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 */
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  */
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      */
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  * @deprecated This flag is deprecated, and will be removed. When it is removed,
159  * the extra palette allocation in AVFrame.data[1] is removed as well. Only
160  * actual paletted formats (as indicated by AV_PIX_FMT_FLAG_PAL) will have a
161  * palette. Starting with FFmpeg versions which have this flag deprecated, the
162  * extra "pseudo" palette is already ignored, and API users are not required to
163  * allocate a palette for AV_PIX_FMT_FLAG_PSEUDOPAL formats (it was required
164  * before the deprecation, though).
165  */
166 #define AV_PIX_FMT_FLAG_PSEUDOPAL    (1 << 6)
167 
168 /**
169  * The pixel format has an alpha channel. This is set on all formats that
170  * support alpha in some way, including AV_PIX_FMT_PAL8. The alpha is always
171  * straight, never pre-multiplied.
172  *
173  * If a codec or a filter does not support alpha, it should set all alpha to
174  * opaque, or use the equivalent pixel formats without alpha component, e.g.
175  * AV_PIX_FMT_RGB0 (or AV_PIX_FMT_RGB24 etc.) instead of AV_PIX_FMT_RGBA.
176  */
177 #define AV_PIX_FMT_FLAG_ALPHA        (1 << 7)
178 
179 /**
180  * The pixel format is following a Bayer pattern
181  */
182 #define AV_PIX_FMT_FLAG_BAYER        (1 << 8)
183 
184 /**
185  * The pixel format contains IEEE-754 floating point values. Precision (double,
186  * single, or half) should be determined by the pixel size (64, 32, or 16 bits).
187  */
188 #define AV_PIX_FMT_FLAG_FLOAT        (1 << 9)
189 
190 /**
191  * Return the number of bits per pixel used by the pixel format
192  * described by pixdesc. Note that this is not the same as the number
193  * of bits per sample.
194  *
195  * The returned number of bits refers to the number of bits actually
196  * used for storing the pixel information, that is padding bits are
197  * not counted.
198  */
199 int av_get_bits_per_pixel(const AVPixFmtDescriptor *pixdesc);
200 
201 /**
202  * Return the number of bits per pixel for the pixel format
203  * described by pixdesc, including any padding or unused bits.
204  */
205 int av_get_padded_bits_per_pixel(const AVPixFmtDescriptor *pixdesc);
206 
207 /**
208  * @return a pixel format descriptor for provided pixel format or NULL if
209  * this pixel format is unknown.
210  */
211 const AVPixFmtDescriptor *av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt);
212 
213 /**
214  * Iterate over all pixel format descriptors known to libavutil.
215  *
216  * @param prev previous descriptor. NULL to get the first descriptor.
217  *
218  * @return next descriptor or NULL after the last descriptor
219  */
220 const AVPixFmtDescriptor *av_pix_fmt_desc_next(const AVPixFmtDescriptor *prev);
221 
222 /**
223  * @return an AVPixelFormat id described by desc, or AV_PIX_FMT_NONE if desc
224  * is not a valid pointer to a pixel format descriptor.
225  */
226 enum AVPixelFormat av_pix_fmt_desc_get_id(const AVPixFmtDescriptor *desc);
227 
228 /**
229  * Utility function to access log2_chroma_w log2_chroma_h from
230  * the pixel format AVPixFmtDescriptor.
231  *
232  * @param[in]  pix_fmt the pixel format
233  * @param[out] h_shift store log2_chroma_w (horizontal/width shift)
234  * @param[out] v_shift store log2_chroma_h (vertical/height shift)
235  *
236  * @return 0 on success, AVERROR(ENOSYS) on invalid or unknown pixel format
237  */
238 int av_pix_fmt_get_chroma_sub_sample(enum AVPixelFormat pix_fmt,
239                                      int *h_shift, int *v_shift);
240 
241 /**
242  * @return number of planes in pix_fmt, a negative AVERROR if pix_fmt is not a
243  * valid pixel format.
244  */
245 int av_pix_fmt_count_planes(enum AVPixelFormat pix_fmt);
246 
247 /**
248  * @return the name for provided color range or NULL if unknown.
249  */
250 const char *av_color_range_name(enum AVColorRange range);
251 
252 /**
253  * @return the AVColorRange value for name or an AVError if not found.
254  */
255 int av_color_range_from_name(const char *name);
256 
257 /**
258  * @return the name for provided color primaries or NULL if unknown.
259  */
260 const char *av_color_primaries_name(enum AVColorPrimaries primaries);
261 
262 /**
263  * @return the AVColorPrimaries value for name or an AVError if not found.
264  */
265 int av_color_primaries_from_name(const char *name);
266 
267 /**
268  * @return the name for provided color transfer or NULL if unknown.
269  */
270 const char *av_color_transfer_name(enum AVColorTransferCharacteristic transfer);
271 
272 /**
273  * @return the AVColorTransferCharacteristic value for name or an AVError if not found.
274  */
275 int av_color_transfer_from_name(const char *name);
276 
277 /**
278  * @return the name for provided color space or NULL if unknown.
279  */
280 const char *av_color_space_name(enum AVColorSpace space);
281 
282 /**
283  * @return the AVColorSpace value for name or an AVError if not found.
284  */
285 int av_color_space_from_name(const char *name);
286 
287 /**
288  * @return the name for provided chroma location or NULL if unknown.
289  */
290 const char *av_chroma_location_name(enum AVChromaLocation location);
291 
292 /**
293  * @return the AVChromaLocation value for name or an AVError if not found.
294  */
295 int av_chroma_location_from_name(const char *name);
296 
297 /**
298  * Return the pixel format corresponding to name.
299  *
300  * If there is no pixel format with name name, then looks for a
301  * pixel format with the name corresponding to the native endian
302  * format of name.
303  * For example in a little-endian system, first looks for "gray16",
304  * then for "gray16le".
305  *
306  * Finally if no pixel format has been found, returns AV_PIX_FMT_NONE.
307  */
308 enum AVPixelFormat av_get_pix_fmt(const char *name);
309 
310 /**
311  * Return the short name for a pixel format, NULL in case pix_fmt is
312  * unknown.
313  *
314  * @see av_get_pix_fmt(), av_get_pix_fmt_string()
315  */
316 const char *av_get_pix_fmt_name(enum AVPixelFormat pix_fmt);
317 
318 /**
319  * Print in buf the string corresponding to the pixel format with
320  * number pix_fmt, or a header if pix_fmt is negative.
321  *
322  * @param buf the buffer where to write the string
323  * @param buf_size the size of buf
324  * @param pix_fmt the number of the pixel format to print the
325  * corresponding info string, or a negative value to print the
326  * corresponding header.
327  */
328 char *av_get_pix_fmt_string(char *buf, int buf_size,
329                             enum AVPixelFormat pix_fmt);
330 
331 /**
332  * Read a line from an image, and write the values of the
333  * pixel format component c to dst.
334  *
335  * @param data the array containing the pointers to the planes of the image
336  * @param linesize the array containing the linesizes of the image
337  * @param desc the pixel format descriptor for the image
338  * @param x the horizontal coordinate of the first pixel to read
339  * @param y the vertical coordinate of the first pixel to read
340  * @param w the width of the line to read, that is the number of
341  * values to write to dst
342  * @param read_pal_component if not zero and the format is a paletted
343  * format writes the values corresponding to the palette
344  * component c in data[1] to dst, rather than the palette indexes in
345  * data[0]. The behavior is undefined if the format is not paletted.
346  * @param dst_element_size size of elements in dst array (2 or 4 byte)
347  */
348 void av_read_image_line2(void *dst, const uint8_t *data[4],
349                         const int linesize[4], const AVPixFmtDescriptor *desc,
350                         int x, int y, int c, int w, int read_pal_component,
351                         int dst_element_size);
352 
353 void av_read_image_line(uint16_t *dst, const uint8_t *data[4],
354                         const int linesize[4], const AVPixFmtDescriptor *desc,
355                         int x, int y, int c, int w, int read_pal_component);
356 
357 /**
358  * Write the values from src to the pixel format component c of an
359  * image line.
360  *
361  * @param src array containing the values to write
362  * @param data the array containing the pointers to the planes of the
363  * image to write into. It is supposed to be zeroed.
364  * @param linesize the array containing the linesizes of the image
365  * @param desc the pixel format descriptor for the image
366  * @param x the horizontal coordinate of the first pixel to write
367  * @param y the vertical coordinate of the first pixel to write
368  * @param w the width of the line to write, that is the number of
369  * values to write to the image line
370  * @param src_element_size size of elements in src array (2 or 4 byte)
371  */
372 void av_write_image_line2(const void *src, uint8_t *data[4],
373                          const int linesize[4], const AVPixFmtDescriptor *desc,
374                          int x, int y, int c, int w, int src_element_size);
375 
376 void av_write_image_line(const uint16_t *src, uint8_t *data[4],
377                          const int linesize[4], const AVPixFmtDescriptor *desc,
378                          int x, int y, int c, int w);
379 
380 /**
381  * Utility function to swap the endianness of a pixel format.
382  *
383  * @param[in]  pix_fmt the pixel format
384  *
385  * @return pixel format with swapped endianness if it exists,
386  * otherwise AV_PIX_FMT_NONE
387  */
388 enum AVPixelFormat av_pix_fmt_swap_endianness(enum AVPixelFormat pix_fmt);
389 
390 #define FF_LOSS_RESOLUTION  0x0001 /**< loss due to resolution change */
391 #define FF_LOSS_DEPTH       0x0002 /**< loss due to color depth change */
392 #define FF_LOSS_COLORSPACE  0x0004 /**< loss due to color space conversion */
393 #define FF_LOSS_ALPHA       0x0008 /**< loss of alpha bits */
394 #define FF_LOSS_COLORQUANT  0x0010 /**< loss due to color quantization */
395 #define FF_LOSS_CHROMA      0x0020 /**< loss of chroma (e.g. RGB to gray conversion) */
396 
397 /**
398  * Compute what kind of losses will occur when converting from one specific
399  * pixel format to another.
400  * When converting from one pixel format to another, information loss may occur.
401  * For example, when converting from RGB24 to GRAY, the color information will
402  * be lost. Similarly, other losses occur when converting from some formats to
403  * other formats. These losses can involve loss of chroma, but also loss of
404  * resolution, loss of color depth, loss due to the color space conversion, loss
405  * of the alpha bits or loss due to color quantization.
406  * av_get_fix_fmt_loss() informs you about the various types of losses
407  * which will occur when converting from one pixel format to another.
408  *
409  * @param[in] dst_pix_fmt destination pixel format
410  * @param[in] src_pix_fmt source pixel format
411  * @param[in] has_alpha Whether the source pixel format alpha channel is used.
412  * @return Combination of flags informing you what kind of losses will occur
413  * (maximum loss for an invalid dst_pix_fmt).
414  */
415 int av_get_pix_fmt_loss(enum AVPixelFormat dst_pix_fmt,
416                         enum AVPixelFormat src_pix_fmt,
417                         int has_alpha);
418 
419 /**
420  * Compute what kind of losses will occur when converting from one specific
421  * pixel format to another.
422  * When converting from one pixel format to another, information loss may occur.
423  * For example, when converting from RGB24 to GRAY, the color information will
424  * be lost. Similarly, other losses occur when converting from some formats to
425  * other formats. These losses can involve loss of chroma, but also loss of
426  * resolution, loss of color depth, loss due to the color space conversion, loss
427  * of the alpha bits or loss due to color quantization.
428  * av_get_fix_fmt_loss() informs you about the various types of losses
429  * which will occur when converting from one pixel format to another.
430  *
431  * @param[in] dst_pix_fmt destination pixel format
432  * @param[in] src_pix_fmt source pixel format
433  * @param[in] has_alpha Whether the source pixel format alpha channel is used.
434  * @return Combination of flags informing you what kind of losses will occur
435  * (maximum loss for an invalid dst_pix_fmt).
436  */
437 enum AVPixelFormat av_find_best_pix_fmt_of_2(enum AVPixelFormat dst_pix_fmt1, enum AVPixelFormat dst_pix_fmt2,
438                                              enum AVPixelFormat src_pix_fmt, int has_alpha, int *loss_ptr);
439 
440 #endif /* AVUTIL_PIXDESC_H */
441