pixdesc.h (7031B)
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 #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. If the format 80 * has chroma components, they must be stored in comp[1] and 81 * comp[2]. 82 */ 83 AVComponentDescriptor comp[4]; 84 }AVPixFmtDescriptor; 85 86 #define PIX_FMT_BE 1 ///< Pixel format is big-endian. 87 #define PIX_FMT_PAL 2 ///< Pixel format has a palette in data[1], values are indexes in this palette. 88 #define PIX_FMT_BITSTREAM 4 ///< All values of a component are bit-wise packed end to end. 89 #define PIX_FMT_HWACCEL 8 ///< Pixel format is an HW accelerated format. 90 #define PIX_FMT_PLANAR 16 ///< At least one pixel component is not in the first data plane 91 #define PIX_FMT_RGB 32 ///< The pixel format contains RGB-like data (as opposed to YUV/grayscale) 92 93 /** 94 * The array of all the pixel format descriptors. 95 */ 96 extern const AVPixFmtDescriptor av_pix_fmt_descriptors[]; 97 98 /** 99 * Read a line from an image, and write the values of the 100 * pixel format component c to dst. 101 * 102 * @param data the array containing the pointers to the planes of the image 103 * @param linesize the array containing the linesizes of the image 104 * @param desc the pixel format descriptor for the image 105 * @param x the horizontal coordinate of the first pixel to read 106 * @param y the vertical coordinate of the first pixel to read 107 * @param w the width of the line to read, that is the number of 108 * values to write to dst 109 * @param read_pal_component if not zero and the format is a paletted 110 * format writes the values corresponding to the palette 111 * component c in data[1] to dst, rather than the palette indexes in 112 * data[0]. The behavior is undefined if the format is not paletted. 113 */ 114 void av_read_image_line(uint16_t *dst, const uint8_t *data[4], const int linesize[4], 115 const AVPixFmtDescriptor *desc, int x, int y, int c, int w, int read_pal_component); 116 117 /** 118 * Write the values from src to the pixel format component c of an 119 * image line. 120 * 121 * @param src array containing the values to write 122 * @param data the array containing the pointers to the planes of the 123 * image to write into. It is supposed to be zeroed. 124 * @param linesize the array containing the linesizes of the image 125 * @param desc the pixel format descriptor for the image 126 * @param x the horizontal coordinate of the first pixel to write 127 * @param y the vertical coordinate of the first pixel to write 128 * @param w the width of the line to write, that is the number of 129 * values to write to the image line 130 */ 131 void av_write_image_line(const uint16_t *src, uint8_t *data[4], const int linesize[4], 132 const AVPixFmtDescriptor *desc, int x, int y, int c, int w); 133 134 /** 135 * Return the pixel format corresponding to name. 136 * 137 * If there is no pixel format with name name, then looks for a 138 * pixel format with the name corresponding to the native endian 139 * format of name. 140 * For example in a little-endian system, first looks for "gray16", 141 * then for "gray16le". 142 * 143 * Finally if no pixel format has been found, returns PIX_FMT_NONE. 144 */ 145 enum PixelFormat av_get_pix_fmt(const char *name); 146 147 /** 148 * Return the short name for a pixel format, NULL in case pix_fmt is 149 * unknown. 150 * 151 * @see av_get_pix_fmt(), av_get_pix_fmt_string() 152 */ 153 const char *av_get_pix_fmt_name(enum PixelFormat pix_fmt); 154 155 /** 156 * Print in buf the string corresponding to the pixel format with 157 * number pix_fmt, or an header if pix_fmt is negative. 158 * 159 * @param buf the buffer where to write the string 160 * @param buf_size the size of buf 161 * @param pix_fmt the number of the pixel format to print the 162 * corresponding info string, or a negative value to print the 163 * corresponding header. 164 */ 165 char *av_get_pix_fmt_string (char *buf, int buf_size, enum PixelFormat pix_fmt); 166 167 /** 168 * Return the number of bits per pixel used by the pixel format 169 * described by pixdesc. 170 * 171 * The returned number of bits refers to the number of bits actually 172 * used for storing the pixel information, that is padding bits are 173 * not counted. 174 */ 175 int av_get_bits_per_pixel(const AVPixFmtDescriptor *pixdesc); 176 177 #endif /* AVUTIL_PIXDESC_H */