3 Replies Latest reply on Oct 15, 2014 9:10 AM by sinious

    Mp3 audio is shorter than the same wav audio

    DenverDesigner

      So i ran into this issue which i have tested several times and I get the same results.

      I start with a WAV file. Convert this to an MP3 file. And the wave forms no longer line up (causing a sync loss).

      I have had caulegues verify this independently and we have no idea why? Is this due file compression and the way Flash access it?

       

      US_ITAR_KPA1_scenario2[1].png

       

      Any help greatly appreciated.

        • 1. Re: Mp3 audio is shorter than the same wav audio
          sinious Most Valuable Participant

          Can you actually hear the WAV playback slower? Trying to determine if it's a waveform drawing issue or an actual playback issue. Also does increasing the FPS to 24 or 30 make any difference in the waveform drawing (just curious)?

          1 person found this helpful
          • 2. Re: Mp3 audio is shorter than the same wav audio
            DenverDesigner Level 1

            The slow down is not noticeable but is occurring. With vocal audio, it still sound "okay" but when overlaid on the original audio there is a delay effect that becomes more and more audible as time progresses.

             

            Frame rate changes appear to have no affect as both (mp3 and wav) are relative to each other.

            • 3. Re: Mp3 audio is shorter than the same wav audio
              sinious Most Valuable Participant

              What are you using to compress the MP3 from the WAV? Since both formats are so old and well known/implemented, this is definitely a strange bug. In fact I'm going to convert something from WAV to MP3 using Audition right now to see if I see a difference in Flash Pro CC 2014 and Flash Pro CS6.

               

              Ok so CS6 has a slight mis-alignment but not an actual progressive problem. Here you can see in the 4000 frame range the sounds are about a frame or two off and the waveforms differ but ultimately are in sync:

               

              soundcs6.png

               

              I opened the same thing in Flash Pro CC 2014 (only I had to include markers and I downgraded from 48Khz Stereo 32bit WAV to 44.1Khz Stereo 320Kbit 16bit MP3 or Flash Pro CC 2014 (but not CS6) kept erroring trying to import). They are offset just like in CS6 but are ultimately in sync. Same 4k range:

               

              soundcc2014.png

               

              How about some details on your source WAV and destination MP3 encode settings?