使用AVMutableComposition将声音与视频合成一个视频

/** *  合成视频输出到指定路径,注意区分是否3D视频 * *  @param audioUrl     音频文件url *  @param videoUrl     视频文件url *  @param storePath    沙盒目录下的文件夹 *  @param storeName    合成的文件名字 *  @param tbool        是否3D视频,YES表示是3D视频 *  @param successBlock 成功block *  @param failureBlcok 失败block */-(void)mergeAudio:(NSURL*)audioUrl andVideo:(NSURL *)videoUrl toStorePath:(NSString *)storePath WithStoreName:(NSString *)storeName andIf3D:(BOOL)tbool success:(void (^)(void))successBlock failure:(void (^)(void))failureBlcok{    AVMutableComposition *mixComposition = [self mergeAudio:audioUrl andVideo:videoUrl];    NSURL *outputFileUrl = [self joinStorePaht:storePath togetherStoreName:storeName];    [self storeAVMutableComposition:mixComposition withStoreUrl:outputFileUrl andVideoUrl:videoUrl WihtName:storeName andIf3D:tbool success:successBlock failure:failureBlcok];}/***  音频视频合成得到AVMutableComposition,以较短文件长度作为时间长度**  @param audioUrl 音频文件*  @param videoUrl 视频文件**  @return AVMutableComposition*/-(AVMutableComposition *)mergeAudio:(NSURL*)audioUrl andVideo:(NSURL *)videoUrl{    AVMutableComposition* mixComposition = [AVMutableComposition composition];        AVURLAsset *audioAsset = [[AVURLAsset alloc]initWithURL:audioUrl options:nil];    AVURLAsset *videoAsset = [[AVURLAsset alloc]initWithURL:videoUrl options:nil];        CMTime ctime;        if (CMTimeGetSeconds(audioAsset.duration)>=CMTimeGetSeconds(videoAsset.duration))    {        ctime = videoAsset.duration;    }else    {        ctime = audioAsset.duration;    }        CMTimeRange audio_timeRange = CMTimeRangeMake(kCMTimeZero, ctime);        AVMutableCompositionTrack *b_compositionAudioTrack = [mixComposition addMutableTrackWithMediaType:AVMediaTypeAudio preferredTrackID:kCMPersistentTrackID_Invalid];    [b_compositionAudioTrack insertTimeRange:audio_timeRange ofTrack:[[audioAsset tracksWithMediaType:AVMediaTypeAudio] objectAtIndex:0] atTime:kCMTimeZero error:nil];            CMTimeRange video_timeRange = CMTimeRangeMake(kCMTimeZero,ctime);        AVMutableCompositionTrack *a_compositionVideoTrack = [mixComposition addMutableTrackWithMediaType:AVMediaTypeVideo preferredTrackID:kCMPersistentTrackID_Invalid];    [a_compositionVideoTrack insertTimeRange:video_timeRange ofTrack:[[videoAsset tracksWithMediaType:AVMediaTypeVideo] objectAtIndex:0] atTime:kCMTimeZero error:nil];    return mixComposition;}/** *  拼接url地址 * *  @param sPath 沙盒文件夹名 *  @param sName 文件名称 * *  @return 返回拼接好的url地址 */-(NSURL *)joinStorePaht:(NSString *)sPath togetherStoreName:(NSString *)sName{    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);    NSString *documentPath = [paths objectAtIndex:0];    NSFileManager *fileManager = [NSFileManager defaultManager];        NSString *storePath = [documentPath stringByAppendingPathComponent:sPath];    BOOL isExist = [fileManager fileExistsAtPath:storePath];    if(!isExist){        [fileManager createDirectoryAtPath:storePath withIntermediateDirectories:YES attributes:nil error:nil];    }    NSString *realName = [NSString stringWithFormat:@"%@.mp4", sName];    storePath = [storePath stringByAppendingPathComponent:realName];    NSURL *outputFileUrl = [NSURL fileURLWithPath:storePath];    return outputFileUrl;}/** *  存储合成的视频 * *  @param mixComposition mixComposition参数 *  @param storeUrl       存储的路径 *  @param successBlock   successBlock *  @param failureBlcok   failureBlcok */-(void)storeAVMutableComposition:(AVMutableComposition*)mixComposition withStoreUrl:(NSURL *)storeUrl andVideoUrl:(NSURL *)videoUrl WihtName:(NSString *)aName andIf3D:(BOOL)tbool success:(void (^)(void))successBlock failure:(void (^)(void))failureBlcok{    __weak typeof(self) welf = self;    AVAssetExportSession* _assetExport = [[AVAssetExportSession alloc] initWithAsset:mixComposition presetName:AVAssetExportPresetHighestQuality];    _assetExport.outputFileType = @"com.apple.quicktime-movie";    //    _assetExport.outputFileType = @"public.mpeg-4";    _assetExport.outputURL = storeUrl;    [_assetExport exportAsynchronouslyWithCompletionHandler:^{        dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{            //在系统相册存储一份            UISaveVideoAtPathToSavedPhotosAlbum([storeUrl path], nil, nil, nil);//            在本地沙盒中存储一份,存储成功返回YES,如果不想存到沙盒,直接返回调用<span style="font-family: Arial, Helvetica, sans-serif;">successBlock();</span>//                        BOOL successful = [welf.photoStore storeVideoImageScale:videoUrl WihtName:aName andIf3D:tbool];//                        dispatch_async(dispatch_get_main_queue(), ^{//                            if (successful) {//                                successBlock();//                            }else//                            {//                                failureBlcok();//                            }//                        });            successBlock();        });    }];}