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// Copyright 2019 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef MEDIA_BASE_VIDEO_TRANSFORMATION_H_
#define MEDIA_BASE_VIDEO_TRANSFORMATION_H_
#include <string>
#include "base/numerics/math_constants.h"
#include "media/base/media_export.h"
namespace media {
// Enumeration to represent 90 degree video rotation for MP4 videos
// where it can be rotated by 90 degree intervals.
enum VideoRotation : int {
VIDEO_ROTATION_0 = 0,
VIDEO_ROTATION_90,
VIDEO_ROTATION_180,
VIDEO_ROTATION_270,
VIDEO_ROTATION_MAX = VIDEO_ROTATION_270
};
// Stores frame rotation & mirroring values. These are usually calculated from
// a rotation matrix from a demuxer, and we only support 90 degree rotation
// increments.
struct MEDIA_EXPORT VideoTransformation {
constexpr VideoTransformation(VideoRotation rotation, bool mirrored)
: rotation(rotation), mirrored(mirrored) {}
constexpr VideoTransformation(VideoRotation r)
: VideoTransformation(r, false) {}
constexpr VideoTransformation()
: VideoTransformation(VIDEO_ROTATION_0, false) {}
// Rotation by angle Θ is represented in the matrix as:
// [ cos(Θ), -sin(Θ)]
// [ sin(Θ), cos(Θ)]
// A vertical flip is represented by the cosine's having opposite signs
// and a horizontal flip is represented by the sine's having the same sign.
VideoTransformation(int32_t matrix[4]);
// The video rotation value, in 90 degree steps.
VideoRotation rotation;
// Whether the video should be flipped about its Y axis.
// This transformation takes place _after_ rotation, since they are not
// commutative.
bool mirrored;
};
MEDIA_EXPORT bool operator==(const struct VideoTransformation& first,
const struct VideoTransformation& second);
constexpr VideoTransformation kNoTransformation = VideoTransformation();
std::string MEDIA_EXPORT VideoRotationToString(VideoRotation rotation);
} // namespace media
#endif // MEDIA_BASE_VIDEO_TRANSFORMATION_H_
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