1 /* 2 * pixel format descriptor 3 * Copyright (c) 2009 Michael Niedermayer <michaelni (at) 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 #include "pixfmt.h" 27 28 typedef struct AVComponentDescriptor{ 29 uint16_t plane :2; ///< which of the 4 planes contains the component 30 31 /** 32 * Number of elements between 2 horizontally consecutive pixels minus 1. 33 * Elements are bits for bitstream formats, bytes otherwise. 34 */ 35 uint16_t step_minus1 :3; 36 37 /** 38 * Number of elements before the component of the first pixel plus 1. 39 * Elements are bits for bitstream formats, bytes otherwise. 40 */ 41 uint16_t offset_plus1 :3; 42 uint16_t shift :3; ///< number of least significant bits that must be shifted away to get the value 43 uint16_t depth_minus1 :4; ///< number of bits in the component minus 1 44 }AVComponentDescriptor; 45 46 /** 47 * Descriptor that unambiguously describes how the bits of a pixel are 48 * stored in the up to 4 data planes of an image. It also stores the 49 * subsampling factors and number of components. 50 * 51 * @note This is separate of the colorspace (RGB, YCbCr, YPbPr, JPEG-style YUV 52 * and all the YUV variants) AVPixFmtDescriptor just stores how values 53 * are stored not what these values represent. 54 */ 55 typedef struct AVPixFmtDescriptor{ 56 const char *name; 57 uint8_t nb_components; ///< The number of components each pixel has, (1-4) 58 59 /** 60 * Amount to shift the luma width right to find the chroma width. 61 * For YV12 this is 1 for example. 62 * chroma_width = -((-luma_width) >> log2_chroma_w) 63 * The note above is needed to ensure rounding up. 64 * This value only refers to the chroma components. 65 */ 66 uint8_t log2_chroma_w; ///< chroma_width = -((-luma_width )>>log2_chroma_w) 67 68 /** 69 * Amount to shift the luma height right to find the chroma height. 70 * For YV12 this is 1 for example. 71 * chroma_height= -((-luma_height) >> log2_chroma_h) 72 * The note above is needed to ensure rounding up. 73 * This value only refers to the chroma components. 74 */ 75 uint8_t log2_chroma_h; 76 uint8_t flags; 77 78 /** 79 * Parameters that describe how pixels are packed. 80 * If the format has 2 or 4 components, then alpha is last. 81 * If the format has 1 or 2 components, then luma is 0. 82 * If the format has 3 or 4 components, 83 * if the RGB flag is set then 0 is red, 1 is green and 2 is blue; 84 * otherwise 0 is luma, 1 is chroma-U and 2 is chroma-V. 85 */ 86 AVComponentDescriptor comp[4]; 87 }AVPixFmtDescriptor; 88 89 /** 90 * Pixel format is big-endian. 91 */ 92 #define AV_PIX_FMT_FLAG_BE (1 << 0) 93 /** 94 * Pixel format has a palette in data[1], values are indexes in this palette. 95 */ 96 #define AV_PIX_FMT_FLAG_PAL (1 << 1) 97 /** 98 * All values of a component are bit-wise packed end to end. 99 */ 100 #define AV_PIX_FMT_FLAG_BITSTREAM (1 << 2) 101 /** 102 * Pixel format is an HW accelerated format. 103 */ 104 #define AV_PIX_FMT_FLAG_HWACCEL (1 << 3) 105 /** 106 * At least one pixel component is not in the first data plane. 107 */ 108 #define AV_PIX_FMT_FLAG_PLANAR (1 << 4) 109 /** 110 * The pixel format contains RGB-like data (as opposed to YUV/grayscale). 111 */ 112 #define AV_PIX_FMT_FLAG_RGB (1 << 5) 113 /** 114 * The pixel format is "pseudo-paletted". This means that FFmpeg treats it as 115 * paletted internally, but the palette is generated by the decoder and is not 116 * stored in the file. 117 */ 118 #define AV_PIX_FMT_FLAG_PSEUDOPAL (1 << 6) 119 /** 120 * The pixel format has an alpha channel. 121 */ 122 #define AV_PIX_FMT_FLAG_ALPHA (1 << 7) 123 124 #if FF_API_PIX_FMT 125 /** 126 * @deprecate use the AV_PIX_FMT_FLAG_* flags 127 */ 128 #define PIX_FMT_BE AV_PIX_FMT_FLAG_BE 129 #define PIX_FMT_PAL AV_PIX_FMT_FLAG_PAL 130 #define PIX_FMT_BITSTREAM AV_PIX_FMT_FLAG_BITSTREAM 131 #define PIX_FMT_HWACCEL AV_PIX_FMT_FLAG_HWACCEL 132 #define PIX_FMT_PLANAR AV_PIX_FMT_FLAG_PLANAR 133 #define PIX_FMT_RGB AV_PIX_FMT_FLAG_RGB 134 #define PIX_FMT_PSEUDOPAL AV_PIX_FMT_FLAG_PSEUDOPAL 135 #define PIX_FMT_ALPHA AV_PIX_FMT_FLAG_ALPHA 136 #endif 137 138 #if FF_API_PIX_FMT_DESC 139 /** 140 * The array of all the pixel format descriptors. 141 */ 142 extern const AVPixFmtDescriptor av_pix_fmt_descriptors[]; 143 #endif 144 145 /** 146 * Read a line from an image, and write the values of the 147 * pixel format component c to dst. 148 * 149 * @param data the array containing the pointers to the planes of the image 150 * @param linesize the array containing the linesizes of the image 151 * @param desc the pixel format descriptor for the image 152 * @param x the horizontal coordinate of the first pixel to read 153 * @param y the vertical coordinate of the first pixel to read 154 * @param w the width of the line to read, that is the number of 155 * values to write to dst 156 * @param read_pal_component if not zero and the format is a paletted 157 * format writes the values corresponding to the palette 158 * component c in data[1] to dst, rather than the palette indexes in 159 * data[0]. The behavior is undefined if the format is not paletted. 160 */ 161 void av_read_image_line(uint16_t *dst, const uint8_t *data[4], const int linesize[4], 162 const AVPixFmtDescriptor *desc, int x, int y, int c, int w, int read_pal_component); 163 164 /** 165 * Write the values from src to the pixel format component c of an 166 * image line. 167 * 168 * @param src array containing the values to write 169 * @param data the array containing the pointers to the planes of the 170 * image to write into. It is supposed to be zeroed. 171 * @param linesize the array containing the linesizes of the image 172 * @param desc the pixel format descriptor for the image 173 * @param x the horizontal coordinate of the first pixel to write 174 * @param y the vertical coordinate of the first pixel to write 175 * @param w the width of the line to write, that is the number of 176 * values to write to the image line 177 */ 178 void av_write_image_line(const uint16_t *src, uint8_t *data[4], const int linesize[4], 179 const AVPixFmtDescriptor *desc, int x, int y, int c, int w); 180 181 /** 182 * Return the pixel format corresponding to name. 183 * 184 * If there is no pixel format with name name, then looks for a 185 * pixel format with the name corresponding to the native endian 186 * format of name. 187 * For example in a little-endian system, first looks for "gray16", 188 * then for "gray16le". 189 * 190 * Finally if no pixel format has been found, returns AV_PIX_FMT_NONE. 191 */ 192 enum AVPixelFormat av_get_pix_fmt(const char *name); 193 194 /** 195 * Return the short name for a pixel format, NULL in case pix_fmt is 196 * unknown. 197 * 198 * @see av_get_pix_fmt(), av_get_pix_fmt_string() 199 */ 200 const char *av_get_pix_fmt_name(enum AVPixelFormat pix_fmt); 201 202 /** 203 * Print in buf the string corresponding to the pixel format with 204 * number pix_fmt, or an header if pix_fmt is negative. 205 * 206 * @param buf the buffer where to write the string 207 * @param buf_size the size of buf 208 * @param pix_fmt the number of the pixel format to print the 209 * corresponding info string, or a negative value to print the 210 * corresponding header. 211 */ 212 char *av_get_pix_fmt_string (char *buf, int buf_size, enum AVPixelFormat pix_fmt); 213 214 /** 215 * Return the number of bits per pixel used by the pixel format 216 * described by pixdesc. Note that this is not the same as the number 217 * of bits per sample. 218 * 219 * The returned number of bits refers to the number of bits actually 220 * used for storing the pixel information, that is padding bits are 221 * not counted. 222 */ 223 int av_get_bits_per_pixel(const AVPixFmtDescriptor *pixdesc); 224 225 /** 226 * Return the number of bits per pixel for the pixel format 227 * described by pixdesc, including any padding or unused bits. 228 */ 229 int av_get_padded_bits_per_pixel(const AVPixFmtDescriptor *pixdesc); 230 231 /** 232 * @return a pixel format descriptor for provided pixel format or NULL if 233 * this pixel format is unknown. 234 */ 235 const AVPixFmtDescriptor *av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt); 236 237 /** 238 * Iterate over all pixel format descriptors known to libavutil. 239 * 240 * @param prev previous descriptor. NULL to get the first descriptor. 241 * 242 * @return next descriptor or NULL after the last descriptor 243 */ 244 const AVPixFmtDescriptor *av_pix_fmt_desc_next(const AVPixFmtDescriptor *prev); 245 246 /** 247 * @return an AVPixelFormat id described by desc, or AV_PIX_FMT_NONE if desc 248 * is not a valid pointer to a pixel format descriptor. 249 */ 250 enum AVPixelFormat av_pix_fmt_desc_get_id(const AVPixFmtDescriptor *desc); 251 252 /** 253 * Utility function to access log2_chroma_w log2_chroma_h from 254 * the pixel format AVPixFmtDescriptor. 255 * 256 * See avcodec_get_chroma_sub_sample() for a function that asserts a 257 * valid pixel format instead of returning an error code. 258 * Its recommanded that you use avcodec_get_chroma_sub_sample unless 259 * you do check the return code! 260 * 261 * @param[in] pix_fmt the pixel format 262 * @param[out] h_shift store log2_chroma_w 263 * @param[out] v_shift store log2_chroma_h 264 * 265 * @return 0 on success, AVERROR(ENOSYS) on invalid or unknown pixel format 266 */ 267 int av_pix_fmt_get_chroma_sub_sample(enum AVPixelFormat pix_fmt, 268 int *h_shift, int *v_shift); 269 270 /** 271 * @return number of planes in pix_fmt, a negative AVERROR if pix_fmt is not a 272 * valid pixel format. 273 */ 274 int av_pix_fmt_count_planes(enum AVPixelFormat pix_fmt); 275 276 void ff_check_pixfmt_descriptors(void); 277 278 /** 279 * Utility function to swap the endianness of a pixel format. 280 * 281 * @param[in] pix_fmt the pixel format 282 * 283 * @return pixel format with swapped endianness if it exists, 284 * otherwise AV_PIX_FMT_NONE 285 */ 286 enum AVPixelFormat av_pix_fmt_swap_endianness(enum AVPixelFormat pix_fmt); 287 288 289 #endif /* AVUTIL_PIXDESC_H */ 290
