nest-open-source / manifest_repos / ffmpeg / 62cf23d89db2251203d6207e2261ddc5498167c6 / . / libavcodec / xface.h

/* | |

* Copyright (c) 1990 James Ashton - Sydney University | |

* Copyright (c) 2012 Stefano Sabatini | |

* | |

* This file is part of FFmpeg. | |

* | |

* FFmpeg is free software; you can redistribute it and/or | |

* modify it under the terms of the GNU Lesser General Public | |

* License as published by the Free Software Foundation; either | |

* version 2.1 of the License, or (at your option) any later version. | |

* | |

* FFmpeg is distributed in the hope that it will be useful, | |

* but WITHOUT ANY WARRANTY; without even the implied warranty of | |

* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |

* Lesser General Public License for more details. | |

* | |

* You should have received a copy of the GNU Lesser General Public | |

* License along with FFmpeg; if not, write to the Free Software | |

* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | |

*/ | |

/** | |

* @file | |

* X-Face common definitions. | |

*/ | |

#ifndef AVCODEC_XFACE_H | |

#define AVCODEC_XFACE_H | |

#include <stdint.h> | |

/* define the face size - 48x48x1 */ | |

#define XFACE_WIDTH 48 | |

#define XFACE_HEIGHT 48 | |

#define XFACE_PIXELS (XFACE_WIDTH * XFACE_HEIGHT) | |

/* compressed output uses the full range of printable characters. | |

* In ASCII these are in a contiguous block so we just need to know | |

* the first and last. The total number of printables is needed too. */ | |

#define XFACE_FIRST_PRINT '!' | |

#define XFACE_LAST_PRINT '~' | |

#define XFACE_PRINTS (XFACE_LAST_PRINT - XFACE_FIRST_PRINT + 1) | |

/* | |

* Image is encoded as a big integer, using characters from '~' to | |

* '!', for a total of 94 symbols. In order to express | |

* 48x48 pixels with the worst case encoding 666 symbols should | |

* be sufficient. | |

*/ | |

#define XFACE_MAX_DIGITS 666 | |

#define XFACE_BITSPERWORD 8 | |

#define XFACE_WORDCARRY (1 << XFACE_BITSPERWORD) | |

#define XFACE_WORDMASK (XFACE_WORDCARRY - 1) | |

// This must be larger or equal to log256(94^XFACE_MAX_DIGITS) | |

#define XFACE_MAX_WORDS 546 | |

/* Portable, very large unsigned integer arithmetic is needed. | |

* Implementation uses arrays of WORDs. */ | |

typedef struct { | |

int nb_words; | |

uint8_t words[XFACE_MAX_WORDS]; | |

} BigInt; | |

/** | |

* Add a to b storing the result in b. | |

*/ | |

void ff_big_add(BigInt *b, uint8_t a); | |

/** | |

* Divide b by a storing the result in b and the remainder in the word | |

* pointed to by r. | |

*/ | |

void ff_big_div(BigInt *b, uint8_t a, uint8_t *r); | |

/** | |

* Multiply a by b storing the result in b. | |

*/ | |

void ff_big_mul(BigInt *b, uint8_t a); | |

/* Each face is encoded using 9 octrees of 16x16 each. Each level of the | |

* trees has varying probabilities of being white, grey or black. | |

* The table below is based on sampling many faces */ | |

enum XFaceColor { XFACE_COLOR_BLACK = 0, XFACE_COLOR_GREY, XFACE_COLOR_WHITE }; | |

/* Data of varying probabilities are encoded by a value in the range 0 - 255. | |

* The probability of the data determines the range of possible encodings. | |

* Offset gives the first possible encoding of the range. */ | |

typedef struct { | |

uint8_t range; | |

uint8_t offset; | |

} ProbRange; | |

extern const ProbRange ff_xface_probranges_per_level[4][3]; | |

extern const ProbRange ff_xface_probranges_2x2[16]; | |

void ff_xface_generate_face(uint8_t *dst, uint8_t * const src); | |

#endif /* AVCODEC_XFACE_H */ |