我正在研究合并两个视频，发现一个奇怪的问题，当我尝试合并一个肖像视频和一个风景视频时，输出结果显示了在potrait模式下的视频横向版本，我不会这样做。我想要发生。 我很确定我在管理方向方面缺少一些基本的东西。
我的代码在这里：
NSMutableArray *videoClipPaths=[[NSMutableArray alloc]init];
[videoClipPaths addObject:[NSURL URLWithString:videoBundleURL1]];
[videoClipPaths addObject:[NSURL URLWithString:videoBundleURL2]];
[videoClipPaths addObject:[NSURL URLWithString:videoBundleURL1]];
float start_time=startSeconds;
float end_time=endSeconds;
AVMutableComposition *mixComposition = [AVMutableComposition composition];
AVMutableCompositionTrack *compositionTrack = [mixComposition addMutableTrackWithMediaType:AVMediaTypeVideo preferredTrackID:kCMPersistentTrackID_Invalid];
AVMutableCompositionTrack *compositionTrack2 = [mixComposition addMutableTrackWithMediaType:AVMediaTypeAudio preferredTrackID:kCMPersistentTrackID_Invalid];
__block CMTime time = kCMTimeZero;
__block CGAffineTransform translate;
__block CGSize size;
for (int i=0; i<[videoClipPaths count]; i++)
{
AVURLAsset *assetClip = [AVURLAsset URLAssetWithURL:[videoClipPaths objectAtIndex:i] options:nil];
AVAssetTrack *clipVideoTrackB = [[assetClip tracksWithMediaType:AVMediaTypeVideo] objectAtIndex:0];
AVAsset *anAsset = [[AVURLAsset alloc] initWithURL:[videoClipPaths objectAtIndex:i] options:nil];
CMTime start;
CMTime duration;
CMTimeRange video_timeRange;
if (i==0){
start = CMTimeMakeWithSeconds(0.0f, anAsset.duration.timescale);
duration = CMTimeMakeWithSeconds(start_time, anAsset.duration.timescale);
video_timeRange = CMTimeRangeMake(kCMTimeZero,duration);
[compositionTrack insertTimeRange:video_timeRange ofTrack:clipVideoTrackB atTime:start error:nil];
size = CGSizeMake(clipVideoTrackB.naturalSize.height, clipVideoTrackB.naturalSize.height);
translate = CGAffineTransformMakeTranslation(-420, 0);
CGAffineTransform newTransform = CGAffineTransformConcat(translate, clipVideoTrackB.preferredTransform);
[compositionTrack setPreferredTransform:newTransform];
time = CMTimeAdd(time, duration);
}else if (i==1){
CMTime duration = anAsset.duration;
float seconds = CMTimeGetSeconds(duration);
start = CMTimeMakeWithSeconds(start_time, anAsset.duration.timescale);
duration = CMTimeMakeWithSeconds(seconds, anAsset.duration.timescale);
video_timeRange = CMTimeRangeMake(kCMTimeZero,duration);
[compositionTrack insertTimeRange:video_timeRange ofTrack:clipVideoTrackB atTime:start error:nil];
translate = CGAffineTransformMakeTranslation(-420, 0);
CGAffineTransform newTransform = CGAffineTransformConcat(translate, clipVideoTrackB.preferredTransform);
[compositionTrack setPreferredTransform:newTransform];
time = CMTimeAdd(time, duration);
}
else if (i==2){
CMTime duration = anAsset.duration;
float seconds = CMTimeGetSeconds(duration);
start = CMTimeMakeWithSeconds(end_time, anAsset.duration.timescale);
duration = CMTimeMakeWithSeconds(seconds-start_time, anAsset.duration.timescale);
// duration = CMTimeMakeWithSeconds(anAsset.duration.timescale, anAsset.duration.timescale);
video_timeRange = CMTimeRangeMake(CMTimeMakeWithSeconds(start_time, anAsset.duration.timescale),duration);
[compositionTrack insertTimeRange:video_timeRange ofTrack:clipVideoTrackB atTime:kCMTimeInvalid error:nil];
translate = CGAffineTransformMakeTranslation(-420, 0);
CGAffineTransform newTransform = CGAffineTransformConcat(translate, clipVideoTrackB.preferredTransform);
[compositionTrack setPreferredTransform:newTransform];
time = CMTimeAdd(time, duration);
}
// video_timeRange = CMTimeRangeMake(start,duration);
//merge audio of video files
AVAssetTrack *clipVideoTrackB1 = [[assetClip tracksWithMediaType:AVMediaTypeAudio] objectAtIndex:0];
/*CMTime start1;
CMTime duration1;
CMTimeRange video_timeRange1;
if (i==0){
start1 = CMTimeMakeWithSeconds(0.0, anAsset.duration.timescale);
duration1 = CMTimeMakeWithSeconds(start_time, anAsset.duration.timescale);
}else if (i==1){
start1 = CMTimeMakeWithSeconds(start_time, anAsset.duration.timescale);
duration1 = CMTimeMakeWithSeconds(end_time-start_time, anAsset.duration.timescale);
}
else if (i==2){
start1 = CMTimeMakeWithSeconds(end_time, anAsset.duration.timescale);
duration1 = CMTimeMakeWithSeconds(anAsset.duration.timescale, anAsset.duration.timescale);
}
video_timeRange1 = CMTimeRangeMake(start,duration);*/
[compositionTrack2 insertTimeRange:video_timeRange ofTrack:clipVideoTrackB1 atTime:start error:nil];
}
以上代码确定3个视频的时间范围（实际上是2个视频），但我必须在预定的时间间隔内将第2个视频嵌入到第1个视频中。
以下代码将创建我所拥有的所有资产的可变组合：
AVMutableVideoCompositionInstruction *vtemp = [AVMutableVideoCompositionInstruction videoCompositionInstruction];
vtemp.timeRange = CMTimeRangeMake(kCMTimeZero, time);
NSLog(@"\nInstruction vtemp's time range is %f %f", CMTimeGetSeconds( vtemp.timeRange.start),
CMTimeGetSeconds(vtemp.timeRange.duration));
// Also tried videoCompositionLayerInstructionWithAssetTrack:compositionVideoTrack
AVMutableVideoCompositionLayerInstruction *vLayerInstruction = [AVMutableVideoCompositionLayerInstruction
videoCompositionLayerInstructionWithAssetTrack:compositionTrack];
[vLayerInstruction setTransform:compositionTrack.preferredTransform atTime:kCMTimeZero];
vtemp.layerInstructions = @[vLayerInstruction];
AVMutableVideoComposition *videoComposition = [AVMutableVideoComposition videoComposition];
videoComposition.renderSize = size;
videoComposition.frameDuration = CMTimeMake(1,30);
videoComposition.instructions = @[vtemp];
AVAssetExportSession *exporter = [[AVAssetExportSession alloc] initWithAsset:mixComposition presetName:AVAssetExportPresetHighestQuality];
NSParameterAssert(exporter != nil);
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsPath = [paths objectAtIndex:0]; //Get the docs directory
documentsPath=[documentsPath stringByAppendingString:@"/MergeVideos"];
.....其余的是将视频保存到照片库
提前致谢!!
答案 0 :(得分：0)
我有Swift版本。我的一个工作完美..这是我的一个..经过几个小时的编码终于让这个工作了。很抱歉在Swift中发布答案。希望您觉得这个有帮助。
readyVideoURLs包含所有视频网址。您可以使用此代码合并任意数量的视频。
我正在制作正方形视频。
mainComposition.renderSize = CGSize(width: 600, height: 600)
func mergeVideos() {
let composition = AVMutableComposition()
let compositionTrack = composition.addMutableTrack(withMediaType: AVMediaTypeVideo, preferredTrackID: kCMPersistentTrackID_Invalid)
var current = kCMTimeZero
var assetArr = [AVURLAsset]()
let mainInstruction = AVMutableVideoCompositionInstruction()
for url in readyVideoURLs {
assetArr.append(AVURLAsset(url: url))
print("readyVideoURL vid url:- \(url)")
}
for asset in assetArr {
do {
try compositionTrack.insertTimeRange(CMTimeRangeMake(kCMTimeZero, asset.duration), of: asset.tracks(withMediaType: AVMediaTypeVideo)[0], at: kCMTimeZero)
} catch let error {
print(error.localizedDescription)
}
let instruction = videoCompositionInstructionForTrack(track: compositionTrack, asset: asset)
mainInstruction.layerInstructions.append(instruction)
mainInstruction.timeRange = CMTimeRangeMake(kCMTimeZero, CMTimeAdd(current, asset.duration))
current = CMTimeAdd(current, asset.duration)
}
let mainComposition = AVMutableVideoComposition()
mainComposition.instructions = [mainInstruction]
mainComposition.frameDuration = CMTimeMake(1, 30)
mainComposition.renderSize = CGSize(width: 600, height: 600)
//add audio track
// if let loadedAudioAsset = audioAsset {
// let audioTrack = composition.addMutableTrack(withMediaType: AVMediaTypeAudio, preferredTrackID: 0)
// do {
// try audioTrack.insertTimeRange(CMTimeRangeMake(kCMTimeZero, current),
// of: loadedAudioAsset.tracks(withMediaType: AVMediaTypeAudio)[0], at: kCMTimeZero)
// } catch _ {
// print("Failed to load Audio track")
// }
// }
let finalVideoPath = NSHomeDirectory().appending("/Documents/finalDailyVideo.mp4")
if FileManager.default.fileExists(atPath: finalVideoPath) {
do {
try FileManager.default.removeItem(atPath: finalVideoPath)
} catch let error {
print(error.localizedDescription)
}
}
guard let exporter = AVAssetExportSession(asset: composition, presetName: AVAssetExportPresetHighestQuality) else { return }
exporter.outputURL = URL(fileURLWithPath: finalVideoPath)
exporter.outputFileType = AVFileTypeMPEG4
exporter.shouldOptimizeForNetworkUse = true
saveToAlbum(mergedVidUrl: URL(string:finalVideoPath)!, exporter: exporter)
}
保存到相册
func saveToAlbum(mergedVidUrl : URL, exporter : AVAssetExportSession) {
exportFinalVideo(exporter: exporter) { (completed) in
if completed {
let assetLib = ALAssetsLibrary()
assetLib.writeVideoAtPath(toSavedPhotosAlbum: mergedVidUrl, completionBlock: { (assetUrl, error) in
if error == nil {
DispatchQueue.main.async {
self.showAlert(title: "Congrats..",message: "Your daily Vlog was saved in albums", actionTitle: "Got it")
}
}
})
}
}
}
让出口商完成
func exportFinalVideo(exporter: AVAssetExportSession, completion:@escaping(Bool) -> ()) {
exporter.exportAsynchronously() {
if exporter.status == .exporting {
print("EXPORTING...")
} else if exporter.status == .completed {
print("merged video exporting DONE")
DispatchQueue.main.async {
self.dismiss(animated: true, completion: nil)
}
completion(true)
} else if exporter.status == .failed {
completion(false)
self.showAlert(title: "Oops!", message: "Something went wrong. Video could not be created.", actionTitle: "Okay!")
}
}
}
用于定位的视频图层说明
func videoCompositionInstructionForTrack(track: AVCompositionTrack, asset: AVAsset) -> AVMutableVideoCompositionLayerInstruction {
let instruction = AVMutableVideoCompositionLayerInstruction(assetTrack: track)
let assetTrack = asset.tracks(withMediaType: AVMediaTypeVideo)[0]
let transform = assetTrack.preferredTransform
let assetInfo = orientationFromTransform(transform: transform)
var scaleToFitRatio = UIScreen.main.bounds.width / assetTrack.naturalSize.width
if assetInfo.isPortrait {
scaleToFitRatio = UIScreen.main.bounds.width / assetTrack.naturalSize.height
let scaleFactor = CGAffineTransform(scaleX: scaleToFitRatio, y: scaleToFitRatio)
instruction.setTransform(assetTrack.preferredTransform.concatenating(scaleFactor),
at: kCMTimeZero)
} else {
let scaleFactor = CGAffineTransform(scaleX: scaleToFitRatio, y: scaleToFitRatio)
var concat = assetTrack.preferredTransform.concatenating(scaleFactor).concatenating(CGAffineTransform(translationX: 0, y: UIScreen.main.bounds.width / 2))
if assetInfo.orientation == .down {
let fixUpsideDown = CGAffineTransform(rotationAngle: CGFloat(Double.pi))
let windowBounds = UIScreen.main.bounds
let yFix = assetTrack.naturalSize.height + windowBounds.height
let centerFix = CGAffineTransform(translationX: assetTrack.naturalSize.width, y: yFix)
concat = fixUpsideDown.concatenating(centerFix).concatenating(scaleFactor)
}
instruction.setTransform(concat, at: kCMTimeZero)
}
return instruction
}
func orientationFromTransform(transform: CGAffineTransform) -> (orientation: UIImageOrientation, isPortrait: Bool) {
var assetOrientation = UIImageOrientation.up
var isPortrait = false
if transform.a == 0 && transform.b == 1.0 && transform.c == -1.0 && transform.d == 0 {
assetOrientation = .right
isPortrait = true
} else if transform.a == 0 && transform.b == -1.0 && transform.c == 1.0 && transform.d == 0 {
assetOrientation = .left
isPortrait = true
} else if transform.a == 1.0 && transform.b == 0 && transform.c == 0 && transform.d == 1.0 {
assetOrientation = .up
} else if transform.a == -1.0 && transform.b == 0 && transform.c == 0 && transform.d == -1.0 {
assetOrientation = .down
}
return (assetOrientation, isPortrait)
}