Saving as an MP3 changes the running length in Audition CC 13

[Dubplate8]

I have a problem saving an MP3 and having the correct length after converting.

For Example:

I have a 57-minute WAV file when I save it at 128Kbps (Constant Bit Rate) it times out to 56:52.

I am using Audition  13.05.36  however when I save it in Audition 3.0 the time is correct. (it uses the MP3PRO codex)

Is there a known issue with the MP3 codex? is there a more accurate MP3 plug-in I can use???

The higher the Sample Rate the closer it gets to being correct... for example, saving it at 320kbps it gets to 56:57.

Thanks

[SteveG_AudioMasters_ · Accepted solution]

All of the MP3 codecs have been bought in from Fraunhofer over the years, and Audition got what was current at the time. So yes, they are all different, and no you can't alter them. Neither can you add your own encoder - that was part of the licensing deal. Personally I rather liked aspects of MP3Pro, but Fraunhofer dropped it ages ago.

There have always been timing issues with MP3 files - yes invariably with VBR but also some with CBR. The lower the bit rate, the less accurately they are reported. If you decode the MP3 you've made and put it next to your original, do they run at the same speed? If they do, then it's definitely a reporting error and not 'real' - if you see what I mean.

[Dubplate8]

wow, So it does seem to be a "reporting error" and not an actual change in length. when I re-import the file with the "wrong length" back into Audition 3 and Audition 13.05 it shows the correct length, even if right-clicking on the properties on the desktop showed it was seconds too short.

Thanks for the answer!