如何将音频添加到iPhone上的视频文件SDK

Question

我有一个视频文件和一个音频文件。是否有可能通过声音文件将它合并到一个视频中。我认为AVMutableComposition应该可以帮助我，但我仍然不知道如何。任何建议？

Answer 1

感谢丹尼尔。我觉得它很简单。

AVURLAsset* audioAsset = [[AVURLAsset alloc]initWithURL:audioUrl options:nil]; 
AVURLAsset* videoAsset = [[AVURLAsset alloc]initWithURL:videoUrl options:nil]; 

AVMutableComposition* mixComposition = [AVMutableComposition composition]; 

AVMutableCompositionTrack *compositionCommentaryTrack = [mixComposition addMutableTrackWithMediaType:AVMediaTypeAudio 
                        preferredTrackID:kCMPersistentTrackID_Invalid]; 
[compositionCommentaryTrack insertTimeRange:CMTimeRangeMake(kCMTimeZero, audioAsset.duration) 
            ofTrack:[[audioAsset tracksWithMediaType:AVMediaTypeAudio] objectAtIndex:0] 
            atTime:kCMTimeZero error:nil]; 

AVMutableCompositionTrack *compositionVideoTrack = [mixComposition addMutableTrackWithMediaType:AVMediaTypeVideo 
                        preferredTrackID:kCMPersistentTrackID_Invalid]; 
[compositionVideoTrack insertTimeRange:CMTimeRangeMake(kCMTimeZero, videoAsset.duration) 
           ofTrack:[[videoAsset tracksWithMediaType:AVMediaTypeVideo] objectAtIndex:0] 
           atTime:kCMTimeZero error:nil]; 

AVAssetExportSession* _assetExport = [[AVAssetExportSession alloc] initWithAsset:mixComposition 
                     presetName:AVAssetExportPresetPassthrough]; 

NSString* videoName = @"export.mov"; 

NSString *exportPath = [NSTemporaryDirectory() stringByAppendingPathComponent:videoName]; 
NSURL *exportUrl = [NSURL fileURLWithPath:exportPath]; 

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

_assetExport.outputFileType = @"com.apple.quicktime-movie"; 
DLog(@"file type %@",_assetExport.outputFileType); 
_assetExport.outputURL = exportUrl; 
_assetExport.shouldOptimizeForNetworkUse = YES; 

[_assetExport exportAsynchronouslyWithCompletionHandler: 
^(void) {  
      // your completion code here 
    }  
} 
]; 

Answer 2

是的，这是可能的，这里是一段代码，用于添加音频到现有的作品，我从苹果示例代码抓住了这个，你应该可以查看整个项目，你会发现它非常有用，项目是AVEditDemo，你可以在他们在这里发布的WWDC 2010资料中找到它。developer.apple.com/videos/wwdc/2010。希望帮助

- (void)addCommentaryTrackToComposition:(AVMutableComposition *)composition withAudioMix:(AVMutableAudioMix *)audioMix 

{ 

NSInteger i; 

NSArray *tracksToDuck = [composition tracksWithMediaType:AVMediaTypeAudio]; // before we add the commentary 



// Clip commentary duration to composition duration. 

CMTimeRange commentaryTimeRange = CMTimeRangeMake(self.commentaryStartTime, self.commentary.duration); 

if (CMTIME_COMPARE_INLINE(CMTimeRangeGetEnd(commentaryTimeRange), >, [composition duration])) 

    commentaryTimeRange.duration = CMTimeSubtract([composition duration], commentaryTimeRange.start); 



// Add the commentary track. 

AVMutableCompositionTrack *compositionCommentaryTrack = [composition addMutableTrackWithMediaType:AVMediaTypeAudio preferredTrackID:kCMPersistentTrackID_Invalid]; 

[compositionCommentaryTrack insertTimeRange:CMTimeRangeMake(kCMTimeZero, commentaryTimeRange.duration) ofTrack:[[self.commentary tracksWithMediaType:AVMediaTypeAudio] objectAtIndex:0] atTime:commentaryTimeRange.start error:nil]; 





NSMutableArray *trackMixArray = [NSMutableArray array]; 

CMTime rampDuration = CMTimeMake(1, 2); // half-second ramps 

for (i = 0; i < [tracksToDuck count]; i++) { 

    AVMutableAudioMixInputParameters *trackMix = [AVMutableAudioMixInputParameters audioMixInputParametersWithTrack:[tracksToDuck objectAtIndex:i]]; 

    [trackMix setVolumeRampFromStartVolume:1.0 toEndVolume:0.2 timeRange:CMTimeRangeMake(CMTimeSubtract(commentaryTimeRange.start, rampDuration), rampDuration)]; 

    [trackMix setVolumeRampFromStartVolume:0.2 toEndVolume:1.0 timeRange:CMTimeRangeMake(CMTimeRangeGetEnd(commentaryTimeRange), rampDuration)]; 

    [trackMixArray addObject:trackMix]; 

} 

audioMix.inputParameters = trackMixArray; 

}

Answer 3

这里是SWIFT版本：

func mixAudio(audioURL audioURL: NSURL, videoURL: NSURL) { 
    let audioAsset = AVURLAsset(URL: audioURL) 
    let videoAsset = AVURLAsset(URL: videoURL) 

    let mixComposition = AVMutableComposition() 

    let compositionCommentaryTrack = mixComposition.addMutableTrackWithMediaType(AVMediaTypeAudio, preferredTrackID: kCMPersistentTrackID_Invalid) 

    // add audio 
    let timeRange = CMTimeRangeMake(kCMTimeZero, audioAsset.duration) 
    let track = audioAsset.tracksWithMediaType(AVMediaTypeAudio)[0] 
    do { 
     try compositionCommentaryTrack.insertTimeRange(timeRange, ofTrack: track, atTime: kCMTimeZero) 
    } 
    catch { 
     print("Error insertTimeRange for audio track \(error)") 
    } 

    // add video 
    let compositionVideoTrack = mixComposition.addMutableTrackWithMediaType(AVMediaTypeVideo, preferredTrackID: kCMPersistentTrackID_Invalid) 

    let timeRangeVideo = CMTimeRangeMake(kCMTimeZero, videoAsset.duration) 
    let trackVideo = videoAsset.tracksWithMediaType(AVMediaTypeVideo)[0] 
    do { 
     try compositionVideoTrack.insertTimeRange(timeRangeVideo, ofTrack: trackVideo, atTime: kCMTimeZero) 
    } 
    catch { 
     print("Error insertTimeRange for video track \(error)") 
    } 

    // export 
    let assetExportSession = AVAssetExportSession(asset: mixComposition, presetName: AVAssetExportPresetPassthrough) 
    let videoName = "export.mov" 
    exportPath = "\(NSTemporaryDirectory())/\(videoName)" 
    let exportURL = NSURL(fileURLWithPath: exportPath!) 

    if NSFileManager.defaultManager().fileExistsAtPath(exportPath!) { 
     do { 
      try NSFileManager.defaultManager().removeItemAtPath(exportPath!) 
     } 
     catch { 
      print("Error deleting export.mov: \(error)") 
     } 
    } 

    assetExportSession?.outputFileType = "com.apple.quicktime-movie" 
    assetExportSession?.outputURL = exportURL 
    assetExportSession?.shouldOptimizeForNetworkUse = true 
    assetExportSession?.exportAsynchronouslyWithCompletionHandler({ 
     print("Mixed audio and video!") 
     dispatch_async(dispatch_get_main_queue(), { 
      print(self.exportPath!) 

     }) 
    }) 

}