2134
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1 /*
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2 * pixel format descriptor
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3 * Copyright (c) 2009 Michael Niedermayer <michaelni@gmx.at>
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4 *
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5 * This file is part of FFmpeg.
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6 *
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7 * FFmpeg is free software; you can redistribute it and/or
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8 * modify it under the terms of the GNU Lesser General Public
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9 * License as published by the Free Software Foundation; either
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10 * version 2.1 of the License, or (at your option) any later version.
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11 *
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12 * FFmpeg is distributed in the hope that it will be useful,
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13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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15 * Lesser General Public License for more details.
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16 *
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17 * You should have received a copy of the GNU Lesser General Public
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18 * License along with FFmpeg; if not, write to the Free Software
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19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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20 */
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21
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22 #ifndef AVUTIL_PIXDESC_H
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23 #define AVUTIL_PIXDESC_H
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24
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25 #include <stdint.h>
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26 #include "pixfmt.h"
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27
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28 typedef struct AVComponentDescriptor{
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29 uint16_t plane :2; ///< which of the 4 planes contains the component
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30
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31 /**
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32 * Number of elements between 2 horizontally consecutive pixels minus 1.
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33 * Elements are bits for bitstream formats, bytes otherwise.
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34 */
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35 uint16_t step_minus1 :3;
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36
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37 /**
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38 * Number of elements before the component of the first pixel plus 1.
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39 * Elements are bits for bitstream formats, bytes otherwise.
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40 */
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41 uint16_t offset_plus1 :3;
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42 uint16_t shift :3; ///< number of least significant bits that must be shifted away to get the value
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43 uint16_t depth_minus1 :4; ///< number of bits in the component minus 1
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44 }AVComponentDescriptor;
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45
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46 /**
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47 * Descriptor that unambiguously describes how the bits of a pixel are
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48 * stored in the up to 4 data planes of an image. It also stores the
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49 * subsampling factors and number of components.
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50 *
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51 * @note This is separate of the colorspace (RGB, YCbCr, YPbPr, JPEG-style YUV
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52 * and all the YUV variants) AVPixFmtDescriptor just stores how values
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53 * are stored not what these values represent.
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54 */
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55 typedef struct AVPixFmtDescriptor{
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56 const char *name;
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57 uint8_t nb_components; ///< The number of components each pixel has, (1-4)
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58
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59 /**
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60 * Amount to shift the luma width right to find the chroma width.
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61 * For YV12 this is 1 for example.
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62 * chroma_width = -((-luma_width) >> log2_chroma_w)
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63 * The note above is needed to ensure rounding up.
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64 * This value only refers to the chroma components.
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65 */
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66 uint8_t log2_chroma_w; ///< chroma_width = -((-luma_width )>>log2_chroma_w)
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67
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68 /**
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69 * Amount to shift the luma height right to find the chroma height.
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70 * For YV12 this is 1 for example.
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71 * chroma_height= -((-luma_height) >> log2_chroma_h)
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72 * The note above is needed to ensure rounding up.
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73 * This value only refers to the chroma components.
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74 */
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75 uint8_t log2_chroma_h;
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76 uint8_t flags;
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77
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78 /**
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79 * Parameters that describe how pixels are packed.
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80 * If the format has 2 or 4 components, then alpha is last.
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81 * If the format has 1 or 2 components, then luma is 0.
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82 * If the format has 3 or 4 components,
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83 * if the RGB flag is set then 0 is red, 1 is green and 2 is blue;
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84 * otherwise 0 is luma, 1 is chroma-U and 2 is chroma-V.
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85 */
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86 AVComponentDescriptor comp[4];
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87 }AVPixFmtDescriptor;
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88
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89 /**
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90 * Pixel format is big-endian.
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91 */
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92 #define AV_PIX_FMT_FLAG_BE (1 << 0)
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93 /**
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94 * Pixel format has a palette in data[1], values are indexes in this palette.
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95 */
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96 #define AV_PIX_FMT_FLAG_PAL (1 << 1)
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97 /**
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98 * All values of a component are bit-wise packed end to end.
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99 */
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100 #define AV_PIX_FMT_FLAG_BITSTREAM (1 << 2)
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101 /**
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102 * Pixel format is an HW accelerated format.
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103 */
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104 #define AV_PIX_FMT_FLAG_HWACCEL (1 << 3)
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105 /**
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106 * At least one pixel component is not in the first data plane.
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107 */
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108 #define AV_PIX_FMT_FLAG_PLANAR (1 << 4)
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109 /**
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110 * The pixel format contains RGB-like data (as opposed to YUV/grayscale).
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111 */
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112 #define AV_PIX_FMT_FLAG_RGB (1 << 5)
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113 /**
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114 * The pixel format is "pseudo-paletted". This means that FFmpeg treats it as
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115 * paletted internally, but the palette is generated by the decoder and is not
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116 * stored in the file.
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117 */
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118 #define AV_PIX_FMT_FLAG_PSEUDOPAL (1 << 6)
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119 /**
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120 * The pixel format has an alpha channel.
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121 */
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122 #define AV_PIX_FMT_FLAG_ALPHA (1 << 7)
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123
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124 #if FF_API_PIX_FMT
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125 /**
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126 * @deprecate use the AV_PIX_FMT_FLAG_* flags
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127 */
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128 #define PIX_FMT_BE AV_PIX_FMT_FLAG_BE
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129 #define PIX_FMT_PAL AV_PIX_FMT_FLAG_PAL
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130 #define PIX_FMT_BITSTREAM AV_PIX_FMT_FLAG_BITSTREAM
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131 #define PIX_FMT_HWACCEL AV_PIX_FMT_FLAG_HWACCEL
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132 #define PIX_FMT_PLANAR AV_PIX_FMT_FLAG_PLANAR
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133 #define PIX_FMT_RGB AV_PIX_FMT_FLAG_RGB
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134 #define PIX_FMT_PSEUDOPAL AV_PIX_FMT_FLAG_PSEUDOPAL
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135 #define PIX_FMT_ALPHA AV_PIX_FMT_FLAG_ALPHA
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136 #endif
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137
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138 #if FF_API_PIX_FMT_DESC
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139 /**
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140 * The array of all the pixel format descriptors.
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141 */
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142 extern const AVPixFmtDescriptor av_pix_fmt_descriptors[];
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143 #endif
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144
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145 /**
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146 * Read a line from an image, and write the values of the
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147 * pixel format component c to dst.
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148 *
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149 * @param data the array containing the pointers to the planes of the image
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150 * @param linesize the array containing the linesizes of the image
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151 * @param desc the pixel format descriptor for the image
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152 * @param x the horizontal coordinate of the first pixel to read
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153 * @param y the vertical coordinate of the first pixel to read
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154 * @param w the width of the line to read, that is the number of
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155 * values to write to dst
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156 * @param read_pal_component if not zero and the format is a paletted
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157 * format writes the values corresponding to the palette
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158 * component c in data[1] to dst, rather than the palette indexes in
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159 * data[0]. The behavior is undefined if the format is not paletted.
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160 */
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161 void av_read_image_line(uint16_t *dst, const uint8_t *data[4], const int linesize[4],
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162 const AVPixFmtDescriptor *desc, int x, int y, int c, int w, int read_pal_component);
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163
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164 /**
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165 * Write the values from src to the pixel format component c of an
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166 * image line.
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167 *
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168 * @param src array containing the values to write
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169 * @param data the array containing the pointers to the planes of the
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170 * image to write into. It is supposed to be zeroed.
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171 * @param linesize the array containing the linesizes of the image
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172 * @param desc the pixel format descriptor for the image
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173 * @param x the horizontal coordinate of the first pixel to write
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174 * @param y the vertical coordinate of the first pixel to write
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175 * @param w the width of the line to write, that is the number of
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176 * values to write to the image line
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177 */
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178 void av_write_image_line(const uint16_t *src, uint8_t *data[4], const int linesize[4],
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179 const AVPixFmtDescriptor *desc, int x, int y, int c, int w);
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180
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181 /**
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182 * Return the pixel format corresponding to name.
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183 *
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184 * If there is no pixel format with name name, then looks for a
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185 * pixel format with the name corresponding to the native endian
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186 * format of name.
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187 * For example in a little-endian system, first looks for "gray16",
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188 * then for "gray16le".
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189 *
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190 * Finally if no pixel format has been found, returns AV_PIX_FMT_NONE.
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191 */
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192 enum AVPixelFormat av_get_pix_fmt(const char *name);
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193
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194 /**
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195 * Return the short name for a pixel format, NULL in case pix_fmt is
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196 * unknown.
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197 *
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198 * @see av_get_pix_fmt(), av_get_pix_fmt_string()
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199 */
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200 const char *av_get_pix_fmt_name(enum AVPixelFormat pix_fmt);
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201
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202 /**
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203 * Print in buf the string corresponding to the pixel format with
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204 * number pix_fmt, or an header if pix_fmt is negative.
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205 *
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206 * @param buf the buffer where to write the string
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207 * @param buf_size the size of buf
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208 * @param pix_fmt the number of the pixel format to print the
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209 * corresponding info string, or a negative value to print the
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210 * corresponding header.
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211 */
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212 char *av_get_pix_fmt_string (char *buf, int buf_size, enum AVPixelFormat pix_fmt);
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213
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214 /**
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215 * Return the number of bits per pixel used by the pixel format
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216 * described by pixdesc. Note that this is not the same as the number
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217 * of bits per sample.
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218 *
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219 * The returned number of bits refers to the number of bits actually
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220 * used for storing the pixel information, that is padding bits are
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221 * not counted.
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222 */
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223 int av_get_bits_per_pixel(const AVPixFmtDescriptor *pixdesc);
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224
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225 /**
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226 * Return the number of bits per pixel for the pixel format
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227 * described by pixdesc, including any padding or unused bits.
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228 */
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229 int av_get_padded_bits_per_pixel(const AVPixFmtDescriptor *pixdesc);
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230
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231 /**
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232 * @return a pixel format descriptor for provided pixel format or NULL if
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233 * this pixel format is unknown.
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234 */
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235 const AVPixFmtDescriptor *av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt);
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236
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237 /**
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238 * Iterate over all pixel format descriptors known to libavutil.
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239 *
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240 * @param prev previous descriptor. NULL to get the first descriptor.
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241 *
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242 * @return next descriptor or NULL after the last descriptor
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243 */
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244 const AVPixFmtDescriptor *av_pix_fmt_desc_next(const AVPixFmtDescriptor *prev);
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245
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246 /**
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247 * @return an AVPixelFormat id described by desc, or AV_PIX_FMT_NONE if desc
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248 * is not a valid pointer to a pixel format descriptor.
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249 */
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250 enum AVPixelFormat av_pix_fmt_desc_get_id(const AVPixFmtDescriptor *desc);
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251
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252 /**
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253 * Utility function to access log2_chroma_w log2_chroma_h from
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254 * the pixel format AVPixFmtDescriptor.
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255 *
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256 * See avcodec_get_chroma_sub_sample() for a function that asserts a
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257 * valid pixel format instead of returning an error code.
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258 * Its recommanded that you use avcodec_get_chroma_sub_sample unless
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259 * you do check the return code!
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260 *
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261 * @param[in] pix_fmt the pixel format
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262 * @param[out] h_shift store log2_chroma_w
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263 * @param[out] v_shift store log2_chroma_h
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264 *
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265 * @return 0 on success, AVERROR(ENOSYS) on invalid or unknown pixel format
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266 */
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267 int av_pix_fmt_get_chroma_sub_sample(enum AVPixelFormat pix_fmt,
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268 int *h_shift, int *v_shift);
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269
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270 /**
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271 * @return number of planes in pix_fmt, a negative AVERROR if pix_fmt is not a
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272 * valid pixel format.
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273 */
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274 int av_pix_fmt_count_planes(enum AVPixelFormat pix_fmt);
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275
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276 void ff_check_pixfmt_descriptors(void);
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277
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278 /**
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279 * Utility function to swap the endianness of a pixel format.
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280 *
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281 * @param[in] pix_fmt the pixel format
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282 *
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283 * @return pixel format with swapped endianness if it exists,
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284 * otherwise AV_PIX_FMT_NONE
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285 */
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286 enum AVPixelFormat av_pix_fmt_swap_endianness(enum AVPixelFormat pix_fmt);
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287
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288
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289 #endif /* AVUTIL_PIXDESC_H */
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