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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 #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 VideoRotationToString(VideoRotation rotation); } // namespace media #endif // MEDIA_BASE_VIDEO_TRANSFORMATION_H_