libavutil/pixdesc.h

   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  * The pixel format contains XYZ-like data (as opposed to YUV/RGB/grayscale).
 162  */
 163 #define AV_PIX_FMT_FLAG_XYZ          (1 << 10)
 164
 165 /**
 166  * Return the number of bits per pixel used by the pixel format
 167  * described by pixdesc. Note that this is not the same as the number
 168  * of bits per sample.
 169  *
 170  * The returned number of bits refers to the number of bits actually
 171  * used for storing the pixel information, that is padding bits are
 172  * not counted.
 173  */
 174 int av_get_bits_per_pixel(const AVPixFmtDescriptor *pixdesc);
 175
 176 /**
 177  * Return the number of bits per pixel for the pixel format
 178  * described by pixdesc, including any padding or unused bits.
 179  */
 180 int av_get_padded_bits_per_pixel(const AVPixFmtDescriptor *pixdesc);
 181
 182 /**
 183  * @return a pixel format descriptor for provided pixel format or NULL if
 184  * this pixel format is unknown.
 185  */
 186 const AVPixFmtDescriptor *av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt);
 187
 188 /**
 189  * Iterate over all pixel format descriptors known to libavutil.
 190  *
 191  * @param prev previous descriptor. NULL to get the first descriptor.
 192  *
 193  * @return next descriptor or NULL after the last descriptor
 194  */
 195 const AVPixFmtDescriptor *av_pix_fmt_desc_next(const AVPixFmtDescriptor *prev);
 196
 197 /**
 198  * @return an AVPixelFormat id described by desc, or AV_PIX_FMT_NONE if desc
 199  * is not a valid pointer to a pixel format descriptor.
 200  */
 201 enum AVPixelFormat av_pix_fmt_desc_get_id(const AVPixFmtDescriptor *desc);
 202
 203 /**
 204  * Utility function to access log2_chroma_w log2_chroma_h from
 205  * the pixel format AVPixFmtDescriptor.
 206  *
 207  * @param[in]  pix_fmt the pixel format
 208  * @param[out] h_shift store log2_chroma_w (horizontal/width shift)
 209  * @param[out] v_shift store log2_chroma_h (vertical/height shift)
 210  *
 211  * @return 0 on success, AVERROR(ENOSYS) on invalid or unknown pixel format
 212  */
 213 int av_pix_fmt_get_chroma_sub_sample(enum AVPixelFormat pix_fmt,
 214                                      int *h_shift, int *v_shift);
 215
 216 /**
 217  * @return number of planes in pix_fmt, a negative AVERROR if pix_fmt is not a
 218  * valid pixel format.
 219  */
 220 int av_pix_fmt_count_planes(enum AVPixelFormat pix_fmt);
 221
 222 /**
 223  * @return the name for provided color range or NULL if unknown.
 224  */
 225 const char *av_color_range_name(enum AVColorRange range);
 226
 227 /**
 228  * @return the AVColorRange value for name or an AVError if not found.
 229  */
 230 int av_color_range_from_name(const char *name);
 231
 232 /**
 233  * @return the name for provided color primaries or NULL if unknown.
 234  */
 235 const char *av_color_primaries_name(enum AVColorPrimaries primaries);
 236
 237 /**
 238  * @return the AVColorPrimaries value for name or an AVError if not found.
 239  */
 240 int av_color_primaries_from_name(const char *name);
 241
 242 /**
 243  * @return the name for provided color transfer or NULL if unknown.
 244  */
 245 const char *av_color_transfer_name(enum AVColorTransferCharacteristic transfer);
 246
 247 /**
 248  * @return the AVColorTransferCharacteristic value for name or an AVError if not found.
 249  */
 250 int av_color_transfer_from_name(const char *name);
 251
 252 /**
 253  * @return the name for provided color space or NULL if unknown.
 254  */
 255 const char *av_color_space_name(enum AVColorSpace space);
 256
 257 /**
 258  * @return the AVColorSpace value for name or an AVError if not found.
 259  */
 260 int av_color_space_from_name(const char *name);
 261
 262 /**
 263  * @return the name for provided chroma location or NULL if unknown.
 264  */
 265 const char *av_chroma_location_name(enum AVChromaLocation location);
 266
 267 /**
 268  * @return the AVChromaLocation value for name or an AVError if not found.
 269  */
 270 int av_chroma_location_from_name(const char *name);
 271
 272 /**
 273  * Converts AVChromaLocation to swscale x/y chroma position.
 274  *
 275  * The positions represent the chroma (0,0) position in a coordinates system
 276  * with luma (0,0) representing the origin and luma(1,1) representing 256,256
 277  *
 278  * @param xpos  horizontal chroma sample position
 279  * @param ypos  vertical   chroma sample position
 280  */
 281 int av_chroma_location_enum_to_pos(int *xpos, int *ypos, enum AVChromaLocation pos);
 282
 283 /**
 284  * Converts swscale x/y chroma position to AVChromaLocation.
 285  *
 286  * The positions represent the chroma (0,0) position in a coordinates system
 287  * with luma (0,0) representing the origin and luma(1,1) representing 256,256
 288  *
 289  * @param xpos  horizontal chroma sample position
 290  * @param ypos  vertical   chroma sample position
 291  */
 292 enum AVChromaLocation av_chroma_location_pos_to_enum(int xpos, int ypos);
 293
 294 /**
 295  * Return the pixel format corresponding to name.
 296  *
 297  * If there is no pixel format with name name, then looks for a
 298  * pixel format with the name corresponding to the native endian
 299  * format of name.
 300  * For example in a little-endian system, first looks for "gray16",
 301  * then for "gray16le".
 302  *
 303  * Finally if no pixel format has been found, returns AV_PIX_FMT_NONE.
 304  */
 305 enum AVPixelFormat av_get_pix_fmt(const char *name);
 306
 307 /**
 308  * Return the short name for a pixel format, NULL in case pix_fmt is
 309  * unknown.
 310  *
 311  * @see av_get_pix_fmt(), av_get_pix_fmt_string()
 312  */
 313 const char *av_get_pix_fmt_name(enum AVPixelFormat pix_fmt);
 314
 315 /**
 316  * Print in buf the string corresponding to the pixel format with
 317  * number pix_fmt, or a header if pix_fmt is negative.
 318  *
 319  * @param buf the buffer where to write the string
 320  * @param buf_size the size of buf
 321  * @param pix_fmt the number of the pixel format to print the
 322  * corresponding info string, or a negative value to print the
 323  * corresponding header.
 324  */
 325 char *av_get_pix_fmt_string(char *buf, int buf_size,
 326                             enum AVPixelFormat pix_fmt);
 327
 328 /**
 329  * Read a line from an image, and write the values of the
 330  * pixel format component c to dst.
 331  *
 332  * @param data the array containing the pointers to the planes of the image
 333  * @param linesize the array containing the linesizes of the image
 334  * @param desc the pixel format descriptor for the image
 335  * @param x the horizontal coordinate of the first pixel to read
 336  * @param y the vertical coordinate of the first pixel to read
 337  * @param w the width of the line to read, that is the number of
 338  * values to write to dst
 339  * @param read_pal_component if not zero and the format is a paletted
 340  * format writes the values corresponding to the palette
 341  * component c in data[1] to dst, rather than the palette indexes in
 342  * data[0]. The behavior is undefined if the format is not paletted.
 343  * @param dst_element_size size of elements in dst array (2 or 4 byte)
 344  */
 345 void av_read_image_line2(void *dst, const uint8_t *data[4],
 346                         const int linesize[4], const AVPixFmtDescriptor *desc,
 347                         int x, int y, int c, int w, int read_pal_component,
 348                         int dst_element_size);
 349
 350 void av_read_image_line(uint16_t *dst, const uint8_t *data[4],
 351                         const int linesize[4], const AVPixFmtDescriptor *desc,
 352                         int x, int y, int c, int w, int read_pal_component);
 353
 354 /**
 355  * Write the values from src to the pixel format component c of an
 356  * image line.
 357  *
 358  * @param src array containing the values to write
 359  * @param data the array containing the pointers to the planes of the
 360  * image to write into. It is supposed to be zeroed.
 361  * @param linesize the array containing the linesizes of the image
 362  * @param desc the pixel format descriptor for the image
 363  * @param x the horizontal coordinate of the first pixel to write
 364  * @param y the vertical coordinate of the first pixel to write
 365  * @param w the width of the line to write, that is the number of
 366  * values to write to the image line
 367  * @param src_element_size size of elements in src array (2 or 4 byte)
 368  */
 369 void av_write_image_line2(const void *src, uint8_t *data[4],
 370                          const int linesize[4], const AVPixFmtDescriptor *desc,
 371                          int x, int y, int c, int w, int src_element_size);
 372
 373 void av_write_image_line(const uint16_t *src, uint8_t *data[4],
 374                          const int linesize[4], const AVPixFmtDescriptor *desc,
 375                          int x, int y, int c, int w);
 376
 377 /**
 378  * Utility function to swap the endianness of a pixel format.
 379  *
 380  * @param[in]  pix_fmt the pixel format
 381  *
 382  * @return pixel format with swapped endianness if it exists,
 383  * otherwise AV_PIX_FMT_NONE
 384  */
 385 enum AVPixelFormat av_pix_fmt_swap_endianness(enum AVPixelFormat pix_fmt);
 386
 387 #define FF_LOSS_RESOLUTION        0x0001 /**< loss due to resolution change */
 388 #define FF_LOSS_DEPTH             0x0002 /**< loss due to color depth change */
 389 #define FF_LOSS_COLORSPACE        0x0004 /**< loss due to color space conversion */
 390 #define FF_LOSS_ALPHA             0x0008 /**< loss of alpha bits */
 391 #define FF_LOSS_COLORQUANT        0x0010 /**< loss due to color quantization */
 392 #define FF_LOSS_CHROMA            0x0020 /**< loss of chroma (e.g. RGB to gray conversion) */
 393 #define FF_LOSS_EXCESS_RESOLUTION 0x0040 /**< loss due to unneeded extra resolution */
 394 #define FF_LOSS_EXCESS_DEPTH      0x0080 /**< loss due to unneeded extra color depth */
 395
 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 */