/* * Copyright (c) 2016 Vittorio Giovara * * 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 * @ingroup lavu_video_spherical * Spherical video */ #ifndef AVUTIL_SPHERICAL_H #define AVUTIL_SPHERICAL_H #include #include /** * @defgroup lavu_video_spherical Spherical video mapping * @ingroup lavu_video * * A spherical video file contains surfaces that need to be mapped onto a * sphere. Depending on how the frame was converted, a different distortion * transformation or surface recomposition function needs to be applied before * the video should be mapped and displayed. * @{ */ /** * Projection of the video surface(s) on a sphere. */ enum AVSphericalProjection { /** * Video represents a sphere mapped on a flat surface using * equirectangular projection. */ AV_SPHERICAL_EQUIRECTANGULAR, /** * Video frame is split into 6 faces of a cube, and arranged on a * 3x2 layout. Faces are oriented upwards for the front, left, right, * and back faces. The up face is oriented so the top of the face is * forwards and the down face is oriented so the top of the face is * to the back. */ AV_SPHERICAL_CUBEMAP, /** * Video represents a portion of a sphere mapped on a flat surface * using equirectangular projection. The @ref bounding fields indicate * the position of the current video in a larger surface. */ AV_SPHERICAL_EQUIRECTANGULAR_TILE, }; /** * This structure describes how to handle spherical videos, outlining * information about projection, initial layout, and any other view modifier. * * @note The struct must be allocated with av_spherical_alloc() and * its size is not a part of the public ABI. */ typedef struct AVSphericalMapping { /** * Projection type. */ enum AVSphericalProjection projection; /** * @name Initial orientation * @{ * There fields describe additional rotations applied to the sphere after * the video frame is mapped onto it. The sphere is rotated around the * viewer, who remains stationary. The order of transformation is always * yaw, followed by pitch, and finally by roll. * * The coordinate system matches the one defined in OpenGL, where the * forward vector (z) is coming out of screen, and it is equivalent to * a rotation matrix of R = r_y(yaw) * r_x(pitch) * r_z(roll). * * A positive yaw rotates the portion of the sphere in front of the viewer * toward their right. A positive pitch rotates the portion of the sphere * in front of the viewer upwards. A positive roll tilts the portion of * the sphere in front of the viewer to the viewer's right. * * These values are exported as 16.16 fixed point. * * See this equirectangular projection as example: * * @code{.unparsed} * Yaw * -180 0 180 * 90 +-------------+-------------+ 180 * | | | up * P | | | y| forward * i | ^ | | /z * t 0 +-------------X-------------+ 0 Roll | / * c | | | | / * h | | | 0|/_____right * | | | x * -90 +-------------+-------------+ -180 * * X - the default camera center * ^ - the default up vector * @endcode */ int32_t yaw; ///< Rotation around the up vector [-180, 180]. int32_t pitch; ///< Rotation around the right vector [-90, 90]. int32_t roll; ///< Rotation around the forward vector [-180, 180]. /** * @} */ /** * @name Bounding rectangle * @anchor bounding * @{ * These fields indicate the location of the current tile, and where * it should be mapped relative to the original surface. They are * exported as 0.32 fixed point, and can be converted to classic * pixel values with av_spherical_bounds(). * * @code{.unparsed} * +----------------+----------+ * | |bound_top | * | +--------+ | * | bound_left |tile | | * +<---------->| |<--->+bound_right * | +--------+ | * | | | * | bound_bottom| | * +----------------+----------+ * @endcode * * If needed, the original video surface dimensions can be derived * by adding the current stream or frame size to the related bounds, * like in the following example: * * @code{c} * original_width = tile->width + bound_left + bound_right; * original_height = tile->height + bound_top + bound_bottom; * @endcode * * @note These values are valid only for the tiled equirectangular * projection type (@ref AV_SPHERICAL_EQUIRECTANGULAR_TILE), * and should be ignored in all other cases. */ uint32_t bound_left; ///< Distance from the left edge uint32_t bound_top; ///< Distance from the top edge uint32_t bound_right; ///< Distance from the right edge uint32_t bound_bottom; ///< Distance from the bottom edge /** * @} */ /** * Number of pixels to pad from the edge of each cube face. * * @note This value is valid for only for the cubemap projection type * (@ref AV_SPHERICAL_CUBEMAP), and should be ignored in all other * cases. */ uint32_t padding; } AVSphericalMapping; /** * Allocate a AVSphericalVideo structure and initialize its fields to default * values. * * @return the newly allocated struct or NULL on failure */ AVSphericalMapping *av_spherical_alloc(size_t *size); /** * Convert the @ref bounding fields from an AVSphericalVideo * from 0.32 fixed point to pixels. * * @param map The AVSphericalVideo map to read bound values from. * @param width Width of the current frame or stream. * @param height Height of the current frame or stream. * @param left Pixels from the left edge. * @param top Pixels from the top edge. * @param right Pixels from the right edge. * @param bottom Pixels from the bottom edge. */ void av_spherical_tile_bounds(const AVSphericalMapping *map, size_t width, size_t height, size_t *left, size_t *top, size_t *right, size_t *bottom); /** * Provide a human-readable name of a given AVSphericalProjection. * * @param projection The input AVSphericalProjection. * * @return The name of the AVSphericalProjection, or "unknown". */ const char *av_spherical_projection_name(enum AVSphericalProjection projection); /** * Get the AVSphericalProjection form a human-readable name. * * @param name The input string. * * @return The AVSphericalProjection value, or -1 if not found. */ int av_spherical_from_name(const char *name); /** * @} */ #endif /* AVUTIL_SPHERICAL_H */