ios - Iphone 在当前帧内旋转视频

Question

嗨，我有一个视频宽度 = 720高度 = 1280

因此视频处于人像模式。

我想让视频旋转 90 度。但是想要旋转的视频在相同大小的视频中，即 720,1280。是的视频将被缩放，但我需要这种类型的轮换。

请检查图片之前和之后:

这是我的代码:

 CGAffineTransform rotationTransform =  CGAffineTransformMakeRotation(DEGREES_TO_RADIANS(90.0));
    CGAffineTransform rotateTranslate =   CGAffineTransformTranslate(rotationTransform,400,320);
    [layerInst setTransform:rotateTranslate atTime:kCMTimeZero];

Answer 1

您可以同时使用缩放、旋转和平移变换，并将每个变换连接到原始 Assets 变换。请针对您的问题尝试以下代码

        // here assetTransform is your AVAssetTrack preferred transform
        CGAffineTransform defaultTransfrom = assetTransform;
        // rotate 90 degree
        CGAffineTransform rotateTransform = CGAffineTransformMakeRotation( M_PI_2);
        //get scale factor of resized video
        float scaleFactor = videoSize.width/videoSize.height;
        CGAffineTransform scaleTransform = CGAffineTransformMakeScale(scaleFactor,scaleFactor);
        // get blank Space At Bottom after rotation and scaling
        float blankSpaceAtBottom = (videoSize.height-scaleFactor*videoSize.width);
        //increase y translation according to scaling factor
        float ytranslation = blankSpaceAtBottom/2/scaleFactor;
        CGAffineTransform translationTransform = CGAffineTransformMakeTranslation(videoSize.height,ytranslation);
        //concat all transform
        CGAffineTransform finalTransform = CGAffineTransformConcat(CGAffineTransformConcat(defaultTransfrom,rotateTransform),translationTransform);
       finalTransform = CGAffineTransformConcat(finalTransform,scaleTransform);
        //apply final transform to layer instruction
        [layerInstruction setTransform:finalTransform atTime:kCMTimeZero];

如果您需要更多说明，请告诉我。