AVAssetExportSession not exporting time range

Question

I have this problem. I'm trimming a sound file via AVAssetExportSession. I set the time range and then export asynchronously. I'm saving the output file under different name than the input file.

It works fine BUT only for the first time. When I try to trim the trimmed file, it exports it with whole duration, but CMTimeRangeShow shows right time range.

Anyone knows, what I'm doing wrong?

Are you sure you're using CMTimeRangeMake correctly? You pass it a start time and a duration, NOT a start and end time. — Nick, Dec 04 '13 at 18:35
Yes, I do it like this: CMTime startTime = CMTimeMultiplyByFloat64(asset.duration, fromPerc); CMTime stopTime = CMTimeMultiplyByFloat64(asset.duration, toPerc); CMTimeRange exportTimeRange = CMTimeRangeFromTimeToTime(startTime, stopTime); — Skiny, Dec 07 '13 at 19:08

score 1 · Answer 1 · answered Oct 27 '14 at 21:41

I am not sure my code is available for you right now because it worked on iOS7. I hope this will help you.

- (BOOL)trimAudio :(NSURL *) url
{
    float vocalStartMarker = timeFrom;
    float vocalEndMarker = timeTo;
    NSURL *audioFileInput = url_Audio;
    NSURL *audioFileOutput = url;

    if (!audioFileInput || !audioFileOutput)
    {
        return NO;
    }

    [[NSFileManager defaultManager] removeItemAtURL:audioFileOutput error:NULL];
    AVAsset *asset = [AVAsset assetWithURL:audioFileInput];

    AVAssetExportSession *exportSession = [AVAssetExportSession exportSessionWithAsset:asset
                                                                            presetName:AVAssetExportPresetAppleM4A];

    if (exportSession == nil)
    {
        return NO;
    }

    CMTime startTime = CMTimeMake((int)(floor(vocalStartMarker * 100)), 100);
    CMTime stopTime = CMTimeMake((int)(ceil(vocalEndMarker * 100)), 100);
    CMTimeRange exportTimeRange = CMTimeRangeFromTimeToTime(startTime, stopTime);

    exportSession.outputURL = audioFileOutput;
    exportSession.outputFileType = AVFileTypeAppleM4A;
    exportSession.timeRange = exportTimeRange;

    [exportSession exportAsynchronouslyWithCompletionHandler:^
     {
         if (AVAssetExportSessionStatusCompleted == exportSession.status)
         {
             // It worked!
         }
         else if (AVAssetExportSessionStatusFailed == exportSession.status)
         {
             // It failed...
             [[[UIAlertView alloc]initWithTitle:@"Unknown Error" message:nil delegate:nil cancelButtonTitle:@"Ok" otherButtonTitles:nil]show];
         }
     }];

    return YES;
}

score 1 · Answer 2 · answered Aug 08 '16 at 08:20

1

You should check if the output file already exists.

"exportAsynchronouslyWithCompletionHandler" does not overwrite outputfile.

answered Aug 08 '16 at 08:20

Sparky

119
1
4

score 0 · Answer 3 · answered Jul 05 '17 at 15:53

Check the export session's state and error info within exportAsynchronouslyWithCompletionHandler, make sure the output URL file not exists.

Refer to these two threads, good luck!

Unable to trim a video using AVAssetExportSession

Creating a time range for AVAssetExportSession

AVAssetExportSession not exporting time range

3 Answers3