iOS-OC-合并视频（两个视频和成一个视频）

说明：两个视频合并成一个视频，左边一部分，右边一部分，可以同时播放；类似于软件Sing，仿Sing视频合并

+ (void)convertWithLocalVideoUrl1:(NSURL *)url1 videoUrl2:(NSURL *)url2 half:(BOOL)half progress:(void (^)(CGFloat prog))progress resultURL:(void (^)(NSString *errorCode, NSString *convertUrl))resultURL
{
//判断本地是否有合成后的视频
NSString *videoName1 = [[[url1 path] componentsSeparatedByString:@"/"]lastObject];
NSString *videoName2 = [[[url2 path] componentsSeparatedByString:@"/"]lastObject];

NSString *str = [NSString stringWithFormat:@"%@%@%@.mp4",
!half?@"xingyin/":@"",
[[videoName1 componentsSeparatedByString:@"."] firstObject],
[[videoName2 componentsSeparatedByString:@"."] firstObject]
];
if ([RequestHelper getCacheDownloadObjectWith:str] != nil && [RequestHelper getCacheDownloadObjectWith:str].length>0) {
//本地有数据
resultURL(@"0",[RequestHelper getCacheDownloadObjectWith:str]);
return;

}

MirrorType type = kMirror4Square;
NSString *mirrorType = @"MirrorType";
NSUserDefaults *userDefaultes = [NSUserDefaults standardUserDefaults];
[userDefaultes setInteger:type forKey:mirrorType];
if (half) {
[userDefaultes setBool:YES forKey:@"kConvertVideo"];
}else{
[userDefaultes setBool:NO forKey:@"kConvertVideo"];
}

dispatch_async(dispatch_get_main_queue(), ^{
AVMutableComposition *composition =[AVMutableComposition composition];
NSMutableArray *audioMixParams = [NSMutableArray array];

//录制的视频1
AVURLAsset *songAsset = [AVURLAsset URLAssetWithURL:url1 options:nil];
CMTime startTime =CMTimeMakeWithSeconds(0,songAsset.duration.timescale);
CMTime trackDuration =songAsset.duration;
//获取视频中的音频素材
[self setUpAndAddAudioAtPath:url1 toComposition:composition start:startTime dura:trackDuration offset:CMTimeMake(14*44100,44100) andArray:audioMixParams];

//录制的视频2
AVURLAsset *songAsset1 = [AVURLAsset URLAssetWithURL:url1 options:nil];
CMTime startTime1 =CMTimeMakeWithSeconds(0,songAsset1.duration.timescale);
CMTime trackDuration1 =songAsset1.duration;
//获取视频中的音频素材
[self setUpAndAddAudioAtPath:url2 toComposition:composition start:startTime1 dura:trackDuration1 offset:CMTimeMake(14*44100,44100) andArray:audioMixParams];

//创建一个可变的音频混合
AVMutableAudioMix *audioMix =[AVMutableAudioMix audioMix];
audioMix.inputParameters =[NSArray arrayWithArray:audioMixParams];//从数组里取出处理后的音频轨道参数

//创建一个输出
AVAssetExportSession *exporter =[[AVAssetExportSession alloc]
initWithAsset:composition
presetName:AVAssetExportPresetAppleM4A];
exporter.audioMix = audioMix;
exporter.outputFileType=@"com.apple.m4a-audio";

//视频的声音，合成后存储
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSLibraryDirectory,NSUserDomainMask,YES);
NSString*path=[paths objectAtIndex:0];

NSString *movDirectory = [path stringByAppendingPathComponent:@"/Caches/overMix.mov"];//[path stringByAppendingPathComponent:@"/Caches/com.hackemist.SDWebImageCache.default/overMix.mov"];

if([[NSFileManager defaultManager]fileExistsAtPath:movDirectory]) {
[[NSFileManager defaultManager]removeItemAtPath:movDirectory error:nil];
}

NSURL *exportURL =[NSURL fileURLWithPath:movDirectory];
exporter.outputURL = exportURL;

[exporter exportAsynchronouslyWithCompletionHandler:^{
//音频合成后
NSArray *array = [NSArray arrayWithObjects:
[url1 relativePath],
[url2 relativePath],
nil];

[[ExportEffects sharedInstance] setExportProgressBlock: ^(NSNumber *percentage){

//label.text = [NSString stringWithFormat:@"%d%%",(int)([percentage floatValue]*100)];
//[percentage intValue] == 1.0?[label removeFromSuperview]:label;
//NSLog(@"percentage = %f",[percentage floatValue]);

progress([percentage floatValue]);
}];
[[ExportEffects sharedInstance] setFinishVideoBlock: ^(BOOL success, id result) {

if([[NSFileManager defaultManager]fileExistsAtPath:movDirectory]) {
[[NSFileManager defaultManager]removeItemAtPath:movDirectory error:nil];
}
dispatch_async(dispatch_get_main_queue(), ^{

resultURL(success?@"0":@"1",success?result:nil);

});
}];

[[ExportEffects sharedInstance] addEffectToVideo:array withAudioFilePath:movDirectory half:half];
}];
});
}


获取视频中的音频素材

//3.通过文件路径建立和添加音频素材
+ (void)setUpAndAddAudioAtPath:(NSURL*)assetURL toComposition:(AVMutableComposition*)composition start:(CMTime)start dura:(CMTime)dura offset:(CMTime)offset andArray:(NSMutableArray *)audioMixParams{

AVURLAsset *songAsset = [AVURLAsset URLAssetWithURL:assetURL options:nil];

AVMutableCompositionTrack *track = [composition addMutableTrackWithMediaType:AVMediaTypeAudio preferredTrackID:kCMPersistentTrackID_Invalid];
AVAssetTrack *sourceAudioTrack = [[songAsset tracksWithMediaType:AVMediaTypeAudio]objectAtIndex:0];

NSError *error = nil;
BOOL ok = NO;

CMTime startTime = start;
CMTime trackDuration = dura;
CMTimeRange tRange =CMTimeRangeMake(startTime,trackDuration);

//设置音量
//AVMutableAudioMixInputParameters（输入参数可变的音频混合）
//audioMixInputParametersWithTrack（音频混音输入参数与轨道）
AVMutableAudioMixInputParameters *trackMix = [AVMutableAudioMixInputParameters audioMixInputParametersWithTrack:track];
[trackMix setVolume:0.8f atTime:startTime];
//素材加入数组
[audioMixParams addObject:trackMix];

//Insert audio into track //offsetCMTimeMake(0, 44100)
ok = [track insertTimeRange:tRange ofTrack:sourceAudioTrack atTime:kCMTimeInvalid error:&error];
}

ExportEffects类下载地址：http://download.csdn.net/detail/u014220518/9529474