Insert audio clip in original audio file at given offset - ios

Question

I am developing an application which has a feature of recording. Now I need to edit it with another clip at specific time location. i.e I have recording of 20 secs, now want to replace it with another audio file at 10th sec with the duration of 5 secs, so my exported audio file will be like first 10sec is my recorded audio, 10th - 15th sec is the clip which I have to replace with original one, and then 15th - 20th sec is again my recorded file.
please help me to find any nearby solution
Thanks in advance.
Here is my code `
-(void)mergeAndSaveWithVideoURLAtFirstOffset:(CMTime)offset1 andSecondOffset:(CMTime)offset2 {
NSURL *video_url = [NSURL fileURLWithPath:[[NSBundle mainBundle] pathForResource:#"Source" ofType:#"mp4"]];
AVMutableComposition* mixComposition = [AVMutableComposition composition];
NSURL *source_audio_url=[NSURL fileURLWithPath:[[NSBundle mainBundle] pathForResource:#"Source" ofType:#"mp3"]];
NSURL *audio_url=[NSURL fileURLWithPath:[[NSBundle mainBundle] pathForResource:#"Asteroid_Sound" ofType:#"mp3"]];
audioAsset = [[AVURLAsset alloc]initWithURL:audio_url options:nil];
source_audioAsset = [[AVURLAsset alloc]initWithURL:source_audio_url options:nil];
CMTimeRange audio_timeRange = CMTimeRangeMake(kCMTimeZero, source_audioAsset.duration);
AVMutableCompositionTrack *b_compositionAudioTrack = [mixComposition addMutableTrackWithMediaType:AVMediaTypeAudio preferredTrackID:kCMPersistentTrackID_Invalid];
[b_compositionAudioTrack insertTimeRange:audio_timeRange ofTrack:[[source_audioAsset tracksWithMediaType:AVMediaTypeAudio] objectAtIndex:0] atTime:kCMTimeZero error:nil];
audio_timeRange = CMTimeRangeMake(kCMTimeZero, audioAsset.duration);
[b_compositionAudioTrack insertTimeRange:audio_timeRange ofTrack:[[audioAsset tracksWithMediaType:AVMediaTypeAudio] objectAtIndex:0] atTime:offset1 error:nil];
[b_compositionAudioTrack insertTimeRange:audio_timeRange ofTrack:[[audioAsset tracksWithMediaType:AVMediaTypeAudio] objectAtIndex:0] atTime:offset2 error:nil];
videoAsset = [[AVURLAsset alloc]initWithURL:video_url options:nil];
CMTimeRange video_timeRange = CMTimeRangeMake(kCMTimeZero,videoAsset.duration);
AVMutableCompositionTrack *a_compositionVideoTrack = [mixComposition addMutableTrackWithMediaType:AVMediaTypeVideo preferredTrackID:kCMPersistentTrackID_Invalid];
[a_compositionVideoTrack insertTimeRange:video_timeRange ofTrack:[[videoAsset tracksWithMediaType:AVMediaTypeVideo] objectAtIndex:0] atTime:kCMTimeZero error:nil];
NSArray *dirPaths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *docsDir = [dirPaths objectAtIndex:0];
NSString *outputFilePath = [docsDir stringByAppendingPathComponent:[NSString stringWithFormat:#"FinalVideo.mov"]];
NSURL *outputFileUrl = [NSURL fileURLWithPath:outputFilePath];
if ([[NSFileManager defaultManager] fileExistsAtPath:outputFilePath])
[[NSFileManager defaultManager] removeItemAtPath:outputFilePath error:nil];
AVAssetExportSession* _assetExport = [[AVAssetExportSession alloc] initWithAsset:mixComposition presetName:AVAssetExportPresetHighestQuality];
_assetExport.outputFileType = #"com.apple.quicktime-movie";
_assetExport.outputURL = outputFileUrl;
[_assetExport exportAsynchronouslyWithCompletionHandler:
^(void ) {
dispatch_async(dispatch_get_main_queue(), ^{
[self exportDidFinish:_assetExport];
});
}];
}`

Answer 1

You have to first trim audio from particular offset may be this url will be helpfull you.
iOS Audio Trimming
After then merge your another audio.