libavutil/pixdesc.h

   1 /*
   2  * pixel format descriptor
   3  * Copyright (c) 2009 Michael Niedermayer <michaelni@gmx.at>
   4  *
   5  * This file is part of Libav.
   6  *
   7  * Libav 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  * Libav 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 Libav; 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
  59 #if FF_API_PLUS1_MINUS1
  60     /** deprecated, use step instead */
  61     attribute_deprecated int step_minus1;
  62
  63     /** deprecated, use depth instead */
  64     attribute_deprecated int depth_minus1;
  65
  66     /** deprecated, use offset instead */
  67     attribute_deprecated int offset_plus1;
  68 #endif
  69 } AVComponentDescriptor;
  70
  71 /**
  72  * Descriptor that unambiguously describes how the bits of a pixel are
  73  * stored in the up to 4 data planes of an image. It also stores the
  74  * subsampling factors and number of components.
  75  *
  76  * @note This is separate of the colorspace (RGB, YCbCr, YPbPr, JPEG-style YUV
  77  *       and all the YUV variants) AVPixFmtDescriptor just stores how values
  78  *       are stored not what these values represent.
  79  */
  80 typedef struct AVPixFmtDescriptor {
  81     const char *name;
  82     uint8_t nb_components;  ///< The number of components each pixel has, (1-4)
  83
  84     /**
  85      * Amount to shift the luma width right to find the chroma width.
  86      * For YV12 this is 1 for example.
  87      * chroma_width = AV_CEIL_RSHIFT(luma_width, log2_chroma_w)
  88      * The note above is needed to ensure rounding up.
  89      * This value only refers to the chroma components.
  90      */
  91     uint8_t log2_chroma_w;
  92
  93     /**
  94      * Amount to shift the luma height right to find the chroma height.
  95      * For YV12 this is 1 for example.
  96      * chroma_height= AV_CEIL_RSHIFT(luma_height, log2_chroma_h)
  97      * The note above is needed to ensure rounding up.
  98      * This value only refers to the chroma components.
  99      */
 100     uint8_t log2_chroma_h;
 101
 102     /**
 103      * Combination of AV_PIX_FMT_FLAG_... flags.
 104      */
 105     uint64_t flags;
 106
 107     /**
 108      * Parameters that describe how pixels are packed. If the format
 109      * has chroma components, they must be stored in comp[1] and
 110      * comp[2].
 111      * If the format is RGB-like, the first component is R, followed
 112      * by G and B.
 113      *
 114      * If the format is YUV-like, the first component is Y, followed
 115      * by U and V.
 116      *
 117      * If present, the Alpha channel is always the last component.
 118      */
 119     AVComponentDescriptor comp[4];
 120
 121     /**
 122      * Alternative comma-separated names.
 123      */
 124     const char *alias;
 125 } AVPixFmtDescriptor;
 126
 127 /**
 128  * Pixel format is big-endian.
 129  */
 130 #define AV_PIX_FMT_FLAG_BE           (1 << 0)
 131 /**
 132  * Pixel format has a palette in data[1], values are indexes in this palette.
 133  */
 134 #define AV_PIX_FMT_FLAG_PAL          (1 << 1)
 135 /**
 136  * All values of a component are bit-wise packed end to end.
 137  */
 138 #define AV_PIX_FMT_FLAG_BITSTREAM    (1 << 2)
 139 /**
 140  * Pixel format is an HW accelerated format.
 141  */
 142 #define AV_PIX_FMT_FLAG_HWACCEL      (1 << 3)
 143 /**
 144  * At least one pixel component is not in the first data plane.
 145  */
 146 #define AV_PIX_FMT_FLAG_PLANAR       (1 << 4)
 147 /**
 148  * The pixel format contains RGB-like data (as opposed to YUV/grayscale).
 149  */
 150 #define AV_PIX_FMT_FLAG_RGB          (1 << 5)
 151 /**
 152  * The pixel format is "pseudo-paletted". This means that Libav treats it as
 153  * paletted internally, but the palette is generated by the decoder and is not
 154  * stored in the file.
 155  */
 156 #define AV_PIX_FMT_FLAG_PSEUDOPAL    (1 << 6)
 157 /**
 158  * The pixel format has an alpha channel.
 159  */
 160 #define AV_PIX_FMT_FLAG_ALPHA        (1 << 7)
 161
 162 /**
 163  * Read a line from an image, and write the values of the
 164  * pixel format component c to dst.
 165  *
 166  * @param data the array containing the pointers to the planes of the image
 167  * @param linesize the array containing the linesizes of the image
 168  * @param desc the pixel format descriptor for the image
 169  * @param x the horizontal coordinate of the first pixel to read
 170  * @param y the vertical coordinate of the first pixel to read
 171  * @param w the width of the line to read, that is the number of
 172  * values to write to dst
 173  * @param read_pal_component if not zero and the format is a paletted
 174  * format writes the values corresponding to the palette
 175  * component c in data[1] to dst, rather than the palette indexes in
 176  * data[0]. The behavior is undefined if the format is not paletted.
 177  */
 178 void av_read_image_line(uint16_t *dst, const uint8_t *data[4],
 179                         const int linesize[4], const AVPixFmtDescriptor *desc,
 180                         int x, int y, int c, int w, int read_pal_component);
 181
 182 /**
 183  * Write the values from src to the pixel format component c of an
 184  * image line.
 185  *
 186  * @param src array containing the values to write
 187  * @param data the array containing the pointers to the planes of the
 188  * image to write into. It is supposed to be zeroed.
 189  * @param linesize the array containing the linesizes of the image
 190  * @param desc the pixel format descriptor for the image
 191  * @param x the horizontal coordinate of the first pixel to write
 192  * @param y the vertical coordinate of the first pixel to write
 193  * @param w the width of the line to write, that is the number of
 194  * values to write to the image line
 195  */
 196 void av_write_image_line(const uint16_t *src, uint8_t *data[4],
 197                          const int linesize[4], const AVPixFmtDescriptor *desc,
 198                          int x, int y, int c, int w);
 199
 200 /**
 201  * Return the pixel format corresponding to name.
 202  *
 203  * If there is no pixel format with name name, then looks for a
 204  * pixel format with the name corresponding to the native endian
 205  * format of name.
 206  * For example in a little-endian system, first looks for "gray16",
 207  * then for "gray16le".
 208  *
 209  * Finally if no pixel format has been found, returns PIX_FMT_NONE.
 210  */
 211 enum AVPixelFormat av_get_pix_fmt(const char *name);
 212
 213 /**
 214  * Return the short name for a pixel format, NULL in case pix_fmt is
 215  * unknown.
 216  *
 217  * @see av_get_pix_fmt(), av_get_pix_fmt_string()
 218  */
 219 const char *av_get_pix_fmt_name(enum AVPixelFormat pix_fmt);
 220
 221 /**
 222  * Print in buf the string corresponding to the pixel format with
 223  * number pix_fmt, or an header if pix_fmt is negative.
 224  *
 225  * @param buf the buffer where to write the string
 226  * @param buf_size the size of buf
 227  * @param pix_fmt the number of the pixel format to print the
 228  * corresponding info string, or a negative value to print the
 229  * corresponding header.
 230  */
 231 char *av_get_pix_fmt_string(char *buf, int buf_size,
 232                             enum AVPixelFormat pix_fmt);
 233
 234 /**
 235  * Return the number of bits per pixel used by the pixel format
 236  * described by pixdesc. Note that this is not the same as the number
 237  * of bits per sample.
 238  *
 239  * The returned number of bits refers to the number of bits actually
 240  * used for storing the pixel information, that is padding bits are
 241  * not counted.
 242  */
 243 int av_get_bits_per_pixel(const AVPixFmtDescriptor *pixdesc);
 244
 245 /**
 246  * @return a pixel format descriptor for provided pixel format or NULL if
 247  * this pixel format is unknown.
 248  */
 249 const AVPixFmtDescriptor *av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt);
 250
 251 /**
 252  * Iterate over all pixel format descriptors known to libavutil.
 253  *
 254  * @param prev previous descriptor. NULL to get the first descriptor.
 255  *
 256  * @return next descriptor or NULL after the last descriptor
 257  */
 258 const AVPixFmtDescriptor *av_pix_fmt_desc_next(const AVPixFmtDescriptor *prev);
 259
 260 /**
 261  * @return an AVPixelFormat id described by desc, or AV_PIX_FMT_NONE if desc
 262  * is not a valid pointer to a pixel format descriptor.
 263  */
 264 enum AVPixelFormat av_pix_fmt_desc_get_id(const AVPixFmtDescriptor *desc);
 265
 266 /**
 267  * Utility function to access log2_chroma_w log2_chroma_h from
 268  * the pixel format AVPixFmtDescriptor.
 269  *
 270  * @param[in]  pix_fmt the pixel format
 271  * @param[out] h_shift store log2_chroma_w (horizontal/width shift)
 272  * @param[out] v_shift store log2_chroma_h (vertical/height shift)
 273  *
 274  * @return 0 on success, AVERROR(ENOSYS) on invalid or unknown pixel format
 275  */
 276 int av_pix_fmt_get_chroma_sub_sample(enum AVPixelFormat pix_fmt,
 277                                      int *h_shift, int *v_shift);
 278
 279 /**
 280  * @return number of planes in pix_fmt, a negative AVERROR if pix_fmt is not a
 281  * valid pixel format.
 282  */
 283 int av_pix_fmt_count_planes(enum AVPixelFormat pix_fmt);
 284
 285 /**
 286  * Utility function to swap the endianness of a pixel format.
 287  *
 288  * @param[in]  pix_fmt the pixel format
 289  *
 290  * @return pixel format with swapped endianness if it exists,
 291  * otherwise AV_PIX_FMT_NONE
 292  */
 293 enum AVPixelFormat av_pix_fmt_swap_endianness(enum AVPixelFormat pix_fmt);
 294
 295 /**
 296  * @return the name for provided color range or NULL if unknown.
 297  */
 298 const char *av_color_range_name(enum AVColorRange range);
 299
 300 /**
 301  * @return the name for provided color primaries or NULL if unknown.
 302  */
 303 const char *av_color_primaries_name(enum AVColorPrimaries primaries);
 304
 305 /**
 306  * @return the name for provided color transfer or NULL if unknown.
 307  */
 308 const char *av_color_transfer_name(enum AVColorTransferCharacteristic transfer);
 309
 310 /**
 311  * @return the name for provided color space or NULL if unknown.
 312  */
 313 const char *av_color_space_name(enum AVColorSpace space);
 314
 315 /**
 316  * @return the name for provided chroma location or NULL if unknown.
 317  */
 318 const char *av_chroma_location_name(enum AVChromaLocation location);
 319
 320 #endif /* AVUTIL_PIXDESC_H */