pixdesc.h 16 KB

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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. #ifndef AVUTIL_PIXDESC_H
  22. #define AVUTIL_PIXDESC_H
  23. #include <inttypes.h>
  24. #include "attributes.h"
  25. #include "pixfmt.h"
  26. typedef struct AVComponentDescriptor {
  27. /**
  28. * Which of the 4 planes contains the component.
  29. */
  30. int plane;
  31. /**
  32. * Number of elements between 2 horizontally consecutive pixels.
  33. * Elements are bits for bitstream formats, bytes otherwise.
  34. */
  35. int step;
  36. /**
  37. * Number of elements before the component of the first pixel.
  38. * Elements are bits for bitstream formats, bytes otherwise.
  39. */
  40. int offset;
  41. /**
  42. * Number of least significant bits that must be shifted away
  43. * to get the value.
  44. */
  45. int shift;
  46. /**
  47. * Number of bits in the component.
  48. */
  49. int depth;
  50. } AVComponentDescriptor;
  51. /**
  52. * Descriptor that unambiguously describes how the bits of a pixel are
  53. * stored in the up to 4 data planes of an image. It also stores the
  54. * subsampling factors and number of components.
  55. *
  56. * @note This is separate of the colorspace (RGB, YCbCr, YPbPr, JPEG-style YUV
  57. * and all the YUV variants) AVPixFmtDescriptor just stores how values
  58. * are stored not what these values represent.
  59. */
  60. typedef struct AVPixFmtDescriptor {
  61. const char *name;
  62. uint8_t nb_components; ///< The number of components each pixel has, (1-4)
  63. /**
  64. * Amount to shift the luma width right to find the chroma width.
  65. * For YV12 this is 1 for example.
  66. * chroma_width = AV_CEIL_RSHIFT(luma_width, log2_chroma_w)
  67. * The note above is needed to ensure rounding up.
  68. * This value only refers to the chroma components.
  69. */
  70. uint8_t log2_chroma_w;
  71. /**
  72. * Amount to shift the luma height right to find the chroma height.
  73. * For YV12 this is 1 for example.
  74. * chroma_height= AV_CEIL_RSHIFT(luma_height, log2_chroma_h)
  75. * The note above is needed to ensure rounding up.
  76. * This value only refers to the chroma components.
  77. */
  78. uint8_t log2_chroma_h;
  79. /**
  80. * Combination of AV_PIX_FMT_FLAG_... flags.
  81. */
  82. uint64_t flags;
  83. /**
  84. * Parameters that describe how pixels are packed.
  85. * If the format has 1 or 2 components, then luma is 0.
  86. * If the format has 3 or 4 components:
  87. * if the RGB flag is set then 0 is red, 1 is green and 2 is blue;
  88. * otherwise 0 is luma, 1 is chroma-U and 2 is chroma-V.
  89. *
  90. * If present, the Alpha channel is always the last component.
  91. */
  92. AVComponentDescriptor comp[4];
  93. /**
  94. * Alternative comma-separated names.
  95. */
  96. const char *alias;
  97. } AVPixFmtDescriptor;
  98. /**
  99. * Pixel format is big-endian.
  100. */
  101. #define AV_PIX_FMT_FLAG_BE (1 << 0)
  102. /**
  103. * Pixel format has a palette in data[1], values are indexes in this palette.
  104. */
  105. #define AV_PIX_FMT_FLAG_PAL (1 << 1)
  106. /**
  107. * All values of a component are bit-wise packed end to end.
  108. */
  109. #define AV_PIX_FMT_FLAG_BITSTREAM (1 << 2)
  110. /**
  111. * Pixel format is an HW accelerated format.
  112. */
  113. #define AV_PIX_FMT_FLAG_HWACCEL (1 << 3)
  114. /**
  115. * At least one pixel component is not in the first data plane.
  116. */
  117. #define AV_PIX_FMT_FLAG_PLANAR (1 << 4)
  118. /**
  119. * The pixel format contains RGB-like data (as opposed to YUV/grayscale).
  120. */
  121. #define AV_PIX_FMT_FLAG_RGB (1 << 5)
  122. /**
  123. * The pixel format has an alpha channel. This is set on all formats that
  124. * support alpha in some way, including AV_PIX_FMT_PAL8. The alpha is always
  125. * straight, never pre-multiplied.
  126. *
  127. * If a codec or a filter does not support alpha, it should set all alpha to
  128. * opaque, or use the equivalent pixel formats without alpha component, e.g.
  129. * AV_PIX_FMT_RGB0 (or AV_PIX_FMT_RGB24 etc.) instead of AV_PIX_FMT_RGBA.
  130. */
  131. #define AV_PIX_FMT_FLAG_ALPHA (1 << 7)
  132. /**
  133. * The pixel format is following a Bayer pattern
  134. */
  135. #define AV_PIX_FMT_FLAG_BAYER (1 << 8)
  136. /**
  137. * The pixel format contains IEEE-754 floating point values. Precision (double,
  138. * single, or half) should be determined by the pixel size (64, 32, or 16 bits).
  139. */
  140. #define AV_PIX_FMT_FLAG_FLOAT (1 << 9)
  141. /**
  142. * The pixel format contains XYZ-like data (as opposed to YUV/RGB/grayscale).
  143. */
  144. #define AV_PIX_FMT_FLAG_XYZ (1 << 10)
  145. /**
  146. * Return the number of bits per pixel used by the pixel format
  147. * described by pixdesc. Note that this is not the same as the number
  148. * of bits per sample.
  149. *
  150. * The returned number of bits refers to the number of bits actually
  151. * used for storing the pixel information, that is padding bits are
  152. * not counted.
  153. */
  154. int av_get_bits_per_pixel(const AVPixFmtDescriptor *pixdesc);
  155. /**
  156. * Return the number of bits per pixel for the pixel format
  157. * described by pixdesc, including any padding or unused bits.
  158. */
  159. int av_get_padded_bits_per_pixel(const AVPixFmtDescriptor *pixdesc);
  160. /**
  161. * @return a pixel format descriptor for provided pixel format or NULL if
  162. * this pixel format is unknown.
  163. */
  164. const AVPixFmtDescriptor *av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt);
  165. /**
  166. * Iterate over all pixel format descriptors known to libavutil.
  167. *
  168. * @param prev previous descriptor. NULL to get the first descriptor.
  169. *
  170. * @return next descriptor or NULL after the last descriptor
  171. */
  172. const AVPixFmtDescriptor *av_pix_fmt_desc_next(const AVPixFmtDescriptor *prev);
  173. /**
  174. * @return an AVPixelFormat id described by desc, or AV_PIX_FMT_NONE if desc
  175. * is not a valid pointer to a pixel format descriptor.
  176. */
  177. enum AVPixelFormat av_pix_fmt_desc_get_id(const AVPixFmtDescriptor *desc);
  178. /**
  179. * Utility function to access log2_chroma_w log2_chroma_h from
  180. * the pixel format AVPixFmtDescriptor.
  181. *
  182. * @param[in] pix_fmt the pixel format
  183. * @param[out] h_shift store log2_chroma_w (horizontal/width shift)
  184. * @param[out] v_shift store log2_chroma_h (vertical/height shift)
  185. *
  186. * @return 0 on success, AVERROR(ENOSYS) on invalid or unknown pixel format
  187. */
  188. int av_pix_fmt_get_chroma_sub_sample(enum AVPixelFormat pix_fmt,
  189. int *h_shift, int *v_shift);
  190. /**
  191. * @return number of planes in pix_fmt, a negative AVERROR if pix_fmt is not a
  192. * valid pixel format.
  193. */
  194. int av_pix_fmt_count_planes(enum AVPixelFormat pix_fmt);
  195. /**
  196. * @return the name for provided color range or NULL if unknown.
  197. */
  198. const char *av_color_range_name(enum AVColorRange range);
  199. /**
  200. * @return the AVColorRange value for name or an AVError if not found.
  201. */
  202. int av_color_range_from_name(const char *name);
  203. /**
  204. * @return the name for provided color primaries or NULL if unknown.
  205. */
  206. const char *av_color_primaries_name(enum AVColorPrimaries primaries);
  207. /**
  208. * @return the AVColorPrimaries value for name or an AVError if not found.
  209. */
  210. int av_color_primaries_from_name(const char *name);
  211. /**
  212. * @return the name for provided color transfer or NULL if unknown.
  213. */
  214. const char *av_color_transfer_name(enum AVColorTransferCharacteristic transfer);
  215. /**
  216. * @return the AVColorTransferCharacteristic value for name or an AVError if not found.
  217. */
  218. int av_color_transfer_from_name(const char *name);
  219. /**
  220. * @return the name for provided color space or NULL if unknown.
  221. */
  222. const char *av_color_space_name(enum AVColorSpace space);
  223. /**
  224. * @return the AVColorSpace value for name or an AVError if not found.
  225. */
  226. int av_color_space_from_name(const char *name);
  227. /**
  228. * @return the name for provided chroma location or NULL if unknown.
  229. */
  230. const char *av_chroma_location_name(enum AVChromaLocation location);
  231. /**
  232. * @return the AVChromaLocation value for name or an AVError if not found.
  233. */
  234. int av_chroma_location_from_name(const char *name);
  235. /**
  236. * Converts AVChromaLocation to swscale x/y chroma position.
  237. *
  238. * The positions represent the chroma (0,0) position in a coordinates system
  239. * with luma (0,0) representing the origin and luma(1,1) representing 256,256
  240. *
  241. * @param xpos horizontal chroma sample position
  242. * @param ypos vertical chroma sample position
  243. */
  244. int av_chroma_location_enum_to_pos(int *xpos, int *ypos, enum AVChromaLocation pos);
  245. /**
  246. * Converts swscale x/y chroma position to AVChromaLocation.
  247. *
  248. * The positions represent the chroma (0,0) position in a coordinates system
  249. * with luma (0,0) representing the origin and luma(1,1) representing 256,256
  250. *
  251. * @param xpos horizontal chroma sample position
  252. * @param ypos vertical chroma sample position
  253. */
  254. enum AVChromaLocation av_chroma_location_pos_to_enum(int xpos, int ypos);
  255. /**
  256. * Return the pixel format corresponding to name.
  257. *
  258. * If there is no pixel format with name name, then looks for a
  259. * pixel format with the name corresponding to the native endian
  260. * format of name.
  261. * For example in a little-endian system, first looks for "gray16",
  262. * then for "gray16le".
  263. *
  264. * Finally if no pixel format has been found, returns AV_PIX_FMT_NONE.
  265. */
  266. enum AVPixelFormat av_get_pix_fmt(const char *name);
  267. /**
  268. * Return the short name for a pixel format, NULL in case pix_fmt is
  269. * unknown.
  270. *
  271. * @see av_get_pix_fmt(), av_get_pix_fmt_string()
  272. */
  273. const char *av_get_pix_fmt_name(enum AVPixelFormat pix_fmt);
  274. /**
  275. * Print in buf the string corresponding to the pixel format with
  276. * number pix_fmt, or a header if pix_fmt is negative.
  277. *
  278. * @param buf the buffer where to write the string
  279. * @param buf_size the size of buf
  280. * @param pix_fmt the number of the pixel format to print the
  281. * corresponding info string, or a negative value to print the
  282. * corresponding header.
  283. */
  284. char *av_get_pix_fmt_string(char *buf, int buf_size,
  285. enum AVPixelFormat pix_fmt);
  286. /**
  287. * Read a line from an image, and write the values of the
  288. * pixel format component c to dst.
  289. *
  290. * @param data the array containing the pointers to the planes of the image
  291. * @param linesize the array containing the linesizes of the image
  292. * @param desc the pixel format descriptor for the image
  293. * @param x the horizontal coordinate of the first pixel to read
  294. * @param y the vertical coordinate of the first pixel to read
  295. * @param w the width of the line to read, that is the number of
  296. * values to write to dst
  297. * @param read_pal_component if not zero and the format is a paletted
  298. * format writes the values corresponding to the palette
  299. * component c in data[1] to dst, rather than the palette indexes in
  300. * data[0]. The behavior is undefined if the format is not paletted.
  301. * @param dst_element_size size of elements in dst array (2 or 4 byte)
  302. */
  303. void av_read_image_line2(void *dst, const uint8_t *data[4],
  304. const int linesize[4], const AVPixFmtDescriptor *desc,
  305. int x, int y, int c, int w, int read_pal_component,
  306. int dst_element_size);
  307. void av_read_image_line(uint16_t *dst, const uint8_t *data[4],
  308. const int linesize[4], const AVPixFmtDescriptor *desc,
  309. int x, int y, int c, int w, int read_pal_component);
  310. /**
  311. * Write the values from src to the pixel format component c of an
  312. * image line.
  313. *
  314. * @param src array containing the values to write
  315. * @param data the array containing the pointers to the planes of the
  316. * image to write into. It is supposed to be zeroed.
  317. * @param linesize the array containing the linesizes of the image
  318. * @param desc the pixel format descriptor for the image
  319. * @param x the horizontal coordinate of the first pixel to write
  320. * @param y the vertical coordinate of the first pixel to write
  321. * @param w the width of the line to write, that is the number of
  322. * values to write to the image line
  323. * @param src_element_size size of elements in src array (2 or 4 byte)
  324. */
  325. void av_write_image_line2(const void *src, uint8_t *data[4],
  326. const int linesize[4], const AVPixFmtDescriptor *desc,
  327. int x, int y, int c, int w, int src_element_size);
  328. void av_write_image_line(const uint16_t *src, uint8_t *data[4],
  329. const int linesize[4], const AVPixFmtDescriptor *desc,
  330. int x, int y, int c, int w);
  331. /**
  332. * Utility function to swap the endianness of a pixel format.
  333. *
  334. * @param[in] pix_fmt the pixel format
  335. *
  336. * @return pixel format with swapped endianness if it exists,
  337. * otherwise AV_PIX_FMT_NONE
  338. */
  339. enum AVPixelFormat av_pix_fmt_swap_endianness(enum AVPixelFormat pix_fmt);
  340. #define FF_LOSS_RESOLUTION 0x0001 /**< loss due to resolution change */
  341. #define FF_LOSS_DEPTH 0x0002 /**< loss due to color depth change */
  342. #define FF_LOSS_COLORSPACE 0x0004 /**< loss due to color space conversion */
  343. #define FF_LOSS_ALPHA 0x0008 /**< loss of alpha bits */
  344. #define FF_LOSS_COLORQUANT 0x0010 /**< loss due to color quantization */
  345. #define FF_LOSS_CHROMA 0x0020 /**< loss of chroma (e.g. RGB to gray conversion) */
  346. #define FF_LOSS_EXCESS_RESOLUTION 0x0040 /**< loss due to unneeded extra resolution */
  347. #define FF_LOSS_EXCESS_DEPTH 0x0080 /**< loss due to unneeded extra color depth */
  348. /**
  349. * Compute what kind of losses will occur when converting from one specific
  350. * pixel format to another.
  351. * When converting from one pixel format to another, information loss may occur.
  352. * For example, when converting from RGB24 to GRAY, the color information will
  353. * be lost. Similarly, other losses occur when converting from some formats to
  354. * other formats. These losses can involve loss of chroma, but also loss of
  355. * resolution, loss of color depth, loss due to the color space conversion, loss
  356. * of the alpha bits or loss due to color quantization.
  357. * av_get_fix_fmt_loss() informs you about the various types of losses
  358. * which will occur when converting from one pixel format to another.
  359. *
  360. * @param[in] dst_pix_fmt destination pixel format
  361. * @param[in] src_pix_fmt source pixel format
  362. * @param[in] has_alpha Whether the source pixel format alpha channel is used.
  363. * @return Combination of flags informing you what kind of losses will occur
  364. * (maximum loss for an invalid dst_pix_fmt).
  365. */
  366. int av_get_pix_fmt_loss(enum AVPixelFormat dst_pix_fmt,
  367. enum AVPixelFormat src_pix_fmt,
  368. int has_alpha);
  369. /**
  370. * Compute what kind of losses will occur when converting from one specific
  371. * pixel format to another.
  372. * When converting from one pixel format to another, information loss may occur.
  373. * For example, when converting from RGB24 to GRAY, the color information will
  374. * be lost. Similarly, other losses occur when converting from some formats to
  375. * other formats. These losses can involve loss of chroma, but also loss of
  376. * resolution, loss of color depth, loss due to the color space conversion, loss
  377. * of the alpha bits or loss due to color quantization.
  378. * av_get_fix_fmt_loss() informs you about the various types of losses
  379. * which will occur when converting from one pixel format to another.
  380. *
  381. * @param[in] dst_pix_fmt destination pixel format
  382. * @param[in] src_pix_fmt source pixel format
  383. * @param[in] has_alpha Whether the source pixel format alpha channel is used.
  384. * @return Combination of flags informing you what kind of losses will occur
  385. * (maximum loss for an invalid dst_pix_fmt).
  386. */
  387. enum AVPixelFormat av_find_best_pix_fmt_of_2(enum AVPixelFormat dst_pix_fmt1, enum AVPixelFormat dst_pix_fmt2,
  388. enum AVPixelFormat src_pix_fmt, int has_alpha, int *loss_ptr);
  389. #endif /* AVUTIL_PIXDESC_H */