mirror of https://github.com/FFmpeg/FFmpeg.git
Add AV_PKT_DATA_DISPLAYMATRIX and AV_FRAME_DATA_DISPLAYMATRIX as stream and frame side data (respectively) to describe a display transformation matrix for linear transformation operations on the decoded video. Add functions to easily extract a rotation angle from a matrix and conversely to setup a matrix for a given rotation angle. Signed-off-by: Anton Khirnov <anton@khirnov.net>pull/68/head
Vittorio Giovara
11 years ago
committed by
Anton Khirnov
parent
9929b3564c
commit
bddd8cbf68
9 changed files with 179 additions and 1 deletions
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/*
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* Copyright (c) 2014 Vittorio Giovara <vittorio.giovara@gmail.com> |
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* |
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* This file is part of Libav. |
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* |
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* Libav is free software; you can redistribute it and/or |
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* modify it under the terms of the GNU Lesser General Public |
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* License as published by the Free Software Foundation; either |
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* version 2.1 of the License, or (at your option) any later version. |
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* |
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* Libav is distributed in the hope that it will be useful, |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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* Lesser General Public License for more details. |
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* |
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* You should have received a copy of the GNU Lesser General Public |
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* License along with Libav; if not, write to the Free Software |
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
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*/ |
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#include <stdint.h> |
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#include <string.h> |
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#include <math.h> |
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#include "display.h" |
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// fixed point to double
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#define CONV_FP(x) ((double) (x)) / (1 << 16) |
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// double to fixed point
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#define CONV_DB(x) (int32_t) ((x) * (1 << 16)) |
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double av_display_rotation_get(const int32_t matrix[9]) |
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{ |
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double rotation, scale[2]; |
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scale[0] = sqrt(CONV_FP(matrix[0]) * CONV_FP(matrix[0]) + |
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CONV_FP(matrix[3]) * CONV_FP(matrix[3])); |
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scale[1] = sqrt(CONV_FP(matrix[1]) * CONV_FP(matrix[1]) + |
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CONV_FP(matrix[4]) * CONV_FP(matrix[4])); |
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if (scale[0] == 0.0 || scale[1] == 0.0) |
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return NAN; |
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rotation = atan2(CONV_FP(matrix[1]) / scale[1], |
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CONV_FP(matrix[0]) / scale[0]) * 180 / M_PI; |
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return rotation; |
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} |
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void av_display_rotation_set(int32_t matrix[9], double angle) |
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{ |
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double radians = angle * M_PI / 180.0f; |
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double c = cos(radians); |
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double s = sin(radians); |
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memset(matrix, 0, 9 * sizeof(int32_t)); |
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matrix[0] = CONV_DB(c); |
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matrix[1] = CONV_DB(-s); |
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matrix[3] = CONV_DB(s); |
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matrix[4] = CONV_DB(c); |
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matrix[8] = 1 << 30; |
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} |
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/*
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* Copyright (c) 2014 Vittorio Giovara <vittorio.giovara@gmail.com> |
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* |
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* This file is part of Libav. |
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* |
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* Libav is free software; you can redistribute it and/or |
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* modify it under the terms of the GNU Lesser General Public |
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* License as published by the Free Software Foundation; either |
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* version 2.1 of the License, or (at your option) any later version. |
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* |
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* Libav is distributed in the hope that it will be useful, |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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* Lesser General Public License for more details. |
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* |
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* You should have received a copy of the GNU Lesser General Public |
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* License along with Libav; if not, write to the Free Software |
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
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*/ |
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#ifndef AVUTIL_DISPLAY_H |
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#define AVUTIL_DISPLAY_H |
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#include <stdint.h> |
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/**
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* The display transformation matrix specifies an affine transformation that |
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* should be applied to video frames for correct presentation. It is compatible |
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* with the matrices stored in the ISO/IEC 14496-12 container format. |
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* |
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* The data is a 3x3 matrix represented as a 9-element array: |
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* |
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* | a b u | |
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* (a, b, u, c, d, v, x, y, w) -> | c d v | |
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* | x y w | |
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* |
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* All numbers are stored in native endianness, as 16.16 fixed-point values, |
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* except for u, v and w, which are stored as 2.30 fixed-point values. |
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* |
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* The transformation maps a point (p, q) in the source (pre-transformation) |
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* frame to the point (p', q') in the destination (post-transformation) frame as |
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* follows: |
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* | a b u | |
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* (p, q, 1) . | c d v | = z * (p', q', 1) |
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* | x y w | |
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* |
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* The transformation can also be more explicitly written in components as |
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* follows: |
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* p' = (a * p + c * q + x) / z; |
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* q' = (b * p + d * q + y) / z; |
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* z = u * p + v * q + w |
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*/ |
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/**
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* Extract the rotation component of the transformation matrix. |
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* |
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* @param matrix the transformation matrix |
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* @return the angle (in degrees) by which the transformation rotates the frame. |
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* The angle will be in range [-180.0, 180.0], or NaN if the matrix is |
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* singular. |
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* |
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* @note floating point numbers are inherently inexact, so callers are |
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* recommended to round the return value to nearest integer before use. |
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*/ |
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double av_display_rotation_get(const int32_t matrix[9]); |
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/**
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* Initialize a transformation matrix describing a pure rotation by the |
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* specified angle (in degrees). |
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* |
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* @param matrix an allocated transformation matrix (will be fully overwritten |
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* by this function) |
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* @param angle rotation angle in degrees. |
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*/ |
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void av_display_rotation_set(int32_t matrix[9], double angle); |
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#endif /* AVUTIL_DISPLAY_H */ |
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