3 Replies Latest reply on Aug 5, 2011 7:22 AM by Stanley Arthur

    MP3 file duration discrepency


      After exporting a file to MP3 from Audition for Mac I am experiencing a discrepency between the file duration that is displayed in the 'File Info,' (i.e. what you see when you right click a file icon and 'Get Info') and the actual duration of the audio file. The 'get info' duration is shorter. The longer the file, the greater the difference (seven seconds or so on a 1 hour file). I would have never noticed this or cared except that one of my clients does automatic compiling of the files (into audiobooks) and the the content is getting truncated. Apparently, the client's software keys off of the 'file info' and not the actual properties. But then, the data should be the same. Advice anyone...?

        • 1. Re: MP3 file duration discrepency
          Stanley Arthur Level 3

          Just a wild guess that it could be a difference in sampling rate. Audio for CDs is recorded at 44.1 kHz. Audio for video is typically recorded at 48kHz. I once made the mistake of recording separate audio onto a recorder that was set for 44.1. When I dropped it into a sequence that was set for 48, there was a time discrepency between the video clip and the audio clip. I made it work through trial and error by using the rate stretch tool on the video until it matched. I might have been able to resample the audio to 48kHz, but I thought I'd waste less time using rate stretch because the clips were over an hour each.


          Check to see if your Audition output is set for 44.1. If so, change it to 48.

          • 2. Re: MP3 file duration discrepency
            Audiolitpub Level 1

            Thanks, Stan. That took care of it. I don't understand what's going on since I only work at 44.1 kHz at all stages of production, but making the sample rate adjustment takes care of the duration discrepency. Thanks! (I've got my fingers crossed that my client won't balk at receiving a different sample rate from the spec).

            • 3. Re: MP3 file duration discrepency
              Stanley Arthur Level 3

              Good deal! Ya know, sometimes clients have to be educated as to best practices, too.