Crop Audio Files - ios

Question

I want to implement audio trimming in iOS, I want something like a two way slider that the user can slide over a particular period of the recorded audio, and then I will save that audio lie the image below

Answer 1

AVAssetExportSession - Exporting a Trimmed Audio Asset
The below code will do the job for you please refer to this link for further detail
- (BOOL)exportAsset:(AVAsset *)avAsset toFilePath:(NSString *)filePath {
// we need the audio asset to be at least 50 seconds long for this snippet
CMTime assetTime = [avAsset duration];
Float64 duration = CMTimeGetSeconds(assetTime);
if (duration < 50.0) return NO;
// get the first audio track
NSArray *tracks = [avAsset tracksWithMediaType:AVMediaTypeAudio];
if ([tracks count] == 0) return NO;
AVAssetTrack *track = [tracks objectAtIndex:0];
// create the export session
// no need for a retain here, the session will be retained by the
// completion handler since it is referenced there
AVAssetExportSession *exportSession = [AVAssetExportSession
exportSessionWithAsset:avAsset
presetName:AVAssetExportPresetAppleM4A];
if (nil == exportSession) return NO;
// create trim time range - 20 seconds starting from 30 seconds into the asset
CMTime startTime = CMTimeMake(30, 1);
CMTime stopTime = CMTimeMake(50, 1);
CMTimeRange exportTimeRange = CMTimeRangeFromTimeToTime(startTime, stopTime);
// create fade in time range - 10 seconds starting at the beginning of trimmed asset
CMTime startFadeInTime = startTime;
CMTime endFadeInTime = CMTimeMake(40, 1);
CMTimeRange fadeInTimeRange = CMTimeRangeFromTimeToTime(startFadeInTime,
endFadeInTime);
// setup audio mix
AVMutableAudioMix *exportAudioMix = [AVMutableAudioMix audioMix];
AVMutableAudioMixInputParameters *exportAudioMixInputParameters =
[AVMutableAudioMixInputParameters audioMixInputParametersWithTrack:track];
[exportAudioMixInputParameters setVolumeRampFromStartVolume:0.0 toEndVolume:1.0
timeRange:fadeInTimeRange];
exportAudioMix.inputParameters = [NSArray
arrayWithObject:exportAudioMixInputParameters];
// configure export session output with all our parameters
exportSession.outputURL = [NSURL fileURLWithPath:filePath]; // output path
exportSession.outputFileType = AVFileTypeAppleM4A; // output file type
exportSession.timeRange = exportTimeRange; // trim time range
exportSession.audioMix = exportAudioMix; // fade in audio mix
// perform the export
[exportSession exportAsynchronouslyWithCompletionHandler:^{
if (AVAssetExportSessionStatusCompleted == exportSession.status) {
NSLog(#"AVAssetExportSessionStatusCompleted");
} else if (AVAssetExportSessionStatusFailed == exportSession.status) {
// a failure may happen because of an event out of your control
// for example, an interruption like a phone call comming in
// make sure and handle this case appropriately
NSLog(#"AVAssetExportSessionStatusFailed");
} else {
NSLog(#"Export Session Status: %d", exportSession.status);
}
}];
return YES;
}