diff options
author | Vittorio Giovara <vittorio.giovara@gmail.com> | 2016-11-12 01:25:43 +0300 |
---|---|---|
committer | Vittorio Giovara <vittorio.giovara@gmail.com> | 2016-12-07 22:39:04 +0300 |
commit | 8f58ecc344a92e63193c38e28c173be987954bbb (patch) | |
tree | 726e17f01ac162d303f21356a118db8e7568e08e /libavutil/spherical.h | |
parent | c188f358aaee5800af5a5d699dd657cef3fb43a6 (diff) |
lavu: Add AVSphericalMapping type and frame side data
While no decoder currently exports spherical information, this type
represents a frame property that has to be passed through from container
to frames.
Signed-off-by: Vittorio Giovara <vittorio.giovara@gmail.com>
Diffstat (limited to 'libavutil/spherical.h')
-rw-r--r-- | libavutil/spherical.h | 137 |
1 files changed, 137 insertions, 0 deletions
diff --git a/libavutil/spherical.h b/libavutil/spherical.h new file mode 100644 index 0000000000..0a669da83a --- /dev/null +++ b/libavutil/spherical.h @@ -0,0 +1,137 @@ +/* + * 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 + * Spherical video + */ + +#ifndef AVUTIL_SPHERICAL_H +#define AVUTIL_SPHERICAL_H + +/** + * @addtogroup lavu_video + * @{ + * + * @defgroup lavu_video_spherical Spherical video mapping + * @{ + */ + +/** + * @addtogroup lavu_video_spherical + * 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, +}; + +/** + * 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]. + /** + * @} + */ +} 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); + +/** + * @} + * @} + */ + +#endif /* AVUTIL_SPHERICAL_H */ |