AVAssetExportSession and fade-in fade-out Effect - ios

Question

I am triming audio file using AVAssetExportSession but unable to achive fade in fade out effect in saved file. Here's the code that i am using.
[[NSFileManager defaultManager] removeItemAtURL:audioFileOutput error:NULL];
AVAsset *asset = [AVAsset assetWithURL:[NSURL fileURLWithPath:file_path]];
AVAssetExportSession *exportSession = [AVAssetExportSession exportSessionWithAsset:asset
presetName:AVAssetExportPresetAppleM4A];
time = floorf(Endtime-startTime);
CMTime start = CMTimeMake(0.0*100,100);
CMTime stop = CMTimeMake(time*100,100);
CMTimeRange exportTimeRange = CMTimeRangeFromTimeToTime(start, stop);
AVMutableAudioMix *mutableAudioMix = [AVMutableAudioMix audioMix];
AVURLAsset* audio = [[AVURLAsset alloc]initWithURL:[NSURL URLWithString:file_path] options:nil];
AVAssetTrack* audioTrack = [[audio tracksWithMediaType:AVMediaTypeAudio]
objectAtIndex:0];
AVMutableAudioMixInputParameters *mixParameters = [AVMutableAudioMixInputParameters audioMixInputParametersWithTrack:audioTrack];
[mixParameters setVolumeRampFromStartVolume:1.0 toEndVolume:0.0 timeRange:exportTimeRange];
mutableAudioMix.inputParameters = #[mixParameters];
exportSession.audioMix = mutableAudioMix;
exportSession.outputURL = audioFileOutput;
exportSession.outputFileType = AVFileTypeAppleM4A;
exportSession.timeRange = exportTimeRange;
[SVProgressHUD showWithStatus:#"Saving Recording.." maskType:SVProgressHUDMaskTypeBlack];
[exportSession exportAsynchronouslyWithCompletionHandler:^
{
dispatch_async(dispatch_get_main_queue(), ^{
if (AVAssetExportSessionStatusCompleted == exportSession.status)
{
[SVProgressHUD dismiss];
NSLog(#"Success!");
NSLog(#"saving complete %#", exportSession.description);
NSLog(#"the Song Path : %#", strOutputFilePath);
}
else if (AVAssetExportSessionStatusFailed == exportSession.status)
{
NSLog(#"failed");
[SVProgressHUD showErrorWithStatus:#"Record Again"];
}
[[NSFileManager defaultManager] removeItemAtPath:file_path error:nil];
});
}];
I don't know what am i missing. Any help is appreciated.

Answer 1

Well try something like this
AVMutableAudioMix *exportAudioMix = [AVMutableAudioMix audioMix];
AVAssetTrack *assetTrack = [[asset tracksWithMediaType:AVMediaTypeAudio]objectAtIndex:0];
AVMutableAudioMixInputParameters *exportAudioMixInputParameters = [AVMutableAudioMixInputParameters audioMixInputParametersWithTrack:assetTrack];
exportAudioMixInputParameters.trackID = [[[asset tracksWithMediaType:AVMediaTypeAudio]objectAtIndex:0] trackID];
NSMutableArray* inputParameters = [NSMutableArray arrayWithCapacity:1];
CMTime startFadeInTime = start;
CMTime endFadeInTime = CMTimeMake((startTime+2)*100, 100);
CMTime startFadeOutTime = CMTimeMake((time-2)*100, 100);
CMTime endFadeOutTime = CMTimeMake(time*100, 100);
CMTimeRange fadeInTimeRange = CMTimeRangeFromTimeToTime(startFadeInTime, endFadeInTime);
CMTimeRange fadeOutTimeRange = CMTimeRangeFromTimeToTime(startFadeOutTime, endFadeOutTime);
[exportAudioMixInputParameters setVolumeRampFromStartVolume:0.0 toEndVolume:1.0 timeRange:fadeInTimeRange];
[exportAudioMixInputParameters setVolumeRampFromStartVolume:1.0 toEndVolume:0.0 timeRange:fadeOutTimeRange];
[inputParameters insertObject:exportAudioMixInputParameters atIndex:0];
Hope it will help. Happy coding.