Objective c 在ios中连接两个视频

我正在尝试合并两个视频，但它总是引发以下异常：

-[NSURL tracksWithMediaType:]：无法识别的选择器发送到实例0x935cf10

2012-08-09 16:26:59.492 videoTest[3920:17903]由于未捕获的异常“NSInvalidArgumentException”而终止应用程序，原因：'-[NSURL tracksWithMediaType:：

代码如下：

AVMutableComposition *mixComposition = [AVMutableComposition composition];
AVMutableCompositionTrack *compositionTrack = [mixComposition addMutableTrackWithMediaType:AVMediaTypeVideo preferredTrackID:kCMPersistentTrackID_Invalid];
NSError * error = nil;
NSMutableArray * timeRanges = [NSMutableArray arrayWithCapacity:videoClipPaths.count];
NSMutableArray * tracks = [NSMutableArray arrayWithCapacity:videoClipPaths.count];
for (int i=0; i<[videoClipPaths count]; i++) {
    AVURLAsset *assetClip = [videoClipPaths objectAtIndex:i];
    AVAssetTrack *clipVideoTrackB = [[assetClip tracksWithMediaType:AVMediaTypeVideo] objectAtIndex:0];
        
    [timeRanges addObject:[NSValue valueWithCMTimeRange:CMTimeRangeMake(kCMTimeZero, assetClip.duration)]];
    [tracks addObject:clipVideoTrackB];
}
[compositionTrack insertTimeRanges:timeRanges ofTracks:tracks atTime:kCMTimeZero error:&error];
    
AVAssetExportSession *exporter = [[AVAssetExportSession alloc] initWithAsset:mixComposition presetName:AVAssetExportPreset1280x720];
NSParameterAssert(exporter != nil);
NSArray *t;
NSString *u;
    
t = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
u = [t objectAtIndex:0];
NSString *finalPath = [u stringByAppendingPathComponent:@"final.mov"];
NSURL *lastURL = [NSURL fileURLWithPath:finalPath];
exporter.outputFileType = AVFileTypeQuickTimeMovie;
exporter.outputURL = lastURL;
[exporter exportAsynchronouslyWithCompletionHandler:^(void){
    switch (exporter.status) {
        case AVAssetExportSessionStatusFailed:
            NSLog(@"exporting failed");
            break;
        case AVAssetExportSessionStatusCompleted:
            NSLog(@"exporting completed");
            //UISaveVideoAtPathToSavedPhotosAlbum(filePath, self, nil, NULL);
            break;
        case AVAssetExportSessionStatusCancelled:
            NSLog(@"export cancelled");
            break;
    }
}]; 

AVMutableComposition*mixComposition=[AVMutableComposition]；
AVMutableCompositionTrack*compositionTrack=[mixComposition addMutableTrackWithMediaType:AVMediaTypeVideo preferredTrackID:kCMPersistentTrackID_无效]；
n错误*错误=nil；
NSMutableArray*时间范围=[NSMutableArray阵列容量：VideoClippath.count]；
NSMutableArray*跟踪=[NSMutableArray阵列容量：VideoClippath.count]；
for（int i=0；i
assetClip
是一个
avurlaste
。但是它看起来像是在给它分配一个
NSURL
对象。然后你在它上面调用
tracksWithMediaType
，这是
NSURL
没有的方法。这就是为什么你会得到“无法识别的选择器”

我对这个特殊的类家族不是很熟悉，但是如果替换它，它可能会解决您的问题

    AVURLAsset *assetClip = [videoClipPaths objectAtIndex:i];

与

我通过替换此代码修复了它：

AVAssetExportSession *exporter = [[AVAssetExportSession alloc] initWithAsset:mixComposition presetName:AVAssetExportPreset1280x720]; NSParameterAssert(exporter != nil);

与：

***由于未捕获异常“NSInternalInconsistencyException”而终止应用程序，原因是：“无效参数不满足：exporter！=nil”，而不是：AVAssetExportSession*exporter=[[AVAssetExportSession alloc]initWithAsset:mixComposition预设名称：AVAssetExportPreset1280x720]；NSParameterAssert（exporter！=nil）；我将AVAssetExportSession*exporter=[[AVAssetExportSession alloc]initWithAsset:mixComposition预设名称：AVAssetExportPresetHighestQuality]；似乎还有另一个问题。很高兴看到你解决了。很抱歉，我昨天无法为你提供更多帮助。
AVAssetExportSession *exporter = [[AVAssetExportSession alloc] initWithAsset:mixComposition presetName:AVAssetExportPreset1280x720]; NSParameterAssert(exporter != nil);

AVAssetExportSession *exporter = [[AVAssetExportSession alloc] initWithAsset:mixComposition presetName:AVAssetExportPresetHighestQuality];