iOS视频添加背景音乐同时保留原音

话不多说，请看代码：

//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; 
} 

以上就是本文的全部内容，希望本文的内容对大家的学习或者工作能带来一定的帮助，同时也希望多多支持！