#pragma mark 裁剪视频
-(void)caiJianVideo:(NSURL*)videoUrl{
//1 — 采集
AVAsset *videoAsset = [AVAsset assetWithURL:videoUrl];
CMTime assetTime = [videoAsset duration];
Float64 duration = CMTimeGetSeconds(assetTime);
NSDate *d = [NSDate dateWithTimeIntervalSince1970:duration];
NSDateFormatter *_dateFormatter = [[NSDateFormatter alloc] init];
if (duration/3600 >= 1) {
[_dateFormatter setDateFormat:@"HH:mm:ss"];
} else {
[_dateFormatter setDateFormat:@"mm:ss"];
}
NSString *newTime = [_dateFormatter stringFromDate:d];
NSLog(@"视频时长 %@",newTime);
// 2 创建AVMutableComposition实例. apple developer 里边的解释 【AVMutableComposition is a mutable subclass of AVComposition you use when you want to create a new composition from existing assets. You can add and remove tracks, and you can add, remove, and scale time ranges.】
AVMutableComposition *mixComposition = [AVMutableComposition composition];
// 3 - 视频通道 工程文件中的轨道，有音频轨、视频轨等，里面可以插入各种对应的素材
AVMutableCompositionTrack *videoTrack = [mixComposition addMutableTrackWithMediaType:AVMediaTypeVideo
preferredTrackID:kCMPersistentTrackID_Invalid];
AVAssetTrack *videoAssetTrack = [[videoAsset tracksWithMediaType:AVMediaTypeVideo] objectAtIndex:0];
NSError *error = nil;
// 这块是裁剪,rangtime .前面的是开始时间,后面是裁剪多长 (我这裁剪的是从第二秒开始裁剪，裁剪2.55秒时长.)
[videoTrack insertTimeRange:CMTimeRangeMake(CMTimeMakeWithSeconds(1.0f, 30), CMTimeMakeWithSeconds(CMTimeGetSeconds([videoAsset duration])-1.0f, 30))
ofTrack:videoAssetTrack
atTime:kCMTimeZero
error:&error];
// 3.1 AVMutableVideoCompositionInstruction 视频轨道中的一个视频，可以缩放、旋转等
AVMutableVideoCompositionInstruction *mainInstruction = [AVMutableVideoCompositionInstruction videoCompositionInstruction];
mainInstruction.timeRange = CMTimeRangeMake(kCMTimeZero, videoAsset.duration);
// 3.2 AVMutableVideoCompositionLayerInstruction 一个视频轨道，包含了这个轨道上的所有视频素材
AVMutableVideoCompositionLayerInstruction *videolayerInstruction = [AVMutableVideoCompositionLayerInstruction videoCompositionLayerInstructionWithAssetTrack:videoTrack];
UIImageOrientation videoAssetOrientation_ = UIImageOrientationUp;
BOOL isVideoAssetPortrait_ = NO;
CGAffineTransform videoTransform = videoAssetTrack.preferredTransform;
if (videoTransform.a == 0 && videoTransform.b == 1.0 && videoTransform.c == -1.0 && videoTransform.d == 0) {
videoAssetOrientation_ = UIImageOrientationRight;
isVideoAssetPortrait_ = YES;
}
if (videoTransform.a == 0 && videoTransform.b == -1.0 && videoTransform.c == 1.0 && videoTransform.d == 0) {
videoAssetOrientation_ = UIImageOrientationLeft;
isVideoAssetPortrait_ = YES;
}
if (videoTransform.a == 1.0 && videoTransform.b == 0 && videoTransform.c == 0 && videoTransform.d == 1.0) {
videoAssetOrientation_ = UIImageOrientationUp;
}
if (videoTransform.a == -1.0 && videoTransform.b == 0 && videoTransform.c == 0 && videoTransform.d == -1.0) {
videoAssetOrientation_ = UIImageOrientationDown;
}
[videolayerInstruction setTransform:videoAssetTrack.preferredTransform atTime:kCMTimeZero];
[videolayerInstruction setOpacity:0.0 atTime:videoAsset.duration];
// 3.3 - Add instructions
mainInstruction.layerInstructions = [NSArray arrayWithObjects:videolayerInstruction,nil];
// AVMutableVideoComposition：管理所有视频轨道，可以决定最终视频的尺寸，裁剪需要在这里进行
AVMutableVideoComposition *mainCompositionInst = [AVMutableVideoComposition videoComposition];
CGSize naturalSize;
if(isVideoAssetPortrait_){
naturalSize = CGSizeMake(videoAssetTrack.naturalSize.height, videoAssetTrack.naturalSize.width);
} else {
naturalSize = videoAssetTrack.naturalSize;
}
float renderWidth, renderHeight;
renderWidth = naturalSize.width;
renderHeight = naturalSize.height;
float value = renderWidth>renderHeight?renderHeight:renderWidth;
mainCompositionInst.renderSize = CGSizeMake(value, value);
mainCompositionInst.instructions = [NSArray arrayWithObject:mainInstruction];
mainCompositionInst.frameDuration = CMTimeMake(1, 30);
// 4 - Get path
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSString *myPathDocs = [documentsDirectory stringByAppendingPathComponent:
[NSString stringWithFormat:@"FinalVideo-%d.mov",arc4random() % 1000]];
self.videoUrl= [NSURL fileURLWithPath:myPathDocs];
AVAssetExportSession *exporter = [[AVAssetExportSession alloc] initWithAsset:mixComposition
presetName:AVAssetExportPresetHighestQuality];
exporter.outputURL=self.videoUrl;
exporter.outputFileType = AVFileTypeQuickTimeMovie;
exporter.shouldOptimizeForNetworkUse = YES;
exporter.videoComposition = mainCompositionInst;
[exporter exportAsynchronouslyWithCompletionHandler:^{
dispatch_async(dispatch_get_main_queue(), ^{
[self exportDidFinish:exporter];
});
}];
}
- (void)exportDidFinish:(AVAssetExportSession*)session {
if (session.status == AVAssetExportSessionStatusCompleted) {
NSURL *outputURL = session.outputURL;
ALAssetsLibrary *library = [[ALAssetsLibrary alloc] init];
if ([library videoAtPathIsCompatibleWithSavedPhotosAlbum:outputURL]) {
//保存视频到本地相册
[library writeVideoAtPathToSavedPhotosAlbum:outputURL completionBlock:^(NSURL *assetURL, NSError *error){
dispatch_async(dispatch_get_main_queue(), ^{
if (error) {
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Error" message:@"Video Saving Failed"
delegate:nil cancelButtonTitle:@"OK" otherButtonTitles:nil];
[alert show];
} else {
_playItem = [AVPlayerItem playerItemWithURL:self.videoUrl];
_player = [AVPlayer playerWithPlayerItem:_playItem];
_playerLayer =[AVPlayerLayer playerLayerWithPlayer:_player];
_playerLayer.frame = _videoView.layer.bounds;
// _playerLayer.videoGravity=AVLayerVideoGravityResizeAspectFill;//视频填充模式
[self.videoView.layer addSublayer:_playerLayer];
[_player play];
}
});
}];
}
}
}
