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Diffstat (limited to 'dependencies/include/libavutil/spherical.h')
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diff --git a/dependencies/include/libavutil/spherical.h b/dependencies/include/libavutil/spherical.h new file mode 100644 index 0000000..828ac83 --- /dev/null +++ b/dependencies/include/libavutil/spherical.h @@ -0,0 +1,227 @@ +/* + * Copyright (c) 2016 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 + */ + +/** + * @file + * @ingroup lavu_video_spherical + * Spherical video + */ + +#ifndef AVUTIL_SPHERICAL_H +#define AVUTIL_SPHERICAL_H + +#include <stddef.h> +#include <stdint.h> + +/** + * @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 */ |