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)
Definition: pixdesc.c:161
av_pix_fmt_swap_endianness
enum AVPixelFormat av_pix_fmt_swap_endianness(enum AVPixelFormat pix_fmt)
Utility function to swap the endianness of a pixel format.
Definition: pixdesc.c:2660
av_get_pix_fmt_loss
int av_get_pix_fmt_loss(enum AVPixelFormat dst_pix_fmt, enum AVPixelFormat src_pix_fmt, int has_alpha)
Compute what kind of losses will occur when converting from one specific pixel format to another.
Definition: pixdesc.c:2844
av_get_padded_bits_per_pixel
int av_get_padded_bits_per_pixel(const AVPixFmtDescriptor *pixdesc)
Return the number of bits per pixel for the pixel format described by pixdesc, including any padding ...
Definition: pixdesc.c:2529
av_chroma_location_from_name
int av_chroma_location_from_name(const char *name)
Definition: pixdesc.c:2979
w
uint8_t w
Definition: llviddspenc.c:38
AVComponentDescriptor::depth
int depth
Number of bits in the component.
Definition: pixdesc.h:57
AVPixFmtDescriptor::name
const char * name
Definition: pixdesc.h:70
data
const char data[16]
Definition: mxf.c:143
AVComponentDescriptor::step
int step
Number of elements between 2 horizontally consecutive pixels.
Definition: pixdesc.h:40
av_color_range_from_name
int av_color_range_from_name(const char *name)
Definition: pixdesc.c:2898
AVColorPrimaries
AVColorPrimaries
Chromaticity coordinates of the source primaries.
Definition: pixfmt.h:451
av_read_image_line
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)
Definition: pixdesc.c:89
av_color_transfer_from_name
int av_color_transfer_from_name(const char *name)
Definition: pixdesc.c:2937
av_pix_fmt_get_chroma_sub_sample
int av_pix_fmt_get_chroma_sub_sample(enum AVPixelFormat pix_fmt, int *h_shift, int *v_shift)
Utility function to access log2_chroma_w log2_chroma_h from the pixel format AVPixFmtDescriptor.
Definition: pixdesc.c:2592
av_color_transfer_name
const char * av_color_transfer_name(enum AVColorTransferCharacteristic transfer)
Definition: pixdesc.c:2931
av_get_bits_per_pixel
int av_get_bits_per_pixel(const AVPixFmtDescriptor *pixdesc)
Return the number of bits per pixel used by the pixel format described by pixdesc.
Definition: pixdesc.c:2516
pix_fmt
static enum AVPixelFormat pix_fmt
Definition: demuxing_decoding.c:41
AVPixFmtDescriptor::log2_chroma_w
uint8_t log2_chroma_w
Amount to shift the luma width right to find the chroma width.
Definition: pixdesc.h:80
av_color_primaries_name
const char * av_color_primaries_name(enum AVColorPrimaries primaries)
Definition: pixdesc.c:2910
AVComponentDescriptor
Definition: pixdesc.h:30
AVPixFmtDescriptor::nb_components
uint8_t nb_components
The number of components each pixel has, (1-4)
Definition: pixdesc.h:71
AVComponentDescriptor::plane
int plane
Which of the 4 planes contains the component.
Definition: pixdesc.h:34
src
#define src
Definition: vp8dsp.c:255
av_chroma_location_name
const char * av_chroma_location_name(enum AVChromaLocation location)
Definition: pixdesc.c:2973
AVPixFmtDescriptor::flags
uint64_t flags
Combination of AV_PIX_FMT_FLAG_...
Definition: pixdesc.h:94
c
Undefined Behavior In the C some operations are like signed integer dereferencing freed accessing outside allocated Undefined Behavior must not occur in a C it is not safe even if the output of undefined operations is unused The unsafety may seem nit picking but Optimizing compilers have in fact optimized code on the assumption that no undefined Behavior occurs Optimizing code based on wrong assumptions can and has in some cases lead to effects beyond the output of computations The signed integer overflow problem in speed critical code Code which is highly optimized and works with signed integers sometimes has the problem that often the output of the computation does not c
Definition: undefined.txt:32
av_color_space_name
const char * av_color_space_name(enum AVColorSpace space)
Definition: pixdesc.c:2952
av_color_range_name
const char * av_color_range_name(enum AVColorRange range)
Definition: pixdesc.c:2892
av_pix_fmt_desc_get
const AVPixFmtDescriptor * av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt)
Definition: pixdesc.c:2564
attributes.h
av_pix_fmt_desc_next
const AVPixFmtDescriptor * av_pix_fmt_desc_next(const AVPixFmtDescriptor *prev)
Iterate over all pixel format descriptors known to libavutil.
Definition: pixdesc.c:2571
AVChromaLocation
AVChromaLocation
Location of chroma samples.
Definition: pixfmt.h:598
av_get_pix_fmt_string
char * av_get_pix_fmt_string(char *buf, int buf_size, enum AVPixelFormat pix_fmt)
Print in buf the string corresponding to the pixel format with number pix_fmt, or a header if pix_fmt...
Definition: pixdesc.c:2549
AVComponentDescriptor::shift
int shift
Number of least significant bits that must be shifted away to get the value.
Definition: pixdesc.h:52
AVPixFmtDescriptor::alias
const char * alias
Alternative comma-separated names.
Definition: pixdesc.h:110
AVColorSpace
AVColorSpace
YUV colorspace type.
Definition: pixfmt.h:505
av_pix_fmt_count_planes
int av_pix_fmt_count_planes(enum AVPixelFormat pix_fmt)
Definition: pixdesc.c:2604
av_read_image_line2
void av_read_image_line2(void *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, int dst_element_size)
Read a line from an image, and write the values of the pixel format component c to dst.
Definition: pixdesc.c:33
pixfmt.h
av_pix_fmt_desc_get_id
enum AVPixelFormat av_pix_fmt_desc_get_id(const AVPixFmtDescriptor *desc)
Definition: pixdesc.c:2583
AVPixFmtDescriptor::comp
AVComponentDescriptor comp[4]
Parameters that describe how pixels are packed.
Definition: pixdesc.h:105
av_get_pix_fmt
enum AVPixelFormat av_get_pix_fmt(const char *name)
Return the pixel format corresponding to name.
Definition: pixdesc.c:2496
av_color_primaries_from_name
int av_color_primaries_from_name(const char *name)
Definition: pixdesc.c:2916
desc
const char * desc
Definition: libsvtav1.c:79
AVPixFmtDescriptor
Descriptor that unambiguously describes how the bits of a pixel are stored in the up to 4 data planes...
Definition: pixdesc.h:69
av_find_best_pix_fmt_of_2
enum AVPixelFormat av_find_best_pix_fmt_of_2(enum AVPixelFormat dst_pix_fmt1, enum AVPixelFormat dst_pix_fmt2, enum AVPixelFormat src_pix_fmt, int has_alpha, int *loss_ptr)
Compute what kind of losses will occur when converting from one specific pixel format to another.
Definition: pixdesc.c:2855
av_get_pix_fmt_name
const char * av_get_pix_fmt_name(enum AVPixelFormat pix_fmt)
Return the short name for a pixel format, NULL in case pix_fmt is unknown.
Definition: pixdesc.c:2484
AVColorRange
AVColorRange
Visual content value range.
Definition: pixfmt.h:544
AVPixFmtDescriptor::log2_chroma_h
uint8_t log2_chroma_h
Amount to shift the luma height right to find the chroma height.
Definition: pixdesc.h:89
av_color_space_from_name
int av_color_space_from_name(const char *name)
Definition: pixdesc.c:2958
AVComponentDescriptor::offset
int offset
Number of elements before the component of the first pixel.
Definition: pixdesc.h:46
av_write_image_line2
void av_write_image_line2(const void *src, uint8_t *data[4], const int linesize[4], const AVPixFmtDescriptor *desc, int x, int y, int c, int w, int src_element_size)
Write the values from src to the pixel format component c of an image line.
Definition: pixdesc.c:100