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; 58 } AVComponentDescriptor; 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 */ 105 AVComponentDescriptor comp[4]; 106 107 /** 108 * Alternative comma-separated names. 109 */ 110 const char *alias; 111 } AVPixFmtDescriptor; 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 */ 175 int av_get_padded_bits_per_pixel(const AVPixFmtDescriptor *pixdesc); 176 177 /** 178 * @return a pixel format descriptor for provided pixel format or NULL if 179 * this pixel format is unknown. 180 */ 181 const AVPixFmtDescriptor *av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt); 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 */ 190 const AVPixFmtDescriptor *av_pix_fmt_desc_next(const AVPixFmtDescriptor *prev); 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 */ 196 enum AVPixelFormat av_pix_fmt_desc_get_id(const AVPixFmtDescriptor *desc); 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 */ 208 int av_pix_fmt_get_chroma_sub_sample(enum AVPixelFormat pix_fmt, 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 */ 215 int av_pix_fmt_count_planes(enum AVPixelFormat pix_fmt); 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 */ 358 enum AVPixelFormat av_pix_fmt_swap_endianness(enum AVPixelFormat pix_fmt); 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 */ 411