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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 #include "version.h"
30 
31 typedef 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 */
63 
64  /** deprecated, use depth instead */
66 
67  /** deprecated, use offset instead */
69 #endif
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  */
81 typedef 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  */
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  */
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  */
118 
119  /**
120  * Alternative comma-separated names.
121  */
122  const char *alias;
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  * Return the number of bits per pixel used by the pixel format
177  * described by pixdesc. Note that this is not the same as the number
178  * of bits per sample.
179  *
180  * The returned number of bits refers to the number of bits actually
181  * used for storing the pixel information, that is padding bits are
182  * not counted.
183  */
184 int av_get_bits_per_pixel(const AVPixFmtDescriptor *pixdesc);
185 
186 /**
187  * Return the number of bits per pixel for the pixel format
188  * described by pixdesc, including any padding or unused bits.
189  */
191 
192 /**
193  * @return a pixel format descriptor for provided pixel format or NULL if
194  * this pixel format is unknown.
195  */
197 
198 /**
199  * Iterate over all pixel format descriptors known to libavutil.
200  *
201  * @param prev previous descriptor. NULL to get the first descriptor.
202  *
203  * @return next descriptor or NULL after the last descriptor
204  */
206 
207 /**
208  * @return an AVPixelFormat id described by desc, or AV_PIX_FMT_NONE if desc
209  * is not a valid pointer to a pixel format descriptor.
210  */
212 
213 /**
214  * Utility function to access log2_chroma_w log2_chroma_h from
215  * the pixel format AVPixFmtDescriptor.
216  *
217  * See av_get_chroma_sub_sample() for a function that asserts a
218  * valid pixel format instead of returning an error code.
219  * Its recommended that you use avcodec_get_chroma_sub_sample unless
220  * you do check the return code!
221  *
222  * @param[in] pix_fmt the pixel format
223  * @param[out] h_shift store log2_chroma_w (horizontal/width shift)
224  * @param[out] v_shift store log2_chroma_h (vertical/height shift)
225  *
226  * @return 0 on success, AVERROR(ENOSYS) on invalid or unknown pixel format
227  */
229  int *h_shift, int *v_shift);
230 
231 /**
232  * @return number of planes in pix_fmt, a negative AVERROR if pix_fmt is not a
233  * valid pixel format.
234  */
236 
237 /**
238  * @return the name for provided color range or NULL if unknown.
239  */
240 const char *av_color_range_name(enum AVColorRange range);
241 
242 /**
243  * @return the name for provided color primaries or NULL if unknown.
244  */
245 const char *av_color_primaries_name(enum AVColorPrimaries primaries);
246 
247 /**
248  * @return the name for provided color transfer or NULL if unknown.
249  */
250 const char *av_color_transfer_name(enum AVColorTransferCharacteristic transfer);
251 
252 /**
253  * @return the name for provided color space or NULL if unknown.
254  */
255 const char *av_color_space_name(enum AVColorSpace space);
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 pixel format corresponding to name.
264  *
265  * If there is no pixel format with name name, then looks for a
266  * pixel format with the name corresponding to the native endian
267  * format of name.
268  * For example in a little-endian system, first looks for "gray16",
269  * then for "gray16le".
270  *
271  * Finally if no pixel format has been found, returns AV_PIX_FMT_NONE.
272  */
273 enum AVPixelFormat av_get_pix_fmt(const char *name);
274 
275 /**
276  * Return the short name for a pixel format, NULL in case pix_fmt is
277  * unknown.
278  *
279  * @see av_get_pix_fmt(), av_get_pix_fmt_string()
280  */
281 const char *av_get_pix_fmt_name(enum AVPixelFormat pix_fmt);
282 
283 /**
284  * Print in buf the string corresponding to the pixel format with
285  * number pix_fmt, or a header if pix_fmt is negative.
286  *
287  * @param buf the buffer where to write the string
288  * @param buf_size the size of buf
289  * @param pix_fmt the number of the pixel format to print the
290  * corresponding info string, or a negative value to print the
291  * corresponding header.
292  */
293 char *av_get_pix_fmt_string(char *buf, int buf_size,
294  enum AVPixelFormat pix_fmt);
295 
296 /**
297  * Read a line from an image, and write the values of the
298  * pixel format component c to dst.
299  *
300  * @param data the array containing the pointers to the planes of the image
301  * @param linesize the array containing the linesizes of the image
302  * @param desc the pixel format descriptor for the image
303  * @param x the horizontal coordinate of the first pixel to read
304  * @param y the vertical coordinate of the first pixel to read
305  * @param w the width of the line to read, that is the number of
306  * values to write to dst
307  * @param read_pal_component if not zero and the format is a paletted
308  * format writes the values corresponding to the palette
309  * component c in data[1] to dst, rather than the palette indexes in
310  * data[0]. The behavior is undefined if the format is not paletted.
311  */
312 void av_read_image_line(uint16_t *dst, const uint8_t *data[4],
313  const int linesize[4], const AVPixFmtDescriptor *desc,
314  int x, int y, int c, int w, int read_pal_component);
315 
316 /**
317  * Write the values from src to the pixel format component c of an
318  * image line.
319  *
320  * @param src array containing the values to write
321  * @param data the array containing the pointers to the planes of the
322  * image to write into. It is supposed to be zeroed.
323  * @param linesize the array containing the linesizes of the image
324  * @param desc the pixel format descriptor for the image
325  * @param x the horizontal coordinate of the first pixel to write
326  * @param y the vertical coordinate of the first pixel to write
327  * @param w the width of the line to write, that is the number of
328  * values to write to the image line
329  */
330 void av_write_image_line(const uint16_t *src, uint8_t *data[4],
331  const int linesize[4], const AVPixFmtDescriptor *desc,
332  int x, int y, int c, int w);
333 
334 /**
335  * Utility function to swap the endianness of a pixel format.
336  *
337  * @param[in] pix_fmt the pixel format
338  *
339  * @return pixel format with swapped endianness if it exists,
340  * otherwise AV_PIX_FMT_NONE
341  */
343 
344 #define FF_LOSS_RESOLUTION 0x0001 /**< loss due to resolution change */
345 #define FF_LOSS_DEPTH 0x0002 /**< loss due to color depth change */
346 #define FF_LOSS_COLORSPACE 0x0004 /**< loss due to color space conversion */
347 #define FF_LOSS_ALPHA 0x0008 /**< loss of alpha bits */
348 #define FF_LOSS_COLORQUANT 0x0010 /**< loss due to color quantization */
349 #define FF_LOSS_CHROMA 0x0020 /**< loss of chroma (e.g. RGB to gray conversion) */
350 
351 /**
352  * Compute what kind of losses will occur when converting from one specific
353  * pixel format to another.
354  * When converting from one pixel format to another, information loss may occur.
355  * For example, when converting from RGB24 to GRAY, the color information will
356  * be lost. Similarly, other losses occur when converting from some formats to
357  * other formats. These losses can involve loss of chroma, but also loss of
358  * resolution, loss of color depth, loss due to the color space conversion, loss
359  * of the alpha bits or loss due to color quantization.
360  * av_get_fix_fmt_loss() informs you about the various types of losses
361  * which will occur when converting from one pixel format to another.
362  *
363  * @param[in] dst_pix_fmt destination pixel format
364  * @param[in] src_pix_fmt source pixel format
365  * @param[in] has_alpha Whether the source pixel format alpha channel is used.
366  * @return Combination of flags informing you what kind of losses will occur
367  * (maximum loss for an invalid dst_pix_fmt).
368  */
369 int av_get_pix_fmt_loss(enum AVPixelFormat dst_pix_fmt,
370  enum AVPixelFormat src_pix_fmt,
371  int has_alpha);
372 
373 /**
374  * Compute what kind of losses will occur when converting from one specific
375  * pixel format to another.
376  * When converting from one pixel format to another, information loss may occur.
377  * For example, when converting from RGB24 to GRAY, the color information will
378  * be lost. Similarly, other losses occur when converting from some formats to
379  * other formats. These losses can involve loss of chroma, but also loss of
380  * resolution, loss of color depth, loss due to the color space conversion, loss
381  * of the alpha bits or loss due to color quantization.
382  * av_get_fix_fmt_loss() informs you about the various types of losses
383  * which will occur when converting from one pixel format to another.
384  *
385  * @param[in] dst_pix_fmt destination pixel format
386  * @param[in] src_pix_fmt source pixel format
387  * @param[in] has_alpha Whether the source pixel format alpha channel is used.
388  * @return Combination of flags informing you what kind of losses will occur
389  * (maximum loss for an invalid dst_pix_fmt).
390  */
391 enum AVPixelFormat av_find_best_pix_fmt_of_2(enum AVPixelFormat dst_pix_fmt1, enum AVPixelFormat dst_pix_fmt2,
392  enum AVPixelFormat src_pix_fmt, int has_alpha, int *loss_ptr);
393 
394 #endif /* AVUTIL_PIXDESC_H */
attribute_deprecated int offset_plus1
deprecated, use offset instead
Definition: pixdesc.h:68
int plane
Which of the 4 planes contains the component.
Definition: pixdesc.h:35
static enum AVPixelFormat pix_fmt
const char * alias
Alternative comma-separated names.
Definition: pixdesc.h:122
ptrdiff_t const GLvoid * data
Definition: opengl_enc.c:101
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)
Read a line from an image, and write the values of the pixel format component c to dst...
Definition: pixdesc.c:34
const char * desc
Definition: nvenc.c:60
const char * av_color_transfer_name(enum AVColorTransferCharacteristic transfer)
Definition: pixdesc.c:2657
#define src
Definition: vp8dsp.c:254
uint8_t log2_chroma_w
Amount to shift the luma width right to find the chroma width.
Definition: pixdesc.h:92
AVColorTransferCharacteristic
Color Transfer Characteristic.
Definition: pixfmt.h:422
Macro definitions for various function/variable attributes.
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:2603
enum AVPixelFormat av_pix_fmt_swap_endianness(enum AVPixelFormat pix_fmt)
Utility function to swap the endianness of a pixel format.
Definition: pixdesc.c:2429
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:2284
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)
Write the values from src to the pixel format component c of an image line.
Definition: pixdesc.c:82
AVComponentDescriptor comp[4]
Parameters that describe how pixels are packed.
Definition: pixdesc.h:117
uint8_t
AVColorSpace
YUV colorspace type.
Definition: pixfmt.h:450
AVColorRange
MPEG vs JPEG YUV range.
Definition: pixfmt.h:471
AVColorPrimaries
Chromaticity coordinates of the source primaries.
Definition: pixfmt.h:400
const char * name
Definition: pixdesc.h:82
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:2360
uint8_t log2_chroma_h
Amount to shift the luma height right to find the chroma height.
Definition: pixdesc.h:101
const char * av_color_range_name(enum AVColorRange range)
Definition: pixdesc.c:2645
const char * av_color_primaries_name(enum AVColorPrimaries primaries)
Definition: pixdesc.c:2651
Libavutil version macros.
uint64_t flags
Combination of AV_PIX_FMT_FLAG_...
Definition: pixdesc.h:106
uint8_t nb_components
The number of components each pixel has, (1-4)
Definition: pixdesc.h:83
const AVPixFmtDescriptor * av_pix_fmt_desc_next(const AVPixFmtDescriptor *prev)
Iterate over all pixel format descriptors known to libavutil.
Definition: pixdesc.c:2339
const char * av_color_space_name(enum AVColorSpace space)
Definition: pixdesc.c:2663
const AVPixFmtDescriptor * av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt)
Definition: pixdesc.c:2332
int av_pix_fmt_count_planes(enum AVPixelFormat pix_fmt)
Definition: pixdesc.c:2372
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:2317
attribute_deprecated int step_minus1
deprecated, use step instead
Definition: pixdesc.h:62
enum AVPixelFormat av_pix_fmt_desc_get_id(const AVPixFmtDescriptor *desc)
Definition: pixdesc.c:2351
Descriptor that unambiguously describes how the bits of a pixel are stored in the up to 4 data planes...
Definition: pixdesc.h:81
void * buf
Definition: avisynth_c.h:690
const char * av_chroma_location_name(enum AVChromaLocation location)
Definition: pixdesc.c:2669
int shift
Number of least significant bits that must be shifted away to get the value.
Definition: pixdesc.h:53
int offset
Number of elements before the component of the first pixel.
Definition: pixdesc.h:47
#define attribute_deprecated
Definition: attributes.h:94
attribute_deprecated int depth_minus1
deprecated, use depth instead
Definition: pixdesc.h:65
pixel format definitions
static AVCodec * c
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:2248
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:2297
AVChromaLocation
Location of chroma samples.
Definition: pixfmt.h:493
int depth
Number of bits in the component.
Definition: pixdesc.h:58
AVPixelFormat
Pixel format.
Definition: pixfmt.h:60
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:2614
enum AVPixelFormat av_get_pix_fmt(const char *name)
Return the pixel format corresponding to name.
Definition: pixdesc.c:2260
int step
Number of elements between 2 horizontally consecutive pixels.
Definition: pixdesc.h:41
const char * name
Definition: opengl_enc.c:103