[FFmpeg-devel] [PATCH 1/3] lavu: Add AVSphericalMapping type and frame side data

Vittorio Giovara vittorio.giovara at gmail.com
Sat Nov 12 00:49:00 EET 2016


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 at gmail.com>
---
Missing version bump (do so when pushing).
Please CC.
Vittorio

 libavutil/Makefile    |   2 +
 libavutil/avutil.h    |   6 +++
 libavutil/frame.h     |   8 ++-
 libavutil/spherical.c |  34 ++++++++++++
 libavutil/spherical.h | 144 ++++++++++++++++++++++++++++++++++++++++++++++++++
 5 files changed, 193 insertions(+), 1 deletion(-)
 create mode 100644 libavutil/spherical.c
 create mode 100644 libavutil/spherical.h

diff --git a/libavutil/Makefile b/libavutil/Makefile
index 0fa90fe..c5af79a 100644
--- a/libavutil/Makefile
+++ b/libavutil/Makefile
@@ -63,6 +63,7 @@ HEADERS = adler32.h                                                     \
           samplefmt.h                                                   \
           sha.h                                                         \
           sha512.h                                                      \
+          spherical.h                                                   \
           stereo3d.h                                                    \
           threadmessage.h                                               \
           time.h                                                        \
@@ -140,6 +141,7 @@ OBJS = adler32.o                                                        \
        samplefmt.o                                                      \
        sha.o                                                            \
        sha512.o                                                         \
+       spherical.o                                                      \
        stereo3d.o                                                       \
        threadmessage.o                                                  \
        time.o                                                           \
diff --git a/libavutil/avutil.h b/libavutil/avutil.h
index 29dd830..e9aaa03 100644
--- a/libavutil/avutil.h
+++ b/libavutil/avutil.h
@@ -118,6 +118,12 @@
  *
  * @}
  *
+ * @defgroup lavu_video Video related
+ *
+ * @{
+ *
+ * @}
+ *
  * @defgroup lavu_audio Audio related
  *
  * @{
diff --git a/libavutil/frame.h b/libavutil/frame.h
index 8e51361..b450092 100644
--- a/libavutil/frame.h
+++ b/libavutil/frame.h
@@ -120,7 +120,13 @@ enum AVFrameSideDataType {
      * The GOP timecode in 25 bit timecode format. Data format is 64-bit integer.
      * This is set on the first frame of a GOP that has a temporal reference of 0.
      */
-    AV_FRAME_DATA_GOP_TIMECODE
+    AV_FRAME_DATA_GOP_TIMECODE,
+
+    /**
+     * The data represents the AVSphericalMapping structure defined in
+     * libavutil/spherical.h.
+     */
+    AV_FRAME_DATA_SPHERICAL,
 };
 
 enum AVActiveFormatDescription {
diff --git a/libavutil/spherical.c b/libavutil/spherical.c
new file mode 100644
index 0000000..816452c
--- /dev/null
+++ b/libavutil/spherical.c
@@ -0,0 +1,34 @@
+/*
+ * Copyright (c) 2016 Vittorio Giovara <vittorio.giovara at 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
+ */
+
+#include "mem.h"
+#include "spherical.h"
+
+AVSphericalMapping *av_spherical_alloc(size_t *size)
+{
+    AVSphericalMapping *spherical = av_mallocz(sizeof(AVSphericalMapping));
+    if (!spherical)
+        return NULL;
+
+    if (size)
+        *size = sizeof(*spherical);
+
+    return spherical;
+}
diff --git a/libavutil/spherical.h b/libavutil/spherical.h
new file mode 100644
index 0000000..57cd36b
--- /dev/null
+++ b/libavutil/spherical.h
@@ -0,0 +1,144 @@
+/*
+ * Copyright (c) 2016 Vittorio Giovara <vittorio.giovara at 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.
+     */
+    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
+     * @{
+     * These fields represent the pose values that measure the rotation
+     * transformation (in degrees) to be applied to the projection.
+     * See this equirectangular projection as example:
+     *
+     * @code{.unparsed}
+     *                   Yaw
+     *     -180           0           180
+     *   90 +-------------+-------------+  180
+     *      |             |             |
+     * P    |             |      o>     |
+     * i    |             ^             |
+     * t  0 +-------------X-------------+    0 Roll
+     * c    |             |             |
+     * h    |             |             |
+     *      |             |             |
+     *  -90 +-------------+-------------+ -180
+     *
+     * X - the default camera center
+     * ^ - the default up vector
+     * > - the up vector for a rotation of 90 degrees
+     * o - the image center for yaw = 90, pitch = 45, roll = 0
+     * @endcode
+     *
+     * The order of transformation is always yaw, followed by pitch, and
+     * finally by roll.
+     */
+    double yaw;   ///< Clockwise rotation around the up vector [-180, 180].
+    double pitch; ///< Counter-clockwise rotation around the right vector [-90, 90].
+    double roll;  ///< Counter-clockwise rotation around the forward vector [-180, 180].
+    /**
+     * @}
+     */
+
+    /**
+     * @name Bounding rectangle
+     * @{
+     * These fields are the amount of pixels to crop from the edge
+     * of the video surface.
+     *
+     * @note For cubemap projections these values apply to each
+     *       face of the cube.
+     */
+    unsigned int left_offset;   ///< Pixels to crop from the left edge.
+    unsigned int top_offset;    ///< Pixels to crop from the top edge.
+    unsigned int right_offset;  ///< Pixels to crop from the right edge.
+    unsigned int bottom_offset; ///< Pixels to crop from the bottom edge.
+    /**
+     * @}
+     */
+} 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 */
-- 
2.10.0



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