如何在iOS中裁剪视频 [英] How to crop a video in iOS
问题描述
我一直以Apple提供的RosyWriter示例代码为起点，我想找到一种方法来裁剪视频.
I was having a look at the RosyWriter Sample Code provided by Apple as a starting point and I'd like to find a way how to crop a video.
所以我有来自iPhone相机的全分辨率视频，但我只想使用其中的裁剪部分(并旋转此子部分).
So i have the full resolution video from the iPhones Camera, but I just want to use a cropped part of it (and also rotate this subpart).
我认为在captureOutput:didOutputSampleBuffer: fromConnection:中，我可以通过修改传入的CMSampleBufferRef来修改每个帧.
I figured that in captureOutput:didOutputSampleBuffer: fromConnection: i can modify each frame by modifying the CMSampleBufferRef that i get passed in.
所以我现在的问题是:
-
这是裁剪视频的合适地方吗?
Is this the right place to crop my video?
在哪里指定最终视频(保存到光盘上)的分辨率比AVCaptureSession捕获的完整视频的分辨率小?设置AVVideoWidthKey和AVVideoHeightKey无效.
Where do I specify that the final video (that get's saved to disc) has a smaller resolution than the full video captured by AVCaptureSession? Setting the AVVideoWidthKey and AVVideoHeightKey has no effect.
如何裁剪视频并仍然具有良好的性能?
How can I crop the video and still have good performance?
感谢您的帮助！
非常感谢！
也许我只想知道如何通过将视频图像旋转90度，然后再次放大以适应宽度来制作以横向拍摄的肖像视频.?！?
Maybe I just need to know how I can make a video that was shot in portrait a landscape one by turning the images of the video by 90 degrees and then zoom in to fit the width again...?!?
推荐答案
在AVVideoSetttings.h中，有AVVideoScalingModeKey.将此键与定义的值组合在一起，可以控制在将图像编码到视频容器时如何缩放/裁剪视频.例如，如果您指定了AVVideoScalingModeFit的值，则使用裁剪.查看标题，了解其他值如何影响视频图像.
In AVVideoSetttings.h there is the AVVideoScalingModeKey. This key combined with the defined values control how the video is scaled/cropped when encoding the images to the video container. For example if you specified a value of AVVideoScalingModeFit then cropping is used. Check out the header for how other values effect the video images.
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