使用AVFoundation裁剪AVAsset视频无法在iOS 8上运行 [英] Cropping AVAsset video with AVFoundation not working iOS 8
问题描述
这是困扰我的最后一天,我曾经在ObjC中使用此方法将视频裁剪为正方形,这似乎是我几年来发现的唯一可行的方法,但最近尝试进行裁剪在Swift&中使用它iOS 8似乎根本没有裁剪视频,希望有人能帮忙吗?
This has been bugging me for the last day, I used to use this method in ObjC to crop videos into square, it seems to be the only method i've found in a few years that worked but after recently trying to crop using it in Swift & iOS 8 it doesn't seem to crop the video at all, Hopefully somebody can help?
func captureOutput(captureOutput: AVCaptureFileOutput!, didFinishRecordingToOutputFileAtURL outputFileURL: NSURL!, fromConnections connections: [AnyObject]!, error: NSError!) {
if error != nil {
println("Error Outputting recording")
} else {
self.writeVideoToAssetsLibrary(self.outputUrl!.copy() as NSURL)
}
}
func writeVideoToAssetsLibrary(videoUrl: NSURL) {
var videoAsset: AVAsset = AVAsset.assetWithURL(videoUrl) as AVAsset
var clipVideoTrack = videoAsset.tracksWithMediaType(AVMediaTypeVideo).first as AVAssetTrack
var composition = AVMutableComposition()
composition.addMutableTrackWithMediaType(AVMediaTypeVideo, preferredTrackID: CMPersistentTrackID())
var videoComposition = AVMutableVideoComposition()
videoComposition.renderSize = CGSizeMake(clipVideoTrack.naturalSize.height, clipVideoTrack.naturalSize.height)
videoComposition.frameDuration = CMTimeMake(1, 30)
var transformer = AVMutableVideoCompositionLayerInstruction(assetTrack: clipVideoTrack)
var instruction = AVMutableVideoCompositionInstruction()
instruction.timeRange = CMTimeRangeMake(kCMTimeZero, CMTimeMakeWithSeconds(60, 30))
var transform1: CGAffineTransform = CGAffineTransformMakeTranslation(clipVideoTrack.naturalSize.height, (clipVideoTrack.naturalSize.width - clipVideoTrack.naturalSize.height) / 2)
var transform2 = CGAffineTransformRotate(transform1, CGFloat(M_PI_2))
var finalTransform = transform2
transformer.setTransform(finalTransform, atTime: kCMTimeZero)
instruction.layerInstructions = [transformer]
videoComposition.instructions = [instruction]
var exporter = AVAssetExportSession(asset: videoAsset, presetName: AVAssetExportPresetHighestQuality)
exporter.videoComposition = videoComposition
exporter.outputURL = videoUrl
exporter.outputFileType = AVFileTypeQuickTimeMovie
exporter.exportAsynchronouslyWithCompletionHandler({ () -> Void in
dispatch_async(dispatch_get_main_queue(), {
self.handleExportCompletion(exporter)
})
})
}
func handleExportCompletion(session: AVAssetExportSession) {
var library = ALAssetsLibrary()
if library.videoAtPathIsCompatibleWithSavedPhotosAlbum(session.outputURL) {
var completionBlock: ALAssetsLibraryWriteVideoCompletionBlock
completionBlock = { assetUrl, error in
if error != nil {
println("error writing to disk")
} else {
}
}
library.writeVideoAtPathToSavedPhotosAlbum(outputUrl, completionBlock: completionBlock)
}
}
推荐答案
因此,事实证明,如果您尝试将导出器的outputUrl设置为与资产相同,那么就像我所做的那样,它不会对其进行编辑,太愚蠢了!因此,为了将来引用,应将outputUrl设置为一个新的唯一
So it turns out that if you try setting the exporter's outputUrl to the same as the asset your editing like I did it doesn't edit it, so stupid! so for future referencing, outputUrl should be set to a new unique one
这篇关于使用AVFoundation裁剪AVAsset视频无法在iOS 8上运行的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!