小编van*_*goz的帖子

我正在尝试使用AVAssetExportSession合并(追加)3个视频,但我一直收到此错误.奇怪的是它有1或2个视频.

Error Domain=AVFoundationErrorDomain Code=-11820 "Cannot Complete Export" UserInfo=0x458120 {NSLocalizedRecoverySuggestion=Try exporting again., NSLocalizedDescription=Cannot Complete Export}

我甚至尝试重做函数以防出错,但我得到的只是无限错误信息.这是我的代码片段.

AVMutableComposition *mixComposition = [AVMutableComposition composition];
AVMutableCompositionTrack *compositionTrack = [mixComposition addMutableTrackWithMediaType:AVMediaTypeVideo preferredTrackID:kCMPersistentTrackID_Invalid];
NSError * error = nil;
NSMutableArray * timeRanges = [NSMutableArray arrayWithCapacity:arrayMovieUrl.count];
NSMutableArray * tracks = [NSMutableArray arrayWithCapacity:arrayMovieUrl.count];

for (int i=0; i<[arrayMovieUrl count]; i++) {
    AVURLAsset *assetClip = [arrayMovieUrl 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]; …

假设我有一个数据库表，我想根据布尔属性（例如“标记”属性）进行过滤。是只向表添加“标记”属性更好，还是创建一个具有基表外键的新表？优缺点都有什么？