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Rotate AVAssetWriter 180 degrees around the x axis

I am creating a Quicktime video file using AVAssetWriter . The output video is currently upside down. Theoretically, I can fix this by rotating the video 180 degrees about the horizontal axis (essentially “flipping” the video). What is the best way to do this?

I am currently trying to assign a CGAffineTransform to myAVAssetWriterInput.transform . Perhaps CGAffineTransformMake(a, b, c, d, tx, ty) will allow me to specify the correct affine transformation matrix?

Neither Apple docs nor wikipedia provide a clear explanation of how the affinity transform matrix works. And everything can be best.

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 myAVAssetWriterInput.transform = CGAffineTransformMakeRotation(M_PI);

if you want to rotate the video 180 degrees around the z axis or

 myAVAssetWriterInput.transform = CGAffineTransformMakeScale(1, -1);

if you want to flip x

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Source: https://habr.com/ru/post/901952/

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