/* * Copyright (c) 2014 Vittorio Giovara <vittorio.giovara@gmail.com> * * 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 */ #ifndef AVUTIL_DISPLAY_H #define AVUTIL_DISPLAY_H #include <stdint.h> /** * The display transformation matrix specifies an affine transformation that * should be applied to video frames for correct presentation. It is compatible * with the matrices stored in the ISO/IEC 14496-12 container format. * * The data is a 3x3 matrix represented as a 9-element array: * * | a b u | * (a, b, u, c, d, v, x, y, w) -> | c d v | * | x y w | * * All numbers are stored in native endianness, as 16.16 fixed-point values, * except for u, v and w, which are stored as 2.30 fixed-point values. * * The transformation maps a point (p, q) in the source (pre-transformation) * frame to the point (p', q') in the destination (post-transformation) frame as * follows: * | a b u | * (p, q, 1) . | c d v | = z * (p', q', 1) * | x y w | * * The transformation can also be more explicitly written in components as * follows: * p' = (a * p + c * q + x) / z; * q' = (b * p + d * q + y) / z; * z = u * p + v * q + w */ /** * Extract the rotation component of the transformation matrix. * * @param matrix the transformation matrix * @return the angle (in degrees) by which the transformation rotates the frame. * The angle will be in range [-180.0, 180.0], or NaN if the matrix is * singular. * * @note floating point numbers are inherently inexact, so callers are * recommended to round the return value to nearest integer before use. */ double av_display_rotation_get(const int32_t matrix[9]); /** * Initialize a transformation matrix describing a pure rotation by the * specified angle (in degrees). * * @param matrix an allocated transformation matrix (will be fully overwritten * by this function) * @param angle rotation angle in degrees. */ void av_display_rotation_set(int32_t matrix[9], double angle); /** * Flip the input matrix horizontally and/or vertically. * * @param matrix an allocated transformation matrix * @param hflip whether the matrix should be flipped horizontally * @param vflip whether the matrix should be flipped vertically */ void av_display_matrix_flip(int32_t matrix[9], int hflip, int vflip); #endif /* AVUTIL_DISPLAY_H */ /* * Copyright (c) 2014 Vittorio Giovara <vittorio.giovara@gmail.com> * * 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 */ #ifndef AVUTIL_DISPLAY_H #define AVUTIL_DISPLAY_H #include <stdint.h> /** * The display transformation matrix specifies an affine transformation that * should be applied to video frames for correct presentation. It is compatible * with the matrices stored in the ISO/IEC 14496-12 container format. * * The data is a 3x3 matrix represented as a 9-element array: * * | a b u | * (a, b, u, c, d, v, x, y, w) -> | c d v | * | x y w | * * All numbers are stored in native endianness, as 16.16 fixed-point values, * except for u, v and w, which are stored as 2.30 fixed-point values. * * The transformation maps a point (p, q) in the source (pre-transformation) * frame to the point (p', q') in the destination (post-transformation) frame as * follows: * | a b u | * (p, q, 1) . | c d v | = z * (p', q', 1) * | x y w | * * The transformation can also be more explicitly written in components as * follows: * p' = (a * p + c * q + x) / z; * q' = (b * p + d * q + y) / z; * z = u * p + v * q + w */ /** * Extract the rotation component of the transformation matrix. * * @param matrix the transformation matrix * @return the angle (in degrees) by which the transformation rotates the frame. * The angle will be in range [-180.0, 180.0], or NaN if the matrix is * singular. * * @note floating point numbers are inherently inexact, so callers are * recommended to round the return value to nearest integer before use. */ double av_display_rotation_get(const int32_t matrix[9]); /** * Initialize a transformation matrix describing a pure rotation by the * specified angle (in degrees). * * @param matrix an allocated transformation matrix (will be fully overwritten * by this function) * @param angle rotation angle in degrees. */ void av_display_rotation_set(int32_t matrix[9], double angle); /** * Flip the input matrix horizontally and/or vertically. * * @param matrix an allocated transformation matrix * @param hflip whether the matrix should be flipped horizontally * @param vflip whether the matrix should be flipped vertically */ void av_display_matrix_flip(int32_t matrix[9], int hflip, int vflip); #endif /* AVUTIL_DISPLAY_H */