pixdesc.h 6.9 KB

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  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. #ifndef AVUTIL_PIXDESC_H
  22. #define AVUTIL_PIXDESC_H
  23. #include <inttypes.h>
  24. #include "pixfmt.h"
  25. typedef struct AVComponentDescriptor{
  26. uint16_t plane :2; ///< which of the 4 planes contains the component
  27. /**
  28. * Number of elements between 2 horizontally consecutive pixels minus 1.
  29. * Elements are bits for bitstream formats, bytes otherwise.
  30. */
  31. uint16_t step_minus1 :3;
  32. /**
  33. * Number of elements before the component of the first pixel plus 1.
  34. * Elements are bits for bitstream formats, bytes otherwise.
  35. */
  36. uint16_t offset_plus1 :3;
  37. uint16_t shift :3; ///< number of least significant bits that must be shifted away to get the value
  38. uint16_t depth_minus1 :4; ///< number of bits in the component minus 1
  39. }AVComponentDescriptor;
  40. /**
  41. * Descriptor that unambiguously describes how the bits of a pixel are
  42. * stored in the up to 4 data planes of an image. It also stores the
  43. * subsampling factors and number of components.
  44. *
  45. * @note This is separate of the colorspace (RGB, YCbCr, YPbPr, JPEG-style YUV
  46. * and all the YUV variants) AVPixFmtDescriptor just stores how values
  47. * are stored not what these values represent.
  48. */
  49. typedef struct AVPixFmtDescriptor{
  50. const char *name;
  51. uint8_t nb_components; ///< The number of components each pixel has, (1-4)
  52. /**
  53. * Amount to shift the luma width right to find the chroma width.
  54. * For YV12 this is 1 for example.
  55. * chroma_width = -((-luma_width) >> log2_chroma_w)
  56. * The note above is needed to ensure rounding up.
  57. * This value only refers to the chroma components.
  58. */
  59. uint8_t log2_chroma_w; ///< chroma_width = -((-luma_width )>>log2_chroma_w)
  60. /**
  61. * Amount to shift the luma height right to find the chroma height.
  62. * For YV12 this is 1 for example.
  63. * chroma_height= -((-luma_height) >> log2_chroma_h)
  64. * The note above is needed to ensure rounding up.
  65. * This value only refers to the chroma components.
  66. */
  67. uint8_t log2_chroma_h;
  68. uint8_t flags;
  69. /**
  70. * Parameters that describe how pixels are packed. If the format
  71. * has chroma components, they must be stored in comp[1] and
  72. * comp[2].
  73. */
  74. AVComponentDescriptor comp[4];
  75. }AVPixFmtDescriptor;
  76. #define PIX_FMT_BE 1 ///< Pixel format is big-endian.
  77. #define PIX_FMT_PAL 2 ///< Pixel format has a palette in data[1], values are indexes in this palette.
  78. #define PIX_FMT_BITSTREAM 4 ///< All values of a component are bit-wise packed end to end.
  79. #define PIX_FMT_HWACCEL 8 ///< Pixel format is an HW accelerated format.
  80. #define PIX_FMT_PLANAR 16 ///< At least one pixel component is not in the first data plane
  81. #define PIX_FMT_RGB 32 ///< The pixel format contains RGB-like data (as opposed to YUV/grayscale)
  82. /**
  83. * The array of all the pixel format descriptors.
  84. */
  85. extern const AVPixFmtDescriptor av_pix_fmt_descriptors[];
  86. /**
  87. * Read a line from an image, and write the values of the
  88. * pixel format component c to dst.
  89. *
  90. * @param data the array containing the pointers to the planes of the image
  91. * @param linesize the array containing the linesizes of the image
  92. * @param desc the pixel format descriptor for the image
  93. * @param x the horizontal coordinate of the first pixel to read
  94. * @param y the vertical coordinate of the first pixel to read
  95. * @param w the width of the line to read, that is the number of
  96. * values to write to dst
  97. * @param read_pal_component if not zero and the format is a paletted
  98. * format writes the values corresponding to the palette
  99. * component c in data[1] to dst, rather than the palette indexes in
  100. * data[0]. The behavior is undefined if the format is not paletted.
  101. */
  102. void av_read_image_line(uint16_t *dst, const uint8_t *data[4], const int linesize[4],
  103. const AVPixFmtDescriptor *desc, int x, int y, int c, int w, int read_pal_component);
  104. /**
  105. * Write the values from src to the pixel format component c of an
  106. * image line.
  107. *
  108. * @param src array containing the values to write
  109. * @param data the array containing the pointers to the planes of the
  110. * image to write into. It is supposed to be zeroed.
  111. * @param linesize the array containing the linesizes of the image
  112. * @param desc the pixel format descriptor for the image
  113. * @param x the horizontal coordinate of the first pixel to write
  114. * @param y the vertical coordinate of the first pixel to write
  115. * @param w the width of the line to write, that is the number of
  116. * values to write to the image line
  117. */
  118. void av_write_image_line(const uint16_t *src, uint8_t *data[4], const int linesize[4],
  119. const AVPixFmtDescriptor *desc, int x, int y, int c, int w);
  120. /**
  121. * Return the pixel format corresponding to name.
  122. *
  123. * If there is no pixel format with name name, then looks for a
  124. * pixel format with the name corresponding to the native endian
  125. * format of name.
  126. * For example in a little-endian system, first looks for "gray16",
  127. * then for "gray16le".
  128. *
  129. * Finally if no pixel format has been found, returns PIX_FMT_NONE.
  130. */
  131. enum PixelFormat av_get_pix_fmt(const char *name);
  132. /**
  133. * Return the short name for a pixel format, NULL in case pix_fmt is
  134. * unknown.
  135. *
  136. * @see av_get_pix_fmt(), av_get_pix_fmt_string()
  137. */
  138. const char *av_get_pix_fmt_name(enum PixelFormat pix_fmt);
  139. /**
  140. * Print in buf the string corresponding to the pixel format with
  141. * number pix_fmt, or an header if pix_fmt is negative.
  142. *
  143. * @param buf the buffer where to write the string
  144. * @param buf_size the size of buf
  145. * @param pix_fmt the number of the pixel format to print the
  146. * corresponding info string, or a negative value to print the
  147. * corresponding header.
  148. */
  149. char *av_get_pix_fmt_string (char *buf, int buf_size, enum PixelFormat pix_fmt);
  150. /**
  151. * Return the number of bits per pixel used by the pixel format
  152. * described by pixdesc.
  153. *
  154. * The returned number of bits refers to the number of bits actually
  155. * used for storing the pixel information, that is padding bits are
  156. * not counted.
  157. */
  158. int av_get_bits_per_pixel(const AVPixFmtDescriptor *pixdesc);
  159. #endif /* AVUTIL_PIXDESC_H */