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 30typedef struct AVComponentDescriptor{ 31 uint16_t plane :2; ///< which of the 4 planes contains the component 32 33 /** 34 * Number of elements between 2 horizontally consecutive pixels minus 1. 35 * Elements are bits for bitstream formats, bytes otherwise. 36 */ 37 uint16_t step_minus1 :3; 38 39 /** 40 * Number of elements before the component of the first pixel plus 1. 41 * Elements are bits for bitstream formats, bytes otherwise. 42 */ 43 uint16_t offset_plus1 :3; 44 uint16_t shift :3; ///< number of least significant bits that must be shifted away to get the value 45 uint16_t depth_minus1 :4; ///< number of bits in the component minus 1 46}AVComponentDescriptor; 47 48/** 49 * Descriptor that unambiguously describes how the bits of a pixel are 50 * stored in the up to 4 data planes of an image. It also stores the 51 * subsampling factors and number of components. 52 * 53 * @note This is separate of the colorspace (RGB, YCbCr, YPbPr, JPEG-style YUV 54 * and all the YUV variants) AVPixFmtDescriptor just stores how values 55 * are stored not what these values represent. 56 */ 57typedef struct AVPixFmtDescriptor{ 58 const char *name; 59 uint8_t nb_components; ///< The number of components each pixel has, (1-4) 60 61 /** 62 * Amount to shift the luma width right to find the chroma width. 63 * For YV12 this is 1 for example. 64 * chroma_width = -((-luma_width) >> log2_chroma_w) 65 * The note above is needed to ensure rounding up. 66 * This value only refers to the chroma components. 67 */ 68 uint8_t log2_chroma_w; ///< chroma_width = -((-luma_width )>>log2_chroma_w) 69 70 /** 71 * Amount to shift the luma height right to find the chroma height. 72 * For YV12 this is 1 for example. 73 * chroma_height= -((-luma_height) >> log2_chroma_h) 74 * The note above is needed to ensure rounding up. 75 * This value only refers to the chroma components. 76 */ 77 uint8_t log2_chroma_h; 78 uint8_t flags; 79 80 /** 81 * Parameters that describe how pixels are packed. 82 * If the format has 2 or 4 components, then alpha is last. 83 * If the format has 1 or 2 components, then luma is 0. 84 * If the format has 3 or 4 components, 85 * if the RGB flag is set then 0 is red, 1 is green and 2 is blue; 86 * otherwise 0 is luma, 1 is chroma-U and 2 is chroma-V. 87 */ 88 AVComponentDescriptor comp[4]; 89}AVPixFmtDescriptor; 90 91/** 92 * Pixel format is big-endian. 93 */ 94#define AV_PIX_FMT_FLAG_BE (1 << 0) 95/** 96 * Pixel format has a palette in data[1], values are indexes in this palette. 97 */ 98#define AV_PIX_FMT_FLAG_PAL (1 << 1) 99/** 100 * All values of a component are bit-wise packed end to end. 101 */ 102#define AV_PIX_FMT_FLAG_BITSTREAM (1 << 2) 103/** 104 * Pixel format is an HW accelerated format. 105 */ 106#define AV_PIX_FMT_FLAG_HWACCEL (1 << 3) 107/** 108 * At least one pixel component is not in the first data plane. 109 */ 110#define AV_PIX_FMT_FLAG_PLANAR (1 << 4) 111/** 112 * The pixel format contains RGB-like data (as opposed to YUV/grayscale). 113 */ 114#define AV_PIX_FMT_FLAG_RGB (1 << 5) 115/** 116 * The pixel format is "pseudo-paletted". This means that FFmpeg treats it as 117 * paletted internally, but the palette is generated by the decoder and is not 118 * stored in the file. 119 */ 120#define AV_PIX_FMT_FLAG_PSEUDOPAL (1 << 6) 121/** 122 * The pixel format has an alpha channel. 123 */ 124#define AV_PIX_FMT_FLAG_ALPHA (1 << 7) 125 126#if FF_API_PIX_FMT 127/** 128 * @deprecated use the AV_PIX_FMT_FLAG_* flags 129 */ 130#define PIX_FMT_BE AV_PIX_FMT_FLAG_BE 131#define PIX_FMT_PAL AV_PIX_FMT_FLAG_PAL 132#define PIX_FMT_BITSTREAM AV_PIX_FMT_FLAG_BITSTREAM 133#define PIX_FMT_HWACCEL AV_PIX_FMT_FLAG_HWACCEL 134#define PIX_FMT_PLANAR AV_PIX_FMT_FLAG_PLANAR 135#define PIX_FMT_RGB AV_PIX_FMT_FLAG_RGB 136#define PIX_FMT_PSEUDOPAL AV_PIX_FMT_FLAG_PSEUDOPAL 137#define PIX_FMT_ALPHA AV_PIX_FMT_FLAG_ALPHA 138#endif 139 140#if FF_API_PIX_FMT_DESC 141/** 142 * The array of all the pixel format descriptors. 143 */ 144extern attribute_deprecated const AVPixFmtDescriptor av_pix_fmt_descriptors[]; 145#endif 146 147/** 148 * Read a line from an image, and write the values of the 149 * pixel format component c to dst. 150 * 151 * @param data the array containing the pointers to the planes of the image 152 * @param linesize the array containing the linesizes of the image 153 * @param desc the pixel format descriptor for the image 154 * @param x the horizontal coordinate of the first pixel to read 155 * @param y the vertical coordinate of the first pixel to read 156 * @param w the width of the line to read, that is the number of 157 * values to write to dst 158 * @param read_pal_component if not zero and the format is a paletted 159 * format writes the values corresponding to the palette 160 * component c in data[1] to dst, rather than the palette indexes in 161 * data[0]. The behavior is undefined if the format is not paletted. 162 */ 163void av_read_image_line(uint16_t *dst, const uint8_t *data[4], const int linesize[4], 164 const AVPixFmtDescriptor *desc, int x, int y, int c, int w, int read_pal_component); 165 166/** 167 * Write the values from src to the pixel format component c of an 168 * image line. 169 * 170 * @param src array containing the values to write 171 * @param data the array containing the pointers to the planes of the 172 * image to write into. It is supposed to be zeroed. 173 * @param linesize the array containing the linesizes of the image 174 * @param desc the pixel format descriptor for the image 175 * @param x the horizontal coordinate of the first pixel to write 176 * @param y the vertical coordinate of the first pixel to write 177 * @param w the width of the line to write, that is the number of 178 * values to write to the image line 179 */ 180void av_write_image_line(const uint16_t *src, uint8_t *data[4], const int linesize[4], 181 const AVPixFmtDescriptor *desc, int x, int y, int c, int w); 182 183/** 184 * Return the pixel format corresponding to name. 185 * 186 * If there is no pixel format with name name, then looks for a 187 * pixel format with the name corresponding to the native endian 188 * format of name. 189 * For example in a little-endian system, first looks for "gray16", 190 * then for "gray16le". 191 * 192 * Finally if no pixel format has been found, returns AV_PIX_FMT_NONE. 193 */ 194enum AVPixelFormat av_get_pix_fmt(const char *name); 195 196/** 197 * Return the short name for a pixel format, NULL in case pix_fmt is 198 * unknown. 199 * 200 * @see av_get_pix_fmt(), av_get_pix_fmt_string() 201 */ 202const char *av_get_pix_fmt_name(enum AVPixelFormat pix_fmt); 203 204/** 205 * Print in buf the string corresponding to the pixel format with 206 * number pix_fmt, or a header if pix_fmt is negative. 207 * 208 * @param buf the buffer where to write the string 209 * @param buf_size the size of buf 210 * @param pix_fmt the number of the pixel format to print the 211 * corresponding info string, or a negative value to print the 212 * corresponding header. 213 */ 214char *av_get_pix_fmt_string (char *buf, int buf_size, enum AVPixelFormat pix_fmt); 215 216/** 217 * Return the number of bits per pixel used by the pixel format 218 * described by pixdesc. Note that this is not the same as the number 219 * of bits per sample. 220 * 221 * The returned number of bits refers to the number of bits actually 222 * used for storing the pixel information, that is padding bits are 223 * not counted. 224 */ 225int av_get_bits_per_pixel(const AVPixFmtDescriptor *pixdesc); 226 227/** 228 * Return the number of bits per pixel for the pixel format 229 * described by pixdesc, including any padding or unused bits. 230 */ 231int av_get_padded_bits_per_pixel(const AVPixFmtDescriptor *pixdesc); 232 233/** 234 * @return a pixel format descriptor for provided pixel format or NULL if 235 * this pixel format is unknown. 236 */ 237const AVPixFmtDescriptor *av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt); 238 239/** 240 * Iterate over all pixel format descriptors known to libavutil. 241 * 242 * @param prev previous descriptor. NULL to get the first descriptor. 243 * 244 * @return next descriptor or NULL after the last descriptor 245 */ 246const AVPixFmtDescriptor *av_pix_fmt_desc_next(const AVPixFmtDescriptor *prev); 247 248/** 249 * @return an AVPixelFormat id described by desc, or AV_PIX_FMT_NONE if desc 250 * is not a valid pointer to a pixel format descriptor. 251 */ 252enum AVPixelFormat av_pix_fmt_desc_get_id(const AVPixFmtDescriptor *desc); 253 254/** 255 * Utility function to access log2_chroma_w log2_chroma_h from 256 * the pixel format AVPixFmtDescriptor. 257 * 258 * See av_get_chroma_sub_sample() for a function that asserts a 259 * valid pixel format instead of returning an error code. 260 * Its recommended that you use avcodec_get_chroma_sub_sample unless 261 * you do check the return code! 262 * 263 * @param[in] pix_fmt the pixel format 264 * @param[out] h_shift store log2_chroma_w 265 * @param[out] v_shift store log2_chroma_h 266 * 267 * @return 0 on success, AVERROR(ENOSYS) on invalid or unknown pixel format 268 */ 269int av_pix_fmt_get_chroma_sub_sample(enum AVPixelFormat pix_fmt, 270 int *h_shift, int *v_shift); 271 272/** 273 * @return number of planes in pix_fmt, a negative AVERROR if pix_fmt is not a 274 * valid pixel format. 275 */ 276int av_pix_fmt_count_planes(enum AVPixelFormat pix_fmt); 277 278void ff_check_pixfmt_descriptors(void); 279 280/** 281 * Utility function to swap the endianness of a pixel format. 282 * 283 * @param[in] pix_fmt the pixel format 284 * 285 * @return pixel format with swapped endianness if it exists, 286 * otherwise AV_PIX_FMT_NONE 287 */ 288enum AVPixelFormat av_pix_fmt_swap_endianness(enum AVPixelFormat pix_fmt); 289 290#define FF_LOSS_RESOLUTION 0x0001 /**< loss due to resolution change */ 291#define FF_LOSS_DEPTH 0x0002 /**< loss due to color depth change */ 292#define FF_LOSS_COLORSPACE 0x0004 /**< loss due to color space conversion */ 293#define FF_LOSS_ALPHA 0x0008 /**< loss of alpha bits */ 294#define FF_LOSS_COLORQUANT 0x0010 /**< loss due to color quantization */ 295#define FF_LOSS_CHROMA 0x0020 /**< loss of chroma (e.g. RGB to gray conversion) */ 296 297/** 298 * Compute what kind of losses will occur when converting from one specific 299 * pixel format to another. 300 * When converting from one pixel format to another, information loss may occur. 301 * For example, when converting from RGB24 to GRAY, the color information will 302 * be lost. Similarly, other losses occur when converting from some formats to 303 * other formats. These losses can involve loss of chroma, but also loss of 304 * resolution, loss of color depth, loss due to the color space conversion, loss 305 * of the alpha bits or loss due to color quantization. 306 * av_get_fix_fmt_loss() informs you about the various types of losses 307 * which will occur when converting from one pixel format to another. 308 * 309 * @param[in] dst_pix_fmt destination pixel format 310 * @param[in] src_pix_fmt source pixel format 311 * @param[in] has_alpha Whether the source pixel format alpha channel is used. 312 * @return Combination of flags informing you what kind of losses will occur 313 * (maximum loss for an invalid dst_pix_fmt). 314 */ 315int av_get_pix_fmt_loss(enum AVPixelFormat dst_pix_fmt, 316 enum AVPixelFormat src_pix_fmt, 317 int has_alpha); 318 319/** 320 * Compute what kind of losses will occur when converting from one specific 321 * pixel format to another. 322 * When converting from one pixel format to another, information loss may occur. 323 * For example, when converting from RGB24 to GRAY, the color information will 324 * be lost. Similarly, other losses occur when converting from some formats to 325 * other formats. These losses can involve loss of chroma, but also loss of 326 * resolution, loss of color depth, loss due to the color space conversion, loss 327 * of the alpha bits or loss due to color quantization. 328 * av_get_fix_fmt_loss() informs you about the various types of losses 329 * which will occur when converting from one pixel format to another. 330 * 331 * @param[in] dst_pix_fmt destination pixel format 332 * @param[in] src_pix_fmt source pixel format 333 * @param[in] has_alpha Whether the source pixel format alpha channel is used. 334 * @return Combination of flags informing you what kind of losses will occur 335 * (maximum loss for an invalid dst_pix_fmt). 336 */ 337enum AVPixelFormat av_find_best_pix_fmt_of_2(enum AVPixelFormat dst_pix_fmt1, enum AVPixelFormat dst_pix_fmt2, 338 enum AVPixelFormat src_pix_fmt, int has_alpha, int *loss_ptr); 339#endif /* AVUTIL_PIXDESC_H */ 340