iOS中如何给视频添加背景音乐同时保留原音

//抽取原视频的音频与需要的音乐混合 -(void)addmusic:(id)sender { [MBProgressHUDshowHUDAddedTo:self.viewanimated:YES]; AVMutableComposition *composition =[AVMutableCompositioncomposition]; audioMixParams =[[NSMutableArrayalloc]initWithObjects:nil]; //录制的视频 NSURL *video_inputFileUrl =[NSURLfileURLWithPath:self.videoPath]; AVURLAsset *songAsset =[AVURLAssetURLAssetWithURL:video_inputFileUrloptions:nil]; CMTime startTime =CMTimeMakeWithSeconds(0,songAsset.duration.timescale); CMTime trackDuration =songAsset.duration; //获取视频中的音频素材 [selfsetUpAndAddAudioAtPath:video_inputFileUrltoComposition:compositionstart:startTimedura:trackDurationoffset:CMTimeMake(14*44100,44100)]; //本地要插入的音乐 NSString *bundleDirectory =[[NSBundlemainBundle]bundlePath]; NSString *path = [bundleDirectorystringByAppendingPathComponent:@"30secs.mp3"]; NSURL *assetURL2 =[NSURLfileURLWithPath:path]; //获取设置完的本地音乐素材 [selfsetUpAndAddAudioAtPath:assetURL2toComposition:compositionstart:startTimedura:trackDurationoffset:CMTimeMake(0,44100)]; //创建一个可变的音频混合 AVMutableAudioMix *audioMix =[AVMutableAudioMixaudioMix]; audioMix.inputParameters =[NSArrayarrayWithArray: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 =[[AVAssetExportSessionalloc] initWithAsset:composition presetName:AVAssetExportPresetAppleM4A]; exporter.audioMix = audioMix; exporter.outputFileType=@"com.apple.m4a-audio"; NSString* fileName =[NSStringstringWithFormat:@"%@.mov",@"overMix"]; //输出路径 NSString *exportFile =[NSStringstringWithFormat:@"%@/%@",[selfgetLibarayPath], fileName]; if([[NSFileManagerdefaultManager]fileExistsAtPath:exportFile]) { [[NSFileManagerdefaultManager]removeItemAtPath:exportFileerror:nil]; } NSLog(@"是否在主线程1%d",[NSThreadisMainThread]); NSLog(@"输出路径===%@",exportFile); NSURL *exportURL =[NSURLfileURLWithPath:exportFile]; exporter.outputURL = exportURL; self.mixURL =exportURL; [exporterexportAsynchronouslyWithCompletionHandler:^{ int exportStatus =(int)exporter.status; switch (exportStatus){ caseAVAssetExportSessionStatusFailed:{ NSError *exportError =exporter.error; NSLog(@"错误，信息: %@", exportError); [MBProgressHUDhideHUDForView:self.viewanimated:YES]; break; } caseAVAssetExportSessionStatusCompleted:{ NSLog(@"是否在主线程2%d",[NSThreadisMainThread]); NSLog(@"成功"); //最终混合 [selftheVideoWithMixMusic]; break; } } }]; } //最终音频和视频混合 -(void)theVideoWithMixMusic { NSError *error =nil; NSFileManager *fileMgr =[NSFileManagerdefaultManager]; NSString *documentsDirectory =[NSHomeDirectory() stringByAppendingPathComponent:@"Documents"]; NSString *videoOutputPath =[documentsDirectorystringByAppendingPathComponent:@"test_output.mp4"]; if ([fileMgrremoveItemAtPath:videoOutputPatherror:&error]!=YES) { NSLog(@"无法删除文件，错误信息：%@",[error localizedDescription]); } //声音来源路径（最终混合的音频） NSURL *audio_inputFileUrl =self.mixURL; //视频来源路径 NSURL *video_inputFileUrl = [NSURLfileURLWithPath:self.videoPath]; //最终合成输出路径 NSString *outputFilePath =[documentsDirectorystringByAppendingPathComponent:@"final_video.mp4"]; NSURL *outputFileUrl = [NSURLfileURLWithPath:outputFilePath]; if([[NSFileManagerdefaultManager]fileExistsAtPath:outputFilePath]) [[NSFileManagerdefaultManager]removeItemAtPath:outputFilePatherror:nil]; CMTime nextClipStartTime =kCMTimeZero; //创建可变的音频视频组合 AVMutableComposition* mixComposition =[AVMutableCompositioncomposition]; //视频采集 AVURLAsset* videoAsset =[[AVURLAssetalloc]initWithURL:video_inputFileUrloptions:nil]; CMTimeRange video_timeRange =CMTimeRangeMake(kCMTimeZero,videoAsset.duration); AVMutableCompositionTrack*a_compositionVideoTrack = [mixCompositionaddMutableTrackWithMediaType:AVMediaTypeVideopreferredTrackID:kCMPersistentTrackID_Invalid]; [a_compositionVideoTrackinsertTimeRange:video_timeRangeofTrack:[[videoAssettracksWithMediaType:AVMediaTypeVideo]objectAtIndex:0]atTime:nextClipStartTimeerror:nil]; //声音采集 AVURLAsset* audioAsset =[[AVURLAssetalloc]initWithURL:audio_inputFileUrloptions:nil]; CMTimeRange audio_timeRange =CMTimeRangeMake(kCMTimeZero,videoAsset.duration);//声音长度截取范围==视频长度 AVMutableCompositionTrack*b_compositionAudioTrack = [mixCompositionaddMutableTrackWithMediaType:AVMediaTypeAudiopreferredTrackID:kCMPersistentTrackID_Invalid]; [b_compositionAudioTrackinsertTimeRange:audio_timeRangeofTrack:[[audioAssettracksWithMediaType:AVMediaTypeAudio]objectAtIndex:0]atTime:nextClipStartTimeerror:nil]; //创建一个输出 AVAssetExportSession* _assetExport =[[AVAssetExportSessionalloc]initWithAsset:mixCompositionpresetName:AVAssetExportPresetMediumQuality]; _assetExport.outputFileType =AVFileTypeQuickTimeMovie; _assetExport.outputURL =outputFileUrl; _assetExport.shouldOptimizeForNetworkUse=YES; self.theEndVideoURL=outputFileUrl; [_assetExportexportAsynchronouslyWithCompletionHandler: ^(void ) { [MBProgressHUDhideHUDForView:self.viewanimated:YES]; //播放 NSURL*url = [NSURLfileURLWithPath:outputFilePath]; MPMoviePlayerViewController *theMovie =[[MPMoviePlayerViewControlleralloc]initWithContentURL:url]; [selfpresentMoviePlayerViewControllerAnimated:theMovie]; theMovie.moviePlayer.movieSourceType=MPMovieSourceTypeFile; [theMovie.moviePlayerplay]; } ]; NSLog(@"完成！输出路径==%@",outputFilePath); } //通过文件路径建立和添加音频素材 - (void)setUpAndAddAudioAtPath:(NSURL*)assetURLtoComposition:(AVMutableComposition*)composition start:(CMTime)startdura:(CMTime)duraoffset:(CMTime)offset{ AVURLAsset *songAsset =[AVURLAssetURLAssetWithURL:assetURLoptions:nil]; AVMutableCompositionTrack *track =[compositionaddMutableTrackWithMediaType:AVMediaTypeAudiopreferredTrackID:kCMPersistentTrackID_Invalid]; AVAssetTrack *sourceAudioTrack =[[songAssettracksWithMediaType: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 =[AVMutableAudioMixInputParametersaudioMixInputParametersWithTrack:track]; [trackMixsetVolume:0.8fatTime:startTime]; //素材加入数组 [audioMixParamsaddObject:trackMix]; //Insert audio into track //offsetCMTimeMake(0, 44100) ok = [trackinsertTimeRange:tRangeofTrack:sourceAudioTrackatTime:kCMTimeInvaliderror:&error]; } #pragma mark - 保存路径 -(NSString*)getLibarayPath { NSFileManager *fileManager =[NSFileManagerdefaultManager]; NSArray* paths =NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask,YES); NSString* path = [pathsobjectAtIndex:0]; NSString *movDirectory = [pathstringByAppendingPathComponent:@"tmpMovMix"]; [fileManagercreateDirectoryAtPath:movDirectorywithIntermediateDirectories:YESattributes:nilerror:nil]; return movDirectory; }

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