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